ALBERT

Notes: The polluting effects of fish farming have been well-documented, but the scale of the problem and the difficulty in effectively controlling the industry are less well known. In approximately twenty years, production by this industry in Scotland has increased by two orders of magnitude and it has been estimated that the population equivalent of fish farming effluents is as high as 1.5 million.The development of a pollution control policy for both land-based and floating-cage farms is described. The role of other controlling agencies is discussed and legislative weaknesses are identified. In addition, the industry's reaction to pollution control is highlighted.Polluting discharges are not controlled only through the issuing of consents, but effective monitoring is also required. Resource constraints resulted in a policy which includes the requirement of certain fish farmers to self-monitor their activities.

Notes: Small differences in water quality standards can mean huge differences in costs for water treatment; difficulties which are compounded by standards for which the derivation is unclear, such as the EC drinking water Directive. Such situations give no indication of the margin of safety for a parameter or the significance to consumers of exceedances. The WHO Guidelines are being revised and will be presented so that the precise derivation of the numbers is absolutely clear. The scientific and quasi-scientific considerations can be separated and the user given the appropriate information to adapt the guidelines to particular circumstances. In deriving standards for toxicological data the factors incorporated reflect uncertainties in the data and extrapolation from animals to man. Understanding the mechanisms of toxicity or carcinogenicity can reduce the uncertainty and improve the quality of the standard, often allowing higher figures to be used with confidence that public health will not be comprised.

Notes: Book reviewed in this article:The Growth and Decay of Ice, by G. S. H. Lock.A Complete Guide to British Moths, by Margaret Brooks.

Notes: The catchment of the upper Clyde estuary has experienced a significant and steady increase of rainfall over the past twenty years. The corresponding increase of runoff has had a positive impact on the water quality both of the individual rivers and of the estuary. Examples are provided to show that approximately one third of some observed improvements are attributable to the additional dilution. It is emphasized that comparisons of water quality data, either by region or by period, should allow for climate variability.

Notes: The use of the sea for sewage disposal has come under increasing scrutiny from the public and from other countries bordering the North Sea. There is a need, therefore, to understand and quantify the environmental impact of sewage discharges from long sea outfalls. Broad-based environmental surveys were carried out at case-study outfalls at Tenby and Weymouth over a four-year period. Studies included (a) sediment sampling on coarse grids and near-outfall transects, (b) bioassays on mussel scope-for-growth and Microtox, and (c) uptake of taint compounds.Although at both Weymouth and Tenby the whole survey area was affected to some extent by sewage-derived material, both outfalls were operating within the dispersive and assimilative capacities of the environment, and thus were having minimal effect. The studies indicated that well-designed and operated long sea outfalls appear to be an acceptable means of domestic waste disposal.

Notes: Increasing concern about rising levels of nitrate in groundwater supplies and their subsequent removal to comply with EC drinking water standards has led to the construction of the first full-scale ion-exchange nitrate-removal plant in the UK by the South Staffordshire Waterworks Company.This paper describes the development of the project from concept, through pilot-plant studies to final design, installation and commissioning. It explains the role of ion-exchange technologies, the use of recently developed nitrate-selective resins and the development of a novel dual regeneration system. The initial performance of the full-scale plant is discussed.

Notes: Actions by employers against their professional advisers are on the increase. With the recent changes in the water industry it is possible that the trend will continue, if only because the new private owners can be expected to be less tolerant than their predecessors. This development is compounded by the complicated technical progress with which water engineers are required to be familiar in an industry which demands skills of a high order.The paper reviews some of the situations in which professional liability can arise, with reference to appropriate case law. The present state of the law in this field is the product of accidental and haphazard development of litigation, with a period of great uncertainty having now become more settled by some recently decided cases.

Notes: A means of improving the energy efficiency of an existing mechanically aerated activated-sludge system by mounting the existing aeration units on jacked platforms is described. The level of the platforms, and hence the immersion of the aerators, is automatically controlled to maintain a constant concentration of dissolved oxygen in the mixed liquor. Comparison of the controlled stream, in which there were two aerators, against an otherwise identical control stream showed energy savings of 20% and 13% respectively when the control involved both or only one aerator, without adverse effect on final effluent quality.

Notes: The water authorities in England and Wales, which have now become water companies, recently had to provide anticipated costs for maintaining the water supply and sewerage systems over the next 20 years. Probabilistic models and statistical inference provide an opportunity to quantify the uncertainty in such exercises. Their use in a study undertaken by a water authority in the north-east of England is described and illustrated with interim data which were available at an early stage in the exercise.

Notes: The Biocarbone process is a new system for water and effluent purification in which biological treatment and physical filtration take place in the same reactor. Because the use of the process for tertiary treatment of sewage effluent had not been fully investigated, a pilot-scale evaluation was undertaken at Severn Trent's Wigston sewage-treatment works. This paper presents the results.The study corroborates performance information published by the manufacturer. It shows that the process is an alternative to conventional technology for producing fully-nitrified tertiary effluents having low biochemical oxygen demand (BOD) and suspended solids (SS) concentrations.

