ALBERT

Notes: The flow of ground water in flat-lying sedimentary rocks of the Appalachian Plateau is significantly influenced by the vertical and horizontal distribution of vertical joints and horizontal bedding plane fractures. Although considerable published data document the geographic distribution of joints in outcrops in this region, few data have been published on the vertical distribution of joints and on the vertical and horizontal distribution of bedding plane fractures.The vertical and horizontal distribution of bedding plane fractures at a site located in central New York was investigated by examination of borehole geophysical logs, continuous rock cores from boreholes drilled to a maximum depth of 175 feet, and rock outcrops. This investigation reveals that three zones of bedding plane fractures can be delineated based on the vertical distribution of horizontal fractures, and that the spacing between these horizontal fractures increases with depth. The occurrence of vertical joints is not noticeably influenced by depth. Because bedrock at this site consists of several hundred feet of relatively homogeneous, thin-bedded, fractured siltstone (the Genesee Formation) having essentially no visible microscopic intergranular porosity, ground water flows exclusively through fractures. Caliper, density, temperature, and neutron logs indicate that submillimeter-wide fractures serve as conduits that transmit ground water. Slug test data reveal that shallower wells exhibit hydraulic conductivities 10 to 100 times greater than those of deeper wells, confirming that increased (wider) fracture spacing at depth results in a lower permeability.Because the spacing of horizontal fractures increases with depth, ground water flow in shallow bedrock is expected to be very different than that in deeper bedrock. Because both vertical joints and horizontal bedding plane fractures are conduits in shallow bedrock, flow might approximate equivalent porous media conditions. However, flow in deeper bedrock might approach fracture flow because bedding plane fractures are sparse and the principal conduits are only vertical joints. These differences can have important implications for modeling ground water flow.

Notes: Non-aqueous phase liquids (NAPLs), such as chlorinated solvents and petroleum products, are present in the subsurface at numerous contamination sites in North America. Determination of NAPL presence should be an early investigation goal to guide site characterization and control efforts. Indirect methods for assessing NAPL presence rely on comparing measured chemical concentrations to effective solubility limits for ground water and to calculated equilibrium partitioning concentrations for soil. Under ideal conditions, NAPL presence can be identified by visual examination of soil or ground water samples. Direct visual detection may be difficult, however, where the NAPL is clear and colorless, present at low saturation, or distributed heterogeneously. There appears to be little documentation of practical, simple methods for direct identification of NAPL in soil or water.For this study, a series of experiments was conducted to test the hypothesis that simple and inexpensive methods can be used to visually identify clear, colorless NAPL in soil and water samples. Specific methods evaluated include direct visual examination, ultraviolet (UV) fluorescence analysis, a soil-water shake test, adding hydrophobic dye to the shake test, and centrifugation. Additionally, the utility of organic vapor analysis was examined as an NAPL screening tool.Of the methods investigated, the hydrophobic dye methods, followed by UV fluorescence, offer the most simple, practical, and effective means for direct visual identification of clear, colorless NAPL in contaminated soil samples. These methods can be utilized in the field or in a lab with minimal time and material expense. For volatile NAPLs, analysis of organic vapors in soil sample headspace can be used to screen samples for further examination and, possibly, to infer NAPL presence. The NAPL in water experiments demonstrate that very small quantities of clear, colorless NAPL in water can be quickly identified by mixing in a tiny amount of hydrophobic dye.

Notes: Soil-pore water sampling by suction lysimeters monitors the fate of soil contaminants as a function of depth and time. However, sampling campaigns must be planned to most effectively monitor the migration of contaminants with a minimum expenditure of resources. The vertical migration of pesticides was studied at two sites treated with systemic s-triazine herbicides and equipped with suction lysimeters. The measured concentrations were compared with those calculated by a simulation model. This modeling was based on the processes that control the transport and fate of pesticide within the soil. The usefulness of such a tool was demonstrated by the good approximation obtained for pesticide concentrations and arrival times. Moreover, the significant spatial variability of concentrations observed justifies the use of a stochastic approach in modeling that takes into account the spatial variability of soil parameters. Also, the rapid transformation of herbicides observed in unsaturated soil zones demonstrates the importance of taking into account the sum of the toxic residues when evaluating the fate of s-triazines in soil.

Notes: The Water Sellers, by Geoffrey D. Wood and Richard Palmer-Jones. Published by Intermediate Technology PublicationsLand, Water and People. Geographical Essays in Australian Resource Management. Edited by R. L. Heathcote and J. A. Mabbutt.Plynlimon Research: The First Two Decades. Institute of Hydrology Report No. 109. Edited by C. Kirby, M. D. Newson and K. Gilman.The Treatment and Handling of Wastes. Edited by A. D. Bradshaw, Sir Richard Southwood and Sir Frederick Warner.Bioaccumulation in Aquatic Systems. Edited by R. Nagel and R. Loskill. Published by VCHLegionella and Building Services, by G. W. Brundrett. Published by Butterworth-Heinemann, Linacre HouseFrench Enterprise and the Challenge of the British Water Industry, by Mairi Maclean. Published by Avebury Academic Publishing GroupAnalytical Information for the Water Industry, by T. R. Crompton. Published by Butterworth-Heinemann Ltd

Notes: A laboratory lead-pipe rig has been used to support Anglian Water's successful orthophosphate dosing programme to reduce plumbosolvency. The hard waters in the region generally fall into low or high plumbosolvency categories according to the types of crystalline deposit formed. To improve the cost-effectiveness of plumbosolvency control, the effects of temperature, phosphate doses, blending and alternation of these waters were investigated.Initial phosphate concentrations must be above 0.6 mg P/l (as phosphorus) to establish plumbosolvency control. Subsequently, phosphate doses may be reduced, provided that dosing is continuous and sufficient phosphate reaches the extremities of the distribution system. When high and low plumbosolvency waters are blended before distribution, both (or the mixture) must be phosphate dosed. However, where waters alternate in distribution, laboratory studies have shown that low plumbosolvency deposits are more stable, resulting in low lead concentrations. The high plumbsolvency of some hard waters may be due to the presence of low concentrations of humic substances.

Notes: The first use of the Sirofloc process in an operational water-treatment works, outside Australia, was commissioned in 1988 by Yorkshire Water at Redmires, Sheffield. The plant represents a major advancement in the development of a new type of treatment process for drinking water.This paper describes the new treatment process and the method and reasons adopted in developing a full-scale plant. The first four months of operation are reviewed, with particular attention to the water quality produced and the performance of the plant. Further areas for development in improving the performance of the process are identified.

Notes: This paper describes the elements and some early results of a major national research programme which was initiated to address the continuing serious problem of the pollution of rivers by farm wastes. This has involved a national assessment of the extent of the problem, aimed at identifying ‘high-risk’areas in the UK. Biological assessment techniques have been developed on the basis of extensive surveys at sites in West Wales, which show potential for the rapid detection of water-quality problems caused by farm effluents. Detailed studies at selected sites have illustrated the variability in the ways that farming activities can affect the biology and chemistry of rivers. The development of tools, which provide the basis for decisions on acceptable levels of farming activity in accordance with environmental quality objectives, is discussed.

