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  • Articles  (92)
  • groundwater  (50)
  • Animals
  • Chemical Engineering
  • Rat
  • phosphorus
  • Springer  (92)
  • Energy, Environment Protection, Nuclear Power Engineering  (75)
  • Technology  (17)
  • 1
    Electronic Resource
    Electronic Resource
    Microbiological groundwater quality and health indicators in Mexico City (2000)
    Springer
    Urban ecosystems 4 (2000), S. 91-103 
    Details
    ISSN: 1573-1642
    Keywords: bacterial indicators ; health indicators ; groundwater ; water quality ; Mexico City
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Groundwater quality was evaluated in the southern and western zones of Mexico City, using bacterial indicators and pathogens. Water quality from 40 wells was related to rates of diarrheal disease with 995 individuals interviewed. The focus of this first study on environmental health indicators (EHI) was based on population data (e.g., drinking water supplies and basic sanitation) and displayed using a Geographic Information System (GIS). Sixty percent of the wells monitored comply with the Mexican drinking water standards; however, based on other microbial evidence, 95% of the wells did not provide good quality water for human consumption. No significant differences were detected among hydrogeological zones. When analyzing by microbial indicators, the southern area was shown to be statistically different (p 〈 0.01) from the western area of the city. The highest rates of diarrheal diseases were detected in the south; the lowest rates were observed in the west. Although wells in the western side of the city appeared to be more contaminated (54%) than in the south (40%), no significant association with health indicators was detected. These preliminary findings suggest ways to improve the potential of EHI, by framing epidemiological data and the use of GIS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011334326405
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  • 2
    Electronic Resource
    Electronic Resource
    Sources, sinks, and fluxes of nutrients (N + P) in a small highly modified urban estuary in southern California (2000)
    Springer
    Urban ecosystems 4 (2000), S. 125-144 
    Details
    ISSN: 1573-1642
    Keywords: nitrogen ; phosphorus ; macroalgae ; estuary ; anthropogenic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Our objective was to begin to investigate sources, sinks, and flux rates of nitrogen (N) and phosphorus (P) in Famosa Slough, a small (12 ha) highly modified urban estuary in San Diego, California, U.S.A. The hydrology of Famosa Slough has been modified by culverts that dampen tidal influence and seasonal runoff from two urban watersheds, each of which has been implicated as a nutrient source that generates nuisance algal blooms. In 1995 and 1996, the ranges of nutrients measured in the water column were extremely wide; upper values exceeded those in other estuaries identified as eutrophic. Average dissolved inorganic nitrogen ranged from 2 to 250 μM, while dissolved inorganic phosphorus ranged from 〈1 to 15 μM. Nutrient content of the water changed rapidly both spatially and temporally depending on the tides and rainfall. While tidal water dominated this system, especially in the dry season, our results indicate that Famosa Slough's small watershed, not the larger watershed of the San Diego River, was the major source of nutrients during rainfall. Sediment nutrients were also high (∼3 mg N g dry wt−1 and 0.600 mg P g dry wt−1). Short-term flux studies suggest that the large accumulations of opportunistic green macroalgae commonly found in this estuary, and possibly the sediments, may act as a large and rapid sink for nutrients during times of high nutrient supply. We suggest that small, shallow estuaries in urban settings may have more complex and rapid nutrient dynamics than those found in larger systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011359311384
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  • 3
    Electronic Resource
    Electronic Resource
    Modulation of Paired-Pulse Responses in the Dentate Gyrus: Effects of Normal Maturation and Vigilance State (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 128-134 
    Details
    ISSN: 1573-9686
    Keywords: Hippocampus ; Vigilance states ; Paired-pulse ; Dentate gyrus ; Dentate granule cells ; Evoked response ; Rat ; In vivo studies ; Perforant path ; Maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract This study examined the effect of normal development and vigilance state on the modulation of dentate granule cell activity in the freely moving rat at 15, 30, and 90 days of age across three vigilance states: quiet waking, slow-wave sleep, and rapid eye movement sleep. Using paired-pulse stimulation, the paired-pulse index (PPI) was obtained for the dentate evoked field potentials elicited by the stimulation of the medial perforant path. Although significant differences in PPI values were observed during development, no significant vigilance state related changes were obtained. Preweaning infant rats, i.e., 15-day old, exhibited significantly less early (interpulse intervals, IPI= 20–50 ms) and late (IPI = 300–1000 ms) inhibition, and less facilitation (IPI = 50–150 ms) when compared to the 90-day old adult rats during all three vigilance states. PPI values obtained from the 30-day old group fell intermediate between the 15- and 90-day old animals. These changes in PPI values provide a quantitative measure of changes in the modulation of dentate granule cell excitability during normal maturation. They can now can be used to evaluate the impact of various insults, such as prenatal protein malnutrition or neonatal stress, on hippocampal development. © 2000 Biomedical Engineering Society. PAC00: 8717Nn, 8719La, 8719Nn
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1114/1.261
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  • 4
    Electronic Resource
    Electronic Resource
    Left Ventricular Contractility is Impaired Following Myocardial Infarction in the Pig and Rat: Assessment by the End Systolic Pressure–Volume Relation Using a Single-Beat Estimation Technique and Cine Magnetic Resonance Imaging (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 484-494 
    Details
    ISSN: 1573-9686
    Keywords: Heart ; Left ventricle ; LV contractility ; ESPVR ; Pig ; Rat ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The end systolic pressure–volume relation (ESPVR) has been shown to be a relatively load independent measure of left ventricular (LV) contractility. Recently, several single-beat ESPVR computation methods have been developed, enabling the quantification of LV contractility without the need to alter vascular loading conditions on the heart. Using a single-beat ESPVR method, which has been validated previously in humans and assumes that normalized elastance is constant between individuals of a species, we studied the effects of myocardial infarction on LV contractility in two species, the rat and the pig. In our studies, LV pressure was acquired invasively and LV volume determined noninvasively with magnetic resonance imaging, at one week postinfarction in pigs and at 12 weeks postinfarction in rats. Normalized systolic elastance curves in both animal species were not statistically different from that of humans. Also, the slope of the ESPVR $$\left( {E_{es} } \right)$$ decreased significantly following infarction in both species, while the volume-axis intercept $$\left( {V_0 } \right)$$ was unaffected. These results indicate that a single-beat ESPVR method can be used to measure the inotropic response of the heart to myocardial infarction, and that the basis for this method (i.e., constant normalized elastance) is applicable to a variety of mammalian species. © 2000 Biomedical Engineering Society. PAC00: 8719Uv, 8761Lh, 8719Hh, 8719Rr, 8719Ff
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1114/1.289
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  • 5
    Electronic Resource
    Electronic Resource
    Quantifying Coevolution of Nonstationary Biomedical Signals Using Time-Varying Phase Spectra (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 1101-1115 
    Details
    ISSN: 1573-9686
    Keywords: Time–frequency analysis ; Coherence ; Cross correlation ; Nonstationary persistent signals ; Central pattern generator ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract We present a novel time-varying phase spectrum (TVPS) method to quantify the dynamics of coevolution of two persistent nonstationary coupled signals. Based on the TVPS, an instantaneous intersignal phase shift is defined within the primary frequency range in which the two signals are highly correlated. The TVPS is estimated using a fixed-window method or an adaptive-window method. In the latter method, the window length changes dynamically and automatically as a function of change in frequency of the signals. The effects of altering window types and lengths on the accuracy of the estimation of the primary phase shift is assessed by analyzing synthesized linear chirp signals with decaying amplitude and constant relative phase shift or decaying amplitude and changing relative phase shifts. The methods developed are also used for determining the evolution of the primary phase shift among ventral root activities during fictive locomotion in an in vitro rat spinal cord preparation. The analyses indicate that the TVPS method in conjunction with the determination of the primary frequency range, allows determination of both the evolution of the coupling strength and the evolution of the phase shift between two persistent nonstationary rhythmic signals in the joint time–frequency domain. An adaptive window reduces the estimation bias and the estimation variability. © 2000 Biomedical Engineering Society. PAC00: 0230-f, 8780Tq
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1114/1.1313775
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  • 6
    Electronic Resource
    Electronic Resource
    Using Bacterial Growth on Insects to Assess Nutrient Impacts in Streams (2000)
    Springer
    Environmental monitoring and assessment 63 (2000), S. 431-446 
    Details
    ISSN: 1573-2959
    Keywords: aquatic bacteria ; benthic macroinvertebrates ; bioindicator ; eutrophication ; nitrogen ; phosphorus ; stream pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A combination field and laboratorystudy was conducted to evaluate the ability of arecently developed bioindicator to detect detrimentalnutrient conditions in streams. The method utilizesbacterial growth on aquatic insects to determinenutrient impacts. Field investigations indicated thatelevated concentrations of nitrate and phosphate wereassociated with growth of filamentous bacteria oninsect body surfaces, and that there was a significantreduction in the density of major insect taxa in thenutrient-enriched stream reaches. Laboratoryinvestigations confirmed a strong linkage betweenbacterial growth and reduced survival of insects. Survival was examined for insects with bacterialinfestation ranging from 0% to greater than 50%coverage of the body surface. A threshold forcatastrophic mortality occurred at about 25% bodycoverage; there were few survivors above that amount. Based on these findings, the diagnostic endpoint forthe bioindicator is 25% body coverage by bacterialgrowth, a level that signifies major impacts and isalso easy to detect visually. This study providesadditional evidence that the insect-bacteriabioindicator is a reliable tool for assessing nutrientimpacts on stream macroinvertebrate communities. Thebioindicator should prove useful for identifyingnutrient-impacted sites as well as monitoring thesuccess of management actions to improve water quality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006211929599
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  • 7
    Electronic Resource
    Electronic Resource
    Nitrogen and Phosphorus Levels in Sediments from Tropical Catatumbo River (Venezuela) (2000)
    Springer
    Water, air & soil pollution 117 (2000), S. 27-37 
    Details
    ISSN: 1573-2932
    Keywords: eutrophication ; nitrogen ; phosphorus ; river ; sediment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Nitrogen (N) and phosphorus (P) concentrations were determined in sediment samples along the bed of Catatumbo river in both Colombian and Venezuelan territories until the river outlet in Maracaibo lake. Total phosphorus was determined by digestion with HCl followed by analysis using the ascorbic acid method and total nitrogen was done using the standard microkjeldahl method plus nitrate-nitrite. Ammonium, orthophosphate and nitrate were determined using standard methods after extraction steps. The mean concentrations along the river bed were found in an interval of 0.035 and 1.492 mg g-1 dry sed. for nitrogen and 0.027 and 1.039 mg g-1 dry sed. for phosphorus at 95% confidence level. The mean molar ratio N/P in the river bed was 4.42 and 3.46 for river outlet zones in the lake, which indicates that nitrogen is the limiting nutrient. For comparison with previous results of lake sediments from sites near the river outlet it was concluded that Catatumbo river is a significant source of nutrients to the Maracaibo Lake system because sediment nutrients concentrations from Catatumbo river were higher than the ones in Maracaibo Lake. Statistic studies showed significant differences between countries, zones and similar behaviour in the river bed as related to the affluent rivers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005189710803
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  • 8
    Electronic Resource
    Electronic Resource
    Biological Denitrification of Groundwater (2000)
    Springer
    Water, air & soil pollution 123 (2000), S. 183-193 
    Details
    ISSN: 1573-2932
    Keywords: bacteria ; biological denitrification ; groundwater ; nitrate removal ; water treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Nitrate concentrations in groundwater have increased in many areas of the world. This causes serious concerns because of the link found between nitrate and the blue-baby syndrome, and of the possible formation of carcinogenic compounds in the digestive tract. Biological denitrification, bacteria-mediated reduction of nitrate to nitrogen gas, is a method used in the treatment of nitrate contaminated groundwater. The denitrifying microorganisms require carbon and energy substrates which may be organic or inorganic compounds. Treatment can take place in the aquifer (in situ treatment) or in above ground reactors. Numerous biological denitrification processes have been reported; this paper reviews some of this work and studies in progress in the author's laboratory. The choice of a biological denitrification system has to be considered on an individual basis. Although preventive measures are curbing the problem in some developed countries, nitrate pollution is still on the rise in many other countries. Innovative, low-cost biological denitrification processes are specially needed in developing countries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005242600186
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  • 9
    Electronic Resource
    Electronic Resource
    External Phosphorus Load Estimates and P-Budget for the Hydroelectric Reservoir of Bort-les-Orgues, France (2000)
    Springer
    Water, air & soil pollution 119 (2000), S. 91-103 
    Details
    ISSN: 1573-2932
    Keywords: eutrophication ; external load ; mass balance ; P-export coefficient ; phosphorus ; reservoir
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This paper presents two methods used to estimate the externalphosphorus load for the hydroelectric reservoir ofBort-Les-Orgues (in France's `Massif Central' region). The Pload calculated from export coefficients (150 t yr-1) agreedwith field measurements taken during a one-year survey carriedout from March 1996 to February 1997 (121 t yr-1). Exportcoefficients represent a good option for estimating phosphorusloads of other reservoirs in the region of Bort-Les-Orgues,provided that they display similar characteristics. Theseexternal load estimates are greater than the maximum permissibleload for a mesotrophic lake calculated from the OECD equations(40 t yr-1); thus, a yearly reduction of about 60 t shouldideally be achieved. This target, however, is probably tooambitious, and measures to reduce both point and non-pointsources must be implemented for the reservoir to tbe mesotrophic.Moreover, Bort-Les-Orgues is a tourist area. As such, thepresence of algal blooms (a regular occurrence on the lake) dueto an excess of P in the lake's water inflow could actuallyexert a negative impact on regional economy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005186122618
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  • 10
    Electronic Resource
    Electronic Resource
    Boron Isotopic Compositions of Near-Surface Fluids: A Tracer for Identification of Natural and Anthropogenic Contaminant Sources (2000)
    Springer
    Water, air & soil pollution 124 (2000), S. 49-60 
    Details
    ISSN: 1573-2932
    Keywords: anthropogenic contamination ; borate minerals ; boron isotopes ; contaminant sources ; groundwater ; landfill leachate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Boron (B) is a sensitive stable isotope tracer which allows identification of different anthropogenic contaminant sources, originating from man-made boron products manufactured from non-marine borates (δ11B ≤ +10‰), in near-surface fluids which are characterized by a different natural background signature of predominantly meteoric origin. The data presented show that the boron isotopic composition of uncontaminated groundwater at the study site (δ11B = +12.0‰) is similar to that of local precipitation and significantly different from two distinct anthropogenic contaminant sources, identified as Ca- and/or Na/Ca-borates and Na-borates in `low-δ11B' (–6.0‰) and `high-δ11B' (+7.5 to +9.0‰) municipalsolid waste landfill leachates, respectively. The boron isotopic signature of contaminants can remain preserved over several decades, in contrast to aqueous B concentrations which are less diagnostic due to their sensitivity to dilution with low-B meteoric waters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005210226830
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  • 11
    Electronic Resource
    Electronic Resource
    Distributions of Mercury and Phosphorous in Everglades Soils From Water Conservation Area 3A, Florida, U.S.A. (2000)
    Springer
    Water, air & soil pollution 121 (2000), S. 133-159 
    Details
    ISSN: 1573-2932
    Keywords: Everglades ; mercury ; mobility ; peat ; phosphorus ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Soils in the southern half of Water Conservation Area3A are mostly peats with some organic-rich marls. Mercury contents of 64 surface samples over a500 km2 area average 28.7 ng cc-1 (209 ppb drysediment), which is typical of organic-rich soils. High Hg contents in Everglades fish are therefore notcaused by anomalously high soil Hg. Hg contents showno systematic lateral variation, consistent withdeposition from well-mixed atmospheric sources ratherthan nearby point sources or runoff from canals.Cores from 9 sites contain more Hg and P at or nearthe surface than at 20–30 cm depth. Hg and P contentsof individual cores correlate well and define separatebackground and anomalous populations. The subsurfacedistribution of P is determined largely by uptake bysawgrass and other plants. The correlation between Pand Hg suggests that, although atmospheric Hgdeposition has undoubtedly increased in recentdecades, postdepositional mobilization of Hg may beimportant in Everglades soils. This finding, togetherwith recent direct measurements of atmospheric Hgdeposition, indicates that previous estimates of Hgdeposition rates based on Everglades peat cores, whichassumed that Hg is immobile in peat after deposition,have yielded large overestimates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005214908516
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  • 12
    Electronic Resource
    Electronic Resource
    The Upcoming Challenge: Transboundary Management of the Hydraulic Cycle (2000)
    Springer
    Water, air & soil pollution 123 (2000), S. 533-549 
    Details
    ISSN: 1573-2932
    Keywords: groundwater ; international water ; Israeli-Arab water ; wastewater ; water management institutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The increase in population and subsequent demand for food will lead to rising demand for water. These, in turn, will lead to increasing utilization of transboundary water resources. In the past treaties have focused primarily on the utilization of freshwater surface resources, in particular rivers. Most of the treaties dealt only with water abstractions and, in some cases, with in-stream uses, mainly navigation and hydro-electricity. However, a hydraulic cycle view suggests that transboundary water resources include not only freshwater flows, but also return flows (direct or as effluents), lakes and reservoirs, aquifers, and precipitation. Moreover, water quality changes along the cycle, and effects the potential and cost of utilization. As water resources would have to accommodate increasing and diversifying demand, better management of all parts of the hydraulic cycle would be needed. This paper argues that as a result of these observations, and the increasing tendency toward decentralization of authority and in some areas separatist trends, this century would be marked by a need to establish increasingly intricate transboundary management structures, that would address all facets of the hydraulic cycle. This argument is demonstrated for the Israeli-Arab case.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005269001462