Notes: Previous attempts to utilize ion chromatography for the analysis of sea water samples have failed through chronic interference by the major ions (na, Mg, Ca) during the preconcentration stage. As part of ongoing research into ion chromatography, a technique has been developed to overcome these interferences, using a two-stage preconcentration step, prior to separation on a cation-exchange column. This has made it possible to detect μg/l quantities of trace metals in samples containing g/l concentrations of sodium, magnesium and calcium. A modified commercially-available ion chromatographic system was used to analyse copper, nickel, zinc, cobalt and manganese in saline waters. Detection limits were typically less than 1 μg/l, with relative standard deviation of less than 10%. Hence this new method has the potential to provide an inexpensive multi-elemental sea water analysis with the minimum of handling. In addition, the simplicity and sensitivity of the technique may make it suitable for unattended use as a remote monitor of metals.

Notes: An increasing number of pesticide compounds are being detected in groundwater supplies worldwide. There has, nevertheless, been little research into the mechanisms by which such pollution occurs and the routes via which pesticides move from the land surface into aquifers. In view of the potential time-lag in the response of groundwater systems to pollution inputs, such knowledge is essential if the current situation is to be appraised adequately and if any necessary controls on pesticide use are to be introduced.From basic data on the physicochemical properties of pesticide compounds and on groundwater flow and pollutant transport in the principal British aquifers, some useful observations can be made about the relative significance of different mechanisms of potential groundwater pollution. These mechanisms and their implications for field research on pesticide pollution of groundwater are discussed. This problem is compared and contrasted to that of nitrate pollution from agricultural land-use practices.

Notes: The process control of sewage-treatment plants is normally carried out by conventional means. Special circumstances forced the application of a state-of-the-art process automation system for The Netherlands’largest sewage-treatment plant (Houtrust) at The Hague.The plant incorporates the use of oxygen-enriched air for use in the secondary treatment process, and the final settling tanks are constructed one above the other (in two tiers). The automation system is built up with locally-placed process computers, and a central video operating system is included with a data-processing computer; these are interconnected by a data transmission bus of redundant design. The central control system is also connected to the main sewage pumping stations of The Hague district, for collecting data and controlling these stations from the plant.After the start-up of the plant, it took several months of tuning the control system to gain proper process control, the main problem being the influence of pump switching in the intermediate pumping stations on the oxygen supply to the aeration tanks.

Notes: The performance of a probabilistic risk assessment (PRA) for a nuclear power plant is a complex undertaking, involving the assembly of an accident frequency analysis, an accident progression analysis, a source term analysis, and a consequence analysis. Each of these analyses is, in itself, quite complex. Uncertainties enter into a PRA from each of these analyses. An important focus in recent PRAs has been to incorporate these uncertainties at each stage of the analysis, propagate the subsequent uncertainties through the entire analysis, and include uncertainty in the final results. Monte Carlo procedures based on Latin hypercube sampling provide one way to perform propagations of this type. In this paper, the results of two complete and independent Monte Carlo calculations for a recently completed PRA for a nuclear power plant are compared as a means of providing empirical evidence on the repeatability of uncertainty and sensitivity analyses for large-scale PRA calculations. These calculations use the same variables and analysis structure with two independently generated Latin hypercube samples. The results of the two calculations show a high degree of repeatability for the analysis of a very complex system.

Notes: This is a study of knowledge, risk perception, and attitudes among nuclear power plant employees. A total of 236 persons participated, belonging to 10 different professional groups and working at two Swedish power plants. Job-related radiation risks were judged about average as compared to a number of other risks. On the whole, the participants in the study were satisfied with the measures of safety at work, but there were some exceptions to this rule, especially among those hired for temporary jobs through external contractors. The experience of job-related radiation risks was related to the level of knowledge about radiation and its risks: those who knew less experienced larger risks. General level of anxiety did not correlate with risk perception. The latter was accounted for mainly by perceived radiation risks. Job satisfaction was more strongly related to perceived conventional job risks than to nuclear risks. Risk ratings were related to how subjects defined the concept of risk. Those who stressed consequences as part of their risk definition gave higher risk ratings.

Notes: A new mathematical dose-response model for reproductive and developmental risk assessment is proposed. The model includes the possibility of an exposure threshold as well as a litter-size effect. Correlation of responses of offspring from the same litter is taken into account through the use of the beta-binomial distribution. Confidence limits for low-dose extrapolation are based on the asymptotic distribution of the likelihood ratio. An empirical comparison of the proposed procedure to that of Rai and Van Ryzin(1) demonstrates the improvement that can be achieved with the new procedure.

Notes: When people consume products violating the Food, Drug, and Cosmetic (FD & C) Act they may experience morbidity or mortality from foodborne illness. Some studies have used survey data to estimate the dollar value of avoiding a few illnesses, but surveys are expensive and the resulting estimates cannot easily be generalized to the wide variety of foodborne illnesses. We develop a method that uses published data to estimate the value of avoiding morbidity and mortality from foodborne illnesses using two metrics–quality-adjusted life-years and dollars. The method first describes the effects of different illnesses on the patient and then converts these descriptions into changes in time spent in different health states with different relative utility weights. We use these estimated changes to compute losses in quality-adjusted life-years with different illnesses. We then use the empirical literature to estimate a value for these lost quality-adjusted life-years. We demonstrate our method and derive estimates for the value of avoiding a future case of botulism, salmonellosis, chronic hepatitis, and bladder cancer. Researchers can use our method to compare the value of avoiding all illnesses caused by violations of the FD & C Act. More importantly, government officials can use our method to quickly and cost-effectively generate morbidity and mortality valuation estimates for any illness for policy purposes.

