bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge and Risk Perception Among Nuclear Power Plant Employees
Authors: Sjöberg Lennart , Drottz‐Sjöberg Britt‐Marie
Published: May 2006

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.
Decision Analysis for Utilizing Hazardous Waste Site Assessments in Real Estate Acquisition
Authors: Noonan Frank , Vidich Charles A.
Published: May 2006

When a buyer needs to purchase commercial or industrial property, the decision of what real estate to purchase should be based on an assessment of the total costs of acquisition. In addition to the direct purchase cost, other possible costs include hazardous waste site assessment studies and clean up costs if the purchased site proves to be contaminated. This paper presents a decision analysis model for determining when and which type of hazardous waste assessment tests should be conducted and how the test output affects the choice of site. The model assumes there are two types of hazardous waste assessment, an historical use review (phase 1 test)and soil and water sampling (phase 2 test). Model inputs include the cost, sensitivity and specificity for each type of test, a site's purchase price, and a priori probability of contamination, along with the clean‐up cost for a contaminated site. The analysis uses the results of a data survey of 17 environmental engineering firms in setting values on the model input requirements. The paper also reports on sensitivity analysis with the model for the purpose of providing decision‐makers with explicit protocols for test utilization.
Determinants of Risk Perceptions of a Hazardous Waste Site
Authors: Bord Richard J. , O'Connor Robert E.
Published: May 2006

A before‐stimulus‐after quasi‐experimental design is used to assess the factors relating to risk perceptions of a hazardous waste site. First, a pretest obtains measures of attitudes and beliefs about hazardous waste and waste sites. Second, a detailed hypothetical “Superfund” scenario, including a complex cleanup plan, is introduced. Finally, indices of health risk estimates, trust, knowledge, and other pertinent beliefs are obtained. Levels of concern, both before and after cleanup, are the dependent variables. Independent variables include risk management options, health risk estimates, trust, and five sociodemographic characteristics. Concern is extremely high prior to cleanup and moderately high after cleanup. Concern is a clear function of health risk estimates. Toxic chemicals from waste sites are viewed as a major cause of multiple health problems, especially cancers. Accurate health risk estimates moderate fears and are linked to levels of education. Education, however, does not explain concern. Trust is a major factor explaining concern and health risk estimates. The implications of these findings for risk communication is discussed.
Risk Perception and the Value of Safety
Authors: McDaniels Timothy L. , Kamlet Mark S. , Fischer Gregory W.
Published: May 2006

This paper examines the relationship between perceived risk and willingness‐to‐pay (WTP)for increased safety from technological hazards in both conceptual and empirical terms. A conceptual model is developed in which a given household's WTP for risk reductions is a function of traditional socioeconomic variables (i.e., income and base level of risk)and perceived characteristics of the hazards (i.e., dread, knowledge, and exposure). Data to estimate the model are obtained through a combined contingent valuation and risk perception survey that considers 10 technological hazards, five of which are well‐defined (e.g., death rates are known and the risks are relatively common)and five are less well‐defined. Econometric results, using TOBIT estimation procedures, support the importance of both types of variables in explaining WTP across all 10 hazards. When the risks are split into two groups, the results show that WTP for well‐defined hazards is most influenced by perceived personal exposure, while WTP for less well‐defined risks is most influenced by levels of dread and severity.
Comparison of the Dependence of the TD50 on Maximum Tolerated Dose for Mutagens and Nonmutagens
Authors: Goodrnan Gay , Wilson Richard
Published: May 2006

The relationship between the minimum TD50(i‐e., the TD50 measured at the most sensitive site)and the maximum dose administered (maxD)in rodent carcinogenicity bioassays was investigated separately for mice and rats. The relationship between log(l/D)and log(l/maxD)was analyzed as a function of(1)mutagenicity and (2)the statistical significance cutoff for selecting the minimum TD50 values. For rat bioassays, the variance of l o g (l)is larger and the correlation of log(l/TD,)with log(l/maxD)is weaker for mutagens than for nonmutagens, suggesting that the rela‐tionship between minimum TD50 and MTD is, in general, stronger for nonmutagens than for mutagens. The difference in correlation does not depend on the TD50 statistical significance cutoff, but the difference in variance is not significant for the most stringently selected dataset. For mouse bioassays, no significant mutagen/nonmutagen differences in log(lRD5)variance are found. A significantly weaker correlation of log(l/TD50)with log(l/maxD)for mutagens in comparison to nonmutagens occurs only for the dataset with minimum TD50 chosen at the least stringent level, suggesting that this difference may be due to chance variation. We also looked for changes in correlation and regression parameters as a function of mutagenic potency in Salmonella; the variance of l o g (l)and its correlation with log(l/maxD)are not found to vary in a consistent manner. Taken as a whole, our results indicate that (1)mutagenicity is a determinant of the TD, dmaxD relationship in rats and (2)any effect that mutagenicity may exert on the TD,dmaxD relationship in mice is unimportant. A pseudo‐single‐dose model, equivalent to that analyzed by Bernstein et al. (Fundurn. Appl. Toxicol. 5, 79‐86, 1985), was imposed upon the experimental data in order to determine the extent to which the resultant artificial datasets reproduce the mutagen/nonmutagen differences in sample variance. We discovered that this model does not approximatethe actual distribution of log(l/TD50)vs. log(l/maxD)closely enough to be useful for examining artifacts in the relationship between these two variables.
Extrapolation of Carcinogenicity Between Species: Qualitative and Quantitative Factors
Authors: Gold Lois Swirsky , Manley Neela B. , Ames Bruce N.
Published: May 2006