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  • 13
    Electronic Resource
    Electronic Resource
    Total System Performance Assessment for Waste Disposal Using a Logic Tree Approach (1999)
    Springer
    Risk analysis 19 (1999), S. 915-931 
    Details
    ISSN: 1539-6924
    Keywords: Yucca Mountain ; performance assessment ; logic tree ; high-level radioactive waste ; Monte Carlo ; expert judgment ; repository ; groundwater ; climate ; infiltration ; percolation ; hydrothermal ; corrosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The Electric Power Research Institute (EPRI) has sponsored the development of a model to assess the long-term, overall “performance” of the candidate spent fuel and high-level radioactive waste (HLW) disposal facility at Yucca Mountain, Nevada. The model simulates the processes that lead to HLW container corrosion, HLW mobilization from the spent fuel, and transport by groundwater, and contaminated groundwater usage by future hypothetical individuals leading to radiation doses to those individuals. The model must incorporate a multitude of complex, coupled processes across a variety of technical disciplines. Furthermore, because of the very long time frames involved in the modeling effort (≫104 years), the relative lack of directly applicable data, and many uncertainties and variabilities in those data, a probabilistic approach to model development was necessary. The developers of the model chose a logic tree approach to represent uncertainties in both conceptual models and model parameter values. The developers felt the logic tree approach was the most appropriate. This paper discusses the value and use of logic trees applied to assessing the uncertainties in HLW disposal, the components of the model, and a few of the results of that model. The paper concludes with a comparison of logic trees and Monte Carlo approaches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007018611145
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  • 14
    Electronic Resource
    Electronic Resource
    Determination of hydraulic diffusivity of aquifers by spectral analysis (1999)
    Springer
    Stochastic environmental research and risk assessment 13 (1999), S. 85-99 
    Details
    ISSN: 1436-3259
    Keywords: Key words: Hydraulic diffusivity ; groundwater ; spectral analysis ; stochastic boundaries.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract: This study uses the cyclical frequency to develop the mathematical relationship between hydraulic diffusivity and spectral density functions calculated from groundwater level variation. Such relationship can be applied to (1) unsteady state, one-dimensional confined aquifer with time-dependent water level on both end boundaries, and (2) linearized unconfined aquifer with or without vertical recharge. The spectral density functions of groundwater fluctuations are largely affected by the spectral density functions obtained from time-dependent end boundaries and their cross-spectral density functions. Hydraulic diffusivity of an aquifer can be solved by type-curve matching technique at a specified frequency band under the conditions of (1) confined aquifer having equal time-dependent boundaries on both ends, (2) unconfined aquifer having equal time-dependent boundaries on both ends with surface recharge, and (3) unconfined aquifer subjected to surface recharge but neglecting the water table fluctuations on both end boundaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004770050033
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  • 15
    Electronic Resource
    Electronic Resource
    Groundwater NO3 and F Contamination Processes in Pushkar Valley, Rajasthan as Reflected from 18O Isotopic Signature and 3H Recharge Studies (1999)
    Springer
    Environmental monitoring and assessment 56 (1999), S. 209-219 
    Details
    ISSN: 1573-2959
    Keywords: contamination process ; δ18O ; fluoride ; groundwater ; nitrate ; Rajasthan ; recharge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Agricultural activity in the Pushkar Valley, Rajasthan is constrained due to limited availability of good quality water. In this context, occurrence of nitrate and fluoride in the groundwater was investigated and reported. Integration of stable isotope (δ18O) data with recharge characteristics (based on 3H-tracer studies) helps in clearly characterizing the processes controlling contamination by point and non-point sources. High nitrate and fluoride groundwaters are associated with high δ18O waters. This indicates that significant quantities of evaporated (isotopically enriched) surface run-off water and rain water infiltrate along with nitrate and fluoride salts in the soil. The applicability of this approach under different hydrometeorological conditions is also confirmed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005903619718
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  • 16
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    Groundwater Quality Assessment of Tehsil Kheragarh, Agra (India) with Special Reference to Fluoride (1999)
    Springer
    Environmental monitoring and assessment 59 (1999), S. 275-285 
    Details
    ISSN: 1573-2959
    Keywords: correlation ; district Agra ; factor analysis ; fluoride ; groundwater ; irrigation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Fluoride concentration and other parameters in groundwater from 261 villages in Tehsil Kheragarh of District Agra were assessed and attempts were made to observe the relationship between fluoride and other water quality parameters. Of 658 groundwater samples (collected from separate sources) analysed for fluoride, 27% were in the range of 0–1.0 mg/L, 25% in 1.0–1.5 mg/L, 32% in1.5–3.0 mg/L and 16% above 3.0 mg/L. The highest fluoride concentration recorded was 12.80 mg/L. Significant correlation of fluoride with pH, alkalinity, Na, SiO2 and PO4 were observed. Factor analysis was also attempted in order to identify the contributing sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006117604763
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  • 17
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    Modeling Variable Density Flow and Solute Transport in Porous Medium: 2. Re‐Evaluation of the Salt Dome Flow Problem (1999)
    Springer
    Transport in porous media 35 (1999), S. 375-394 
    Details
    ISSN: 1573-1634
    Keywords: groundwater ; density driven flow ; numerical simulation ; salt dome.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Case 5, Level 1 of the international HYDROCOIN groundwater flow modeling project is an example of idealized flow over a salt dome. The groundwater flow is strongly coupled to solute transport since density variations in this example are large (20%). Several independent teams simulated this problem using different models. Results obtained by different codes can be contradictory. We develop a new numerical model based on the mixed hybrid finite elements approximation for flow, which provides a good approximation of the velocity, and the discontinuous finite elements approximation to solve the advection equation, which gives a good approximation of concentration even when the dispersion tensor is very small. We use the new numerical model to simulate the salt dome flow problem. In this paper we study the effect of molecular diffusion and we compare linear and non‐linear dispersion equations. We show the importance of the discretization of the boundary condition on the extent of recirculation and the final salt distribution. We study also the salt dome flow problem with a more realistic dispersion (very small dispersion tensor). Our results are different to prior works with regard to the magnitude of recirculation and the final concentration distribution. In all cases, we obtain recirculation in the lower part of the domain, even for only dispersive fluxes at the boundary. When the dispersion tensor becomes very small, the magnitude of recirculation is small. Swept forward displacement could be reproduced by using finite difference method to compute the dispersive fluxes instead of mixed hybrid finite elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006504326005
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  • 18
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    Modeling Variable Density Flow and Solute Transport in Porous Medium: 1. Numerical Model and Verification (1999)
    Springer
    Transport in porous media 35 (1999), S. 345-373 
    Details
    ISSN: 1573-1634
    Keywords: groundwater ; density driven flow ; numerical simulation ; mixed finite elements ; discontinuous finite elements ; Elder problem.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract A new numerical model for the resolution of density coupled flow and transport in porous media is presented. The model is based on the mixed hybrid finite elements (MHFE) and discontinuous finite elements (DFE) methods. MHFE is used to solve the flow equation and the dispersive part of the transport equation. This method is more accurate in the calculation of velocities and ensures continuity of fluxes from one element to the adjacent one. DFE is used to solve the convective part of the transport equation. Combined with a slope limiting procedure, it avoids numerical instabilities and creates a very limited numerical dispersion, even for high grid Peclet number. Flow and transport equations are coupled by a standard iterative scheme. Residual based criterion is used to stop the iterations. Simulations of an unstable equilibrium show the effects of the criteria used to stop the iterations and the stopping criterion in the solver. The effects are more important for finer grids than for coarser grids. The numerical model is verified by the simulation of standard benchmarks: the Henry and the Elder test cases. A good agreement is found between the revised semi‐analytical Henry solution and the numerical solution. The Elder test case was also studied. The simulations were similar to those presented in previous works but with significantly less unknowns (i.e. coarser grids). These results show the efficiency of the used numerical schemes.
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    URL: http://dx.doi.org/10.1023/A:1006564309167
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    Effect of nitrogen and phosphorus addition on phenanthrene biodegradation in four soils (1999)
    Springer
    Biodegradation 10 (1999), S. 43-50 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; nitrogen ; nutrients ; phenanthrene ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phenanthrene mineralization rates were found to vary widely among four soils; differences in soil nutrient levels was one hypothesis to explain this variation. To test this hypothesis, phenanthrene mineralization rates were measured in these soils with, and without, added nitrogen and phosphorus. Mineralization rates either remained unchanged or were depressed by the addition of nitrogen and phosphorus. Phenanthrene degradation rates remained unchanged in the soil which had the highest indigenous levels of nitrogen and phosphorus and which showed the largest increase in phosphorus levels after nutrients were added. The soils in which degradation rates were depressed had lower initial phosphorus concentrations and showed much smaller or no measurable increase in phosphorus levels after nutrients were added to the soils. To understand the response of phenanthrene degradation rates to added nitrogen and phosphorus, it may be necessary to consider the bioavailability of added nutrients and nutrient induced changes in microbial metabolism and ecology.
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    URL: http://dx.doi.org/10.1023/A:1008359606545
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  • 20
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    Agricultural Chemicals in the Alluvial Aquifer of a Typical County of the Arkansas Delta (1999)
    Springer
    Environmental monitoring and assessment 58 (1999), S. 151-172 
    Details
    ISSN: 1573-2959
    Keywords: GIS ; ground water vulnerability ; leaching index ; nitrate ; pesticide ; phosphorus ; potassium ; statistical analysis ; uncertainty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Statistical methods and a Geographic Information System (GIS) were used to investigate potential indicators of ground water vulnerability to agricultural chemical contamination in a representative area of the Mississippi River alluvial aquifer. A total of 47 wells were sampled for analysis of nitrate, phosphorus, potassium, and 13 pesticides commonly-used in the area. Ten soil and hydrogeologic variables and five ground water vulnerability indices were examined to explain the variations of chemical concentrations. The results showed that no individual soil or hydrogeologic variables or their linear combinations could explain more than 25% of the variation of the chemical concentrations. A quadratic response surface model with the values of confining unit thickness, slope, soil permeability, depth to ground water, and recharge rate accounted for 62% of the variation of nitrate, 43% of P, and 83% of K, suggesting that the interactions among soil and hydrogeologic variables were significant. Observed trends of decreasing nitrate and P concentrations with increasing well depth and/or depth to ground water seemed to correlate with carbonate equilibrium in the aquifer and more reduced environment with depth. In view of uncertainties involved, it was recognized that the limitations associated with input data resolution used in GIS and the formulation of leaching indices limited their use for predicting ground water vulnerability. Misuse of pesticides could be another factor that would complicate the relationships between pesticide concentrations and the vulnerability indices.
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    URL: http://dx.doi.org/10.1023/A:1006023731801
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  • 21
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    A Case of Hydrochemical Characterization of an Alluvial Aquifer Influenced by Human Activities (1999)
    Springer
    Water, air & soil pollution 112 (1999), S. 365-387 
    Details
    ISSN: 1573-2932
    Keywords: alluvial aquifer ; groundwater ; hydrochemistry ; multivariateanalysis ; water pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract 21 physico-chemical parameters have been determined in 47 groundwater samples collected in October 1994 from the alluvial aquifer of the Pisuerga river, located at the north-east of Valladolid (north-western Spain). Conventional hydrochemical methods and multivariate statistical analysis have been used to discriminate natural phenomena and pollution processes in the area. It has been demonstrated the existence of a heterogeneity in groundwater mineral contents related to anthropic actions such as irrigation, source of irrigation water and location of polluting sources. This study demonstrates the existence of two sub-units in the alluvial aquifer (left and right river banks) with different hydrochemical characteristics, and identifies three different singular areas in the left bank. Groundwater from this bank showed higher levels of dissolved ions caused by concentration processes derived from the predominant use of groundwater for crop irrigation, whilst in the right bank of the aquifer less saline water from canals is used. Degradation of groundwater quality has been observed in some areas of the left aquifer sub-unit (north, Santovenia and south-central sites) where anomalous high concentrations of sulphate, sodium, chloride and nitrate were measured, and can be related to the presence of potentially polluting sources such as leachates from industrial waste disposals, sewage effluents and use of organic and inorganic fertilizers.
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    URL: http://dx.doi.org/10.1023/A:1005065422156
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  • 22
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    Bubble Extraction of Dissolved Gases from Groundwater Samples (1999)
    Springer
    Water, air & soil pollution 115 (1999), S. 525-534 
    Details
    ISSN: 1573-2932
    Keywords: dissolved methane ; gas chromatograph ; groundwater ; headspace
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A technique is described for measuring the concentration of dissolved methane in water samples. A 250 μL bubble is injected into a 5 mL vial to create a headspace. The headspace gas is subsequently analysed by gas chromatograph. The technique requires a headspace equilibrium time of at least 13 hours. The extraction efficiency of the method for methane saturated water was 101.9% ± 1%. The technique is applicable to other dissolved gases in groundwater. The method was used during a comparative evaluation of groundwater sampling devices at a field site. It was found that low flow rate sampling with either a Grundfos electric submersible pump or a peristaltic pump were more precise than using a bailer to measure dissolved methane.
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    URL: http://dx.doi.org/10.1023/A:1005102925436
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    Aluminium precipitates formed downstream of springs in a mountainous environment (1999)
    Springer
    Water, air & soil pollution 114 (1999), S. 121-135 
    Details
    ISSN: 1573-2932
    Keywords: acid rain ; aluminium ; groundwater ; mountainousenvironment ; Nordic countries ; precipitates ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Areas a few square metres in size, devoid of higher vegetation other than moss, have been mapped at 600–700 m above sea level in the mountains of the western part of central Norway. The moss is covered by a grey precipitate during dry summer periods. The precipitate has been identified by ICP-AES analysis of HNO3-extract, X-ray diffraction (XRD) and by scanning electron microscopy (SEM) as an aluminium(Al)-hydroxide, probably amorphous Al-hydroxide and diaspore (Al(OH)3), containing 21–25% Al by weight. In comparison, the underlying moraine deposits contain 1.5–3.5% Al by weight. A small spring, where groundwater discharges, is located uphill of each contaminated area. The Al content of the water which emerges from these springs decreases downhill away from the spring and is inversely proportional to the pH. The runoff waters originating at the springs have been modelled using the computer-codes MINTEQA2 and ALCHEMI and are found to be saturated with respect to amorphous Al(OH)3. This study raises the very important question as to what extent a lower pH in the influent meltwater may leach out more aluminium and possibly lead to the formation of larger amounts of precipitate.
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    URL: http://dx.doi.org/10.1023/A:1005173117738
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  • 24
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    Arsenic Concentrations in Water, Soil, Milk and Forage in Comarca Lagunera, Mexico (1999)
    Springer
    Water, air & soil pollution 112 (1999), S. 133-149 
    Details
    ISSN: 1573-2932
    Keywords: arsenic ; cow's milk ; forage ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Arsenic levels were determined in seventy three samples of well water, and in fifty samples of soil, forage and cow's milk collected at the most important dairy farms of the Comarca Lagunera located in Coahuila and Durango, Mexico, region naturally rich in As. The total inorganic arsenic concentration in well water ranged from 7 to 740 μg L-1 and about ninety percent of the total arsenic was found as As(V). The agricultural soil texture of the sampled area was sandy clay loam type with total arsenic levels up to 30 μg g-1, however, the extractable arsenic was not higher than 12% of the total and it was higher in the 0–30 cm depth horizon. In alfalfa, the most important crop, the total aresenic ranged from 0.24 to 3.16 μg g-1, with 40% of it accumulated at the root level. Significant correlations (p=0.05) were obtained between arsenic (III), (V) and total inorganic arsenic in groundwater with arsenic in soil (0–30 cm depth), and with arsenic in alfalfa (leaves and roots). It was also found a good correlation between extractable arsenic in soil with As concentrations in alfalfa (roots). Arsenic concentrations found in milk ranged from 〈0.9 to 27.4 ng g-1. The cow's milk biotransfer factor for arsenic was up to 6 × 10-4, applying a pharmacokinetic approach. It was associated with the exposure not only to food but also to water arsenic.