Notes: Dose-response curves were developed for the immobilization response in Daphnia magna to four toxicants. The purpose of this work was to study the effect of the form of the model and the number of concentration levels used on the estimates of typical low-dose effective concentrations (1%, 5%, 10%). The generalized four-parameter logistic model was used as the reference. When using 12 concentration levels, one of the logistic family two- or three-parameter models was shown reliably to represent each of these various sets of dose-response data, and to provide adequate estimates of EC01 and EC05, as well as EC10 and EC50. For two of the toxicants, an asymmetric model was required. When reducing the number of concentrations to five, the EC10 and EC50 were well estimated by the probit model, with acceptable results at the EC05 level.

Notes: The present study utilizes an operational model as well as simple empirical relationships for estimating hazard zones due to fire, explosion, and toxic vapor cloud dispersion. The empirical relationships are based on giving appropriate weightage to each of the parameters on which the hazard in question (viz. fire, explosion, toxic vapour dispersion) is dependent. Results from these two approaches [i.e., an operational model FLAMCALC of U.K. Health and Safety Executive (HSE) and an empirical model named FIREX] have been compared with the data obtained from the Mexico City disaster in 1984. In general, results from the empirical approach and FLAMCALC are comparable to the observed effects.

Notes: Annual concentrations of toxic air contaminants are of primary concern from the perspective of chronic human exposure assessment and risk analysis. Despite recent advances in air quality monitoring technology, resource and technical constraints often impose limitations on the availability of a sufficient number of ambient concentration measurements for performing environmental risk analysis. Therefore, sample size limitations, representativeness of data, and uncertainties in the estimated annual mean concentration must be examined before performing quantitative risk analysis. In this paper, we discuss several factors that need to be considered in designing field-sampling programs for toxic air contaminants and in verifying compliance with environmental regulations. Specifically, we examine the behavior of SO2, TSP, and CO data as surrogates for toxic air contaminants and as examples of point source, area source, and line source-dominated pollutants, respectively, from the standpoint of sampling design. We demonstrate the use of bootstrap resampling method and normal theory in estimating the annual mean concentration and its 95% confidence bounds from limited sampling data, and illustrate the application of operating characteristic (OC) curves to determine optimum sample size and other sampling strategies. We also outline a statistical procedure, based on a one-sided t-test, that utilizes the sampled concentration data for evaluating whether a sampling site is in compliance with relevant ambient guideline concentrations for toxic air contaminants.

Notes: Heavy gas dispersion models have been developed at IIT (hereinafter referred as IIT heavy gas models I and II) with a view to estimate vulnerable zones due to accidental (both instantaneous and continuous, respectively) release of dense toxic material in the atmosphere. The results obtained from IIT heavy gas models have been compared with those obtained from the DEGADIS model [Dense Gas Dispersion Model, developed by Havens and Spicer (1985) for the U.S. Coast Guard] as well as with the observed data collected during the Burro Series, Maplin Sands, and Thorney Island field trials. Both of these models include relevant features of dense gas dispersion, viz., gravity slumping, air entrainment, cloud heating, and transition to the passive phase, etc. The DEGADIS model has been considered for comparing the performance of IIT heavy gas models in this study because it incorporates most of the physical processes of dense gas dispersion in an elaborate manner, and has also been satisfactorily tested against field observations. The predictions from IIT heavy gas models indicate a fairly similar trend to the observed values from Thorney Island, Burro Series, and Maplin experiments with a tendency toward overprediction. There is a good agreement between the prediction of IIT heavy Gas models I and II with those from DEGADIS, except for the simulations of IIT heavy gas model-I pertaining to very large release quantities under highly stable atmospheric conditions. In summary, the performance of IIT heavy gas models have been found to be reasonably good both with respect to the limited field data available and various simulations (selected on the basis of relevant storages in the industries and prevalent meteorological conditions performed with DEGADIS). However, there is a scope of improvement in the IIT heavy gas models (viz., better formulation for entrainment, modification of coefficients, transition criteria, etc.).Further, isotons (nomograms) have been prepared by using IIT heavy gas models for chlorine, which provide safe distance for various storage amounts for 24 meteorological scenarios prevalent in the entire year. These nomograms are prepared such that a nonspecialist can use them easily for control and management in case of an emergency requiring the evacuation of people in the affected region. These results can also be useful for siting and limiting the storage quantities.

Notes: A quantitative structure-activity relationship (QSAR) model has been developed to estimate maximum tolerated doses (MTD) from structural features of chemicals and the corresponding oral acute lethal doses (LD50) as determined in male rats. The model is based on a set of 269 diverse chemicals which have been tested under the National Cancer Institute/National Toxicology Program (NCI/NTP) protocols. The rat oral LD50 value was the strongest predictor. Additionally, 22 structural descriptors comprising nine substructural MOLSTAC(c) keys, three molecular connectivity indices, and sigma charges on 10 molecular fragments were identified as endpoint predictors. The model explains 76% of the variance and is significant (F= 35.7) at p 〈 0.0001 with a standard error of the estimate of 0.40 in the log(1/mol) units used in Hansch-type equations. Cross-validation showed that the difference between the average deleted residual square (0.179) and the model residual square (0.160) was not significant (t= 0.98).