Prediction of human cancer risk from the results of rodent bioassays requires two types of extrapolation: a qualitative extrapolation from short‐lived rodent species to long‐lived humans, and a quantitative extrapolation from near‐toxic doses in the bioassay to low‐level human exposures. Experimental evidence on the accuracy of prediction between closely related species tested under similar experimental conditions (rats, mice, and hamsters)indicates that: (1)if a chemical is positive in one species, it will be positive in the second species about 75% of the time; however, since about 50% of test chemicals are positive in each species, by chance alone one would expect a predictive value between species of about 50%. (2)If a chemical induces tumors in a particular target organ in one species, it will induce tumors in the same organ in the second species about 50% of the time. Similar predictive values are obtained in an analysis of prediction from humans to rats or from humans to mice for known human carcinogens. Limitations of bioassay data for use in quantitative extrapolation are discussed, including constraints on both estimates of carcinogenic potency and of the dose‐response in experiments with only two doses and a control. Quantitative extrapolation should be based on an understanding of mechanisms of carcinogenesis, particularly mitogenic effects that are present at high and not low doses.
Modeling Receptor‐Mediated Processes with Dioxin: Implications for Pharmacokinetics and Risk Assessment
Authors: Andersen Melvin E. , Mills Jeremy J. , Gargas Michael L. , Kedderis Lorrene , Birnbaum Linda S. , Neubert Diether , Greenlee William F.
Published: May 2006

Dioxin (2,3,7,8‐tetrachlorodibenzo‐p‐dioxin; TCDD), a widespread polychlorinated aromatic hydrocarbon, caused tumors in the liver and other sites when administered chronically to rats at doses as low as 0.01 μg/kg/day. It functions in combination with a cellular protein, theAh receptor, to alter gene regulation, and this resulting modulation of gene expression is believed to be obligatory for both dioxin toxicity and carcinogenicity. The U.S. EPA is reevaluating its dioxin risk assessment and, as part of this process, will be developing risk assessment approaches for chemicals, such as dioxin, whose toxicity is receptor‐mediated. This paper describes a receptor‐mediated physiologically based pharmacokinetic (PB‐PK) model for the tissue distribution and enzyme‐inducing properties of dioxin and discusses the potential role of these models in a biologically motivated risk assessment. In this model, ternary interactions among the Ah receptor, dioxin, and DNA binding sites lead to enhanced production of specific hepatic proteins. The model was used to examine the tissue disposition of dioxin and the induction of both a dioxin‐binding protein (presumably, cytochrome P4501A2), and cytochrome P4501A1. Tumor promotion correlated more closely with predicted induction of P4501A1 than with induction of hepatic binding proteins. Although increased induction of these proteins is not expected to be causally related to tumor formation, these physiological dosimetry and gene‐induction response models will be important for biologically motivated dioxin risk assessments in determining both target tissue dose of dioxin and gene products and in examining the relationship between these gene products and the cellular events more directly involved in tumor promotion.
A Physiologically Based Pharmacokinetic Assessment of Tetrachloroethylene in Groundwater for a Bathing and Showering Determination
Authors: Rao Hari V. , Brown David R.
Published: May 2006

A two‐step methodology is described to make a health‐based determination for the bathing and showering use of the water from a private well contaminated with volatile organic chemicals. The chemical perchloroethylene (PERC) is utilized to illustrate the approach. First, a chemical‐specific exposure model is used to predict the concentration of PERC in the shower air, shower water, and in the air above the bathtub. Second, a physiologically based pharmacokinetic (PBPK) model is used to predict the concentration of PERC delivered to the target tissue, the brain, since the focus is on neurological endpoints. The simulation exercise includes concurrent dermal and inhalation routes of exposure. A reference target tissue level (RTTL) in the brain is estimated using the PBPK model. A hazard index based on this benchmark guideline is used to make a regulatory determination for bathing and showering use of the contaminated water.
Uncertainties in Pharmacokinetic Modeling for Perchloroethylene: II. Comparison of Model Predictions with Data for a Variety of Different Parameters
Authors: Hattis Dale , White Paul , Koch Paul
Published: May 2006