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    URL: http://dx.doi.org/10.1023/A:1005095900193
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    Sulphate Mobilization and Pore Water Chemistry in Relation to Groundwater Hydrology and Summer Drought in two Conifer Swamps on the Canadian Shield (1999)
    Springer
    Water, air & soil pollution 113 (1999), S. 97-114 
    Details
    ISSN: 1573-2932
    Keywords: catchment hydrology ; conifer swamp ; groundwater ; peat ; porewater ; sulphate mobilization ; summer drought ; water levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Variations in sulphate (SO4 2-) concentration of porewater and net SO4 2- mobilization were related to differences in water level fluctuations during wet and dry summers in two conifer swamps located in catchments which differed in till depth and seasonality of groundwater flow. Sulphate depletion at the surface and in 20 cm porewater coincided with anoxia and occurred mainly during the summer when water levels were near the peat surface and water flow rates were low in both catchments. There was an inverse relationship between net SO4 2- mobilization and water level elevation relative to the peat surface, explaining variation in SO4 2- dynamics between the swamps during summer drought periods. Aeration of peat to 40 cm and a large net SO4 2- mobilization (10–70 mg SO4 2- m-2 d-1) occurred during a dry summer in which the water level dropped to 60 cm below the surface in the swamp receiving ephemeral groundwater inputs from shallow tills within the catchment. This resulted in high SO4 2- concentrations in the surface water and porewater (30–50 mg L-1), and elevated SO4 2- concentrations remained through the fall and winter. In contrast, within the swamp located in the catchment with greater till depth (〉 1 m), continuous groundwater inputs maintained surface saturation during the dry summer, and SO4 2- mobilization and concentrations of SO4 2- in the pore water during the following fall did not increase. Susceptibility to large water table drawdown and mobilization of accumulated SO4 2- is influenced by the occurrence of ephemeral vs. continuous groundwater inputs to valley swamps during dry summer periods in the Canadian Shield landscape. This study reveals that extrapolation of results of SO4 2- cycling from one wetland to another requires knowledge of the hydrogeology of the catchment in which the wetlands are located.
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    URL: http://dx.doi.org/10.1023/A:1005081505086
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    Effects of Nitrogen and Phosphorus Supply on Hexadecane Biodegradation in Soil Systems (1999)
    Springer
    Water, air & soil pollution 111 (1999), S. 1-18 
    Details
    ISSN: 1573-2932
    Keywords: biodegradation ; hydrocarbon ; nitrogen ; nutrient ratios ; phosphorus ; soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The biodegradation of hexadecane (C as hexadecane-C) was assessed under 34 different external nitrogen (N supplied as NO3-N) and phosphorus (P supplied as PO4-3-P) supply conditions in order to determine how different nutrient formulations affected nutrient limitation conditions during degradation. CO2 production yields indicated that shifts in N and P supply levels resulted in variable biodegradation responses due to shifts in the limiting-nutrient (e.g., from N to P). For example, the estimated maximum fractional CO2 yield ratio was 0.24 (mg CO2-C produced mg-1 hexadecane-C) for P-limited nutrient formulations (P:hexadecane-C〈0.01), whereas the yield ratio was more than two times greater when the system was not P- limited. Similar effects were observed for N-limited (N:hexadecane- C〈0.15) versus non-N-limited formulations. The relative bioavailability of natural soil-N and soil-P also was examined. In the soil studied, background soil-N was 96.3% organic-N and was found to be largely nonbioavailable. In contrast, high CO2 yields were observed even when no external P was supplied. An iterative mathematical procedure indicated that the Olsen soil-P subfraction (inorganic soil-P plus soluble organic soil- P) best approximated bioavailable soil-P for this soil. Our results indicate that both N and P additions affect biodegradation yields, but that stoichiometrically inappropriate nutrient mixes produce suboptimal CO2 yields. We also found that the bioavailable fractions of soil-N and soil-P should be incorporated into estimating the most suitable nutrient formulations for a given contamination scenario.
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    URL: http://dx.doi.org/10.1023/A:1005091427942
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    Chromium speciation in natural waters draining contaminated land, Glasgow, U.K. (1999)
    Springer
    Water, air & soil pollution 112 (1999), S. 389-405 
    Details
    ISSN: 1573-2932
    Keywords: Cr (III) ; Cr (VI) ; groundwater ; porewater ; riverwater ; sediments ; stream water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Historically, solid waste from chromite ore processing has been disposed of at a number of sites in Glasgow, Scotland. Leachate from these sites has been implicated as a source of chromium (Cr) contamination to both groundwaters and stream waters in the south east area of the city. In this study, chromium speciation has been determined in ground-, stream-, river- and pore waters, to assess the extent of contamination and the associated risk. The speciation of chromium is important, as the trivalent species of chromium (Cr(III)) is an essential form of the element, while hexavalent chromium (Cr(VI)) is a known carcinogen to humans via inhalation. Concentrations of total chromium have also been determined in sediments from the River Clyde, to assess the significance of local concentrations relative to those elsewhere in the catchment. High concentrations of Cr(VI) were found in groundwaters and streamwaters in the area immediately surrounding the contaminated sites, and high concentrations of chromium were also found in River Clyde sediments downstream of these sites. However, these concentrations rapidly decrease away from the chromium-contaminated south eastern side of the city. Data from porewaters suggest that some reduction of Cr(VI) occurs naturally in the sediments, indicating that the risk posed by high concentrations of Cr(VI) should be decreased over the longer term.
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    URL: http://dx.doi.org/10.1023/A:1005017506227
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  • 28
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    Use of the Urease Inhibitor N-(n-BUTYL)-Thiophosphoric Triamide Decreased Nitrogen Leaching from Urea in a Fine Sandy Soil (1999)
    Springer
    Water, air & soil pollution 116 (1999), S. 587-595 
    Details
    ISSN: 1573-2932
    Keywords: groundwater ; nitrogen ; sandy soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Application of soluble forms of nitrogen (N) fertilizers to citrus trees in sandy soils of central Florida may cause leaching of NO 3 − below the rooting depth. A leaching column study was conducted to evaluate the leaching of urea, NH 4 + and NO3 − forms of N from calcium nitrate, urea, and urease inhibitor coated urea (Agrotain: N-(-n butyl) thiophosphoric triamide (NBPT)) applied to a Candler fine sand (hyperthermic, uncoated Typic Quartzipsamments) during six cycles of intermittent leaching with 220 mL each of water (total 1320 mL) through the soil columns (equivalent to 30 cm rainfall). The amount of NO3-N recovered in the leachate from calcium nitrate treated soil accounted for 43% of the total N applied. Leaching of N from urea and Agrotain treated soil was pronounced during the second and third leaching events. Cumulative leaching of urea form of N accounted for 12 and 8% of total N applied as urea and Agrotain, respectively. The cumulative amounts of NO3-N and NH4-N recovered in six leachate fractions from urea treated soil accounted for 14 and 21%, respectively, of the total N applied to the column. The corresponding values for the Agrotain treated soil were 8 and 17%, respectively. Soil analysis after the completion of leaching showed no urea throughout the entire depth of column in either urea or Agrotain treatments. The total recovery of N (leachate plus soil) was 48.1, 40.4, and 49.7% of total N applied as urea, Agrotain, and calcium nitrate, respectively. This study demonstrated a significant reduction in leaching of N forms from Agrotain as compared with that from urea.
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    URL: http://dx.doi.org/10.1023/A:1005116911788
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  • 29
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    Transport of Phosphorus and Fractionation of Residual Phosphorus in Various Horizons of a Spodosol (1999)
    Springer
    Water, air & soil pollution 109 (1999), S. 303-312 
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    ISSN: 1573-2932
    Keywords: adsorption ; citrus ; fractionation ; leaching ; phosphorus ; Spodosol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The retention and transport of P by three horizon samples (A, E, and Bh) of a Spososol (Oldsmar sand: sandy, silicious, hyperthermic Alfic Arenic Haplaquods) were evaluated using a batch-equilibration and leaching column techniques with application of P in rates equivalent to 25 and 100 kg P ha-1. Adsorption coefficient (K) values followed the order: Bh 〉 A 〉 E. Adsorption of P by the E horizon soil sample was negligible (M = 4 μg g-1 soil) as compared to that of either A or Bh horizon samples, e.g., 303 and 479 μg g-1, respectively. The leaching column study with application of P equivalent to 100 kg ha-1 showed 39, 68, and 98% of applied P were leached from the Bh, A, and E horizons, respectively, with eight pore volumes of leachate. Elution curves showed the peak P elution at the second pore volume (equivalent to 3.7 cm of water addition). After leaching with eight pore volumes, the residual P in the soil was present primarily in non-occluded Fe and Al-P forms in the A and Bh horizons.
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    Non-Newtonian Flow in a Variable Aperture Fracture (1998)
    Springer
    Transport in porous media 30 (1998), S. 75-86 
    Details
    ISSN: 1573-1634
    Keywords: fracture ; aperture ; heterogeneity ; non-Newtonian ; power-law fluid ; groundwater ; transmissivity ; nonlinear seepage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The transmissivity of a variable aperture fracture for flow of a non-Newtonian, purely viscous power-law fluid with behavior index n is studied. The natural logarithm of the fracture aperture is considered to be a two-dimensional, spatially homogeneous and correlated Gaussian random field. We derive an equivalent fracture aperture for three flow geometries: (1) flow perpendicular to aperture variation; (2) flow parallel to aperture variation; (3) flow in an isotropic aperture field. Under ergodicity, results are obtained for cases 1 and 2 by discretizing the fracture into elements of equal aperture and assuming that the resistances due to each aperture element are, respectively, in parallel and in series; for case 3, the equivalent aperture is derived as the geometric mean of cases 1 and 2. When n=1 all our expressions for the equivalent aperture reduce to those derived in the past for Newtonian flow and lognormal aperture distribution. As log-aperture variance increases, the equivalent aperture is found to increase for case 1, to decrease for case 2, and to be a function of flow behavior index n for case 3.
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    On the Influence of Pore-Scale Dispersion in Nonergodic Transport in Heterogeneous Formations (1998)
    Springer
    Transport in porous media 30 (1998), S. 57-73 
    Details
    ISSN: 1573-1634
    Keywords: groundwater ; nonergodic transport ; dispersion ; heterogeneous formations ; hydrogeology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Flow of an inert solute in an heterogeneous aquifer is usually considered as dominated by large-scale advection. As a consequence, the pore-scale dispersion, i.e. the pore scale mechanism acting at scales lower than that characteristic of the heterogeneous field, is usually neglected in the computation of global quantities like the solute plume spatial moments. Here the effect of pore-scale dispersion is taken into account in order to find its influence on the longitudinal asymptotic dispersivity D11we examine both the two-dimensional and the three-dimensional flow cases. In the calculations, we consider the finite size of the solute initial plume, i.e. we analyze both the ergodic and the nonergodic cases. With Pe the Péclat number, defined as Pe=Uλ/D, where U, λ, D are the mean fluid velocity, the heterogeneity characteristic length and the pore-scale dispersion coefficient respectively, we show that the infinite Péclat approximation is in most cases quite adequate, at least in the range of Péclat number usually encountered in practice (Pe 〉 102). A noteworthy exception is when the formation log-conductivity field is highly anisotropic. In this case, pore-scale may have a significant impact on D11, especially when the solute plume initial dimensions are not much larger than the heterogeneities' lengthscale. In all cases, D11 appears to be more sensitive to the pore-scale dispersive mechanisms under nonergodic conditions, i.e. for plume initial size less than about 10 log-conductivity integral scales.
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    Flow-driven Diameter Response in Rat Femoral Arteries Perfused In Vitro (1998)
    Springer
    Annals of biomedical engineering 26 (1998), S. 526-533 
    Details
    ISSN: 1573-9686
    Keywords: Rat ; Artery: femoral ; Arterial diameter ; Vasomotion ; Shear stress ; Flow-dependent constriction ; Step flow ; Oscillating flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The effects of flow and flow changes on arterial diameter were investigated in vitro on isolated rat femoral arteries. Segments of femoral arteries were excised, mounted on microcannulas, and perfused with Tyrode's solution (37°C). Perfusion pressure was kept constant at 90 mm Hg. The mean external diameter after equilibration at a transmural pressure of 90 mm Hg was 720 ± 50 μ m (n=12). Vessels were then constricted with norepinephrine (1 μM in the superfusion solution) to 77% ± 13% of the resting diameter; acetylcholine was used to check endothelial function. The external diameter was measured continuously using video microscopy. The arteries were subjected to two different types of flow variations: (a) step changes in flow (increase and decrease, n=6) and (b) low-frequency sinusoidal flow variations (frequencies ranging from 0.002 to 0.1 Hz, n=11). Flow ranged from 0 to 800 μ l/min (shear stress ranging from 0 to 15 dyn/cm2). All measured vessels constricted as flow increased. Flow steps induced exponential-like contractions (flow increase) or relaxations (flow decrease) with mean characteristic time constants 31 ± 4 and 22 ± 2 s, respectively. Sinusoidal flow oscillations induced sinusoidal diameter oscillations with a time delay. An increase in the frequency of the flow led to a decrease of both the amplitude of the flow-induced diameter oscillations and the phase shift between flow and diameter. The dynamic diameter response to flow changes could be characterized by a first-order low-pass filter with a time constant of 22 s. © 1998 Biomedical Engineering Society. PAC98: 8745Hw
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    On the Displacement of NAPL Lenses and Plumes in a Phreatic Aquifer (1998)
    Springer
    Transport in porous media 33 (1998), S. 227-255 
    Details
    ISSN: 1573-1634
    Keywords: groundwater ; contamination ; NAPL lens ; phreatic aquifer ; water table ; vertical equilibrium ; analytical solution ; similarity solution ; two‐dimensional plumes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The movement of an LNAPL lens above a sloping or horizontal water table, and a DNAPL lens above an impermeable surface is discussed. The governing equations are derived, using the vertical equilibrium approach and assuming the water mobility to be much greater than that of the NAPL. Analytical solutions are obtained for one‐dimensional movement of a lens along a sloping water table. They describe the lens movement with the formation of a jump at the leading front (large-scale approximation), and the distribution of NAPL in the transition zone near the jump (small‐scale approximation). A model,describing the movement of a lens, taking into account NAPL retention,is proposed. Approximate one‐dimensional solutions for the movement of a NAPL lens along sloping or horizontal surfaces under such conditions are presented for this model. Some approximate analytical solutions for two‐dimensional lens (plume) formation and movement are obtained for the case of a point source at a sloping surface.
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    Spatial and Temporal Variabilities in Nitrogen and Phosphorous in the Nakdong River System, Korea (1998)
    Springer
    Water, air & soil pollution 102 (1998), S. 37-60 
    Details
    ISSN: 1573-2932
    Keywords: behavior ; distribution ; Nakdong River ; nitrogen ; phosphorus ; spatial ; temporal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The concentrations of nitrogen (N) and phosphorous (P) species and relevant hydrographic parameters were determined in main stream and tributary waters of the Nakdong River system during the periods of May through October 1994. During the entire period, the total N (TN) and total P (TP) concentrations in surface waters were found within the ranges of 0.4–7.0 (N=241) and 0.02–1.536 mg L-1 (N=241), respectively. To help derive meaningful interpretations of temporal and geographical variabilities in the nutrient bahavior, the entire data were evaluated for each individual parameter after employing several different grouping schemes. The results of this comparative analysis can be expressed in terms of: (1) high summer/fall ratios for most of nutrient species; and (2) low summer/fall ratios for most of nutrient-to-nutrient ratios and relevant hydrographic parameters. Interestingly, while the former case was found to be more significant in tributary waters than main stream waters, such geographical dependence was not strongly evident for the latter case. A z-statistic test, conducted to check the significance of temporal (between summer and fall) and spatial (between tributary and main stream regions) differences, confirm that the observed variabilities are in most cases strong enough for most of variables studied – nutrient species, their ratios, and relevant hydrographic parameters. In addition, comparison of nutrient species between dissolved and particulate phases reveals several interesting features. Unlike dissolved nutrient species, the concentrations of particulate N or P (PN or PP) exhibited quite extraoridanry behavior. While PN appears to be rather minor component of the total N budget for the Nakdong river, PP seems to make rather strong contributions to its total P budgets with its strong input from tributary waters during rainy summer season. Through an application of correlation analysis, relationships between different parameters were investigated for both before and after the grouping of data sets. The overall picture of this analysis showed that nutrient species were strongly correlated with each other, while the strongest correlations were among such hydrographic parameters as DO, BOD, COD, and conductivity. This analysis was further conducted to more deliberately divided data groups. The results of analyses on these sub-grouped data sets indicate that the occurrences of significant corelations were common from tributary waters relative to main streams for both (1) between different nutrient species and (2) between nutrient and hydrographic parameters. Using the line of evidence gathered from the statistical tests and from the correlation analysis, we conclude that the environmental health of the Nakdong river system is affected by the combined effects of various factors and processes.