Notes: Mathematical models of carcinogenesis are one tool used for research into the mechanisms of carcinogenesis and for assessing risks from exposure to carcinogenic agents. Recent research into carcinogenic mechanisms has focused on the role of cell replication in fixing damage to cellular DNA and increasing the incidence of malignancies. The most commonly used multistage model of carcinogenesis does not explicitly account for DNA damage and the contribution of cell replication rates on the transformation of cells through the various stages. In this manuscript, a generalized multistage model of carcinogenesis is developed in which DNA damage, cell replication, and DNA repair are explicitly included.

Notes: Existing approaches to routing hazardous material shipments by rail recognize that track condition is an important influence, but have not included it in the risk assessment and routing models. This note explores the influence of track condition based on predictions of internal defects in the rail. The method developed predicts the expected frequency of accidents and subsequent consequences in terms of the expected number of fatalities accounting for one aspect of track condition—internal defects. It is intended to indicate the magnitude and impact of track condition. The formulation integrates models of consequences and the risk of a hazardous spill found in the literature with the frequency of accidents as a function of the number of defects. The number of defects may be based on observations or predicted as a function of the cumulative traffic. The models are used to calculate the expected number of fatalities per year for a particular route. Application of the methodology to a hypothetical route shows that the risk associated with the transportation of hazardous material shipments varies significantly with the expected number of defects in the track. Therefore, risk not only varies from route to route but over time for any section of track as the condition deteriorates.

Notes: This note presents parameterized distributions of estimates of the amount of soil ingested by children based on data collected by Binder et al. (1986). Following discussions with Dr. Binder, we modified the Binder study data by using the actual stool weights instead of the 15 g value used in the original study. After testing the data for lognormality, we generated parameterized distributions for use in risk assessment uncertainty analyses such as Monte Carlo simulations.

Notes: Books are reviewed in this article: Biologic Markers in Pulmonary Toxicology Risk Perspectives on Environmental Impact Assessment Edited by A.P. Grima, C.D. Fowle, and R.E. Munn Environmental Impacts of Hazardous Waste Treatment, Storage, and Disposal Facilities By Rodolfo N. Salcedo, Frank L. Cross, Jr., and Randolph L. Chrismon Lancaster Analytical Groundwater Modeling: Flow and Contaminant Migration By William C. Walton Chelsea Numerical Groundwater Modeling: Flow and Contaminant Migration By William C. Walton Chelsea Principles of Hazardous Materials Management By Roger D. Griffin Chelsea Biohazards of Drinking Water Treatment Edited by Richard A. Larson Chelsea Hazardous Waste Minimization Handbook By Thomas E. Higgins Chelsea Benchmarks: Alternative Methods in Toxicology Edited by M.A. Mehlman Intermedia Pollutant Transport: Modeling and Field Measurements Edited by David T. Allen, Yoram Cohen, and Isaac R. Kaplan

Notes: Annual radiation doses and risks to passengers and crew are calculated for shipments of radioactive materials in passenger aircraft under accident-free and incident-free conditions (i.e., under normal transportation conditions). The 1982 database developed by Sandia National Laboratories is used, and calculations are made using RADTRAN 4.0. This paper is one of two papers estimating radiological risk associated with incident-free transportation of radioactive materials.

Notes: Annual radiation doses and risks to the public living near, and traveling on, public highways, and occupational doses are calculated for highway shipments of radioactive materials under accident-free and incident-free conditions (i.e., under normal transportation conditions). The database developed by Sandia National Laboratories is used, and calculations are made using RADTRAN 4.0. This report is one of two reports estimating radiological risk associated with transportation of radioactive materials.

Notes: Typically, the uncertainty affecting the parameters of physiologically based pharmacokinetic (PBPK) models is ignored because it is not currently practical to adjust their values using classical parameter estimation techniques. This issue of parametric variability in a physiological model of benzene pharmacokinetics is addressed in this paper. Monte Carlo simulations were used to study the effects on the model output arising from variability in its parameters. The output was classified into two categories, depending on whether the output of the model on a particular run was judged to be generally consistent with published experimental data. Statistical techniques were used to examine sensitivity and interaction in the parameter space. The model was evaluated against the data from three different experiments in order to test for the structural adequacy of the model and the consistency of the experimental results. The regions of the parameter space associated with various inhalation and gavage experiments are distinct, and the model as presently structured cannot adequately represent the outcomes of all experiments. Our results suggest that further effort is required to discern between the structural adequacy of the model and the consistency of the experimental results. The impact of our results on the risk assessment process for benzene is also examined.

Notes: This paper addresses the use of mitigation and compensation as incentives policies to stimulate agreement between parties interested in siting a hazardous waste facility and potential host communities. We develop a model of facility siting that distinguishes five key factors which influence the acceptability of a proposed facility when considered in relation to status quo conditions. This model then is used to examine the effectiveness of different incentives policies with regard to (a) mitigating the perceived risks and (b) compensating the adverse impacts of a hazardous waste facility.