Notes: As part of several groundwater investigations of the Permo-Triassic Sandstone aquifers in north west England, a detailed measurement of piezometric heads and groundwater flow within observation boreholes was made which showed that vertical differences of groundwater heads persist within aquifers. A number of case histories of these studies are presented, which are used to consider the impact of head variations on typical groundwater level and groundwater quality measurements taken in observation boreholes, with a view to recommending design criteria for observation boreholes and groundwater monitoring programmes.

Notes: The EC bathing water Directive and the recent EC urban waste water treatment Directive have provided, and will continue to provide, a strong stimulus for the provision of environmental improvement through the upgrading of sewerage assets. The positive response by Lothian Regional Council to necessary improvements in the last fifteen years, and the proposed improvements in the next fifteen years, are reviewed against the background of financial constraints. It is suggested that parts of the urban waste water treatment Directive relating to estuarial and coastal discharges are not appropriate or necessary in the context of conditions in Lothian Region.

Notes: A recently introduced EC Directive requires that soils receiving sewage sludge should be sampled to a greater depth (250 mm) than previously.The Water Research Centre foresaw the difficulties that could arise for responsible Authorities if they were to cope with the extra workload and maintain the quality of sampling, and therefore it funded the development of an automatic sampler.This report traces the development of the sampler which was mounted on an all-terrain vehicle, and illustrates its suitability for the task by reporting one year's operating experiences. Work rates have been up to eight times those with hand sampling.A production machine from the first batch is also described.

Notes: Since 1 April 1990, the Electricity at Work Regulations 1989 have placed legal requirements on employers, employees and the self-employed to take precautions against the risk of death or injury from electricity in work activities. This paper (a) examines the requirements, (b) reports on an initiative by the Lee Valley Water Company, and (c) proposes a management strategy for an organization to comply with the legislation.

Notes: The use of automated equipment for monitoring water quality is a concept which has received considerable impetus since the Water Act 1989 was introduced. This paper reports on two initiatives by the National Rivers Authority to develop systems for use in their role as the guardians of the water environment. Portable systems have been developed for detection of episodic pollution events and instantaneous spot measurement of water quality.This paper outlines the principal activities of the development of the systems and their use.

Notes: The shortage of land together with heavy industrialization in Japan makes incineration, and its associated process of sludge melting, favoured methods for the disposal of sewage sludge. The technology used in Japan for thermal drying of sludge and sludge incineration is similar to that used in other industrialized countries. The sludge melting processes which are used in a few installations are unusual. Most of the ash or slag which is produced from the burning of sewage sludge is disposed of by landfill, although an increasing amount of ash and slag is being disposed of by incorporation into construction materials.

Notes: The EC Directive (91/271/EEC) concerning urban waste water treatment has far-reaching financial and technological implications for local authorities in Scotland which are responsible for sewerage. Increased capital consent limits and additional financial assistance from central government are essential if the requirements of the legislation are to be met.Although the Directive is welcomed in general terms, the sections of the legislation dealing with the identification of sensitive waters and the provision of primary treatment for coastal discharges to less sensitive waters are of limited environmental significance in Scotland.The elimination of sewage sludge disposal at sea will create severe difficulties for Scottish authorities as a high percentage of sewage sludge is currently disposed of at sea. Each of the main alternative disposal options presents environmental, financial and technical problems and, in the case of incineration, the certainty of widespread unpopularity with the public.

Notes: Coastal wetlands are an important natural resource, providing habitat for fish and wildlife, particularly many rare or endangered species. These wetlands also serve important functions for the treatment of urban runoff and effluent discharges, the dissipation of wave energy, and shore protection. The US Fish and Wildlife Service estimates that approximately 45 000 km2 of US wetlands have been destroyed in the past two centuries.The importance of wetlands in the ecosystem has only begun to be understood during the past two decades, and there has been a major legislative effort to preserve, protect, and enhance existing coastal wetlands. The productivity of tidal wetlands is related directly to the hydrologic characteristics of the system, and some considerations for the hydrologic design for the enhancement or construction of tidal wetlands are outlined. Recent attention has focused on the use of dredged spoil materials from harbours or shippping channels to restore historic tidal wetlands. The hydrologic design criteria are illustrated through a series of case studies in California.

Notes: The Environment White Paper entitled ‘This Common Inheritance’, published in September 1990, set out for the first time a comprehensive statement of the Government's environmental policies and its strategy for their implementation. It established a number of principles on which that strategy is based, the key one being that we have a duty to hand on our world in good order to future generations.Another principle is that we must only act on the best available scientific evidence, but if that evidence is inconclusive we must take precautionary action. In applying this principle, the Government is aware of the need to promote scientific research to ensure that the results are given wide and clear dissemination.Everyone is involved in protecting and improving the environment. Many businesses are already investigating ways of reducing damage to the environment that, in fact, make good commercial sense. Local authorities, voluntary groups and individuals can and do help.

Notes: Probabilistic risk analysis, based on the identification of failure modes, points to technical malfunctions and operator errors that can be direct causes of system failure. Yet component failures and operator errors are often rooted in management decisions and organizational factors. Extending the analysis to identify these factors allows more effective risk management strategies. It also permits a more realistic assessment of the overall failure probability. An implicit assumption that is often made in PRA is that, on the whole, the system has been designed according to specified norms and constructed as designed. Such an analysis tends to overemphasize scenarios in which the system fails because it is subjected to a much higher load than those for which it was designed. In this article, we find that, for the case of jacket-type offshore platforms, this class of scenarios contributes only about 5% of the failure probability. We link the PRA inputs to decisions and errors during the three phases of design, construction, and operation of platforms, and we assess the contribution of different types of error scenarios to the overall probability of platform failure. We compute the benefits of improving the design review, and we find that, given the costs involved, improving the review process is a more efficient way to increase system safety than reinforcing the structure.

Notes: This study integrates previous research methodologies to compare the risk perceptions and responses to risk messages of agency personnel and neighbors of Superfund sites in Michigan. The integration attempted and the focus on risk messages are shaped by a critical review of the social amplification conceptual framework. The study involved all four agency groups and three groups of site neighbors actively involved in Superfund planning across the state. The first part of the study utilized the psychometric techniques of hazard rating and hazard profiles that had not previously been used in studies involving stakeholders. While agency personnel responded similarly to experts in previous studies, the responses of individuals in the neighbor groups reflected experience with toxic sites and were dissimilar to previous ratings by the general public. The second part of the study consisted of a hypothetical toxic site scenario that focused on specific risk messages at different times in the site history. Results indicate that the difference in perception of risk occurs after the first testing at a site, and that dramatic differences arise between agency and resident groups regarding the credibility of information sources and the need for independent testing. A general lack of trust in the Superfund program was demonstrated by all groups. The results indicate that problems of institutional credibility and program adequacy cannot be addressed by better risk comunication.