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    URL: http://dx.doi.org/10.1023/A:1004973616860
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    Leaching of Nutrients, Organic Carbon and Iron from Finnish Forestry Land (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 239-250 
    Details
    ISSN: 1573-2932
    Keywords: Finland ; forested catchments ; iron ; leaching ; nitrogen ; nutrients ; organic carbon ; peatland ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This study provides an assessment of the spatial variability of the long-term leaching of nutrients, total organic carbon (TOC) and iron (Fetot) from 22 forested catchments (0.69-56 km2), distributed across all but the northenmost areas of Finland. The natural, unmanaged Kruunuoja catchment is located in a national park, while the other catchments represent Finnish forestry land. The average leaching of Ptot (4.2 kg km-2 yr-1) from the Kruunuoja catchment was small compared to the catchments representing forestry land (on average 10 kg km-2 yr-1). Moreover, P fertilization was the most important predictor for the spatial variation in Ptot leaching (r2=0.45). Leaching of TOC, Fetot and N compounds was not closely related to forestry practices. Median C/N ratio in the study streams was high (range 34-66). The average inorganic N proportion and leaching of Ptot were lowest in the Kruunuoja catchment (7.3 % and 2.8 kg km-2 yr-1, respectively) and highest in the southernmost Teeressuonoja catchment (54 % and 100 kg km-2 yr-1, respectively) located in the highest N deposition area. The most important forestry practices since the 1960's have affected about 2.4 % of the area of study sites per year (cf. 2% in the entire country in 1991). Moreover, the mean annual runoff from the catchments (230-430 mm yr-1) agrees with the mean annual runoff from Finland (301 mm yr-1). Consequently, the results of the study catchments can be used to estimate average total annual leaching from Finnish forestry land: 2,700 t of Ptot, 48,000 t of Ntot, 110,000 t of Fetot and 1.5 million t of TOC.
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    URL: http://dx.doi.org/10.1023/A:1005049408225
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    A Computational Analysis of FXa Generation by TF:FVIIa on the Surface of Rat Vascular Smooth Muscle Cells (1998)
    Springer
    Annals of biomedical engineering 26 (1998), S. 28-36 
    Details
    ISSN: 1573-9686
    Keywords: Mathematical model ; Tissue factor ; Wall shear rate ; FXa generation ; TF:FVIIa ; Rat ; Vascular ; Smooth muscle ; Factor X ; Coagulation ; Clot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract A computational model was developed to investigate the contribution of classical mass transport and flow parameters to factor X (FX) activation by the tissue factor–factor VIIa complex (TF:VIIa) on one wall of a parallel-plate flow chamber. The computational results were compared to previously obtained experimental data for the generation of factor Xa (FXa) by TF:VIIa on the surface of cultured rat vascular smooth muscle cells. In this study, the complete steady-state convection–diffusion equation was solved using the commercial software package, FLUENT (Fluent Inc., Lebanon, New Hampshire). A user-defined subroutine interfaced with FLUENT implemented the surface reaction which was modeled using classical Michaelis–Menten reaction kinetics. The numerical solutions were obtained for 12 cases which used combinations of three wall shear rates and four reaction rates. The numerically obtained fluxes for a given reaction rate displayed a wall shear rate dependence which ranged from classical kinetic reaction control (no dependence) to pure diffusional control (maximum dependence). The experimental data, however, were not represented by numerical data generated using a single reaction rate. The three numerically obtained fluxes which corresponded most closely to the experimental fluxes were determined using three different V max values. This finding supports the hypothesis that there may be a direct effect of flow on the TF:VIIa complex or the cell membrane. © 1998 Biomedical Engineering Society. PAC98: 8722-q, 8710+e
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    URL: http://dx.doi.org/10.1114/1.120
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    Trace Elements in Groundwater from Some Crystalline Rocks in the Upper Regions of Ghana (1998)
    Springer
    Water, air & soil pollution 103 (1998), S. 71-89 
    Details
    ISSN: 1573-2932
    Keywords: bedrock ; boreholes ; concentration levels ; groundwater ; trace elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract About 20 trace elements were analysed in samples from 60 boreholes located in the Upper East and West Regions of Ghana. Findings from the analysis indicated that most trace element concentrations were higher as compared to their concentrations found in natural water systems. The available chemical data of rocks in the area suggest that local bedrock is the dominant source of the trace elements found in goundwater. Aluminium, Fe, Mn, Zn, Sr, and Ba were excessively high in concentration. In comparison with WHO guidelines, all except Al, Fe, Fe and Mn values were below the recommended limits.
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    URL: http://dx.doi.org/10.1023/A:1004968109028
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    Estimation of Nutrient Atmospheric Deposition to Long Island Sound (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 521-538 
    Details
    ISSN: 1573-2932
    Keywords: atmosperic deposition ; Long Island Sound ; modeling ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Anthropogenic nutrient sources (especially nitrogen and phosphorus) released into the Long Island Sound (LIS) causes excessive phytoplankton growth resulting in hypoxic conditions. Atmospheric deposition (both wet and dry deposition) has significant effect on aquatic and terrestrial ecosystems. Two dry deposition monitoring sites were established along the north shore of LIS in February 1991. Wet and dry deposition samples were collected since then. A dry deposition velocity model, based on the characteristics of the water surface, was used to estimate the loading as well as the seasonal variability (dynamics) of nutrients in atmospheric deposition to LIS. The average nitrogen flux from each site was 6.64 kg (as-N) ha-yr-1. The total atmospheric nitrogen loading was estimated to be 2240 metric tons yr-1 which correcponds to 2.5% of the estimated total nitrogen loading to the Sound from all sources. The average phosphorus flux was 37.44 g (as-P) ha-yr-1. The total atmospheric phosphorus loading to the Sound was estimated to be 12.62 metric tons yr-1. The results show that wet deposition was the predominant source of atmospheric contribution to the Sound.
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    URL: http://dx.doi.org/10.1023/A:1004954923033
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    Beryllium Chemistry in the Lysina Catchment, Czech Republic (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 409-415 
    Details
    ISSN: 1573-2932
    Keywords: acid deposition ; beryllium ; catchment ; groundwater ; soil solution ; stream water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The environmental chemistry of beryllium (Be) was investigated at the Lysina catchment in western Bohemia, Czech Republic, a forest ecosystem with high loadings of acidic atmospheric deposition. The catchment supports Norway spruce plantations; it is underlain by leucogranite and the soils are Spodosols. Average concentrations of Be were high in groundwater (3.3 µg L-1) and in stream water (1.5 µg L-1), in comparison to the drinking water standard of the Czech Republic (0.2 µg L-1). Chemical equilibrium calculations suggest that aquoberyllium Be2+ was the prevailing inorganic species in drainage waters at the site. Atmospheric deposition of Be (45 µg m-2 yr-1) was small in comparison to drainage outflow (586 µg m-2 yr-1) at Lysina. Elevated Be concentrations in drainage water appear to be the result of the mobilization of Be from soils and weathered bedrock due to acidic atmospheric deposition. Increased mobility of Be due to acidification may have serious ecological consequences in acid-sensitive areas with terrestrial pools of available Be.
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    URL: http://dx.doi.org/10.1023/A:1005091728272
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    Soil and Minespoil Fill as Media for Renovation of Nitrogen and Phosphorus in Domestic Wastewater (1998)
    Springer
    Water, air & soil pollution 102 (1998), S. 361-375 
    Details
    ISSN: 1573-2932
    Keywords: alternative on-site wastewatertreatment and disposal systems ; fill material ; low pressuredistribution systems ; minespoil ; nitrogen ; phosphorus ; wastewater renovation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Development of Appalachian coal mining regions of the USA has been severely hampered by lack of domestic waste disposal technologies suited to fills. The suitability of on-site wastewater treatment and disposal systems (OSWTDS) in fill material is uncertain due to the effects of surface mining on soil physical properties. This research was conducted to evaluate the potential for renovation of N and P present in domestic wastewater by fills produced from mining operations. Nitrogen and P were chosen because of their potential adverse environmental impacts. Soil-fill (a mixture of Jefferson, fine-loamy, siliceous, mesic Typic Hapludult and Muskingom, fine-loamy, mixed, mesic Typic Dystrochrept soils) and minespoil (spoil)-fill (blasted rock material associated with the Taggart Marker and Low Splint Bench coal seams of the Upper Middle Wise Formation) were used in this study. Septic tank effluent (STE) and sand filter effluent (SFE) were applied to spoil-fill columns at four loading rates (0, 5.4, 10.8, and 21.6 L m-2d-1) and spoil-fill columns at one loading rate (21.6 L m-2d-1) for a period of 20 wk. Renovation of wastewater was assessed by determining the concentration of N and P present in column leachate. Reduction of inorganic N (NO3 - + NH4 +), based on N/Cl ratios, ranged from 14.9 to 32.1% after the varying application rates of STE and SFE passed through the soil columns. However, leachate NO3 --N concentrations were still above the 10 mg-1 drinking water standard. The quantity of P emerging from the spoil-fill columns (3.0 mg P L-1) was higher than anticipated and may be related to the indigenous P present in the minespoil. Sorption of P in the soil-fill column decreased with increased STE and SFE application (reductions ranged from 99.1 to 74.4%). Results from this study indicate that there is potential for renovating wastewater in OSWTDS in selected soil-fill areas in reclaimed minelands.
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    URL: http://dx.doi.org/10.1023/A:1004943424958
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    Hydrology and Chemistry of the Choptank River Basin (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 387-397 
    Details
    ISSN: 1573-2932
    Keywords: Chesapeake Bay ; Choptank River ; iron ; nitrogen ; phosphorus ; river water chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The Choptank River basin is a coastal plain catchment dominated by agriculture (52% of land use). We summarize an 11 year data set of discharge and chemistry from a gauged subbasin. Discharge exhibited seasonal variations driven by seasonal evapotranspiration. There were double seasonal maxima of pH, NH4 +, NO3 -, total N, Fe, and total P concentrations in late spring and fall as the saturated zone rose and fell within the soil. Significant interannual variability in discharge was the result of rainfall variation. There were positive nterannual trends in NO3 - concentrations and negative interannual trends in NH4 + and PO4 3- concentrations. These data were combined to estimate N and P export coefficients of 3-11 kg N ha-1 yr-1 and 0.14-0.66 kg P ha-1 yr-1, driven primarily by interannual variations in discharge. These export coefficients are low compared to other coastal plain watersheds dominated by agriculture and may be responsible for the small anthropogenic effects in the Choptank estuary compared to other Chesapeake drainages.
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    URL: http://dx.doi.org/10.1023/A:1005001525063
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    Sulfate Reduction in a Lake and the Groundwater of a Former Lignite Mining Area Studied by Stable Sulfur and Carbon Isotopes (1998)
    Springer
    Water, air & soil pollution 108 (1998), S. 271-284 
    Details
    ISSN: 1573-2932
    Keywords: carbon isotopes ; degradation ; groundwater ; isotope fractionation ; landfill ; mining lakes ; sulfate reduction ; sulfur isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The isotopic and chemical composition of water and dissolved sulfur and carbon compounds from a flooded lignite-mining lake and a dump site in Central Germany (today partly covered by a landfill) is used to investigate the sulfate reduction and degradation process of organic matter in the lake and the groundwater. The isotopic composition of both the sulfate/sulfide and the dissolved inorganic carbon (DIC) confirm similarities between the processes in the subhydrical landfill site and in the anaerobic zone of the lake (monimolimnion). The strong reducing conditions are expressed by an enrichment of δ34S of sulfate (landfill: δ34S-SO4 = +37ℵ, bottom of the lake: δ34S-SO4 = +27ℵ), despite varying sulfate supply. More than 50% of the sulfate in the landfill and up to 95% of the sulfate in the monimolimnion were calculated to have been reduced according to the Rayleigh relation. The carbon isotopic composition of DIC ranges from δ13C = -10ℵ to δ13C = -19ℵ in the landfill and from δ13C = -8ℵ to δ13C = -18ℵ in the lake. It was shown that these values represent the complex interactions between the production of methane and carbon dioxide and the formation of bicarbonate from intermediate products.
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    URL: http://dx.doi.org/10.1023/A:1005164121739
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    Implementation of natural attenuation at a JP-4 jet fuel release after active remediation (1997)
    Springer
    Biodegradation 8 (1997), S. 265-273 
    Details
    ISSN: 1572-9729
    Keywords: natural attenuation ; biodegradation ; hydrocarbon ; groundwater ; BTEX ; MTBE ; site characterization ; fate and transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract After eighteen months of active remediation at a JP-4 jet-fuel spill, aresidual of unremediated hydrocarbon remained. Further site characterizationwas conducted to evaluate the contribution of natural attenuation to controlexposure to hazards associated with the residual contamination in thesubsurface. Activities included the detailed characterization ofground-water flow through the spill; the distribution of fuel contaminantsin groundwater; and the analysis of soluble electron acceptors moving intothe spill from upgradient. These activities allowed a rigorous evaluation ofthe transport of contaminants from the spill to the receptor of groundwater,the Pasquotank River. The transport of dissolved contaminants of concern,that is benzene, toluene, ethyl benzene, xylene isomers (BTEX) andmethyl-tertiary-butyl ether (MTBE), into the river from the source area wascontrolled by equilibrium dissolution from the fuel spill to the adjacentgroundwater, diffusion in groundwater from the spill to permeable layers inthe aquifer, and advective transport in the permeable layers. The estimatedyearly loading of BTEX compounds and MTBE into the receptor was trivial evenwithout considering biological degradation. The biodegradation ofhydrocarbon dissolved in groundwater through aerobic respiration,denitrification, sulfate reduction, and iron reduction was estimated fromchanges in ground-water chemistry along the flow path. The concentrations oftarget components in permanent monitoring wells continue to decline overtime. Long term monitoring will ensure that the plume is under control, andno further active remediation is required.
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    Cost-Effective Nutrient Reductions to the Baltic Sea (1997)
    Springer
    Environmental and resource economics 10 (1997), S. 341-362 
    Details
    ISSN: 1573-1502
    Keywords: Baltic Sea ; eutrophication ; nitrogen ; phosphorus ; cost effective
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract Due to eutrophication caused by heavy loads of nitrogen and phosphorus, the biological conditions of the Baltic Sea have been disturbed: large sea bottom areas without any biological life, low stocks of cods, and toxic blue green algaes. It is recognized that the nitrogen and phosphorus loads to the Baltic Sea must be reduced by 50% in order to restore the sea. The main purpose of this paper is to calculate cost effective nitrogen and phosphorus reductions to the Baltic Sea from the nine countries surrounding the Baltic Sea. The results show a significant difference in minimum costs of decreasing nitrogen and phosphorus loads to the Sea: approximately 12 000 millions of SEK per year and 3 000 millions of SEK respectively for reductions by 50%. It is also shown that a change from a policy of cost-effective nutrient reductions to a policy where each country reduces the nutrient loads by 50% increase total costs for both nitrogen and phosphorus reductions by about 300%. The results are, however, sensitive to several of the underlying assumptions and should therefore be interpreted with much caution.