Notes: Natural gas distribution systems in the United States were developed primarily in the first half of this century, utilizing materials such as cast iron and then steel. Over time, cast iron and steel pipe sections became weak from corrosion and are subject to failure which in turn can lead to explosions and possible injury and loss of life. Gas utilities maintain system integrity through repair-replacement programs where pipe sections are prioritized for replacement in any given year through cost-benefit analysis; however, the total annual amount to be budgeted for replacement is left to engineering judgment. This approach has left some utilities vulnerable to criticism that their current replacement rate on cast iron pipe is not great enough and that public safety is being compromised. This paper addresses the problem situation by formulating a linear programming replacement decision model which augments cost-benefit analysis with explicit constraints on acceptable risk to human life from fire/explosion. The model is illustrated for a hypothetical utility.

Notes: This study investigates the potential impacts of the proposed nuclear waste repository at Yucca Mountain, Nevada, upon tourism, retirement and job-related migration, and business development in Las Vegas and the state. Adverse impacts may be expected to result from perceptions of risk, stigmatization, and socially amplified reactions to “unfortunate events” associated with the repository (major and minor accidents, discoveries of radiation releases, evidence of mismanagement, attempts to sabotage or disrupt the facility, etc.). The conceptual underpinnings of risk perception, stigmatization, and social amplification are discussed and empirical data are presented to demonstrate how nuclear images associated with Las Vegas and the State of Nevada might trigger adverse economic effects. The possibility that intense negative imagery associated with the repository may cause significant harm to Nevada's economy can no longer be ignored by serious attempts to assess the risks and impacts of this unique facility. The behavioral processes described here appear relevant as well to the social impact assessment of any proposed facility that produces, uses, transports, or disposes of hazardous materials.

Notes: Book Review in this article:Petroleum Contaminated Soils, Vol. 1: Remediation Techniques, Environmental Fate, Risk Assessment Edited by Paul T. Kostecki and Edward J. Calabrese Chelsea, Michigan: Lewis Publishers, 1989 260 pp, $55.50 hbManaging Industrial Hazardous Waste: A Practical Handbook Gary Lindgren Chelsea, Michigan: Lewis Publishers, 1989 350 pp., $59.95 hbRisk Analysis Section, Oak Ridge National Laboratory, Chinn Building, MS-6492, Oak Ridge, Tennessee 37831.Health Effects of Drinking Water Treatment Technologies Drinking Water Health Effects Task Force Chelsea, Michigan: Lewis Publishers, 1989 145 pp., $37.50Chemical Hazards in the Workplace Ronald M. Scott Chelsea, Michigan: Lewis Publishers, 1989 196 pp., $39.95Environmental Chemistry and Toxicology of Aluminum Edited by Timothy E. Lewis Chelsea, Michigan: Lewis Publishers, 1989 344 pp., $59.95 hbLight Water Reactor Safety Bengt Pershagen New York: Pergamon Press, 1989 470 pp., $90.00Biologically Based Methods for Cancer Risk Assessment Edited by Curtis C. Travis New York: Plenum Press, 1989 355 pp.Social Decision Methodology for Technological Projects Edited by Charles Vlek and George Cvetkovich Boston: Kluwer Academic Publishers, 1989 343 pp., $87.00

Notes: Benzene is one of the best studied of the known human carcinogens. It causes leukemia in humans and a variety of solid tumors in rats and mice. Decades of research on benzene metabolism, pharmacokinetics, cytotoxicity, genotoxicity, and carcinogenicity in vivo and in vitro are starting to converge on a small set of overlapping hypotheses about the most probable biological mechanisms of benzene toxicity and carcinogenicity. Although there is still room for surprises, it seems likely that the ultimate answer to the mystery of how benzene exerts its multiple effects will consist of elaborations and extensions of one or more of the current hypotheses. This paper reviews benzene health effects and biology, showing how various aspects of metabolism and cytotoxicity fit together with genotoxic and nongenotoxic effects to help explain how benzene may cause cancer. Its goals are: (i) to introduce the qualitative biological background needed for detailed quantitative dose-response modeling of benzene cancer risks; and (ii) to survey a rapidly evolving area of research that shows promise of producing fundamental insights into the mechanisms of toxicity and carcinogenesis for several chemicals–benzene and perhaps phenols, catechols, and other hydroxylated ring hydrocarbons–in the decade ahead.

Notes: ONGC's Hazira Gas-Processing Complex (HGPC) consists of facilities for receiving natural gas along with associated condensate from an off-shore field at a rate of 20 MMN M3 per day. After separating the condensate, which is processed in condensate fractionation units, the gas is processed through various steps to recover LPG and to reduce its dew point to less than 5°C in order to make it suitable for transportation over long distances. The acid gas recovered during the gas-sweetening step is processed to obtain sulphur. The major products manufactured at HGPC therefore are lean sweet gas, LPG, NGL, and sulphur. The Oil and Natural Gas Commission awarded the assignment on Hazard Study and Risk Analysis of their Hazira Gas-Processing Complex (HGPC) to the Council of Scientific and Industrial Research (CSIR) in association with the Netherlands Organisation for Applied Scientific Research (TNO). The scope of this assignment covered a number of closely related and fully defined activities normally encountered in this type of work. Identification of hazards through the most appropriate methods, assigning frequency of occurrence of major unwanted incidents, quantification and assessment of probable damage to plant equipment, environment, human and animal life due to an unexpected event, and evaluation of various methods for reducing risk, together constituted the methodology for this assignment. Detailed recommendations aimed at reducing risk and enhancing reliability of plant and machinery were made. This article gives an overview of the assignment.