In this paper we compare expectations derived from 10 different human physiologically based pharmacokinetic models for perchloroethylene with data on absorption via inhalation, and concentrations in alveolar air and venous blood. Our most interesting finding is that essentially all of the models show a time pattern of departures of predictions of air and blood levels relative to experimental data that might be corrected by more sophisticated model structures incorporating either (a) heterogeneity of the fat compartment (with respect to either perfusion or partition coefficients or both) or (b) intertissue diffusion of perchloroethylene between the fat and muscle/VRG groups. Similar types of corrections have recently been proposed to reduce analogous anomalies in the fits of pharmacokinetic models to the data for several volatile anesthetics.(17‐20) A second finding is that models incorporating resting values for alveolar ventilation in the region of 5.4 L/min seemed to be most compatible with the most reliable set of perchloroethylene uptake data.
Comparing Toxicologic and Epidemiologic Studies: Methylene Chloride‐A Case Study
Authors: Stayner Leslie T. , Bailer A. John
Published: May 2006

Exposure to methylene chloride induces lung and liver cancers in mice. The mouse bioassay data have been used as the basis for several cancer risk assessments. (1,2) The results from epidemiologic studies of workers exposed to methylene chloride have been mixed with respect to demonstrating an increased cancer risk. The results from a negative epidemiologic study of Kodak workers have been used by two groups of investigators to test the predictions from the EPA risk assessment models.(3,4) These two groups used very different approaches to this problem, which resulted in opposite conclusions regarding the consistency between the animal model predictions and the Kodak study results. The results from the Kodak study are used to test the predictions from OSHA's multistage models of liver and lung cancer risk. Confidence intervals for the standardized mortality ratios (SMRs) from the Kodak study are compared with the predicted confidence intervals derived from OSHA's risk assessment models. Adjustments for the “healthy worker effect,” differences in length of follow‐up, and dosimetry between animals and humans were incorporated into these comparisons. Based on these comparisons, we conclude that the negative results from the Kodak study are not inconsistent with the predictions from OSHA's risk assessment model.
The Risk of Photochemical Reactions
Authors: Rezvanova Dina R. , Menshikov Valery V.
Published: May 2006

In January 1987, an incident occurred at a petrochemical complex in Salavat, Russia. The incident resulted in the poisioning of 17 people by the products of photochemical smog. This paper describes the incident and discusses the possibility of chemical reactions that pose toxic hazardous situations for chemical plant personnel. Pollutants present in the atmosphere as a result of continuous releases can result in the formation of toxic substances and the poisioning of people, even when permissible levels of concentrations are not exceeded for the initial pollutants. In addition, this paper addresses the need to consider the possibility of secondary chemical reactions in the environment while planning chemical plant activity.
Societal Risk Perception and Media Coverage
Authors: Koné Daboula , Mullet Etienne
Published: May 2006

The study compares societal risk ratings by inhabitants of two countries which differ markedly in terms of geography, economics, politics, and ethnic background, but which are similar as regards media coverage. The two populations were represented by a sample of French students and a sample of Burkina Faso intellectuals. The overall Burkinabè mean ratings appeared much closer to the mean observed in France (and in the United States–roughly 40 out of 100) than the means reported for other countries like Norway or Hungary. The correlation between Burkinabè and French ratings was very high:.852. The findings argue in favor of a practically totally determinant effect of the media in risk perception.
Natural Disasters in the United States as Release Agents of Oil, Chemicals, or Radiological Materials Between 1980‐1989: Analysis and Recommendations
Authors: Showalter Pamela Sands , Myers Mary Fran
Published: May 2006

Generally, hazards research and literature has treated natural and technological disasters as separate entities. This study attempts to determine how frequently interaction between these two types of disaster took place in the United States from 1980‐1989. Data were collected by performing a literature review, contacting organizations and individuals active in hazards research and mitigation, and through a questionnaire sent to the emergency management agencies of all 50 states. The consensus derived from the data is that the number of incidents where natural and technological disasters interact is rising while preparations, which recognize the complications inherent in such combined events, remain cursory. There is a pressing need for states to record, and make available to managers, information regarding the number of combined natural/technological events affecting their areas. Only when such data are available will it be possible to make appropriate decisions regarding the best way to reduce the effects of a natural disaster causing a catastrophic release of hazardous materials.
Dose‐Response Assessment of Airborne Methyl Isothiocyanate (MITC) Following a Metam Sodium Spill
Authors: Alexeeff George V. , Shusterman Dennis J. , Howd Robert A. , Jackson Richard J.
Published: May 2006