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    URL: http://dx.doi.org/10.1023/A:1026497515871
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    Factors Regulating the Flux of Phosphate at the Sediment - Water Interface of a Subtropical Calcareous Lake: a Simulation Study with Intact Sediment Cores (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 401-409 
    Details
    ISSN: 1573-2932
    Keywords: phosphorus ; P flux ; microbial activity ; redox ; simulation ; Lake Kinneret ; sediment ; accumulative P release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Different factors which interactively control the flux of soluble reactive phosphorus (SRP) at the sediment-water interface (SWI) of Lake Kinneret were studied seasonally. The influence of pH, Eh and microbial activity on SRP flux at the SWI was investigated by manipulating the conditions in the overlying water of intact sediment cores. The calculated diffusive SRP flux out of the sediment was lower in cores sampled during winter and spring than during the period of amixis. Potential SRP release, as measured in the absence of microbial activity, was strongly enhanced upon the transition from oxic to anoxic conditions indicating P release from iron(III)-bound phosphorus. In spring and summer cores, an enhanced SRP flux from sediments at pH 7 in comparison to pH 8 indicated P release from carbonate-bound P which sedimented previously as result of high pH values during the algal spring bloom. Microbial uptake at the SWI was the most important sink for SRP and no net-flux occured under oxic conditions. The higher net-flux of P under anoxic conditions was linked to carbon limitation of the bacteria at the SWI.
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    URL: http://dx.doi.org/10.1023/A:1018335305539
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    Bottom sediments in a humic lake with artificially increased calcium content: sink or source for phosphorus? (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 457-464 
    Details
    ISSN: 1573-2932
    Keywords: sediment ; phosphorus ; fractionation ; release ; humic lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Lake Flosek (north-eastern part of Poland) is a small shallow and without outflow lake which has been limed in 1970. The concentration of Ca was increased from 3-4 mg L-1 to 17 mg L-1 in the water and from 0.2-0.3% dry weight to 0.9-1.7% dry weight in sediments (5 cm upper layer) due to CaCO3 addition to the lake. In the spring-summer seasons of 1992 and 1993, an experimental study was conducted in Lake Flosek to assess the capacity of bottom sediments to uptake and release mineral phosphorus. The rate of phosphorus exchange between sediments and near-bottom water was experimentally measured under conditions of high (100%), and of reduced (10%) oxygen saturation in near-bottom water. To determine the component of sediments responsible for the uptake of most phosphorus, the proportions of phosphorus forms in sediments were analysed. Sediments of Lake Flosek showed a slight tendency to release phosphates. The rate of this process was similar under high (100%) and low (10%) oxygen saturations ranging from - 0.161 to + 0.200 mg P m-2 d-1. This is much lower (by 1-2 orders of magnitude) than reported from other harmonic, non-humic lakes. In the total phosphorus pool, the highest content of phosphorus was found in the organic and residual phosphorus fractions (over 70% of the total phosphorus in sediments). The largest part of the readily extractable phosphorus was found in the fraction bound to Al and humic substances (41%). Both these fractions determine a weak exchange of phosphorus between sediments and water. No difference in P-release related to P-fraction compound was found in the cores taken from three sites in the lake.
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    Sediment Accumulation of Nutrients (N, P) in the Eastern Gulf of Finland (Baltic Sea) (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 477-486 
    Details
    ISSN: 1573-2932
    Keywords: sediment ; nitrogen ; phosphorus ; organic matter ; cluster analysis ; Gulf of Finland ; estuaries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Dry weight (DW), ignition loss (IL) and concentrations of total nitrogen (TN) and total phosphorus (TP) of the sediment surface layer (0 to 10 cm, 1 cm slices) were analyzed from 20 sites in the eastern Gulf of Finland. The distance of the sampling sites from the mouth of the River Neva explained the nutrient concentrations of the sediments well, while the effect of water depth was negligible. The increase of TN and the decrease of TP along the transect from the river mouth towards the open Gulf were caused by the diminishing share of allochthonous material supplied from the River Neva. The mean TN concentration of the different accumulation areas was about 40 % higher in the sediment surface than in the deeper layer (9 to 10 cm). The corresponding difference for TP varied from 53 to 56 %. The results suggest considerable netflux of nutrients from sediment to water. The net sediment accumulation of nutrients were estimated as 6.0 g m-2 a-1 of N and 1.7 g m-2 a-1 of P corresponding 22 000 t a-1 of N and 6 100 t a-1 of P for the whole eastern Gulf.
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    Benthic fluxes of dissolved inorganic carbon, nutrients and oxygen in the Gulf of Trieste (Northern Adriatic) (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 305-314 
    Details
    ISSN: 1573-2932
    Keywords: Adriatic Sea ; nutrients ; benthic fluxes ; carbon ; nitrogen ; silicon ; phosphorus ; budgets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Benthic fluxes of dissolved inorganic N, Si and P nutrients, alkalinity, dissolved inorganic C (DIC), and O2 from sediments in the Gulf of Trieste (northern Adriatic, Italy) were measured monthly in the period September 1995 – August 1996 using in situ incubated light benthic chambers. The highest efluxes of DIC, NH4 +, PO4 3−, Si(OH)4, and NO3 − influxes encountered in late summer — early autumn were the consequence of degradation of benthic microalgae, and in autumn mostly of sedimented phytoplankton. High NO3 − efflux was observed in spring. Only NH4 + and Si(OH)4 fluxes were significantly correlated with temperature. This correlation suggests that the rate of downward input and the quality and quantity of sedimentary organic matter (autochthonous and allochthonous) were superimposed on the temperature fluctuations. High DIC, NH4 + and Si(OH)4 effluxes observed in July 1996 were due to the late spring — early summer degradation of sedimentary organic matter produced by benthic microalgae, while the autumn phytoplankton bloom was quickly reflected in enhanced benthic fluxes due to higher temperature. Significant correlations between NH4 +, PO4 3− and Si(OH)4 fluxes suggested their parallel regeneration and utilization at the sediment-water interface. The nutrient fluxes were linked to O2 consumption, suggesting that aerobic oxidation processes were important at the sediment-water interface in the Gulf. The N, P and Si nutrients released from sediment pore waters are probably utilized in benthic microalgal and bottom-water primary production. This indicates that pelagic and benthic communities in the central part of the Gulf of Trieste function relatively independently of each other.
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    URL: http://dx.doi.org/10.1007/BF02406870
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    Trophic modifications in Lake Como (N. Italy) caused by the zebra mussel (Dreissena polymorpha) (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 633-640 
    Details
    ISSN: 1573-2932
    Keywords: zebra mussel ; Dreissena polyrnorpha ; phosphorus ; trophic state ; recovery ; take Como
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A large scale study on the western basin of Lake Como (N. Italy) was started in 1995 to examine the effects of the zebra mussel colonization which began in early '90. Our results have been related to '91–92 data (pre-Dreissena period), before the maximum colonization of zebra mussel. In spring and summer of the post-Dreissena period total phosphorus, P-PO4, nitrate and chlorophyll values decreased, while ammonium and tranparency increased at every sampling station. Zebra mussel does not modify the trophic state of this sub-basin but it plays an important role in nutrient cycling. The entire population can filter epilimnetic craters 2.1 times per year and can produce 2.9 × 104 t y of pseudofaeces which are transferred to sediments.
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    URL: http://dx.doi.org/10.1007/BF02406902
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    PESTICIDE OCCURRENCE IN GROUNDWATER IN TULARE COUNTY, CALIFORNIA (1997)
    Springer
    Environmental monitoring and assessment 45 (1997), S. 101-127 
    Details
    ISSN: 1573-2959
    Keywords: groundwater ; pesticide contamination ; Goss model ; leaching potential ; Pesticide Contamination Index ; GIS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Geographic Information Systems (GIS) and statistical methodswere used to identify the major factors affecting pesticideleaching in groundwater from agricultural fields in TulareCounty, California. Residues of bromacil, diuron, and simazineincreased in groundwater during the 1980s. Bromacil, diuron,and simazine contamination were positively correlated to cropdiversity and water demand. Diuron and simazine were positively correlated to groundwater depth and negatively correlatedto soil water-holding capacity. DBCP concentration in groundwater was related to the crop coverage. The Goss model wasused to examine soil-pesticide interactions and a PesticideContamination Index (PCI) was developed. Areas having highleaching potentials were mainly associated with citrus andorchards and coarse-textured sandy soils along the SierraNevada foothills, while areas having low leaching potentialswere associated with field crops and clay soils of the southwest region. The PCI was largest for DBCP during the 1980s,suggesting that it was the most significant contaminant before1977 when it was widely used; however, wells were not testedfor this pesticide during that period. Twelve years after DBCPwas banned, it was still the most significant health riskcontaminant. Spatial maps showing the distribution of leachingpotentials and soil interactions for these pesticides canprovide useful information to regulatory and planning agenciesfor land use planning and pesticide management.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005734610694
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    Well Hydraulics with the Weber–Goldstein Transforms (1997)
    Springer
    Transport in porous media 29 (1997), S. 225-246 
    Details
    ISSN: 1573-1634
    Keywords: Well hydraulics ; Weber–Goldstein transforms ; groundwater ; analytic solution ; integral transform ; aquifer characterization ; parameter estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Two new integral transforms, ideally suited for solving boundary value problems in well hydraulics, are derived from one of the Goldstein identities which generalizes a corresponding Weber identity. The two transforms are, therefore, named the Weber–Goldstein transforms. Their properties are presented. For the first, second, and third type boundary conditions, the new transforms remove the radial portion of a Laplacian in the cylindrical coordinates. They are used to straightforwardly rederive known solutions to the problems of a fully penetrating flowing well and a fully penetrating pumped well. A novel solution for a fully penetrating flowing well with infinitesimal skin situated in a leaky aquifer is also found by means of one of the new transforms. This solution is validated by comparison to a numerical solution obtained via the finite-difference method and to a quasi-analytic solution obtained by numerical inversion of the corresponding solution in the Laplace domain. Based on the new solution, a flowing well test is proposed for estimating the hydraulic conductivity and specific storativity of the aquifer and the skin factor of the well. The test can also be used in a constant-head injection mode. A type-curve estimation procedure is developed and illustrated with an example. The effectiveness of the test in estimating the well skin factor and aquifer parameters depends on the availability of data on the sufficiently early well response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006542203102
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    Factors regulating the flux of phosphate at the sediment — water interface of a subtropical calcareous lake: A simulation study with intact sediment cores (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 401-409 
    Details
    ISSN: 1573-2932
    Keywords: phosphorus ; P flux ; microbial activity ; redox ; simulation ; Lake Kinneret ; sediment ; accumulative P release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Different factors which interactively control the flux of soluble reactive phosphorus (SRP) at the sediment water irterface (SWI) of Lake Kinneret were studied seasonally. The influence of pH, Eh and microbial activity on SRP flux at the SWI was investigated by manipulating the conditions in the overlying water of intact sediment cores. The calculated diffusive SRP flux out of the sediment was lower in cores sampled during winter and spring than during the period of amixis. Potential SRP release, as measured in the absence of microbial activity, was strongly enhanced upon the transition from oxic to anoxic conditions indicating P release from iron(III)-bound phosphorus. In spring and summer cores, an enhanced SRP flux from sediments at pH 7 in comparison to pH 8 indicated P release from carbonate-bound P which sedimented previously as result of high pH values during the algal spring bloom. Microbial uptake at the SWI was the most important sink for SRP and no net-flux occured under oxic conditions. The higher net-flux of P under anoxic conditions was linked to carbon limitation ofthe bacteria at the SWI.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02406880
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    Sediment accumulation of nutrients (N, P) in the eastern Gulf of Finland (Baltic Sea) (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 477-486 
    Details
    ISSN: 1573-2932
    Keywords: sediment ; nitrogen ; phosphorus ; organic matter ; cluster analysis ; Gulf of Finland ; estuaries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Dry weight (DW), ignition loss (IL) and concentrations of total nitrogen (TN) and total phosphorus (TP) of the sediment surface layer (0 to 10 cm, 1 cm slices) were analyzed from 20 sites in the eastern Gulf of Finland. The distance of the sampling sites from the mouth of the River Neva explained the nutrient concentrations of the sediments well, while the effect of water depth was negligible. The increase of TN and the decrease of TP along the transect from the river mouth towards the open Gulf were caused by the diminishing share of allochthonous material supplied from the River Neva. The mean TN concentration of the different accumulation areas was about 40 % higher in the sediment surface than in the deeper layer (9 to 10 cm). The corresponding difference for TP varied from 53 to 56 %. The results suggest considerable netflux of nutrients from sediment to water. The net sediment accumulation of nutrients were estimated as 6.0 g m−2 a−1 of N and 1.7 g m−2 a−1 of P corresponding 22 000 t a− of N and 6 100 t a−1 of P for the whole eastern Gulf.
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    URL: http://dx.doi.org/10.1007/BF02406887
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    occurrence and distribution of nitrate and pesticides in bowdle aquifer, south dakota (1997)
    Springer
    Environmental monitoring and assessment 47 (1997), S. 223-237 
    Details
    ISSN: 1573-2959
    Keywords: contamination ; groundwater ; monitoring ; nitrate ; pesticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A shallow aquifer in central South Dakota was monitored for thepresence of nitrate and pesticides. A total of 593 nitrate samples and428 pesticide samples were analyzed from nine different sites and 14wells between 1989 and 1994. Nested wells were installed at four sitesto characterize the distribution pattern of nitrate and pesticidemovement in ground water. Nitrate concentrations and pesticidedetections were qualitatively compared with area precipitation and watertable fluctuations. The results indicate that nitrates tend to betransported by a leaching mechanism in a matrix flow and may appearin ground water within months after the fertilizer application in thefields. The pesticide movement is primarily controlled by geologicaland chemical characteristics of medium and pesticides.
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    URL: http://dx.doi.org/10.1023/A:1005746504457
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    Hydrochemistry of the aquifers in the Rio las Avenidas basin, Pachuca, Hidalgo, Mexico (1997)
    Springer
    Water, air & soil pollution 96 (1997), S. 185-201 
    Details
    ISSN: 1573-2932
    Keywords: Avenidas basin ; Pachuca mines ; hydrochemistry ; hydrochemical facies ; heavy metals ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Groundwater in the Rio de las Avenidas sub-basin corresponds to the bicarbonate-sodium and bicarbonate-calcium hydrochemical facies, which result from the mineralization of water passing through alkaline rocks (andesites) which prevail in this basin. However, the presence of high concentrations of Na+ and K+ reveals the existence of an external inflow of these elements: the registered mean values are respectively 94.3 and 19.0 ppm, with the Tèllez and Tizayuca areas standing out with reported values of up to 142 ppm. As for the concentration of soluble water cations, we find in decreasing order: Na+, Ca2+, Mg2+, K+, along with the anions HCO3 −, Cl−, SO4 2−, CO3 −, which combine to form the NaHCO3, NaCl, Ca(HCO3)2, MgSO4 and KCl salts. The presence of biological contaminants, P and detergents in the groundwater indicates that it may have been contaminated by waste water. In addition to the contaminants mentioned above, large quantities of Pb, B, Zn, Fe, Mn, Cr, Co were detected and although Fe, Pb, Zn, B, and Mn are closely related to the local lithology, the high concentrations of these elements along with the occurrence of Co, Cr, Cd, and Ni confirm the gradual degradation of the aquifers in the sub-basin. The water temperature indicates the existence of low temperature thermal processes in the area.
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    URL: http://dx.doi.org/10.1007/BF02407204
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    HYDROCHEMISTRY OF THE AQUIFERS IN THE RIO LAS AVENIDAS BASIN, PACHUCA, HIDALGO, MEXICO (1997)
    Springer
    Water, air & soil pollution 96 (1997), S. 185-201 
    Details
    ISSN: 1573-2932
    Keywords: Avenidas basin ; Pachuca mines ; hydrochemistry ; hydrochemical facies ; heavy metals ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Groundwater in the Rio de las Avenidas sub-basin corresponds to the bicarbonate-sodium and bicarbonate-calcium hydrochemical facies, which result from the mineralization of water passing through alkaline rocks (andesites) which prevail in this basin. However, the presence of high concentrations of Na+ and K+ reveals the existence of an external inflow of these elements: the registered mean values are respectively 94.3 and 19.0 ppm, with the Tèllez and Tizayuca areas standing out with reported values of up to 142 ppm. As for the concentration of soluble water cations, we find in decreasing order: Na+, Ca2+, Mg2+, K+,along with the anions HCO3 -, Cl-, SO4 2-, CO3 -, which combine to form the NaHCO3, NaCl, Ca(HCO3 2, MgSO4 and KCl salts. The presence of biological contaminants, P and detergents in the groundwater indicates that it may have been contaminated by waste water. In addition to the contaminants mentioned above, large quantities of Pb, B, Zn, Fe, Mn, Cr, Co were detected and although Fe, Pb, Zn, B,and Mn are closely related to the local lithology, the high concentrations of these elements along with the occurrence of Co, Cr, Cd, and Ni confirm the gradual degradation of the aquifers in the sub-basin. The water temperature indicates the existence of low temperature thermal processes in the area.