Notes: McKone has recently proposed an innovative two-layer model for dermal uptake of organic chemicals from a soil matrix that explicitly includes variables for properties of the chemical, the soil, the skin, and the exposure. In this note, we investigate the joint time- and loading-dependencies implicit in the model by using MATHEMATICA to find and plot a closed-form function for the uptake fraction for six aromatic hydrocarbons.

Notes: Upperbound lifetime excess cancer risks were calculated for activities associated with asbestos abatement using a risk assessment framework developed for EPA's Superfund program. It was found that removals were associated with cancer risks to workers which were often greater than the commonly accepted cancer risk of 1 × 10−6, although lower than occupational exposure limits associated with risks of 1 × 10−3. Removals had little effect in reducing risk to school populations. Risks to teachers and students in school buildings containing asbestos were approximately the same as risks associated with exposure to ambient asbestos by the general public and were below the levels typically of concern to regulatory agencies. During abatement, however, there were increased risks to both workers and nearby individuals. Careless, everyday building maintenance generated the greatest risk to workers followed by removals and encapsulation. If asbestos abatement was judged by the risk criteria applied to EPA's Superfund program, the no-action alternative would likely be selected in preference to removal in a majority of cases. These conclusions should only be interpreted within the context of an overall asbestos risk management program, which includes consideration of specific fiber types and sizes, sampling and analytical limitations, physical condition of asbestos-containing material, episodic peak exposures, and the number of people potentially exposed.

Notes: The effects of exposure to two carcinogens are explored within the context of the two-stage clonal expansion model of carcinogenesis. This biologically based model provides a useful framework for the quantitative description of carcinogenesis, and for defining carcinogenic agents that act as initiators, promoters, and completers. This paper addresses the combined effects of simultaneous lifetime exposure to two carcinogens as well as nonoverlapping partial lifetime exposure to each agent. Whereas the age-specific relative risk for exposure to two initiators or two completers is additive, a multiplicative relative risk model holds for exposure to an initiator and a completer, or to a promoter and a completer. Exposure to two promoters yields supra-multiplicative relative risk. Exposure to an initiator and promoter leads to multiplicative and supra-multiplicative relative risks for simultaneous lifetime and nonoverlapping partial lifetime exposures, respectively. Although departures from the additive relative risk model may thus occur at moderate to high doses, conditions are identified under which additivity will provide a good approximation to the joint risk at low doses. The methods of analysis used in this paper can also be used to determine the joint effects of exposure to two carcinogens which may affect more than one stage (initiation, promotion, completion) of the process of carcinogenesis. In general, the joint effects of exposure to such agents depends on the relative magnitude of the effects on individual stages.

Notes: A conceptual framework is developed for the prescriptive evaluation of health and safety risks to an individual. This framework allows one to compare chronic vs. acute health risks, accidents vs. illness, and physical vs. psychological impacts. To do this, value judgments are necessary to quantify one's health state in terms of both physical and psychological well-being. Probabilities are necessary to describe implications of activities such as skiing or smoking and conditions such as cancer or third-degree bums in terms of these health states. Suggestions are made to operationalize and use the framework to evaluate and compare very different individual health and safety risks. Essentially, all existing measures of individual risk can be derived as special cases of the proposed framework.

Notes: This study develops a theoretical model for accident evolutions and how they can be arrested. The model describes the interaction between technical and human-organizational systems which may lead to an accident. The analytic tool provided by the model gives equal weight to both these types of systems and necessitates simultaneous and interactive accident analysis by engineers and human factors specialists. It can be used in predictive safety analyses as well as in post hoc incident analyses. To illustrate this, the AEB model is applied to an incident reported by the nuclear industry in Sweden. In general, application of the model will indicate where and how safety can be improved, and it also raises questions about issues such as the cost, feasibility, and effectiveness of different ways of increasing safety.