A tank car derailment in northern California in 1991 spilled metam sodium into the Sacramento River, and released its breakdown product, methyl isothiocyanate (MITC), into the air. This paper describes the risk evaluation process used. Over 240 individuals reported symptoms such as eye and throat irritation, dizziness, and shortness of breath. Reference exposure levels (RELs) for 1 hr were developed for MITC and compared to exposure concentrations. Ocular irritation in cats was the most sensitive endpoint reported. The no observed adverse effect level (NOAEL), divided by an uncertainty factor (UF) of 100, produced an REL of 0.5 ppb of MITC in air to prevent discomfort. An REL to prevent disability was estimated to be 40 ppb. An REL to prevent life‐threatening injury was estimated to be 150 ppb. Measured MITC levels ranged from 0.2‐37 ppb and estimated peak levels ranged from 140‐1600 ppb. The usefulness of RELs for emergency planning is discussed.
How Children Spend Their Time: A Sample Survey for Use in Exposure and Risk Assessments
Authors: Silvers Abraham , Florence B. Thomas , Rourke Daniel L. , Lorimor Ronald J.
Published: May 2006

Children are becoming an increasingly important focus for exposure and risk assessments because they are more sensitive than adults to environmental contaminants. A necessary step in measuring the extent of children's exposure and in calculating risk assessments is to document how and where children spend their time. This 1990‐1991 survey of 1000 households was designed for this purpose, targeting children between 5 and 12 years of age, in six states in varied geographic regions. The behavior of children was sampled on both weekdays and weekends over all four seasons of the year using a retrospective time diary to allocate time to activities during the previous 24 h. Information was obtained on the kinds and locations of activities, the nature of the microenvironments of the locations, and the time spent in the different environments. Measures of variability in addition to mean hours per day are reported. Results of this study closely match those of earlier research on California children's activities done by the California Air Resources Board. One important finding of the survey was that 5‐ to 12‐year‐old children in all geographic regions spend most of their time indoors at home, indicating that risk assessments should focus on indoor, on‐site hazards.
The Importance of Biological Realism in Dioxin Risk Assessment Models Michael
Authors: Kohn C. , Lucier George W. , Portier Christopher J.
Published: May 2006

Mechanistic mathematical models of hepatocarcinogenesis in the female rat were constructed to investigate possible relationships among the Ah, estrogen, and EGF receptors in TCDD hepato‐carcinogenicity. Each model generates dose‐response curves for the expression of biomarker liver proteins CYP1A1, CYP1A2, and residual plasma membrane EGF receptor consequent to exposure to TCDD. The shapes of the response curves were strongly dependent on the assumed mechanisms of constitutive expression of these proteins. Assuming a constant level of the hepatic Ah receptor, a sigmoidal dose‐response of hepatic CYP1A1 to total liver TCDD was computed. However, inclusion of induction of the Ah receptor by TCDD in a physiologically realistic dosimetric model produced a linear low‐dose response of CYP1A1. This behavior was computed to arise from the net effect of sublinear response of CYP1A1 mRNA to the concentration of the Ah‐TCDD complex and supralinear response of the protein concentration to the mRNA level, illustrating the importance of biological realism in dose‐response modeling. The dosimetric model also computed effects of TCDD on the hepatic estradiol concentration and consequent effects on the binding capacity of the EGF receptor and suggests plausible mechanisms for tumor promotion by TCDD. Setting circulating estradiol levels in the model to values typical of the male rat indicated possible sources of the differences in the responses of the EGF receptor and in development of tumors in the two sexes.
Times Are Tough—Brother, Can You Paradigm?
Authors: Barnes Donald G.
Published: May 2006

Ten years ago, the National Academy of Science released its risk assessment/risk management (RA/RM) “paradigm” that served to crystallize much of the early thinking about these concepts. By defining RA as a four‐step process, operationally independent from RM, the paradigm has presented society with a scheme, or a conceptually common framework, for addressing many risky situations (e.g., carcinogens, noncarcinogens, and chemical mixtures). The procedure has facilitated decision‐making in a wide variety of situations and has identified the most important research needs. The past decade, however, has revealed that additional progress is needed. These areas include addressing the appropriate interaction (not isolation) between RA and RM, improving the methods for assessing risks from mixtures, dealing with “adversity of effect,” deciding whether “hazard” should imply an exposure to environmental conditions or to laboratory conditions, and evolving the concept to include both health and ecological risk. Interest in and expectations of risk assessment are increasing rapidly. The emerging concept of “comparative risk” (i.e., distinguishing between large risks and smaller risks that may be qualitatively different) is at a level comparable to that held by the concept of “risk” just 10 years ago. Comparative risk stands in need of a paradigm of its own, especially given the current economic limitations. “Times are tough; Brother, can you paradigm?”
Managing Uncertainty: The Tropospheric Ozone Challenge
Authors: Chao Hung‐po , Peck Stephen C. , Wan Y. Steve
Published: May 2006