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    URL: http://dx.doi.org/10.1023/A:1026452116613
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    Benthic Fluxes of Dissolved Inorganic Carbon, Nutrients and Oxygen in the Gulf of Trieste (Northern Adriatic) (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 305-314 
    Details
    ISSN: 1573-2932
    Keywords: Adriatic Sea ; nutrients ; benthic fluxes ; carbon ; nitrogen ; silicon ; phosphorus ; budgets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Benthic fluxes of dissolved inorganic N, Si and P nutrients, alkalinity, dissolved inorganic C (DIC), and O2 from sediments in the Gulf of Trieste (northern Adriatic, Italy) were measured monthly in the period September 1995 - August 1996 using in situ incubated light benthic chambers. The highest efluxes of DIC, NH4+, PO43-, Si(OH)4, and NO3- influxes encountered in late summer - early autumn were the consequence of degradation of benthic microalgae, and in autumn mostly of sedimented phytoplankton. High NO3- efflux was observed in spring. Only NH4+ and Si(OH)4 fluxes were significantly correlated with temperature. This correlation suggests that the rate of downward input and the quality and quantity of sedimentary organic matter (autochthonous and allochthonous) were superimposed on the temperature fluctuations. High DIC, NH4+ and Si(OH)4 effluxes observed in July 1996 were due to the late spring - early summer degradation of sedimentary organic matter produced by benthic microalgae, while the autumn phytoplankton bloom was quickly reflected in enhanced benthic fluxes due to higher temperature. Significant correlations between NH4+, PO43- and Si(OH)4 fluxes suggested their parallel regeneration and utilization at the sediment-water interface. The nutrient fluxes were linked to O2 consumption, suggesting that aerobic oxidation processes were important at the sediment-water interface in the Gulf. The N, P and Si nutrients released from sediment pore waters are probably utilized in benthic microalgal and bottom-water primary production. This indicates that pelagic and benthic communities in the central part of the Gulf of Trieste function relatively independently of each other.
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    URL: http://dx.doi.org/10.1023/A:1018398231038
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    Seasonal Changes in Cystoseira Myrica and Phosphorus Input at Two Sites of the Red Sea Egyptian Coast (1997)
    Springer
    Water, air & soil pollution 93 (1997), S. 199-211 
    Details
    ISSN: 1573-2932
    Keywords: Cystoseira myrica ; Red Sea ; coral reefs ; nitrogen ; phosphorus ; pollution ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Elevated phosphate concentrations at Safaga and Quseir, Red Sea, Egyptian coast, wererelated to some ecological and nutritional aspects of the macro-alga Cystoseira myrica during1985. The results obtained were compared with those recorded for a non-polluted control site atGhardaqa. Chemical analysis of surface seawater samples revealed that the concentrations of dissolvedphosphate at Safaga and Quseir were 3 and 20 times as much as that at Ghardaqa, respectively.The standing crop of C. myrica showed two peaks in spring and autumn. Maximum biomass yield(491 g m-2) and number of individuals (127 m-2) of C. myrica were recorded in the spring at theGhardaqa site. Quseir C. myrica samples contained significantly higher protein-N, total-N andtotal-P values but lower carbohydrate values than the Safaga and Ghardaqa samples (LSD at 1%level). Tissue N:P molar ratios for C. myrica, Laurencia papillosa and Ulva lactuca collected fromGhardaqa ranged from 68-98, compared to 30-59 for the same species collected at thephosphorus polluted sites at Safaga and Quseir. The carbon levels and the C:N ratios of C. myricaexhibited no significant variations in the three studied sites. However, the C:P ratios of Ghardaqaplants were significantly higher than those of Safaga and Quseir.
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    URL: http://dx.doi.org/10.1023/A:1022196227853
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    TRANSPORT OF BACTERIA AND BACTERIOPHAGES IN IRRIGATED EFFLUENT INTO AND THROUGH AN ALLUVIAL GRAVEL AQUIFER (1997)
    Springer
    Water, air & soil pollution 98 (1997), S. 17-42 
    Details
    ISSN: 1573-2932
    Keywords: aquifer ; bacteria ; bacteriophages ; contamination ; effluent ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The movement of bacteria and bacteriophages into and through an alluvial gravel aquifer was investigated at a bordered strip effluent irrigation scheme near Christchurch, New Zealand. Irrigation of one set of strips resulted in the contamination, by faecal coliform bacteria, and somatic and F-RNA coliphages, of two bores, approximately 60 m and 445 m downstream of the centre of the strips. F-RNA coliphages showed the greatest attenuation between the soil surface and the first bore, and faecal coliforms the least. Estimates of percolation times through the 13 m vadoze zone (based on times to peak concentration in the groundwater) ranged from 1.6 to 10.5 hr, with travel times for the bacteriophages being 1.4–3.4 times longer than for the bacteria. Injection of oxidation pond effluent containing rhodamine WT dye into the first bore resulted in contamination of the second bore (385 m downstream) by the dye, F-RNA coliphages, and faecal coliforms. In a second experiment, injection (into the same bore) of a mixture of phage MS–2, the bacterial tracer Escherichia coli J6–2, and rhodamine WT dye, produced a similar result in the downstream bore and in a newly-installed bore, 401 m downstream. In both injection experiments, the phages exhibited the shortest times to peak concentrations in the downstream bore(s), followed by the bacteria, and then the dye. Attenuation of the bacteria and phages was similar, but the microbes exhibited 100-fold greater reduction than the dye. Flow direction and longitudinal dispersivity were determined in a preliminary analysis using an idealised 2-D dispersion model. This information, and other measured and reported data, were then used as inputs in a 3-D dispersion model. The predicted concentration curves were matched to the observed curves by trial and error adjustment of the decay constant (λ). The best curve fits were obtained with λ values higher than those reported elsewhere. It is suggested that many of the reported microbial decay values underestimate microbial reductions in groundwater because they do not account for other removal mechanisms, such as filtration, sedimentation and irreversible adsorption.
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    URL: http://dx.doi.org/10.1023/A:1026492110757
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    Transport of bacteria and bacteriophages in irrigated effluent into and through an alluvial gravel aquifer (1997)
    Springer
    Water, air & soil pollution 98 (1997), S. 17-42 
    Details
    ISSN: 1573-2932
    Keywords: aquifer ; bacteria ; bacteriophages ; contamination ; effluent ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The movement of bacteria and bacteriophages into and through an alluvial gravel aquifer was investigated at a bordered strip effluent irrigation scheme near Christchurch, New Zealand. Irrigation of one set of strips resulted in the contamination, by faecal coliform bacteria, and somatic and F-RNA coliphages, of two bores, approximately 60 m and 445 m downstream of the centre of the strips. F-RNA coliphages showed the greatest attenuation between the soil surface and the first bore, and faecal coliforms the least. Estimates of percolation times through the 13 m vadoze zone (based on times to peak concentration in the groundwater) ranged from 1.6 to 10.5 hr, with travel times for the bacteriophages being 1.4–3.4 times longer than for the bacteria. Injection of oxidation pond effluent containing rhodamine WT dye into the first bore resulted in contamination of the second bore (385 m downstream) by the dye, F-RNA coliphages, and faecal coliforms. In a second experiment, injection (into the same bore) of a mixture of phage MS-2, the bacterial tracerEscherichia coli J6-2, and rhodamine WT dye, produced a similar result in the downstream bore and in a newly-installed bore, 401 m downstream. In both injection experiments, the phages exhibited the shortest times to peak concentrations in the downstream bore(s), followed by the bacteria, and then the dye. Attenuation of the bacteria and phages was similar, but the microbes exhibited 100-fold greater reduction than the dye. Flow direction and longitudinal dispersivity were determined in a preliminary analysis using an idealised 2-D dispersion model. This information, and other measured and reported data, were then used as inputs in a 3-D dispersion model. The predicted concentration curves were matched to the observed curves by trial and error adjustment of the decay constant (λ). The best curve fits were obtained with λ values higher than those reported elsewhere. It is suggested that many of the reported microbial decay values underestimate microbial reductions in groundwater because they do not account for other removal mechanisms, such as filtration, sedimentation and irreversible adsorption.
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    Animal Consciousness and Ethics in Asia and the Pacific (1997)
    Springer
    Journal of agricultural and environmental ethics 10 (1997), S. 249-267 
    Details
    ISSN: 1573-322X
    Keywords: Animals ; Asia ; consciousness ; Australia ; Hong Kong ; India ; Israel ; Japan ; New Zealand ; The Philippines ; Russia ; Singapore ; Thailand
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships.
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    Seasonal changes inCystoseira myrica and phosphorus input at two sites of the Red Sea Egyptian Coast (1997)
    Springer
    Water, air & soil pollution 93 (1997), S. 199-211 
    Details
    ISSN: 1573-2932
    Keywords: Cystoseira myrica ; Red Sea ; coral reefs ; nitrogen ; phosphorus ; pollution ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Elevated phosphate concentrations at Safaga and Quseir, Red Sea, Egyptian coast, were related to some ecological and nutritional aspects of the macro-algaCystoseira myrica during 1985. The results obtained were compared with those recorded for a non-polluted control site at Ghardaqa. Chemical analysis of surface seawater samples revealed that the concentrations of dissolved phosphate at Safaga and Quseir were 3 and 20 times as much as that at Ghardaqa, respectively. The standing crop ofC. myrica showed two peaks in spring and autumn. Maximum biomass yield (491 g m−2) and number of individuals (127 m−2) ofC. myrica were recorded in the spring at the Ghardaqa site. QuseirC. myrica samples contained significantly higher protein-N, total-N and total-P values but lower carbohydrate values than the Safaga and Ghardaqa samples (LSD at 1% level). Tissue N:P molar ratios forC. myrica, Laurencia papillosa andUlva lactuca collected from Ghardaqa ranged from 68–98, compared to 30–59 for the same species collected at the phosphorus polluted sites at Safaga and Quseir. The carbon levels and the C:N ratios ofC. myrica exhibited no significant variations in the three studied sites. However, the C:P ratios of Ghardaqa plants were significantly higher than those of Safaga and Quseir.
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    Phosphate-enhanced movement of arsenic out of lead arsenate-contaminated topsoil and through uncontaminated subsoil (1997)
    Springer
    Water, air & soil pollution 93 (1997), S. 243-254 
    Details
    ISSN: 1573-2932
    Keywords: arsenic ; lead ; phosphorus ; heavy metal ; mobility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Past use of lead arsenate insecticides has resulted in elevated concentrations of lead (Pb) and arsenic (As) in topsoils of many existing and former deciduous tree fruit orchard sites throughout the world. Application of phosphate (PO4)-containing fertilizers to these soils can increase soil As solubility, phytoavailability and downward mobility. A laboratory soil column experiment was conducted to determine if As released by phosphate additions to a topsoil artificially contaminated with lead arsenate (1.65 mmol total Pb/kg; 1.10 mmol total As/kg) would be appreciably resorbed by the underlying uncontaminated subsoil. Treatments were a factorial combination of topsoil amendment with monoammonium phosphate (MAP, 0 or 16.67 mmol PO4/kg), and amount of leaching (1, 5 and 10 pore volume displacements (PVD) with distilled water under saturated flow conditions). Soil As decreased in the topsoil with increasing amount of leaching and increased in the subsoil. Addition of MAP substantially increased loss of topsoil As, promoted As transport into and through the subsoil, and increased dissolved As concentrations in the column leachates. After 10 PVDs, 95% of the initial soil As remained in the −MAP columns, while 56% of the initial soil As remained the +MAP columns. Dissolved Pb concentrations were 〈0.05μmol/L in all column leachates. The data are consistent with a mechanism of PO4-enhanced release of As in the topsoil and subsequent promotion of As movement through the subsoil by continuing competition of dissolved As and PO4 for ion adsorption sites. The experimental results indicate that use of PO4-containing fertilizers on lead arsenate-contaminated soils has the potential to greatly enhance downward movement of soil As.
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    URL: http://dx.doi.org/10.1007/BF02404759
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    Trophic Modifications in Lake Como (N. Italy) caused by the Zebra Mussel (Dreissena Polymorpha) (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 633-640 
    Details
    ISSN: 1573-2932
    Keywords: zebra mussel ; Dreissena polymorpha ; phosphorus ; trophic state ; recovery ; Lake Como
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A large scale study on the western basin of Lake Como (N. Italy) was started in 1995 to examine the effects of the zebra mussel colonization which began in early '90. Our results have been related to '91-92 data (pre-Dreissena period), before the maximum colonization of zebra mussel. In spring and summer of the post-Dreissena period total phosphorus, P-PO4,, nitrate and chlorophyll values decreased, while ammonium and transparency increased at every sampling station. Zebra mussel does not modify the trophic state of this sub-basin but it plays an important role in nutrient cycling. The entire population can filter epilimnetic waters 2.1 times per year and can produce 2.9 × 104 t/y of pseudofaeces which are transferred to sediments.
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    URL: http://dx.doi.org/10.1023/A:1018380515534
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    Phosphate-Enhanced Movement of Arsenic Out of Lead Arsenate-Contaminated Topsoil and Through Uncontaminated Subsoil (1997)
    Springer
    Water, air & soil pollution 93 (1997), S. 243-254 
    Details
    ISSN: 1573-2932
    Keywords: arsenic ; lead ; phosphorus ; heavy metal ; mobility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Past use of lead arsenate insecticides has resulted in elevated concentrations of lead (Pb) andarsenic (As) in topsoils of many existing and former deciduous tree fruit orchard sites throughoutthe world. Application of phosphate (PO4)-containing fertilizers to these soils can increase soil Assolubility, phytoavailability and downward mobility. A laboratory soil column experiment wasconducted to determine if As released by phosphate additions to a topsoil artificially contaminatedwith lead arsenate (1.65 mmol total Pb/kg; 1.10 mmol total As/kg) would be appreciably resorbedby the underlying uncontaminated subsoil. Treatments were a factorial combination of topsoilamendment with monoammonium phosphate (MAP, 0 or 16.67 mmol PO4/kg), and amount ofleaching (1, 5 and 10 pore volume displacements (PVD) with distilled water under saturated flowconditions). Soil As decreased in the topsoil with increasing amount of leaching and increased inthe subsoil. Addition of MAP substantially increased loss of topsoil. As, promoted As transportinto and through the subsoil, and increased dissolved As concentrations in the column leachates.After 10 PVDs, 95% of the initial soil As remained in the -MAP columns, while 56% of the initialsoil As remained the +MAP columns. Dissolved Pb concentrations were 〈0.05 µmol/Lin all column leachates. The data are consistent with a mechanism of PO4-enhanced release of Asin the topsoil and subsequent promotion of As movement through the subsoil by continuingcompetition of dissolved As and PO4 for ion adsorption sites. The experimental results indicatethat use of PO4-containing fertilizers on lead arsenate-contaminated soils has the potential togreatly enhance downward movement of soil As.
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    URL: http://dx.doi.org/10.1023/A:1022196704677
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    Bottom sediments in a humic lake with artificially increased calcium content: Sink or source for phosphorus? (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 457-464 
    Details
    ISSN: 1573-2932
    Keywords: sediment ; phosphorus ; fractionation ; release ; humic lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Lake Flosek (north-eastern part of Poland) is a small shallow and without outflow lake which has been limed in 1970. The concentration of Ca was increased from 3–4 mg L−1 to 17 mg L−1 in the water and from 0.2–0.3% dry weight to 0.9–1.7% dry weight in sediments (5 cm upper layer) due to CaCO3 addition to the lake. In the spring-summer seasons of 1992 and 1993, an experimental study was conducted in Lake Flosek to assess the capacity of bottom sediments to uptake and release mineral phosphorus. The rate of phosphorus exchange between sediments and near-bottom water was experimentally measured under conditions of high (100%), and of reduced (10%) oxygen saturation in near-bottom water. To determine the component of sediments responsible for the uptake of most phosphorus, the proportions of phosphorus forms in sediments were analysed. Sediments of Lake Flosek showed a slight tendency to release phosphates. The rate of this process was similar under high (100%) and low (10%) oxygen saturations ranging from - 0.161 to + 0.200 mg P m−2 d−1. This is much lower (by 1–2 orders of magnitude) than reported from other harmonic, non-humic lakes. In the total phosphorus pool, the highest content of phosphorus was found in the organic and residual phosphorus fractions (over 70% of the total phosphorus in sediments). The largest part of the readily extractable phosphorus was found in the fraction bound to AI and humic substances (41%). Both these fractions determine a weak exchange of phosphorus between sediments and water. No difference in P-release related to P-fraction compound was found in the cores taken from three sites in the lake.