Notes: This paper reports on an experiment to test the hypothesis that people respond better to risk communication that reflects more closely the conditions of their social and cultural lives. The experiment used the case of radon to determine whether technical or narrative forms of risk communication were more effective at drawing people's attention, imparting information, and modifying behavior. Two series of articles on radon were placed in the local newspapers of two Massachusetts communities. Homeowner attitudes, knowledge, and responses were monitored in baseline and follow-up telephone surveys. A third community was selected for comparison. The newspaper series were developed on the basis of previous research and six focus groups conducted with homeowners. The technical series presented authoritative, factual risk information, in the scientific style of the passive voice with generalized and impersonal language. The narrative series consisted of dramatized accounts of individuals making decisions about radon testing and mitigation, written in a more personal style. The findings from the focus groups confirm the results of previous studies, but the small size of the follow-up samples was a limiting factor in drawing definitive conclusions about the relative effectiveness of the two formats. The experiment demonstrates the difficulty of any risk communication effort on radon and underscores the need for good research design. The study illustrates the need for further research on the role of sociological and cultural factors in the public perception and response to risk.

Notes: To investigate the extent to which personal values and experiences among scientists might affect their assessment of risks from dioxin, radon, and environmental tobacco smoke (ETS), we conducted an experiment through a telephone survey of 1461 epidemiologists, toxicologists, physicians, and general scientists. Each participant was read a vignette designed to reflect the mainstream scientific thinking on one of the three substances. For half of the participants (group A) the substance was named. For the other half (group B), the substance was not named but was identified only as Substance X, Y, or Z. Knowing the name of the substance had little effect on the scientists’ evaluation of dioxin, although those who knew the substance to be dioxin were more likely to rate the substance as a serious environmental health hazard (51% vs. 42%, p= 0.062). For radon, those who knew the substance by name were significantly more likely to consider it an environmental health hazard than were those who knew it as substance Z (91% vs. 78%, p〈0.001). Participants who knew they were being asked about ETS rather than substance X were significantly more likely to consider the substance an environmental health hazard (88% vs. 66%, p〈0.001), to consider the substance a serious environmental health hazard (70% vs. 33%, p〈0.001), to believe that background exposure required public health intervention (85% vs. 41%,p〈0.001), and to believe that above-background exposure required public health intervention (90% vs. 74%, p〈0.001). These findings suggest that values and experiences may be influencing health risk assessments for these substances, and indicate the need for more study of this phenomenon.

Notes: The 1989 DC-10 crash at Sioux City, Iowa presented a rare instance in which a potential threat to safety was both (i) intensely publicized over a short period and (ii) also amenable to the unobtrusive measurement of the market reaction it evoked. As such, it allowed a useful case study of the extent and duration of behavior change caused by a frightening event. Using reservations data from travel agencies in five states, this paper estimates the short-term effects of the Sioux City crash on passenger willingness to fly the DC-10. The data suggest that, in the first few weeks after the crash, more than one third of travelers who would normally have booked DC-10 flights chose instead to fly other aircraft. Within 2 months of the disaster, however, DC-10 bookings rebounded to within 10% of the level that would have been expected had the Sioux City crash not occurred. At no time, apparently, did the airlines that operate DC-10s use their “yield-management” computer pricing systems unofficially to lower DC-10 fares relative to those on other types of plane.

Notes: Most public health risk assessments assume and combine a series of average, conservative, and worst-case values to derive a conservative point estimate of risk. This procedure has major limitations. This paper demonstrates a new methodology for extended uncertainty analyses in public health risk assessments using Monte Carlo techniques. The extended method begins as do some conventional methods—with the preparation of a spreadsheet to estimate exposure and risk. This method, however, continues by modeling key inputs as random variables described by probability density functions (PDFs). Overall, the technique provides a quantitative way to estimate the probability distributions for exposure and health risks within the validity of the model used. As an example, this paper presents a simplified case study for children playing in soils contaminated with benzene and benzo(a)pyrene (BaP).

Notes: For risk assessments, the average current residence time (time since moving into current residence) has often been used as a surrogate for the average total residence time (time between moving into and out of a residence). Since the distributions of the two quantities are not necessarily the same, neither are their averages. Housing surveys provide current residence time data; total residence times must, therefore, be inferred. By modeling the moving process, the total residence time distribution can be estimated from current residence time data. Using 1985 and 1987 U.S. housing survey data, distributions and averages for both current and total residence times were calculated for several housing categories. The average total residence time calculated for all U.S. households, 4.6 (se= 0.6) years, is less than half the average current residence time, 10.6 (se= 0.1) years.

Notes: The regulation and management of hazardous industrial activities increasingly rely on formal expert judgment processes to provide wisdom in areas of science and technology where traditional “good science” is, in practice, unable to supply unambiguous “facts.” Expert judgment has always played a significant, if often unrecognized, role in analysis; however, recent trends are to make it formal, explicit, and documented so it can be identified and reviewed by others. We propose four categories of expert judgment and present three case studies which illustrate some of the pitfalls commonly encountered in its use. We conclude that there will be an expanding policy role for formal expert judgment and that the openness, transparency, and documentation that it requires have implications for enhanced public involvement in scientific and technical affairs.

Notes: In this paper we describe a simulation, by Monte Carlo methods, of the results of rodent carcinogenicity bioassays. Our aim is to study how the observed correlation between carcinogenic potency (β or ln2/TD50) and maximum tolerated dose (MTD) arises, and whether the existence of this correlation leads to an artificial correlation between carcinogenic potencies in rats and mice. The validity of the bioassay results depends upon, among other things, certain biases in the experimental design of the bioassays. These include selection of chemicals for bioassay and details of the experimental protocol, including dose levels. We use as variables in our simulation the following factors: (1) dose group size, (2) number of dose groups, (3) tumor rate in the control (zero-dose) group, (4) distribution of the MTD values of the group of chemicals as specified by the mean and standard deviation, (5) the degree of correlation between β and the MTD, as given by the standard deviation of the random error term in the linear regression of log β on log (1/MTD), and (6) an upper limit on the number of animals with tumors. Monte Carlo simulation can show whether the information present in the existing rodent bioassay database is sufficient to reject the validity of the proposed interspecies correlations at a given level of stringency. We hope that such analysis will be useful for future bioassay design, and more importantly, for discussion of the whole NCI/ NTP program.

Notes: We fit lognormal distributions to data collected in a national survey for both total water intake and tap water intake by children and adults for these age groups in years: 0 〈 age 〈 1; 1 ≤ age 〈 11; 11 ≤ age 〈 20; 20 ≤ age 〈 65; 65 ≤ age; and all people in the survey taken as a single group. These distributions are suitable for use in public health risk assessments.

Notes: The use of average qualitative concordance between two bioassay endpoints is considered, with emphasis directed at agreement between rats and mice from results of long-term carcinogenicity studies. It is noted that concordance varies as a function of the underlying potency or toxicity of the chemicals over which the averaging is performed. Thus, the averaging process dilutes large observed concordances from potent chemicals, and possibly inflates lower observed concordances from weakly active chemicals. Stratification over some measure of potency is suggested as a method for taking these effects into account. Statistical simulations of concordance analyses limited to low-potency ranges are employed to examine the concordance measure in greater detail. It is seen that at low potencies, observed concordance is consistently underestimated, reaching maximum levels of only about 80%.