Although it has been over two decades since Congress passed the Clean Air Act of 1968, ozone in the lower atmosphere remains a serious environmental concern in the United States. Significant scientific progress has been made over the past three decades, yet many important uncertainties remain unresolved. How to manage in a situation characterized by these uncertainties is a major challenge that must be overcome to develop an effective ozone abatement strategy. In this paper, we describe a decision framework for evaluation of alternative ozone abatement strategies. The framework, which embodies two major components‐a simulation module and a decision module–incorporates uncertainty in a dynamic decision‐making process and enables evaluation of NOx and VOC controls on a systematic basis. We demonstrate the application of the framework through an illustrative analysis to provide insight into the value of flexible ozone abatement strategies in reducing the total cost of achieving air‐quality goals and the tradeoffs between the timing and the accuracy of additional information.
Treatment of Uncertainty in Performance Assessments for Complex Systems
Authors: Helton Jon C.
Published: May 2006

When viewed at a high level, performance assessments (PAs) for complex systems involve two types of uncertainty: stochastic uncertainty, which arises because the system under study can behave in many different ways, and subjective uncertainty, which arises from a lack of knowledge about quantities required within the computational implementation of the PA. Stochastic uncertainty is typically incorporated into a PA with an experimental design based on importance sampling and leads to the final results of the PA being expressed as a complementary cumulative distribution function (CCDF). Subjective uncertainty is usually treated with Monte Carlo techniques and leads to a distribution of CCDFs. This presentation discusses the use of the Kaplan/Garrick ordered triple representation for risk in maintaining a distinction between stochastic and subjective uncertainty in PAs for complex systems. The topics discussed include (1) the definition of scenarios and the calculation of scenario probabilities and consequences, (2) the separation of subjective and stochastic uncertainties, (3) the construction of CCDFs required in comparisons with regulatory standards (e.g., 40 CFR Part 191, Subpart B for the disposal of radioactive waste), and (4) the performance of uncertainty and sensitivity studies. Results obtained in a preliminary PA for the Waste Isolation Pilot Plant, an uncertainty and sensitivity analysis of the MACCS reactor accident consequence analysis model, and the NUREG‐1150 probabilistic risk assessments are used for illustration.
Evaluating Risk Communications: Completing and Correcting Mental Models of Hazardous Processes, Part II
Authors: Bostrom Ann , Atman Cynthia J. , Fischhoff Baruch , Morgan M. Granger
Published: May 2006

We propose a decision‐analytic framework, called the mental models approach, for evaluating the impact of risk communications. It employs multiple evaluation methods, including think‐aloud protocol analysis, problem solving, and a true‐false test that allows respondents to express uncertainty about their answers. The approach is illustrated in empirical comparisons of three brochures about indoor radon.
A Process for Incorporating Comparative Risk into Environmental Policymaking in Louisiana
Authors: Thompson Regina , Templet Paul H. , Gamman John K. , McCleary Scott T. , Reams Margaret A.
Published: May 2006

The goal of Louisiana's 1990–1991 comparative risk project, also called the Louisiana Environmental Action Plan (LEAP), was to incorporate risk assessment into state environmental planning and policymaking. Scientists, government officials, and citizens were brought together to estimate the relative risk to human health, natural resources, and quality of life posed by 33 selected environmental issues. The issues were then ranked according to their relative estimated risks. It was hoped that this ranking of “comparative risks” would enable state policymakers to target the most important environmental problems and allocate scarce public resources more rationally and efficiently. As a result of the project, the governor issued an Executive Order forming a permanent Public Advisory Committee to continue this type of comparative risk assessment in Louisiana.
Using Automated Emergency Notification Systems to Inform the Public: A Field Experiment
Authors: Rich Richard C. , Conn W. David
Published: May 2006

Research and experience have shown that it can be difficult to get citizens to pay attention to risk messages and preparedness information in the absence of an actual emergency. As the use computerized systems that alert the public to hazards by automatically ringing their home phones increases, we thought it important to ask if tests of these “call down” systems can also be used to convey preemergency information. We worked with a local government to add instructions on how to shelter‐in‐place to the message on a routine test of a call down system. We then surveyed a test group and a control group before and after the test call and a second control group on after the call. The results indicate that the test call raised awareness of the emergency notification system without generating undue concern about the possibility of a chemical accident. Those who received the test call demonstrated significant improvements in their knowledge of how to shelter‐in‐place while no such improvement was observed in those who did not get the call. While the nature of the sample used in this study limits generalizability, we feel this outcome is positive enough to warrant further exploration of this method of disseminating risk information and preparedness instructions.
Calculation of Benchmark Doses from Continuous Data
Authors: Crump Kenny S.
Published: May 2006