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    URL: http://dx.doi.org/10.1007/BF02406885
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    NITRATE CONCENTRATIONS IN RIYADH, SAUDI ARABIA DRINKING WATER SUPPLIES (1997)
    Springer
    Environmental monitoring and assessment 47 (1997), S. 315-324 
    Details
    ISSN: 1573-2959
    Keywords: groundwater ; nitrate ; nitrate removal ; water treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Riyadh, Saudi Arabia is supplied with drinking water fromboth desalinated sea water and treated groundwater sources. Sampleswere analysed for NO3 from selected deep and shallow wells, two locations within the city's six groundwater treatment plants, thedesalinated sea water and distribution network. Average nitrateconcentrations (as NO3) were 8.2 and 15.8 mg/L for deep andshallow well waters, respectively. The average nitrate concentrations (asNO3) in the groundwater treatment plants influent waters and thefinal product water were 16.2 and 8.5 mg/L, respectively. Due toblending of the plants' product water with the desalinated sea water, theaverage network nitrate concentration was 4.4 mg/L. The scheduledwater interruption does not seem to cause any appreciable change in thenitrate levels in the distribution network.
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    URL: http://dx.doi.org/10.1023/A:1005756904710
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    Phosphorus Retention and Release Characteristics of Sewage-Impacted Wetland Sediments (1997)
    Springer
    Water, air & soil pollution 100 (1997), S. 163-179 
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    ISSN: 1573-2932
    Keywords: iron ; natural wetlands ; phosphorus ; retention ; sediments ; sewage ; sorption-desorption ; wetlands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Sediment deposited in traps positioned along a sewage-impacted wetland receiving phosphorus (P)-retaining reactants from natural wetland water was fractionated into different particle sizes, and the amount of P retained in these particle sizes was investigated. Subsamples of the sediments collected from different sites along the wetland system were also equilibrated with water at different water:sediment ratios and equilibration periods to investigate the extent of P released from these sediments under aerobic and anaerobic conditions. Results obtained showed that most of P deposited in sediments is in fine fractions (〈16 µm), particularly in sediments collected from confluence sites where water inflow from the natural wetland provides P-retaining reactants and from sites immediately below these confluence sites (postconfluence sites). The extent of P release from sediments depended on the aerobic-anaerobic conditions of the sediments, equilibration period, water:sediment ratio and the position of sites within the wetland. The rate of P released from sediments associated with an increase in equilibration period tended to be higher under aerobic than anaerobic conditions. Water:sediment ratio was found to be a more important factor in controlling the release of P from sediments under anaerobic than aerobic conditions. The amount of P released from the confluence and postconfluence sites was higher than that from other sites over a range of equilibration periods and water:sediment ratios under aerobic and anaerobic conditions.
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    URL: http://dx.doi.org/10.1023/A:1018340028411
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    Unsaturated zone pore water chemistry and the edge effect in a beech forest in Southern England (1996)
    Springer
    Water, air & soil pollution 92 (1996), S. 421-450 
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    ISSN: 1573-2932
    Keywords: forest edge ; forest gaps ; beech ; scavenging ; groundwater ; nitrate leaching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Twenty one pore water chemistry profiles were obtained for a range of inorganic solutes from the Chalk unsaturated zone in or adjacent to Black Wood, a 2.4 kM2 mature beech wood in southern England. The depth sampled was normally 10 m, but some boreholes were shallower and one was deeper (30 m). Towards the centre of the wood, average pore water concentrations were: Cl (17–25 mg l-1), SO4 (20–40 mg l-1) and NO3-N (5–10 mg 1-1). In small clearings within the wood, concentrations of Cl (12–20 mg l-1) and SO4 (27–36 mg 1-1) were somewhat lower but the average concentration of nitrate-N was higher (16 mg 1-1). Pore water chloride and nitrate concentrations under a small area of ash were lower than under the beech. There was a significant increase in the concentration of a number of solutes, especially Cl, Na, Mg and SO4, close to the exposed western edge of Black Wood. This ‘edge effect’ decreased exponentially with a half distance of about 9 m. The effect was less consistent at the more sheltered eastern edge. Average pore water concentrations of up to 310 mg 1-1 Cl and 312 mg 1-1 SO4 were found at the western edge. Paradoxically, close to the western edge pore water nitrate concentrations were often very low, frequently less than 1 mg 1-1 NO3-N. Using the parameters derived from a simple exponential model of the Black Wood data, calculations suggested that the edge effect would lead to significantly enhanced Cl and SO4 pore water concentrations in forests of a few hectares, a size typical of many of those currently being planted. The consistently lower moisture content of the Chalk close to the forest edges suggested that groundwater recharge may have been lower there.
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    Two approaches to modeling unstable flow and mixing of variable density fluids in porous media (1996)
    Springer
    Transport in porous media 23 (1996), S. 219-236 
    Details
    ISSN: 1573-1634
    Keywords: groundwater ; gravitational instability ; fingering ; variable density fluids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Density variation of aqueous phase fluids flowing in a porous medium, resulting from spatial and temporal variation of solute concentration, often gives rise to unstable flow, and therefore has a significant effect on solute transport. Studies on simulating unstable flow and mixing of variable density fluids in seemingly homogeneous porous media are rare. In this study, a three-dimensional (3-D) and a one-dimensional (1-D) model were developed to simulate unstable flow and mixing in a vertical, nominally 1-D system. In the 3-D model, the fluid flow and solute transport equations were solved numerically with a very fine spatial discretization. The 1-D numerical model was derived from a theoretical model to simulate the flow and mixing of fluids with variable density and viscosity at the field scale. To evaluate the models, simulated results were compared with experimental data from displacement experiments in a vertical sand column. The results show that the 1-D model provides fairly good prediction of breakthrough curves and that the 3-D model is able to qualitatively simulate breakthrough curves for highly unstable flow and mixing.
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    URL: http://dx.doi.org/10.1007/BF00178127
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    Fractionation of heavy metals and phosphorus in suspended sediments of the Yamuna river, India (1996)
    Springer
    Environmental monitoring and assessment 43 (1996), S. 117-124 
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    ISSN: 1573-2959
    Keywords: geochemistry ; metals ; phosphorus ; fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The Yamuna river is the largest tributary of the Ganges river system. It originates in the Himalayas and flows through a varied geological terrain encompassing a large basin area. Metals Fe, Mn, Pb, Zn, Cu in different chemical fractions of suspended sediments such as exchangeable, carbonates, Fe−Mn oxides, organics and residual fractions were studied. Phosphorus associated with different chemical forms are discussed. The metals are mostly associated with residual fractions in the sediments followed by organics, Fe−Mn oxides, exhangeable and carbonates. Intensive use of chemical fertilizers and pesticides in agriculture in the basin affects the high inorganic phosphorus content in sediments.
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    Evaluation of contaminated groundwater cleanup objectives (1996)
    Springer
    Water, air & soil pollution 90 (1996), S. 83-92 
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    ISSN: 1573-2932
    Keywords: cleanup objectives ; groundwater ; public risk ; worker risk ; cost ; hypothetical homesteader risk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The U.S. Department of Energy's (DOE'S) Ernrironmental Restoration Program will be responsible for remediating the approximately 230 contaminated groundwater sites across the DOE Complex. A major concern for remediation is choosing the appropriate cleanup objective. The the cleanup objective chosen will influence the risk to the nearby public during and after remediation; risk to remedial and non-involved workers during remediation; and the cost of remediation. This paper will discuss the trends shown in analyses currently being performed at Oak Ridge National Laboratories' (ORNL's) Center for Risk Management (CRM). To evaluate these trends, CRM is developing a database of contaminated sites. This paper examines several contaminated groundwater sites selected for assessment from CRM s database. The sites in this sample represent potential types of contaminated groundwater sites commonly found at an installation within DOE. The baseline risk from these sites to various receptors will be presented. Residual risk and risk during remediation will be reported for different cleanup objectives. The cost associated with remediating to each of these objectives will also be estimated for each of the representative sites. Finally, the general trends of impacts as a function of cleanup objective will be summarized.
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    Groundwater acidification at Birkenes, southern Norway: Comparing trends of chemical composition of precipitation, throughfall, soilwater and groundwater (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 1861-1866 
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    ISSN: 1573-2932
    Keywords: acidification ; buffering ; groundwater ; monitoring ; precipitation ; seasalt ; soil ; soilwater ; throughfall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Chemical time trends for precipitation, throughfall, and soilwater (1986–1992), and groundwater (1980–1993) at Birkenes, southern Norway, are compared to gain insights into possible causes for the recent increase in groundwater acidification there. Precipitation and throughfall trends do not show evidence for an increase in anthropogenic acids (e.g. sulphate), but seasalt deposition (e.g. chloride) has been marginally greater in 1990–1992 than in most previous years on record. Soilwater composition partly indicates increasing acidification in recent years (pH, Al and ANC), but hardness and sulphate content are decreasing. Soilwater ANC became negative in 1989, revealing a lasting deficit in its potential to buffer acidity. Groundwater shows clear signs of intensifying acidification (pH, Al, ANC, hardness and sulphate), and this may result partly from climatic conditions (mild winters, ‘seasalt episodes’) and partly from the deterioration of an acid buffering system within the soil cover. Acidification via sulphate deposition certainly is not a direct cause. The declining hardness of soilwater suggests that the ion-exchange buffer in the soil may have ceased to function properly. The necessity for obtaining long-term time-series of water chemistry is underscored by this study.
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    An integral equation formulation for the unconfined flow of groundwater with variable inlet conditions (1995)
    Springer
    Transport in porous media 18 (1995), S. 15-36 
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    ISSN: 1573-1634
    Keywords: Analytical solution ; unconflned flow ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract We combine an integral equation formulation with a hodograph transformation to solve self-similar problems describing the unconfined flow of groundwater with variable inlet conditions. A class of new semi-analytical solutions is obtained for both rectilinear and radial flow geometries. The solutions are in general agreement with those derived by Barenblatt, although there are some discrepancies for the case of radial flow. The formulation presented provides additional analytical insight, and for computational purposes is simpler than Barenblatt's. In addition, the method proposed can be successfully used for the solution of a host of other nonlinear problems that admit self-similarity.
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    URL: http://dx.doi.org/10.1007/BF00620658
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    Effect of infra-red low-power laser irradiation on regeneration of myelinated axons (1995)
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    Lasers in medical science 10 (1995), S. 273-277 
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    ISSN: 1435-604X
    Keywords: Ga-As laser ; Myelinated fibre regression ; Rat ; Sciatic nerve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract The purpose of the present study was to examine the regeneration of myelinated axons under the effect of laser irradiation at various wavelengths and energy densities. Laser irradiation at 890 nm with an energy dose of 0.33 J cm−2 as well as He-Ne laser irradiation failed to change the number of regenerating myelinated axons in distal nerve stumps on the 30th day after cutting the nerve. An increase of dose delivered to the skin to 9.33 J cm−2 resulted in a 49% decrease in the number of myelinated axons. A 24% suppression of nerve regeneration was also registered using 1220 nm wavelength laser (dose 0.98 J cm−2). This phenomenon is likely to be attributed to the stimulating effect of laser irradiation of the near-infra-red range on proliferation of fibroblasts and scar formation. 1220 nm of 7.2 J cm−2 dose effected neither the growth nor the myelinization of axons in distal nerve stumps on the 20th day following nerve damage.
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    The frontier problem in incipient groundwater management regimes in Balochistan (Pakistan) (1995)
    Springer
    Human ecology 23 (1995), S. 53-74 
    Details
    ISSN: 1572-9915
    Keywords: groundwater ; resource management ; Balochistan ; Pakistan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Ethnic Sciences
    Notes: Abstract Using case material on the exploitation of groundwater in Balochistan Province in Pakistan, the article studies how resource management regimes evolve or fail to evolve. Incipient resource management regimes face two problems: the definition of access rights and the lack of knowledge on the limits and regenerative capacities of the resource as well as on the behavior of the co-users. These problems will usually be addressed as soon as increased exploitation makes itself first felt in declining groundwater exploitation, though this does not necessary mean that the resource is exploited at levels that are not sustainable. As exploitation will continue to increase however the point of overexploitation may be reached, beyond which it will be much more difficult for a resource management regime to evolve.
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    Soil water chemistry dependence on water pathways and turnover (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 1695-1700 
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    ISSN: 1573-2932
    Keywords: Acidification ; groundwater ; hydraulic conductivity ; leaching ; tracer ; transit time ; till ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Water flow and transit in the soil are important to water supply and transport of chemical compounds. Flows through forested till soils are by vertical percolation in the upslope areas, groundwater flows along the slope to discharge in downslope sites. The flow is divided into slow and fast parts both in the unsaturated percolation and the saturated groundwater. Soil development influences the flow and in coarse grained and well drained soils groundwater flow is stable but in finer grained physically stratified soils, variations in flow are considerable. Large flows occur in the upper soil layers and small flows in deep layers. Chemical composition of soil water varies in a similar way. In the upper layers, water is more acid and has a lower content of base cations compared to deeper layers. In downslope areas discharging deep groundwater contributes to less acidic conditions also in the upper soil layers. This discharge and a dominating lateral water flow in the upper layers partly protect deep layers from acidification which is emphasised by slow water turnover in these layers.
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    Methods for treating acid groundwater results and evaluation of long-term tests (1995)
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    Water, air & soil pollution 85 (1995), S. 1849-1854 
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    ISSN: 1573-2932
    Keywords: acidification ; groundwater ; countermeasures ; liming ; filters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Acid groundwater can corrode plumbing systems and solubilize metals in the soil or in the plumbing systems. Since the soluble forms of some metals are toxic, concerns regarding the effects of groundwater acidification on human health have been raised. A number of new methods for treating acidified groundwater have been developed and tested during the last decade. In addition conventional filter devices have been tested and evaluated. Seven methods of in situ alkalization, i.e. treatment of the soil around the well with an alkalizer, have been tested for 1–8 years. These methods involve the application of limestone or slaked lime in the recharge area of the well or in/near the well. Target values set for the tests were: pH〉6,5 and alkalinity 〉60 mg/l. Almost all of these methods have led to improvements in water quality, but in some cases target values were not reached. Most of the treatments have resulted in significant reductions in iron and aluminium contents in drinking water. Eight types of more conventional devices for processing acidified well water have been tested for a couple of years. These de-acidification filters are installed indoors or in some cases inside the well. The majority of them performed well, providing acceptable values of pH and alkalinity under normal water flows. However,after periods of more intense water flushing, some of the filters showed a decreased capacity to neutralize the water. Inexpensive types of equipment, e.g. some of the filters placed inside the well, performed just as well as the more expensive types.
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    Mining the soil: Agricultural production system on peatland (1995)
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    Environmental and resource economics 6 (1995), S. 119-138 
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    ISSN: 1573-1502
    Keywords: Exhaustible resource ; peatland ; optimal control ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract Soil is usually considered as a renewable resource for dynamic crop and production management decision problems. For peatland, however, soil should be regarded as an exhaustible resource. This paper determines the optimal utilization of peatland for agricultural production within a dynamic context and it also presents an empirical study where the quasirent function is convex in the input and not concave as assumed in many economic studies. As a result of this convexity a corner solution is obtained. Moreover, the study demonstrates that there is only a slight difference between short- and farsighted behavior, and that both lead ultimately to an accelerated exhaustion of the resource. Private optimization leads to intensive use of the peat in the production of high value crops, which depletes the peat in a relatively short period of time. However, peatland also possesses a value as an environmental asset. The study provides a benchmark for the decision as to whether to convert peatland into productive agricultural land or to conserve it.
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    Optimization and maintenance of soluble methane monooxygenase activity inMethylosinus trichosporium OB3b (1994)
    Springer
    Biodegradation 5 (1994), S. 1-11 
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    ISSN: 1572-9729
    Keywords: Methylosinus trichosporium ; methanotroph ; trichloroethene ; methane monooxygenase ; maximization of enzyme activity ; groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soluble methane monooxygenase (sMMO) maximization studies were carried out as part of a larger effort directed towards the development and optimization of an aqueous phase, multistage, membrane bioreactor system for treatment of polluted groundwater. A modified version of the naphthalene oxidation assay was utilized to determine the effects of methane:oxygen ratio, nutrient supply, and supplementary carbon sources on maximizing and maintaining sMMO activity inMethylosinus trichosporium OB3b.Methylosinus trichosporium OB3b attained peak sMMO activity (275–300 nmol of naphthol formed h−1 mg of protein−1 at 25°C) in early stationary growth phase when grown in nitrate mineral salts (NMS) medium. With the onset of methane limitation however, sMMO activity rapidly declined. It was possible to define a simplified nitrate mineral salts (NMS) medium, containing nitrate, phosphate and a source of iron and magnesium, which allowed reasonably high growth rates (μmax 0.08 h−1) and growth yields (0.4–0.5 g cells/g CH4) and near maximal activities of sMMO. In long term batch culture incubations sMMO activity reached a stable plateau at approximately 45–50% of the initial peak level and this was maintained over several weeks. The addition of d-biotin, pyridoxine, and vitamin B12 (cyanocobalamin) increased the activity level of sMMO in actively growing methanotrophs by 25–75%. The addition of these growth factors to the simplified NMS medium was found to increase the plateau sMMO level in long term batch cultures up to 70% of the original peak activity.
