ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (3)
  • Blackwell Publishing Ltd  (3)
  • Dordrecht [u.a.] : Springer Netherlands
  • Society for Sedimentary Geology (SEPM)
  • Energy, Environment Protection, Nuclear Power Engineering  (3)
Collection
  • Articles  (3)
Source
Publisher
Years
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Effects of Sample Isolation and Handling on the Recovery of Purgeable Organic Compounds (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Ground water monitoring & remediation 14 (1994), S. 0 
    Details
    ISSN: 1745-6592
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: This report compares the recovery of purgeable organic compounds (POCs) obtained by using a downhole isobaric sampler developed by the U.S. Geological Survey, a helical-rotor submersible pump, and a point source bailer to collect and isolate samples of ground water from three wells in Now York and New Jersey: the samples contained a total of 13 PCX's delectable at concentrations ranging from 0.5 μg/L to about 400 μg/L. This report also compares the effects of sample handling, specifically the differences in PCX concentration recovery when an isobaric sample container is filled at land surface vs. when it is filled downhole. and when samples art taken using a bailer with and without a bottom-emptying device. These case studies are used to quantify the possible effects of different sample-isolation find sample-handling techniques on POC recovery.The relative effectiveness of the three devices varied by site and by compound. Overall, the POC recoveries achieved by using the helical-rotor submersible pump and the downlink isobaric sampler were not significantly different at the 95 percent confidence, level. POC recovery obtained by using the point source bailer was 11 percent lower overall. The downhole isobaric sampler results exhibited smaller coefficients of variation than did the helical-rotor submersible pump or the point-source bailer results. However, the differences between the coefficients of variation of the downhole isobaric sampler and those of the helical-rotor submersible pump were not significant at the 95 percent confidence level. The nonsignificant smaller coefficient of variation of the downhole isobaric sampler apparently resulted from two fewer sample handling steps that exposed the sample water to ambient air. An independent experiment performed with a different downhole sampler at one of the wells used in this investigation produced a similar statistical result. Also, the POC recovery obtained by pouring sample water out the lop of a point source bailer into 40-mL vials was S percent lower than that obtained by filling vials from a bailer with a bottom-emptying device.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-6592.1994.tb00109.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Estimating Rainfall Recharge and Soil Water Residence Times in Pukekohe, New Zealand, by Combining Geophysical, Chemical, and Isotopic Methods (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 37 (1999), S. 0 
    Details
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: The combined use of geophysical (time domain reflectometry [TDR]), isotopic (δ18 O and δ2H) and chemical (NO 3 -N, Cl) techniques indicates that residence times in the unsaturated zone of a fractured basalt aquifer in the Pukekohe region of the North Island, New Zealand, are at least six months. Each technique provides useful information on specific aspects of recharge and residence times, but combined they provide a basis for determining the mechanisms of water movement in the unsaturated zone. TDR soil moisture measurements provide similar rainfall recharge estimates as model calculations over longer time periods (monthly or seasonal) but may be more accurate for shorter time scales (weekly or daily).The TDR measurements indicate that recharge occurs mainly in the late autumn and winter months. Measurements of nitrate concentrations in the soil profile over this same period, suggest that nitrate is mineralized in the soil during the summer and is flushed past the root zone at the beginning of the recharge period, in early winter. Nitrate concentrations in the soil profile do not increase in concentration later in the recharge period, even after significant recharge events have occurred, because all stored nitrate has already been released. This pattern of nitrate movement indicates that fertilizer applications in spring and early summer will leach less to ground water and applications made in autumn and winter will leach more. Estimations of yearly recharge from mean monthly chloride concentrations (730 mm/yr) are roughly in agreement with the TDR estimates (680 mm/year). However, there is a large range in the chloride estimates (〉100%) because monthly chloride concentration measurements in both the rain and soil water vary due to the proximity of the site to the ocean.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-6584.1999.tb01182.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Comparison of Downhole and Surface Sampling for the Determination of Volatile Organic Compounds (VOCs) in Ground Water (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Ground water monitoring & remediation 12 (1992), S. 0 
    Details
    ISSN: 1745-6592
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: The relative precision and accuracy of sampling and analysis methods for the determination of trace concentrations of volatile organic compounds (VOCs) in ground water were compared. Samples were collected from a well containing nanogram-per-liter (ng/L) to microgram-per-liter (μg/L) levels of VOCs. A Keck helical rotor submersible pump was used to collect samples at the surface for analysis by purge and trap (P&T) and for analysis by adsorption/thermal desorption (ATD). Downhole samples were collected by passing water through an ATD cartridge. Although slight spontaneous bubble outgassing occurred when the water was brought to the surface, the relative precisions and comparabilities of the surface and downhole methods were generally found to be equivalent from a statistical point of view. A main conclusion of this study is that bringing sample water to the surface for placement in VOC vials (and subsequent analysis by P&T) can be done reliably under many circumstances. However, care must still be taken to prevent adsorption losses and cross contamination. Samples subject to strong bubble outgassing will need to be handled in a special fashion (e.g., by downhole ATD) to minimize volatilization losses. Additionally, the higher sensitivity of the ATD method allows lower detection limits than are possible with P&T. For example, several compounds present at the ng/L level could be determined with confidence by ATD, but not by P&T.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-6592.1992.tb00418.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...