A benchmark dose (BMD) is the dose of a substance that corresponds to a prescribed increase in the response (called the benchmark response or BMR) of a health effect. A statistical lower bound on the benchmark dose (BMDL) has been proposed as a replacement for the no‐observed‐adverse‐effect‐level (NOAEL) in setting acceptable human exposure levels. A method is developed in this paper for calculating BMDs and BMDLs from continuous data in a manner that is consistent with those calculated from quantal data. The method involves defining an abnormal response, either directly by specifying a cutoff x0 that separates continuous responses into normal and abnormal categories, or indirectly by specifying the proportion P0 of abnormal responses expected among unexposed subjects. The method does not involve actually dichotomizing individual continuous responses into quantal responses, and in certain cases can be applied to continuous data in summarized form (e.g., means and standard deviations of continuous responses among subjects in discrete dose groups). In addition to specifying the BMR and either x0 or P0, the method requires specification of the distribution of continuous responses, including specification of the dose‐response θ(d) for a measure of central tendency. A method is illustrated for selecting θ(d) to make the probability of an abnormal response any desired dose‐response function. This enables the same dose‐response model (Weibull, log‐logistic, etc.) to be used for the probability of an abnormal response, regardless of whether the underlying data are continuous or quantal. Whenever the continuous responses are normally distributed with standard deviation σ (independent of dose), the method is equivalent to defining the BMD as the dose corresponding to a prescribed change in the mean response relative to σ.
Citizen Advisory Committees and Environmental Policy: What We Know, What's Left to Discover
Authors: Lynn Frances M. , Busenberg George J.
Published: May 2006

Citizen Advisory Committees (CACs) are being used in increasing numbers to provide public input into environmental policy and management decisions. While there is a large body of literature consisting of guidelines for establishing and running CACs, the body of literature of empirical evaluations of CACs is markedly smaller. Fourteen empirical studies of CACs involved in environmental policy decisions (spanning the period from 1976 to 1994) are reviewed here, including case studies, large‐scale surveys, and consultant reports. For each study consideration is given to the methods of study, the issues considered by the CACs, the organizations advised, the definitions of success used in the study, and the suggested factors contributing to the success, or lack of success, experienced by the CACs. The review shows that the influence of CACs on policy outcomes have varied from case to case, with some accomplishing little and others having significant policy impacts. The increased use of CACs by government and industry presents an excellent opportunity for academics and practitioners to strengthen their understanding of the internal processes and capabilities of CACs through comparative evaluation research.
Physiologically‐Based Pharmacokinetic Modeling of a Mixture of Toluene and Xylene in Humans
Authors: Tardif Robert , Laparé Sylvain , Charest‐Tardif Ginette , Brodeur Jules , Krishnan Kannan
Published: May 2006

A physiologically‐based pharmacokinetic (PBPK) model for a mixture of toluene (TOL) and xylene (XYL), developed and validated in the rat, was used to predict the uptake and disposition kinetics of TOL/XYL mixture in humans. This was accomplished by substituting the rat physiological parameters and the blood:air partition coefficient with those of humans, scaling the maximal velocity for hepatic metabolism on the basis of body weight0.75, and keeping all other model parameters species‐invariant. The human TOL/XYL mixture PBPK model, developed based on the quantitative biochemical mechanism of interaction elucidated in the rat (i.e., competitive metabolic inhibition), simulated adequately the kinetics of TOL and XYL during combined exposures in humans. The simulations with this PBPK model indicate that an eight hour co‐exposure to concentrations that remain within the current threshold limit values of TOL (50 ppm) and XYL (100 ppm) would not result in significant pharmacokinetic interferences, thus implying that data on biological monitoring of worker exposure to these solvents would be unaffected during co‐exposures.
Perception of Nuclear Energy and Coal in France and the Netherlands
Authors: Wiegman Oene , Gutteling Jan M. , Cadet Bernard
Published: May 2006

This study focuses on the perception of large scale application of nuclear energy and coal in the Netherlands and France. The application of these energy‐sources and the risks and benefits are judged differently by various group in society. In Europe, France has the highest density of nuclear power plants and the Netherlands has one of the lowest. In both countries scientists and social scientists completed a questionnaire assessing the perception of the large scale application of both energy sources. Furthermore, a number of variables relating to the socio cultural and political circumstances were measured. The results indicate that the French had a higher risk perception and a more negative attitude toward nuclear power than the Dutch. But they also assess the benefits of the use of nuclear power to be higher. Explanations for these differences are discussed.
Groundwater to Surface Water Conversion in the Houston‐Galveston Region: Impact of Mandates on Water Quality, Subsidence, and Water Rates
Authors: Larson John R. , Dziuk Larry J.
Published: May 2006

Legislative mandates have resulted in large‐scale conversion from groundwater to surface water sources of supply for Public Water Supply Systems in Harris and Galveston Counties, Texas. Geographically‐defined Regulatory Areas in the region are governed by the Harris Galveston Coastal Subsidence District. The district's mission, to end subsidence or loss of land elevation by allocating water usage by Area, has focused attention on potential health hazards and monetary issues related to substandard water quality and increased consumer utility rates. Study variables of: (1) Total Hardness (TH); (2) Total Trihalomethanes (TTHMs) concentrations; and (3) Water Utility Rates ($), were compared for each water source because of their suggested impacts on human health (TH:CVD; TTHMs:Cancer) and relative economic welfare (Utility Rates: $) as byproducts of current mandate requirements. Strong evidence of statistically significant differences in water quality parameters, and utility rates of groundwater and surface water source data, suggest that regulations dictating conversion need review and possible amending. This presentation describes the results of a 2‐year study of the issues regarding conversion of Public Water supplies from groundwater to surface water.
Determination of a Tolerable Daily Intake of DDT for Consumers of DDT Contaminated Fish from the Lower Yakima River, Washington*
Authors: Mariën Koenraad , Laflamme Denise M.
Published: May 2006