Notes: Human populations are generally exposed simultaneously to a number of toxicants present in the environment, including complex mixtures of unknown and variable origin. While scientific methods for evaluating the potential carcinogenic risks of pure compounds are relatively well established, methods for assessing the risks of complex mixtures are somewhat less developed. This article provides a report of a recent workshop on carcinogenic mixtures sponsored by the Committee on Toxicology of the U.S. National Research Council, in which toxicological, epidemiological, and statistical approaches to carcinogenic risk assessment for mixtures were discussed. Complex mixtures, such as diesel emissions and tobacco smoke, have been shown to have carcinogenic potential. Bioassay-directed fractionation based on short-term screening tests for genotoxicity has also been used in identifying carcinogenic components of mixtures. Both toxicological and epidemiological studies have identified clear interactions between chemical carcinogens, including synergistic effects at moderate to high doses. To date, laboratory studies have demonstrated over 900 interactions involving nearly 200 chemical carcinogens. At lower doses, theoretical arguments suggest that risks may be near additive. Thus, additivity at low doses has been invoked as a working hypothesis by regulatory authorities in the absence of evidence to the contrary. Future studies of the joint effects of carcinogenic agents may serve to elucidate the mechanisms by which interactions occur at higher doses.

Notes: Estimates have been made of the cancer potency of aflatoxin exposure among the U.S. population. Risk modeling is used to assess the dose-response relationship between aflatoxin exposure and primary liver cancer, controlling for hepatitis B virus (HBV), based on data provided by the Yeh et al. study in China.(1) A relative risk model is proposed as a more appropriate alternative to the additive (“absolute” risk) model for transportation of risk coefficients between populations with different baseline rates. Several general relative risk models were examined; the exponential model provided the best fit. The Poisson regression method was used to fit the relative risk model to the grouped data. The effects of exposure to aflatoxin (AFB1) and hepatitis B infection were both found to be statistically significant. The risk of death from liver cancer for those exposed to AFB1 relative to the unexposed population, increases by 0.05% per ng/kg/day exposure of AFB1 (p〈0.001). The results also indicated a 25-fold increase in the risk of death from liver cancer among those infected with hepatitis B virus, relative to noncarriers (p〈0.0001). With a hepatitis prevalence rate of 1%, the aflatoxin intake level associated with liver cancer lifetime excess risk of 1 × 10−5 for the U.S. population was estimated as 253 ng/day, based on a liver cancer baseline rate of 3.4 /100,000/yr.

Notes: One of the challenges of introducing greater biological realism into stochastic models of cancer induction is to find a way to represent the homeostatic control of the normal cell population over its own size without complicating the analysis too much to obtain useful results. Current two-stage models of carcinogenesis typically ignore homeostatic control. Instead, a deterministic growth path is specified for the population of “normal” cells, while the population of “initiated” cells is assumed to grow randomly according to a birth-death process with random immigrations from the normal population. This paper introduces a simple model of homeostatically controlled cell division for mature tissues, in which the size of the nonmalignant population remains essentially constant over time. Growth of the nonmalignant cell population (normal and initiated cells) is restricted by allowing cells to divide only to fill the “openings” left by cells that die or differentiate, thus maintaining the constant size of the nonmalignant cell population. The fundamental technical insight from this model is that random walks, rather than birth-and-death processes, are the appropriate stochastic processes for describing the kinetics of the initiated cell population. Qualitative and analytic results are presented, drawn from the mathematical theories of random walks and diffusion processes, that describe the probability of spontaneous extinction and the size distribution of surviving initiated populations when the death/differentiation rates of normal and initiated cells are known. The constraint that the nonmalignant population size must remain approximately constant leads to much simpler analytic formulas and approximations, flowing directly from random walk theory, than in previous birth-death models. As in other stochastic models, our analysis implies that individual susceptibility to carcinogens affecting the second (malignant) transformation rate should follow an age-dependent frequency distribution in a population of initially identical individuals; hence, individual risks are heterogeneous even in the absence of individual differences in exposure patterns or pharmacokinetics. A theoretical formula is developed for the approximate frequency distribution of individual susceptibilities in a population exposed to a simple initiator/ delay/completor regimen.

Notes: Because of the inherent complexity of biological systems, there is often a choice between a number of apparently equally applicable physiologically based models to describe uptake and metabolism processes in toxicology or risk assessment. These models may fit the particular data sets of interest equally well, but may give quite different parameter estimates or predictions under different (extrapolated) conditions. Such competing models can be discriminated by a number of methods, including potential refutation by means of strategic experiments, and their ability to suitably incorporate all relevant physiological processes. For illustration, three currently used models for steady-state hepatic elimination—the venous equilibration model, the parallel tube model, and the distributed sinusoidal perfusion model—are reviewed and compared with particular reference to their application in the area of risk assessment. The ability of each of the models to describe and incorporate such physiological processes as protein binding, precursor-metabolite relations and hepatic zones of elimination, capillary recruitment, capillary heterogeneity, and intrahepatic shunting is discussed. Differences between the models in hepatic parameter estimation, extrapolation to different conditions, and interspecies scaling are discussed, and criteria for choosing one model over the others are presented. In this case, the distributed model provides the most general framework for describing physiological processes taking place in the liver, and has so far not been experimentally refuted, as have the other two models. These simpler models may, however, provide useful bounds on parameter estimates and on extrapolations and risk assessments.

Notes: Book reviewed in this article. Chemical Exposures: Low Levels and High Stakes By Nicholas A. Ashford and Claudia S. Miller Significance and Treatment of Volatile Organic Compounds in Water Supplies Edited by N. M. Ram, R. F. Christman, and K. P. Cantor Active and Passive Smoking Hazards in the Workplace By Judith A. Douville Uncertainty in Environmental Health Risk Assessment By Kenneth T. Bogen Practical Applications of Quantitative Structure-Activity Relationships (QSAR) in Environmental Chemistry and Toxicology Edited by W. Karcher and J. Devillers Boston Handbook of Environmental Fate and Exposure Data for Organic Chemicals, Vol II. Solvents Edited by Philip H. Howard What Happened? Diagnosing Unfamiliar Real-Life Situations By A.J.M. Groenewegen Occupational and Environmental Safety Engineering and Management By H.R. Kavianian and C.A. Wentz Health and Medical Aspects of Diaster Preparedness Edited by John C. Duffy Chemicals in the Human Food Chain Edited by Carl K. Winter, James N. Seiber, and Carole F. Nuckton Developmental Toxicology: Risk Assessment and the Future Edited by Ronald D. Hood

Notes: The paper attempts to review current and future practices in the UK against a European background.Sludge disposal has become a subject which is developing rapidly again and, since the presentation of this paper, there have been a number of developments, e.g. the adoption by the EC of its hazardous waste Directive in December 1991. Untreated sludge or sludge which is unsuitable for use in agriculture will be classified as a hazardous waste, subject to certain criteria. This makes the work on sludge classification even more crucial.