Notes: Book review in this Article:San Francisco: Center for Science Information (CSI) 1 Risk Analysis Section, Oak Ridge National LaboratoryPurdue University Industrial Waste Conference Proceedings Edited by John M. Bell ChelseaHealth and Safety in Small Industry: A Practical Guide for Managers Environmental and Occupational Health Information ProgramDrinking Water Health Advisory: Pesticides U.S. Environmental Protection AgencySafety Series 100: Evaluating the Reliability of Predictions Made Using Environmental Transfer Models The International Atomic Energy Agency ViennaIrrigation-Induced Water Quality Problems: what Can Be Learned from the San Joaquin Valley ExperienceCommittee on Irrigation-Induced Water Quality Problems, Water Science and Technology Board, Commission on Physical SciencesToxicology Chemistry: A Guide to Toxic Substances in ChemistryHandbook of Environmental Fate and Exposure of Organic Chemicals, Volume I: Large Production and Priority PollutantsChelsea, Michigan:Biologic Markers in Reproductive Toxicology Subcommittee on Reproductive and Neurodevelopmental Toxicology, Committee on Biologic Markers, Board on Environmental Studies and Toxicology, Commission on Life Sciences, National Research Council

Notes: The dependence of the radiological consequences of the “Demokritos” research reactor on the operating schedule of the reactor is assessed in this paper. The 5 MW reactor is located within the limits of Athens city, a large population center with over 3 million inhabitants. The consequences examined would be due to the occurrence of a postulated accident, a 20% core melt loss of coolant accident, that is also considered as the design basis accident of the reactor. Three operating schedules are taken into account: (a) a continuous operation schedule; (b) a 16 hr/day, 5 days/week schedule; and (c) the present 8 hr/day, 5 days/week operating schedule. The assessment of the source term emerges from a conservative estimation of fission product releases to the reactor operating floor, and further under the conservative assumptions of no filter mitigation, and a ground release to the environment. The results of the analysis indicate that there is a direct relation between consequences and duration of operation, the former becoming appreciable as the continuous operation limit is approached. In all cases examined, the thyroid dose and the latent thyroid health effects would be the limiting consequences.

Notes: A survey has been conducted among decision-makers from the urban area of Lyon (France). It aimed at elicitating attitudes toward industrial risk, with an emphasis on major hazards. The sample was quite small (23 individuals), but most of the actual decision-makers of the area belonged to it. A questionnaire allowed to look at the weights that are given to “catastrophic accidents,” when compared to more usual ones. It showed that decision-makers are strongly “adverse to catastrophes.” The findings support many risk management approaches that are based on assigning an “extra weight” to potential accidents that may cause a high number of casualties.

Notes: In 1982 the Council of the European Communities issued a Directive on the Major Accident Hazards of Certain Industrial Activities, commonly known as the Seveso Directive. Besides other requirements, the Directive specifies that members of the public liable to be affected by a major accident from certain industrial activities must be informed of safety measures and how they should behave in the event of an accident. The Directive was subsequently amended in an extensive way. Upon the transposition of the Seveso Directive and its amendments into national legislations, the 12 European Member States are faced with the task of “appropriately and effectively” informing the public about major accident hazards. Delays are observed throughout the community, both in transposing the Directives and implementing public information. A pilot study on “Risk Information Needs” was commissioned and carried out at two Seveso sites in Italy in order to begin to resolve some of the problems involved in the provision of public information and to suggest appropriate guidelines. One hundred subjects answered an experimental protocol designed to assess their “information needs.” This article presents the theoretical background, the pragmatic aims, and the design of the study. It also summarizes its most relevant findings and suggests some recommendations for the provision of information to the public.

Notes: Waste management has become a major environmental issue in Germany. The siting of waste incineration especially arouses strong local opposition. The study presented here is related to such a case (i.e., a planned waste incineration facility in a small West German village). The study is based on a telephone survey aimed at the information needs of the residents. Two topics are stressed: (1) the thematic relevance of the siting project as seen by the public; and (2) the residents’information needs. The results show that a majority of residents are concerned about the planned facility, and the most important topics of their information needs refer to the risks and the safety systems of the planned facility, as well as information about waste management alternatives. Furthermore, the information needs depend on the personal relevance of the issue and the perceived knowledge deficit about it. Conclusions are drawn with regard to the design of a risk communication program. Here, four groups of residents are distinguished in terms of knowledge and motivation and, thus, need to be approached in different ways.

Notes: Probabilistic risk assessment (PRA) is an important methodology for assessing the risks of complex technologies. This paper discusses the strengths and weaknesses of PRA. Its application is explored in three different settings: adversarial policy processes, regulatory/licensing procedures, and plant safety audits. It is concluded that PRA is a valuable tool for auditing safety precautions of existing or planned technologies, especially when it is carried out as an interactive process involving designers and plant personnel who are familiar with actual, everyday operations. PRA has not proven to be as well-suited in providing absolute risk estimates in public-policy debates concerning the acceptability of a technology, or for the licensing and regulatory procedures. The reasons for this are discussed.

Notes: Many would tend to characterize modern society as steeped in complexity. This complexity is seen by a number of professional people to imply risk-taking — or risk-making — on a high level. “A single mistake may give consequences of quite different proportions from earlier times,” as one critic puts it. This hypothesis of increasing risks on a high level — of worst things getting worse — has been tested on fires in Sweden. Fire has always been a powerfully upsetting agent to the social fabric. Today industrial fires dominate the picture economically. The cost of industrial fires is about three times the cost of residential fires in Sweden. It is of interest to note that the damage cost of the worst fires (as measured in insurance payments) does not form an increasing part of overall fire damage costs, as one would expect from the above hypothesis. Whether the hypothesis holds with regard to indirect costs due to production stand-still is more uncertain. We can conclude that the potential of complexity to create large abnormal occurrences may have been somewhat prematurely announced — at least with regard to fires in Sweden.