DDT, DDE, and DDD have been detected at elevated concentrations in sediments and fish of the Yakima River, its tributaries and drainages. An assessment was conducted to evaluate the public health significance of eating fish from the river. This was accomplished by establishing a daily intake level of DDT for the population of greatest concern, and comparing this level to a tolerable daily intake. The most sensitive and highly exposed group was determined to be breastfeeding infants. Infant daily intakes of DDT, based on estimated mother's DDT‐breast milk levels, were compared to a recommended tolerable daily intake. Results indicate that mothers who frequently consume Yakima River bottom‐feeding fish could have breast milk DDT concentrations sufficiently high to expose their infants to levels above the tolerable daily intake.
Risk Perception: An Empirical Study of the Relationship Between Worldview and the Risk Construct
Authors: Palmer Christina G. S.
Published: May 2006

This study empirically assesses the performance of Holtgrave and Weber's Simplified Conjoint Expected Risk (SCER) model for financial and health stimuli in 3 groups of “worldview holders”—12 hierarchists, 10 individualists, and 16 egalitarians—as described by cultural theory. The SCER model performed well, however, distinctive patterns of model variable selection appeared within each group. Interestingly, the pattern of variable selection paralleled cultural theory's descriptions of each worldview. Differences in the mean perceived risk of activities also tended to correspond to predictions made by cultural theory. Results suggest two mechanisms to explain differences in perceived risk among worldviews: (i) same model variables are evaluated, but given different weight; (ii) different variables are evaluated. Identifying the relevant mechanism for a given situation may enhance the effectiveness of risk communication.
Estimation of Dietary Exposure to Chemicals: A Case Study Illustrating Methods of Distributional Analyses for Food Consumption Data
Authors: Driver Jeffrey H. , Ginevan Michael E. , Whitmyre Gary K.
Published: May 2006

There are a number of sources of variability in food consumption patterns and residue levels of a particular chemical (e.g., pesticide, food additive) in commodities that lead to an expected high level of variability in dietary exposures across a population. This paper focuses on examples of consumption pattern survey data for specific commodities, namely that for wine and grape juice, and demonstrates how such data might be analyzed in preparation for performing stochastic analyses of dietary exposure. Data from the NIAAA/NHIS wine consumption survey were subset for gender and age group and, with matched body weight data from the survey database, were used to define empirically‐based percentile estimates for wine intake (μl wine/kg body weight) for the strata of interest. The data for these two subpopulations were analyzed to estimate 14‐day consumption distributional statistics and distributions for only those days on which wine was consumed. Data subsets for all wine‐consuming adults and wine‐consuming females ages 18 through 45, were determined to fit a lognormal distribution (R2= 0.99 for both datasets). Market share data were incorporated into estimation of chronic exposures to hypothetical chemical residues in imported table wine. As a separate example, treatment of grape juice consumption data for females, ages 18–40, as a simple lognormal distribution resulted in a significant underestimation of intake, and thus exposure, because the actual distribution is a mixture (i.e., multiple subpopulations of grape juice consumers exist in the parent distribution). Thus, deriving dietary intake statistics from food consumption survey data requires careful analysis of the underlying empirical distributions.
Developing and Testing a Facility Location Model for Canadian Nuclear Fuel Waste
Authors: Ballard Kevin R. , Kuhn Richard G.
Published: May 2006

The purpose of this paper is to develop and test a facility location model for the siting of a nuclear fuel waste disposal facility in Canada. The model is based on successful Canadian siting processes related to hazardous waste and low level radioactive waste facilities, as well as attributes of facility siting found in the literature. The proposed model was presented to a sample of participants in the federal environmental assessment review of the technical feasibility of the Canadian Nuclear Fuel Waste Disposal Concept (CNFWDC) held throughout Canada in 1990. Results demonstrate that despite the fact that over half of the survey respondents did not support the CNFWDC during the public hearings, the majority favorably rated the proposed facility location model. Components of the model that were tested included siting criteria and goals, decision‐making groups, and siting safeguards. On the basis of these results, it is concluded that the siting of a nuclear fuel waste disposal facility must make the decentralization of decision‐making authority to local communities and governments a priority.
Fishing in a Polluted Estuary: Fishing Behavior, Fish Consumption, and Potential Risk
Authors: May Helen , Burger Joanna
Published: May 2006