Notes: The creation and management of beaches using natural mobile materials can often provide a cost-effective and environmentally appropriate coastal defence. This paper summarizes recent practical endeavours in beach creation and management. Reference is made to the natural sources of beach building materials and to the numerical and physical models that may be employed to assist in the definition both of material transport paths and their magnitude. Risk analysis is noted to be a necessary part of the beach design process together with an appraisal of the coastal hydrodynamics and topographical constraints of the site of interest. The techniques that have been employed to recycle beach materials on some frontages are described, with comments on bypassing materials around obstructions. The paper describes the important considerations to be made when material is being imported to a beach, and notes some of the presently used techniques. Important points are drawn out for the future of beach creation and management, and a number of research needs and administrative difficulties are highlighted.

Notes: In 1988, water undertakers in England and Wales were charged with producing asset management plans as a prelude to privatization. These plans had to provide an auditable statement with respect to the condition and performance of underground assets, with a view to defining and setting priorities for investment requirements.Some water authorities were ill-prepared for producing the required formalized plans, resulting in variable confidence limits being placed on the identified investment requirements. A need existed to refine most plans, which was reinforced by a statutory requirement to update the asset management plans.This paper deals particularly with water distribution systems and provides an insight into the production of asset management plans. A brief review of the current approach used by a certain major water plc, to update and refine their plans, is also included. The contribution of asset management plans to the effective management of distribution network investment and operation in England and Wales should not be underestimated and is equally relevant in Scotland.

Notes: Lee Valley Water plc has, in a joint study with the University of Birmingham, been reassessing the reliable yields of its existing chalk sources in order to make maximum use of the available groundwater resources. An approach to yield assessment was developed which took into account the hydrogeology and flow processes in the vicinity of pumping stations, and within the contributing area. The yield of many sources was found to be very dependent on regional water level conditions. Initial estimates of potential yields were made but future monitoring should aim to clarify the interrelationship between source output and aquifer state.

Notes: Models are being used extensively to study the impact on the environment of a wide range of man-made influences. These include land-use change (e.g. afforestation), effluent discharges, flood-relief channels, reservoir developments, atmospheric pollution and the impacts of agrochemicals. In this paper several models are described which are being used by the Institute of Hydrology for environmental impact assessment. These models include MAGIC (Model of Acidification of Groundwater in Catchments), QUASAR (Quality Simulation Along Rivers) and a nitrogen simulation model for investigating the behaviour of nitrate in reservoirs.

Notes: As landfills become larger, the enormous quantities of putrescible wastes which they contain have increased the potential to generate highly polluting leachates as they decompose anaerobically over many years. If severe environmental impacts are to be avoided, operators must control these liquors: many landfill proposals stand or fall on the ability of the operator to demonstrate that leachate can be collected, managed and disposed of in an environmentally acceptable manner. During the early years of tipping in containment cells, high BOD and COD values (to 50 000 mg/l or more) are measured, with very high ammonia concentrations (to more than 1000 mg/l as N) persisting for many years.The authors have been involved with the full-scale on-site treatment of leachates to high standards in automated aerated lagoon plants since the early 1980s. The first plant was constructed in 1982, and a further seven have since been built at landfills throughout the UK, with many more at various stages of design and construction – both in the UK and overseas.This paper describes detailed operational experiences from several of these landfill sites, with particular emphasis on the reduction of ammonia concentrations to low values. The use of reed-bed treatment schemes as effluent polishing facilities is also discussed.

Notes: This paper outlines the engineering design philosophy for development sites affected by landfill gas. The hazards of landfill gas need to be fully understood and evaluated in relation to the location and type of building structure proposed, and a comprehensive assessment and design process should be undertaken. This involves interpretation of investigation and monitoring data, prediction of future trends, selection of appropriate design parameters, evaluation of gas-control measures, safety during construction, and long-term serviceability and monitoring.A description is given of the principal types of gas control measures which allow building development to take place on sites affected by landfill gas, and guidance is provided for the design of such measures. These measures include site encapsulation, gas-venting trenches and wells, gas-resistant membranes and barriers, natural ventilation to structures, and gas-detection and management systems.

Notes: A procedure for land-surface zoning, related to the protection of groundwater against both point and diffuse pollution, is described. The procedure is based upon two independent elements:(i) Division of the entire land surface on the basis of the aquifer pollution vulnerability, which relates to protection of groundwater resources; and(ii) A series of special protection areas for individual sources, in which various potentially polluting activities are either prohibited or strictly controlled.The procedure is hydrogeologically based, but not so complex as to be unworkable in practice. For resource protection three classes of formation type are defined, with a further subdivision on the basis of depth to saturated aquifer. In the case of diffuse pollution, it will also be necessary to consider the nature of the soil cover in the area where the polluting activity occurs. For source protection, up to four special protection areas are specified, and the criteria used to define them are discussed.

Notes: The deliberate formation of solid precipitates is a treatment process commonly used to remove undesirable ions from solution. Where the chemistry of the water to be treated is complex, a knowledge of the chemical species present, and their concentrations, can be an effective tool in evaluating the effectiveness of the treatment process and in optimizing reagent dosage and operator control. The use of chemical equilibrium speciation computer programs offers a relatively rapid method to determine the type and concentrations of chemical species present at equilibrium. Some sulphate-rich waters of significance to South Africa have been speciated using the MINTEQA2 computer program. The effects of treating these waters with barium carbonate have been evaluated. The computer predictions of treated water quality have been experimentally verified.

Notes: A major capital programme is being undertaken by Yorkshire Water to rebuild its water-treatment plants.Despite good process design, more stringent standards mean that process control, in particular chemical dosing, has become increasingly important.This paper describes the investigation of chemical dosing control using streaming current detection, which was initially applied at Langsett water-treatment works as a means of controlling the ferric sulphate dose in the clarification process.Following this successful application, further evaluation was carried out using streaming current detection to control the polyelectrolyte dose in the sludge thickening process.

Notes: The paper covers the design of improvements to a water distribution system serving a rural area to eliminate low chlorine residuals and to cater for large potential increases in demand from an agricultural estate. A model of the existing system was analysed at current and increased demands to identify weaknesses in the system. The model was altered by the addition of pumping mains, two storage reservoirs at new locations, and the strengthening of distribution mains to provide a solution to meet the client's requirements.The location and size of the proposed reservoirs were optimized with respect to the construction costs of the reservoirs, pumping and distribution pipelines, and pump running costs.Areas were zoned to provide better strategic storage, whilst also reducing retention times, thus eliminating the problems of low chlorine residuals.

Notes: Book Reviewed in this article:Prevention of Corrosion and Scaling in Water Supply Systems. by L. Legrand and P. Leroy. Published by Ellis Horwood LtdThe Law of Sewers and Drains (7th Edition), by J. F. Garner. Published by Shaw & Sons Ltd, Shaway HouseGround Water and Soil Contamination Remediation: Towards Compatible Science, Policy and Public Perception. Report on a colloquium sponsored by the Water Science and Technology Board. Published by National Academy PressGround Water Models: Scientific and Regulatory Applications. Committee on Ground Water Modelling Assessment, Water Science and Technology Board.