Notes: Floods in the U.S. kill an average of 162 people each year and cause $3.4 billion in property damage. Flood control programs have been successful in lowering, but not eliminating, the risks to lives and property. Since the late 1960s, the federal government has emphasized flood insurance as a primary tool for improving location and flood-proofing decisions, as well as for reimbursing flood losses. Since only 12.7% of houses in flood plain areas are covered by flood insurance, the program has been ineffective. We interviewed people living in three communities that had recently been flooded. Most people had little knowledge of the cause of floods or what could be done to prevent damage. People who work and who are better educated know more and are more likely to have flood insurance. Current government publications about flood risks are not likely to be understood by those at risk. There is little effective communication about the nature and magnitude of the risks and what individuals can do to protect their lives and property and lower their financial risks. The risk management program should both emphasize communication and enforcement of the current law requiring people at risk who hold federally funded loans to be insured.

Notes: Accidents with automatic production systems are reported to be on the order of one in a hundred or thousand robot-years, while fatal accidents are found to occur one or two orders of magnitude less frequently. Traditions in occupational safety tend to seek for safety targets in terms of zero severe accidents for automatic systems. Decision-making requires a risk assessment balancing potential risk reduction measures and costs within the cultural environment of a production company. This paper presents a simplified procedure which acts as a decision tool. The procedure is based on a risk concept approaching prevention both in a deterministic and in a probabilistic manner. Eight accident scenarios are shown to represent the potential accident processes involving robot interactions with people. Seven prevention policies are shown to cover the accident scenarios in principle. An additional probabilistic approach may indicate which extra safety measures can be taken against what risk reduction and additional costs. The risk evaluation process aims at achieving a quantitative acceptable risk level. For that purpose, three risk evaluation methods are discussed with respect to reaching broad consensus on the safety targets.

Notes: A testable hypothesis of deterrence theory is that efforts to increase the expected cost of criminal activity by increasing the threat of punishment should, other things being equal, reduce the crime rate. In this paper, we examine whether the incidence of drinking and driving is responsive to escalation of the punitive threat. The recent national campaign against drunk driving provides a natural experiment in which to test the predictions of deterrence theory. Using state level data over the 1975–1986 period, we report no conclusive evidence that any specific form of punitive legislation is having a measurable effect on motor vehicle fatalities. We report suggestive evidence that multiple laws designed to increase the certainty of punishment (e.g., sobriety checkpoints and preliminary breath tests) have a synergistic deterrent effect. The most striking finding is that mandatory seat belt use laws and beer taxes may be more effective at reducing drunk driving fatalities than policies aimed at general deterrence.

Notes: Risk perception studies show that individuals tend to underestimate significant risks, overestimate negligible ones, and distrust authorities. They also rely on a variety of strategies or heuristics to reach decisions regarding their risk-taking behavior. We report on a survey of fishermen and crabbers engaged in recreational and subsistence fishing in a Puerto Rican estuary (near Humacao), which has been declared a “Superfund site” because of suspected contamination by mercury, and at ecologically similar control sites. Nearly everyone interviewed at the Humacao site was aware of the mercury contamination, but either denied its importance, believed the contamination was restricted to a distant part of the estuary, or assumed that the estuary would be closed by the authorities if the threat was real. All site-users consumed the fish and crabs they caught. At Humacao, the average catch was 7 fish per fishermen (mostly tilapia, Tilapia mossambica, and tarpon, Megalops atlantica) and 13 crabs per crabber (all blue crabs, Callinectes sapidus). On average, the site-users returned to the lagoons about 3-4 times per month. At control sites, fewer fish were eaten. The worst case consumption of tarpon, a species which concentrated mercury at Eastern Puerto Rico, provided an exposure exceeding the EPA reference dose, whereas consumption of one tarpon per week did not entail excess exposure. Fortunately, few individuals caught tarpon exclusively. Unlike counterparts in the northeastern United States, they trusted authorities and indicated that they would have heeded warnings of mercury contamination posted where they fished.

Notes: The primary mission of search and rescue (SAR) is the saving of lives. To assess SAR operations from a planning perspective, one must draw a connection between operations and the number of lives saved. Our approach is to model the probability that an incident results in at least one fatality, given the response time between the time of incident occurrence and time of rescue. We show that incidents involving air crashes, capsizing, foundering, grounding and other/unknown types of incidents tended to have higher probabilities of fatalities as the response time became higher. However, other emergency types did not exhibit the same overall tendency as these did. These statistical results do not prove causality between faster response times and lower fatality incidence for the above-mentioned emergency types. They can be used, however, for estimating the average number of fatalities for a given distribution of response time, and ultimately the marginal savings in lives for a change in the mix of resources and locations.

Notes: A common mental response to risk is worry. Though generally associated with fear and anxiety, worry is primarily a cognitive activity that can, under some circumstances, be beneficial for developing coping strategies to deal with stressful events. The present study reports an assessment of worry done both before and after the reactor accident at Three Mile Island (TMI). Worries over nuclear risks were assessed in the context of central life concerns such as financial, physical, and interpersonal well-being. The TMI incident elevated nuclear energy worries to a level near those of central life concerns. The productive value of worry is discussed in terms of its relationship with opportunities for personal control.