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    Metabolic diversity of aromatic hydrocarbon-degrading bacteria from a petroleum-contaminated aquifer (1993)
    Springer
    Biodegradation 4 (1993), S. 249-259 
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    ISSN: 1572-9729
    Keywords: aromatic hydrocarbons ; biodegradation ; bioremediation ; denitrification ; groundwater ; Pseudomonas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We characterized bacteria from contaminated aquifers for their ability to utilize aromatic hydrocarbons under hypoxic (oxygen-limiting) conditions (initial dissolved oxygen concentration about 2 mg/l) with nitrate as an alternate electron acceptor. This is relevant to current intense efforts to establish favorable conditions forin situ bioremediation. Using samples of granular activated carbon slurries from an operating groundwater treatment system, we isolated bacteria that are able to use benzene, toluene, ethylbenzene, orp-xylene as their sole source of carbon under aerobic or hypoxic-denitrifying conditions. Direct isolation on solid medium incubated aerobically or hypoxically with the substrate supplied as vapor yielded 103 to 105 bacteria ml−1 of slurry supernatant, with numbers varying little with respect to isolation substrate or conditions. More than sixty bacterial isolates that varied in colony morphology were purified and characterized according to substrate utilization profiles and growth condition (i.e., aerobic vs. hypoxic) specificity. Strains with distinct characteristics were obtained using benzene compared with those isolated on toluene or ethylbenzene. In general, isolates obtained from direct selection on benzene minimal medium grew well under aerobic conditions but poorly under hypoxic conditions, whereas many ethylbenzene isolates grew well under both incubation conditions. We conclude that the conditions of isolation, rather than the substrate used, will influence the apparent characteristic substrate utilization range of the isolates obtained. Also, using an enrichment culture technique, we isolated a strain ofPseudomonas fluorescens, designated CFS215, which exhibited nitrate dependent degradation of aromatic hydrocarbons under hypoxic conditions.
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    The tradition of groundwater irrigation in Northwestern India (1993)
    Springer
    Human ecology 21 (1993), S. 51-86 
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    ISSN: 1572-9915
    Keywords: groundwater ; irrigation ; Rajasthan ; Aquifer Recharge ; complexity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Ethnic Sciences
    Notes: Abstract Ethnographic research in the central Aravalli Hills of Rajasthan documents a coherent system of groundwater irrigation distinctively different from the system of dams, wiers, and perennial canals redesigned for India by the British during the early nineteenth century and continued by contemporary Indian governments. This paper articulates these indigenous principles and practices and contrasts them with those found in the scholarly literature on irrigation in Rajasthan which follows modern engineering concerns. Our analysis indicates a difference set of questions to guide future research on surface impoundments and groundwater management. Furthermore, this study has broader implications for an understanding of the human-shaped hydrology of northwestern India, where the earlier system has been overlaid, but not fully displaced by subsequent irrigation projects. Indeed, indigenous practices involving groundwater recharge and retrieval may have continued to flourish and expand, achieving a new order of hydrologic and adaptive complexity, through the local initiative of the peasantry to adapt to the unintended spillage, soakage, and siltage from the grand system of dams and perennial canals constructed by the state.
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    Aboveground nitrogen and phosphorus use by five plantation-grown trees with different leaf longevities (1991)
    Springer
    Biodegradation 14 (1991), S. 167-191 
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    ISSN: 1572-9729
    Keywords: leaf longevity ; nitrogen ; nutrient use efficiency ; phosphorus ; requirement ; retranslocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Aboveground nitrogen (N) and phosphorus (P) requirement, retranslocation and use efficiency were determined for 28-year-old red oak (Quercus rubra L.), European larch (Larix decidua Miller), white pine (Pinus strobes L.), red pine (Pinus resinosa Ait.) and Norway spruce (Picea abies (L) Karst.) plantations on a similar soil in southwestern Wisconsin. Annual aboveground N and P requirements (kg/ha/yr) totaled 126 and 13 for red oak, 86 and 9 for European larch, 80 and 9 for white pine, 38 and 6 for red pine, and 81 and 13 for Norway spruce, respectively. Nitrogen and P retranslocation from current foliage ranged from 81 and 72%, respectively, for European larch, whereas red pine retranslocated the smallest amount of N (13%) and Norway spruce retranslocated the smallest amount of P (18%). In three evergreen species, uptake accounted for 72 to 74% of annual N requirement whereas for two deciduous species retranslocation accounted for 76 to 77% of the annual N requirement. Nitrogen and P use (ANPP/uptake) was more efficient in deciduous species than evergreen species. The results from this common garden experiment demonstrate that differences in N and P cycling among species may result from intrinsic characteristics (e.g. leaf longevity) rather than environmental conditions.
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    Groundwater contribution to the nutrient budget of Tomales Bay, California (1990)
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    Biodegradation 10 (1990), S. 199-216 
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    ISSN: 1572-9729
    Keywords: coastal water quality ; groundwater ; land-sea interface ; nutrient cycling ; Tomales Bay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tomales Bay, a graben structure along the San Andreas Fault, was selected for modeling ecosystem nutrient dynamics because of its linear, one-dimensional morphology and relatively pristine state. Groundwater is a potentially important term in the nutrient budget. The geologic complexities created by the San Anreas Fault, however, complicate the hydrogeology and require the area to be subdivided into three regions: granite to the west, Franciscan Formation to the east, and alluvial fill in the trough. Nutrient concentrations in the groundwater were determined through extensive well sampling; groundwater discharge was estimated using both Darcy's Law calculations and a soil moisture budget. Results indicate that groundwater discharge is of the same order of magnitude as summer streamflow into the Bay, while being significantly less than other freshwater inputs in winter. Dissolved nutrient (phosphate, nitrate + nitrite, ammonium, silica and DIC) concentrations in groundwater were consistently higher (by as much as an order of magnitude) than in surface water discharges. During the summer months, groundwater flow contributes about as much nutrient load to the bay as does streamflow. During the winter, the groundwater contribution to nutrient loading is about 20% of the streamflow contribution. Our findings indicate that groundwater is a significant component of terrestrial nutrient and freshwater loading to Tomales Bay, particularly so during the summer months. However, neither groundwater nor streamflow nutrient fluxes are large in comparison to the mixing flux at the bay mouth or the flux of N2 gas across the air-water interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003144
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    The influence of tidal marshes on upland groundwater discharge to estuaries (1990)
    Springer
    Biodegradation 10 (1990), S. 217-236 
    Details
    ISSN: 1572-9729
    Keywords: groundwater ; hydrology ; pore water chemistry ; salt marshes ; solute transport ; tidal freshwater marshes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We investigated subsurface hydrology in two fringing tidal marshes and in underlying aquifers in the coastal plain of Virginia. Vertical distributions of hydraulic conductivity, hydraulic head and salinity were measured in each marsh and a nearby subtidal sediment. Discharge of hillslope groundwater into the base of the marshes and subtidal sediment was calculated using Darcy's law. In the marshes, fluxes of pore water across the sediment surface were measured or estimated by water balance methods. The vertical distribution of salt in shoreline sediments was modeled to assess transport and mixing conditions at depth. Hydraulic gradients were upward beneath shoreline sediments; indicating that groundwater was passing through marsh and subtidal deposits before reaching the estuary. Calculated discharge (6 to 10 liters per meter of shoreline per day) was small relative to fluxes of pore water across the marsh surface at those sites; even where discharge was maximal (at the upland border) it was 10 to 50 times less than infiltration into marsh soils. Pore water turnover in our marshes was therefore dominated by exchange with estuarine surface water. In contrast, new interstitial water entering subtidal sediments appeared to be primarily groundwater, discharged from below. The presence of fringing tidal marshes delayed transport and increased mixing of groundwater and solute as it traveled towards the estuaries. Soil-contact times of discharged groundwater were up to 100% longer in marshes than in subtidal shoreline sediments. Measured and modeled salinity profiles indicated that, prior to export to estuaries, the solutes of groundwater, marsh pore water and estuarine surface water were more thoroughly mixed in marsh soils compared to subtidal shoreline sediments. These findings suggest that transport of reactive solutes in groundwater may be strongly influenced by shoreline type. Longer soil-contact times in marshes provide greater opportunity for immobilization of excess nutrients by plants, microbes and by adsorption on sediment. Also, the greater dispersive mixing of groundwater and pore water in marshes should lead to increased availability of labile, dissolved organic carbon at depth which could in turn enhance microbial activity and increase the rate of denitrification in situations where groundwater nitrate is high.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003145
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    Nitrogen inputs to a marine embayment: the importance of groundwater (1990)
    Springer
    Biodegradation 10 (1990), S. 309-328 
    Details
    ISSN: 1572-9729
    Keywords: estuaries ; groundwater ; nitrogen ; nitrogen cycle ; nitrogen loading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We examined the importance of nitrogen inputs from groundwater and runoff in a small coastal marine cove on Cape Cod, MA, USA. We evaluated groundwater inputs by three different methods: a water budget, assuming discharge equals recharge; direct measurements of discharge using bell jars; and a budget of water and salt at the mouth of the Cove over several tidal cycles. The lowest estimates were obtained by using a water budget and the highest estimates were obtained using a budget of water and salt at the Cove mouth. Overall there was more than a five fold difference in the freshwater inputs calculated by using these methods. Nitrogen in groundwater appears to be largely derived from on site septic systems. Average nitrate concentrations were highest in the region where building density was greatest. Nitrate in groundwater appeared to behave conservatively in sandy sediments where groundwater flow rates were high (〉 11/m2/h), indicating that denitrification was not substantially reducing external nitrogen loading to the Cove. Nitrogen inputs from groundwater were approximately 300 mmol-N/m3/y of Cove water. Road runoff contributed an additional 60 mmol/m3/y. Total nitrogen inputs from groundwater and road runoff to this cove were similar in magnitude to river dominated estuaries in urbanized areas in the United States.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003150
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    Identification of brain tumours in rats using laser-induced fluorescence and haematoporphyrin derivative (1989)
    Springer
    Lasers in medical science 4 (1989), S. 241-249 
    Details
    ISSN: 1435-604X
    Keywords: Brain tumour ; Rat ; Detection ; Fluorescence ; Laser ; Haematoporphyrin derivative
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Laser-induced fluorescence has been used for the identification of brain tumours in rats, which have been previously given tumour-seeking haematoporphyrin derivative. A pulsed nitrogen laser (λ=337 nm) was used in conjunction with an optical multichannel analyzer. For both inoculated RG-2 and TCVC rat-brain-tumour models, the blue autofluorescence was strongly reduced in the tumour compared with normal brain tissue, and at the same time the characteristic red-drug signal increased. The contrast between tumour and normal tissue was strongly enhanced by forming the ratio between the two signals. Implications for possible improvement of tumour delineation in brain tumour surgery are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02032454
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    Co-kriging for stochastic flow models (1989)
    Springer
    Transport in porous media 4 (1989), S. 585-598 
    Details
    ISSN: 1573-1634
    Keywords: Geostatistics ; kriging ; groundwater ; inverse problem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Co-kriging equations for log-transmissivity and heads are derived for a two-dimensional stochastic model. The behavior of the weights as a function of the unknown value of mean hydraulic gradient J are discussed and the procedure is illustrated by studying the ‘screening’ effects of adjacent measurements and added head measurements. In addition, the bias of the estimator for head values is studied when J is also estimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223629
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    Micro-scale modelling in the study of plume evolution in heterogeneous media (1987)
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 263-279 
    Details
    ISSN: 1436-3259
    Keywords: Porous media ; heterogeneity ; groundwater ; dispersion ; stochastic theory ; plume evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The migration of contaminants in heterogeneous aquifers involves dispersive processes that act at different scales. The interaction of these processes as a plume evolves can be studied by micro-scale modelling whereby two scales, a local- or micro-scale and an aquifer- or macro-scale, are covered simultaneously. Local-scale dispersive processes are represented through the local dispersion coefficient in the transport equation, while large-scale dispersion due to heterogeneities is represented through the resolution of the flow field and the diffusive exchange between streamtubes. The micro-scale model provides both the high degree of resolution compatible with local-scale processes, and the extent required for the approach to asymptotic conditions, using grids of up to a million nodal points. The model is based on the dual potential-streamfunction formulation for flow, and the transport problem is formulated in a natural coordinate system provided by the flownet. Simulations can be used to verify stochastic theories of dispersion, without the restrictive assumptions inherent in the theory. For the two-dimensional case, results indicate convergence of the effective dispersivity to the theoretical macrodispersivity value. Convergence takes place within a travel distance of about 50 correlation lengths of the hydraulic conductivity field. However, the approach taken to asymptotic conditions, as well as the macrodispersivity value, may differ for different realizations of the same medium. The influence of early-time events such as plume splitting on the asymptotic convergence remains to be investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543098
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    Solutions for steady groundwater flow in multi-layer aquifer systems (1986)
    Springer
    Transport in porous media 1 (1986), S. 419-429 
    Details
    ISSN: 1573-1634
    Keywords: Aquifers ; computation ; groundwater ; irrigation ; layered aquifer systems ; mathematics ; matrices ; seepage ; water resources ; wells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract A method is shown that enables closed-form solutions to be calculated for steady flow in leaky multi-layer aquifer systems. The method requires, as a prerequisite, the numerical solution of a generalized eigenvalue problem. This eigenvalue problem always has real positive eigenvalues, and the eigenvectors are always orthogonal relative to the transmissivity matrix. Partial solutions are given for a number of examples, and a numerical example is used to show how a solution can be obtained for flow to a well when the well abstracts water from more than one aquifer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00208046
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    The anthropic catchment-ecosystem concept: An Irish example (1985)
    Springer
    Human ecology 13 (1985), S. 209-240 
    Details
    ISSN: 1572-9915
    Keywords: catchment-ecosystem ; nutrient-budget ; anthropogenic inputs ; nitrogen ; phosphorus ; eutrophication ; agricultural policies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Ethnic Sciences
    Notes: Abstract The catchment-ecosystem concept is adapted to investigate the nutrient-budget of the highly-modified Colebrooke drainage basin in Northern Ireland. Anthropogenic inputs, mainly manures and fertilizers, account for 86% of the nitrogen and 96% of the phosphorus added to the catchment. These inputs greatly exceed the streamflow outputs, thereby indicating that the flow of nutrients is dominated by agriculture. This is explained by the transformation of traditional mixed farming into more intensive livestock production and is linked to policies encouraging increased agricultural production, amalgamation of farms, afforestation, rural depopulation, and urbanization. Substantial increases in the Nand Poutput of the catchment and further eutrophication of the recipient lake, Lough Erne, are predicted without the implementation of policies to reduce agricultural nutrient losses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01531096
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    Animals as indicators of ecosystem responses to air emissions (1984)
    Springer
    Environmental management 8 (1984), S. 309-324 
    Details
    ISSN: 1432-1009
    Keywords: Animals ; Indicators ; Air pollution ; Ecosystem responses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract With existing and proposed air-quality regulations, ecological disasters resulting from air emissions such as those observed at Copperhill, Tennessee, and Sudbury, Ontario, are unlikely. Current air-quality standards, however, may not protect ecosystems from subacute and chronic exposure to air emissions. The encouragement of the use of coal for energy production and the development of the fossil-fuel industries, including oil shales, tar sands, and coal liquification, point to an increase and spread of fossil-fuel emissions and the potential to influence a number of natural ecosystems. This paper reviews the reported responses of ecosystems to air-borne pollutants and discusses the use of animals as indicators of ecosystem responses to these pollutants. Animal species and populations can act as important indicators of biotic and abiotic responses of aquatic and terrestrial ecosystems. These responses can indicate long-term trends in ecosystem health and productivity, chemical cycling, genetics, and regulation. For short-term trends, fish and wildlife also serve as monitors of changes in community structure, signaling food-web contamination, as well as providing a measure of ecosystem vitality. Information is presented to show not only the importance of animals as indicators of ecosystem responses to air-quality degradation, but also their value as air-pollution indices, that is, as air-quality-related values (AQRV), required in current air-pollution regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868030
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