Notes: The serious pollution of groundwater under cities is demonstrated with data from Coventry (UK), Madras (India) and Birmingham (UK). Microbiological organisms, nitrates, and organic chemicals are common, but many other pollutants are also found. The main sources are industry and inadequate sewerage. The provision of sewerage must remain a priority, on health grounds, for cities in the developing world. Virtually all industrial sites pollute the soil and groundwater through careless handling of chemicals. Industrial sites should be treated like landfills: contained and carefully monitored. If industrialists had to use groundwater from below their own sites, they would suffer the consequences of any pollution. This would also clean up the aquifer by pumping out polluted water.

Notes: The Badenoch Group of Experts on Cryptosporidium recommended that a survey should be made of river and borehole sources to assess the incidence of oocysts. This paper presents the results of a national survey of three river stretches and six boreholes carried out between January 1990 and March 1991. A total of 1754 samples were analysed and 266 (15%) of these were subjected to independent checks in reference laboratories. The results show a low incidence of oocysts in the sources (range 0–4 oocysts/1). One river stretch gave consistent positive results but with low concentrations (range 0.04–3 oocysts/1, n = 318). Parallel epidemiological studies showed a low incidence of cases in the community, none of which could be related specifically to water supplies. The concentrations of oocysts found are generally lower than those found in studies in the US particularly in comparison with published results for large industrialized rivers.

Notes: The approach to the investigation of contamination is similar in both Europe and North America. However, the assessment of the resultant data can and does vary significantly. This paper seeks to address the concepts employed in contamination assessment in the UK, mainland Europe, Canada and the US. Details are presented of the relevant legislation in each country and the governmental guidance which is issued. Comparisons are made of the approach to the assessment and remediation that would be adopted for sites with identified levels of chemical contamination. The paper also looks forward and expresses views on how the approaches may progress over the next five years.

Notes: The sewage from the Greater Athens area is discharged without treatment to the nearby Saronicos Gulf. Recently the Greek government decided to implement an appropriate treatment and disposal scheme, on the basis of a study of the hydrodynamic behaviour of the Gulf and the fate of the discharged pollutants. The study was conducted with the aid of suitable hydrodynamic and water quality models for a number of alternative treatment schemes, ranging from primary treatment to biological treatment with seasonal nitrogen removal, combined with outfalls of different lengths. The results indicate that, although none of the examined schemes will lead to an immediate substantial impact, the scheme that includes biological treatment with seasonal nitrogen removal can eliminate the danger of serious ecological disturbances at a reasonable cost.

Notes: The design parameters for the City of Copenhagen sewage-treatment works were established on an experimental basis, and parallel studies of six pilot plants were made over a two-year period. The key parameters are (a) the rate of nitrification and denitrification, (b) temperature, and (c) BOD: N ratio in the influent. The data obtained from different methods had to be normalized with respect to the fraction of nitrifiers, temperature, and concentrations of substrates in order to achieve consistent results. The results indicated a substantial inhibition of the nitrifiers, i.e. a 20–30% reduction of the reaction rate. Significant savings were made possible by a comprehensive analysis of the temperature conditions.

Notes: The internationalization of the European market means that the new technologies used in the Belgian water supply sector are very similar to those used in other European countries. Belgian experience of the following new technologies is described in this paper: denitrification, automation, remote reading of water meters, network cartography, directional drilling, leak detection, and experiments with new materials and equipment.

Notes: The EC Directive on urban wastewater treatment will have a considerable impact on the methods used for the treatment and disposal of sewage at coastal locations. The Directive requires the natural processes involved in marine treatment to be enhanced by the use of land-based treatment to meet the same standards.This paper discusses the implications of this change, in particular the problems involved in constructing and operating conventional treatment plants at coastal locations. Planning problems, both locally and on a catchment basis, are considered. It is concluded that these difficulties point to a need for new thinking in catchment planning and in the design and construction methods used for treating wastewaters in coastal communities. This is illustrated with UK and continental examples.In addition, the implications in terms of outfall design are discussed. It is shown that the change of emphasis towards land-based treatment does not necessarily reduce the need for a high degree of dilution and dispersion in the sea in order to meet environmental standards. As a result, sound planning, design and operation of long sea outfalls remain as important as ever.

Notes: A detailed investigation of contamination by chlorinated solvents of the Chalk Aquifer underlying the towns of Luton and Dunstable was undertaken to assess the extent, causes and mechanisms of pollution. The research programme incorporated land-use surveys, regional groundwater surveys, monitoring of groundwater abstraction points and aquifer profiling by means of the drilling of observation boreholes, the analysis of the recovered core material and the depth sampling of these and other boreholes.Low-level solvent contamination of the Chalk Aquifer was found to be widespread with ‘hotspots’of higher concentrations. At the drilling sites, both the saturated and unsaturated zones were contaminated with solvents, although free product was not observed. The presence of an additional contaminant, oil, at some sites was noted to influence the distribution of solvents within the aquifer.Clean-up of the aquifer is not a practical option, and treatment of the groundwater at the abstraction points has been adopted.

Notes: New holistic approaches to environmental management by local authorities are described. Two kinds of audit, the state of the environment report and the internal audit, are defined. State of the environment reports are assessments of the condition of the local environment, generally based on existing data. They provide information about the environment to the general public and enable councils to determine environmental strategy priorities. They are giving local authorities a new environmental stewardship function. An internal audit is an assessment not only of the authority's impacts as a producer but of its environmental interactions as a regulator, influencer and manager of the environment. For some councils, auditing is becoming a continuous process through which environmental factors can be taken into account as a routine part of policy making and implementation.Both kinds of audit are changing the relationships of local authorities, reducing internal departmentalism and leading to wider consultation and partnership with local communities.

Notes: In 1990, the health hazards associated with cyanobacteria attracted widespread interest. In this study, the risks associated with dinghy sailing on two water reservoirs in Avon were examined when the National Rivers Authority concentration threshold for ‘a potential to cause harm’was exceeded at one of these sites. No unusual illnesses were identified and the patterns of reported minor health symptoms were similar at each site. These patterns were also similar to those found amongst freshwater dinghy sailors in Hampshire when the NRA cyanobacteria threshold was exceeded, and similar to patterns of minor morbidity identified amongst dinghy sailors in marine waters when the EC bathing water quality standards are met. The consistency of these findings from three different studies suggests that present Royal Yachting Association guidelines for dinghy sailors are adequate to safeguard their health from cyanobacteria exposure.

Notes: The report describes visits made as part of a mission to Japan which included, under the IWEM/JSWA Technology Exchange Programme, a Technical Workshop on sewage sludge technology held in Tokyo on 11–18 November 1991.

Notes: The greatest threat of contamination to groundwater resources is posed by pollutants from diffuse sources, yet legislation in the UK has until recently been focused on point sources. The problem of widespread pollution from industrial sources is described and compared with that from agriculture. The legislative controls available under the Water Resources Act 1991 are outlined, and the approach adopted by the National Rivers Authority in its Groundwater Protection Policy is discussed with respect to the concept of groundwater vulnerability.