People make subjective judgments about hazards relying on what they know and feel. These risk perceptions may be based on accurate or inaccurate information and are often optimistically biased. The existence of uncertainties in the evaluation of many environmental hazards effects how risks are perceived. This paper examines fish consumption and risk perception of urban fishermen in the New York/New Jersey estuary, in areas where there were consumption advisories. We interviewed 318 fishermen and crabbers in the Arthur Kill, Raritan Bay, and New Jersey shore. Fish were eaten an average of at least four times per month in all regions, but fishermen in the Arthur Kill fished most frequently, averaging over eight times per month. Although 60% of fishermen and crabbers in the Arthur Kill reported hearing warnings about consuming fish caught in these waters, 70% of fishermen and 76% of crabbers said they ate their catch. Significantly fewer fishermen in the Bay and Shore regions had heard warnings (28% and 30%, respectively), and more reported consuming their catch (88% and 82%, respectively). In all regions, most people thought that the fish were safe to eat, many believing they were “fresher” than store bought fish. Thus, most people ignored the consumption advisories in effect for these waters. Some of these people are consuming high quantities of fish and crabs, and thus are exposed to potentially deleterious levels of contaminants. In general, people failed to consider the possibility of chronic effects and did not perceive that this enjoyable, familiar pastime could be hazardous. Further, fishermen generally had great confidence in their own knowledge, which proved to be inaccurate in many cases, and often expressed distrust in the information source (government). Clearly, simply issuing consumption advisories is insufficient to promote risk‐reducing behavior.
An Analytical Framework for Relating Dose, Risk, and Incidence: An Application to Occupational Tuberculosis Infection
Authors: Nicas Mark
Published: May 2006

An adverse health impact is often treated as a binary variable (response vs. no response), in which case the risk of response is defined as a monotonically increasing function R of the dose received D. For a population of size N, specifying the forms of R(D) and of the probability density function (pdf) for D allows determination of the pdf for risk, and computation of the mean and variance of the distribution of incidence, where the latter parameters are denoted E[SN] and Var[SN], respectively. The distribution of SN describes uncertainty in the future incidence value. Given variability in dose (and risk) among population members, the distribution of incidence is Poisson‐binomial. However, depending on the value of E[SN], the distribution of incidence is adequately approximated by a Poisson distribution with parameter μ=E[SN], or by a normal distribution with mean and variance equal to E[SN] and Var[SN]. The general analytical framework is applied to occupational infection by Mycobacterium tuberculosis (M. tb). Tuberculosis is transmitted by inhalation of 1–5 μm particles carrying viable M. tb bacilli. Infection risk has traditionally been modeled by the expression: R(D)= 1 – exp(–D), where D is the expected number of bacilli that deposit in the pulmonary region. This model assumes that the infectious dose is one bacillus. The beta pdf and the gamma pdf are shown to be reasonable and especially convenient forms for modeling the distribution of the expected cumulative dose across a large healthcare worker cohort. Use of the the analytical framework is illustrated by estimating the efficacy of different respiratory protective devices in reducing healthcare worker infection risk.
The Determinants of Trust and Credibility in Environmental Risk Communication: An Empirical Study
Authors: Peters Richard G. , Covello Vincent T. , McCallum David B.
Published: May 2006

This study examines a key component of environmental risk communication; trust and credibility. The study was conducted in two parts. In the first part, six hypotheses regarding the perceptions and determinants of trust and credibility were tested against survey data. The hypotheses were supported by the data. The most important hypothesis was that perceptions of trust and credibility are dependent on three factors: perceptions of knowledge and expertise; perceptions of openness and honesty; and perceptions of concern and care. In the second part, models were constructed with perceptions of trust and credibility as the dependent variable. The goal was to examine the data for findings with direct policy implications. One such finding was that defying a negative stereotype is key to improving perceptions of trust and credibility.
Culture, Cosmopolitanism, and Risk Management
Authors: Earle Timothy C. , Cvetkovich George
Published: May 2006

Most cultural approaches to risk management deal with the connections between the forms of social relations within groups and the risk concerns of those groups. According to these theories, a certain limited set of different relational forms (usually three, four, or five) lead to specific, different and conflicting, risk concerns. In contrast to these theories, cosmopolitanism is an approach to culture that focuses, not on forms of sociality, but on changes among forms—expansions and contractions in the inclusivity of forms and movement by persons from one form of sociality to another. Relative to other cultural theories, cosmopolitanism thus is much more concerned with the solution of risk management problems than with their origins. Cosmopolitanism can be thought of as a cultural continuum, with cosmopolitanism at one end and pluralism at the other. Cosmopolitan persons are more open to cultural change—and thus the solution of risk management problems. In this article, we outline our new theory of cosmopolitanism, describe a method for measuring it and present an experimental study that tests some implications of the theory. Results from the study support the theory by showing that, compared to pluralistic respondents, cosmopolitan respondents are more inclusive in their risk management judgments—that is, they express equal concern for a local and a national issue, whereas the pluralistic respondents express greater concern in the local case. We discuss the risk management implications of a cosmopolitan approach to culture.