Notes: This paper describes a system for supplying hot water for a small community by utilizing the waste heat generated during the incineration of sludge at a site on Rokko Island, which is a new artificial island built inside the port of Kobe, Japan.The system was designed to use the heat from the hot water, produced during the cleansing of exhaust gases in the scrubber system of the sludge incineration plant, by recycling it via a heat exchanger in order to supply the occupants of neighbouring apartment complexes with clean hot water. The system has been in operation since 1988. On a yearly average the water supplied is 20° hotter than normal tap water, helping to reduce considerably the use of city gas.

Notes: There is an increasing need for engineered liners to prevent the escape of leachate and to control the migration of landfill gas. This has been influenced by new European and UK legislation and codes of practice.General principles of site design are explained, followed by a review of the advantages and disadvantages of different liner systems, including mineral liners (natural clay, mudrocks and soil/bentonite admixtures), geomembranes and composite liners.The need for conservative factors of safety in site design and high standards of quality control, involving full-time supervision and independent certification of the installation works, are considered essential to ensure the effectiveness of the barrier.There is no one ideal liner material. Composite mineral/geomembrane liners provide the highest degree of security against leakage and, as such, should be considered as ‘the norm’rather than for use only in particularly high-risk situations.

Notes: A study of two major environmental issues in upland water management is presented. Discolouration and reservoir sedimentation are seen to affect water managers on different timescales and to different degrees. Rates of reservoir sedimentation, adjusted for empirically derived trap efficiency, are measured and found to be higher than previously believed. A link between sediments found within the reservoir basin and the generation of colour is described.

Notes: In spite of many aquifers still being in good condition, groundwater pollution is becoming a serious problem in some areas of continental and insular Spain, although it is not always recognized. Irrigated agriculture is an important source of pollutants, but industrial, mining and urban-related problems also exist. These go in parallel with serious salinity problems of diverse origin. The degree of knowledge with regard to these problems is still poor, and in many instances low priority is given to studies, prevention, control and remedial action. Water quantity aspects still receive most of the attention and economic resources. A new Water Act includes provisions for dealing with groundwater quality and pollution; they seem adequate to cope with existing problems, but their effectiveness, feasibility and willingness to be applied is still uncertain. The success not only depends on scientific and technical issues, but mainly in achieving an administration and management structure capable of coping with real problems and able to obtain the trust and cooperation of water users.

Notes: This paper considers the scientific basis of epidemiological research into marine bathing water quality in the UK, and places it in the context of policy development for the water industry and regulatory agencies in Europe. Results of the latest UK studies employing internationally recognized methods are reviewed, together with the output of other studies including those based on the use of healthy adult volunteers. It is concluded that methods based on captive volunteer populations may have merit in inland waters used by defined groups of recreational users. However, there is no epidemiologically defensible way of linking the output of such methods to the results of more conventional techniques for assessing risks in marine recreational waters. This observation may have implications for the formulation of new standards for bathing water quality in Europe.

Notes: Traditionally, the control of discharges to UK surface waters has been achieved using a chemical-specific approach. There are, however, benefits in also applying toxicity-based consents to effluents of complex composition.This paper describes the approach to direct toxicity assessment of discharges being developed by the Water Research Centre for and with, the National Rivers Authority.

Notes: In Germany there is much legislation to guarantee adequate protection of groundwater quality and quantity. The main objective of the legislation is to maintain the natural high quality of groundwater. The most important Act in this context is the Water Resources Policy Act.One aspect of German groundwater protection is the possibility to delineate up to four wellhead protection zones in the recharge area of a drinking-water well. The time-distance integrated protection zone concept, with bans and limitations on use increasing towards the well, was developed in the 1930s. It has guaranteed for decades a safe drinking water supply from the point of view of quality. However, recent scientific investigations have shown gaps especially with regard to (a) the importance of the 50-days line, (b) the behaviour of micro-organisms and (c) the mobility and persistence of man-made pollutants.

Notes: Even though groundwater resources in Finland are adequate, and theoretically the total water consumption could be supplied from this source, in practice only about 50% of the total consumption is from groundwater. There are thousands of unconnected small aquifers dispersed all over the country, and the use of these as water supplies is not economically possible.Biological iron and manganese removal systems appear to be a promising alternative to chemical treatment. In Finland the following biological treatment systems are in use: (i) VYREDOX method; (ii) overland flow method; (iii) slow sand filtration; (iv) re-infiltration; and (v) biological reactors.Active iron and manganese bacteria play the most essential role in all these applications, and different methods of removal are discussed in detail in the paper.

Notes: The presence of stable foams can seriously impair the ability of an activated sludge to produce a high-quality effluent. This paper examines how the physicochemical characteristics of the solids are related to foam formation and describes how the foaming potential of full-scale plants can be assessed. It also confirms that Microthrix parvicella can exhibit a variable morphology and shows that these variations are related to the physicochemical properties that characterize foam-forming solids.

Notes: Development Toxicology: Risk Assessment and the Future. Edited by R. D. Hood.Ecological Effects of Thermal Discharges, by Terry Langford. Published by Elsevier Applied Science Publishers Ltd.Integrated Design of Water Treatment Facilities, by S. Kawamura. Published by John Wiley and Sons Ltd.Technologies for Small Water and Wastewater Systems, by Edward J. Martin and Edward T. Martin. Published by Van Nostrand ReinholdPotentiometric Water Analysis, by Derek Midgley and Kenneth Torrance. Published by John Wiley and Sons Ltd.Working with the Community. A Guide to Corporate Social Responsibility, by D. Clutterbuck and D. Snow.Fluid Transients in Pipeline Systems, by Prof. A. R. D. Thorley, Published by D & L George Ltd.Environmentally-Sound Water Management. Edited by N. C. Thanh and A. S. Biswas. Published by S. K. Mookerjee

Notes: Sediments in the Chelmarsh pump-storage reservoir have provided a valuable record of the 137Cs levels associated with suspended particulates transported by the River Severn since 1965. The presence of Chernobyl-derived 137Cs and 134Cs within the sedimentary record of the site, despite the absence of any direct fallout on the local area, confirmed that radiocaesium from the Ukrainian reactor accident has been mobilized from the upper reaches of the Severn basin where atmospheric deposition was relatively high. The incorporation of Chernobyl radiocaesium within these sediments can be used to date the 1986 fallout episode, and the established geochronology indicated variable rates of post-1986 sediment accumulation. As radiocaesium is strongly bound to fluvial particulates, this mechanism of redistribution has not adversely affected the quality of the drinking-water source at the site which was studied.

Notes: Lancashire County Council was one of the first local authorities in the UK to audit the environment of its locality and to review the environmental impact of its operations. The paper outlines the reasons for this and how it has been put into effect. The management structure devised to carry forward and coordinate the initiative is outlined first, encompassing elements internal to the County Council and the establishment of a Lancashire Environment Forum. Secondly, the preparation of a county-wide state-of-the-environment audit is described, together with the implementation stages which have ensued. The paper is completed by an account of the County Council's internal review of the impact of its own activities.

Notes: The European countries where sewage treatment in waste stabilization ponds is largely developed and commonly used are West Germany (more than 2000 operational systems) and France (about 2500 plants). Portugal has over 50 systems at present and will have about 100 by the year 1993. Spain has more than 10 operational plants and in Denmark there are 50 ponds for tertiary treatment. A survey on the present practice in the countries where the process is largely applied, including size of plants, type of ponds, type of influent and design criteria, is presented. It is found that waste stabilization ponds are particularly appropriate for full treatment of effluents from small communities (less than 5000 population equivalent) and for tertiary treatment following conventional larger plants.

Notes: Samples of fruits (grapes, pomegranates, and tomatoes), and vegetables (onions, potatoes, and spinach) were collected directly from randomly selected commercial farms along the Tripoli-Zawiya major road, at the appropriate harvest seasons, during the period of May through November 1988. The objective was to determine the extent of contamination of the crops with toxic heavy metals, lead and cadmium, from traffic emissions. For the purpose of comparison, similar crops were collected, within the same periods, from farms in Waddy Al-Rabia, far away from any major road.The samples were dry-ashed, and analyzed using flameless Atomic Absorption Spectrophotometer (AAS).The statistical analyses of the experimental data showed that the major road contributed significantly (P 〈 0.05) to higher concentrations of lead in all the crops examined; and also cadmium in all the crops except in potatoes. Vegetable crops were found to have higher contents of these two metals than the fruits. Substantial amounts of these metals could be removed by washing the samples with triple distilled water.

Notes: The ability of Lactococcus lactis 11454, Pediococcus pentosaceus 43200 and Lactobacillus bavaricus MN, originally isolated from dairy, vegetable, and meat products, respectively, to inhibit growth of Listeria monocytogenes Scott A in a model beef gravy was examined. In the first series of experiments, where the lactic acid bacteria and L. monocytogenes were inoculated at levels of 105 CFU/mL and 103 CFU/mL, respectively only L. bavaricus inhibited listerial growth at 10C. Subsequent experiments using L. bavaricus MN confirmed that the inhibition was caused by a bacteriocin, occurred at temperatures at low as 4C, and could be initiated by 103 CFU/mL L. bavaricus in the presence of L. monocytogenes at levels 10-fold higher. Although the inhibitory agent was protease-sensitive and inhibition occurred in the absence of a fermentable carbohydrate, the presence of acid enhanced efficacy of the bacteriocin.

Notes: Existing estimates of societal costs of food-borne pathogens use only out-of-pocket expenses, such as hospital charges, and ignore the cost of (or willingness to pay to avoid) the pain and suffering associated with a food-borne disease. This paper develops and implements a method to determine consumers’willingness to pay for safer food products. The results show that, for each meal that may be contaminated, participants in this study would pay 55 cents to eliminate Salmonella and 81 cents to eliminate Trichinella spiralis.

Notes: Seafood is a common cause of food allergy. Allergic reactions are reported by consumers following ingestion of seafood meat and by processing workers after occupational exposure to seafood by inhalation of vapors generated during cooking. Although seafood allergy is commonly observed in clinical practice, its precise prevalence is not established. Based on our estimates, approximately 100,000 to 250,000 Americans are at risk of developing allergic reactions to seafood products. In this study, skin testing, in vitro assays and double-blind, placebo-controlled food challenge were employed to investigate seafood allergy in shrimp-allergic individuals. As in most food allergy studies only 1/3 of the alleged shrimp-sensitive subjects had a positive shrimp challenge test. The combination of a positive shrimp skin test and shrimp RAST (〉11% bound) had the best predictive value (87%) for a positive challenge response. Although occupational seafood allergy is not well-studied, based on a Canadian investigation, it can be estimated that 57,000 American seafood workers are at risk of developing work-related allergic reactions. Since seafood is a major food allergen in consumers and industrial workers, further studies are necessary. Despite developments of new antiallergic therapies, avoidance continues to be the best “treatment”for allergic ingestive, inhalative and occupational disease.

Notes: Risk communication theory is used to address consumer concerns about food safety and pesticide residues. Risk perception is a function of actual hazard and “outrage”factors. If concerns are acknowledged and information is provided on how risks are being addressed, the outrage component of perception is reduced. Two 2-min videos were prepared to present information on the environmentally responsive integrated pest management (IPM) approach to farming. The video was shown to a total of 197 consumers in controlled group settings. Although about 90% of participants expressed confidence in the safety of produce grown in California and the United States, 40% said they avoided some produce items due to safety concerns. Pre-and post-attitude assessments and group discussions documented a significant change in attitudes toward food safety, farming practices, and university efforts to help farmers. This project indicates that consumer concerns are significantly reduced when their knowledge of IPM practices is increased.

Notes: Three studies were conducted to assess the effects of disconfirmed consumer expectations on food acceptability. In the first, disconfirmed expectations for the sensory attributes of an edible film had a negative effect on acceptability of the film. Greater disconfirmation resulted in lower acceptance and purchase intent. In the second study, written product information was used to establish three levels of expected acceptability and expected bitterness for a novel fruit beverage. Comparison of preexposure (expected) and postexposure (perceived) ratings of acceptability and bitterness supported an assimilation model of disconfirmation effects for conditions in which expectations of acceptability were high and expectations of bitterness were low. A contrast effect was observed for bitterness judgments when expectations of bitterness were high. Associative effects resulting from the expectation manipulation were observed on other sensory attributes. In the third study, expectations were manipulated to influence both direction (positive versus negative) and degree of disconfirmation for the acceptance of cola beverages. Results provided further support for an assimilation model of these effects.

Notes: Studies of the Receiver Operating Characteristic (ROC) for taste are reviewed and new data on its shape are presented. What evidence there is suggests that ROCs for taste conform to the normal-normal equal variance model of signal detection theory. Few ROCs for taste have been reported, probably because the large number of trials required by detection theory makes the task arduous for subjects in taste experiments. However, pooling ratings from several subjects and estimating the parameters of the pooled ROC by jackknife techniques circumvents that problem to some extent. Because experiments on taste are often based on a small number of trials, it is especially useful to determine the standard errors of ROC parameters. Methods for estimating these standard errors, including that of the area measure, p(A), are therefore presented.

Notes: Pungent spices are well-recognized for their aromatic and pungent nature; however, relatively little is known about their pungent or ‘burning’ responses. Therefore, this research was undertaken to characterize oral pungency of the principal irritants or red pepper (capsaicin), black pepper (piperine), cinnamon (cinnamaldehyde), cumin (cuminaldehyde), cloves (eugenol), ginger (ginger oleoresin), and alcohol (ethanol). These compounds were evaluated for four pungent qualities (burning, tingling, numbing, overall), two temporal qualities (lag time, overall duration), and three spatial qualities (longitudinal location, lateral location, localized/diffuse). The pungency of cinnamaldehyde was primarily burning and tingling. It had a quick onset and rapid decay. The pungency of eugenol had a long-lasting, predominantly numbing effect. The pungency piperine, capsaicin and ginger were primarily burning, but had different temporal and spatial responses. The pungency of ethanol was most diffuse in nature, with some burning and tingling sensations. It had the shortest perceived onset and overall duration. The pungency of cuminaldehyde was equally burning, tingling and numbing.