bluuebunny/crossref_metadata_2025 huggingface dataset:
Societal Risk as Seen by the French Public
Authors: Karpowicz‐Lazreg C. , Mullet E.
Published: May 2006

Mean risk magnitude judgments expressed by French students on 90 hazardous activities are reported and compared with findings on American, Hungarian, and Norwegian samples. In many respects, rating of perceived risk in the French sample is highly comparable to rating in American subjects. American and French people tend to share the same preoccupations to the same extent. The only major differences concern hallucinatory drugs and oral contraceptives. The Norwegians and French ratings differ much more. Norwegians and French people generally have the same preoccupations (which make Norwegian ratings the best predictor of French ratings) but not to the same extent. The French are much more concerned with a whole series of activities connected to violence, the implementation of high technology or agricultural technology. However, like the Norwegians, the French are extremely concerned about the spread of hallucinogenic drugs. The Hungarian and French ratings differ on practically all instances, except on basic activities or substances in all industrialized nations (caffeine, motorcycles, …). Differences were observed within the French sample itself. Women more than men consider that home appliances in general and large‐scale public transportation are potentially dangerous. Science students more than art students tend to fear a certain number of medical techniques and a certain number of toxic substances (e.g., smoking).
Risk Assessment of Nitrated Polycyclic Aromatic Hydrocarbons
Authors: Möller L. , Lax I. , Torndal U.‐B. , Eriksson L. C.
Published: May 2006

Nitrated polycyclic aromatic hydrocarbons (nitro‐PAHs) constitute a group of substances formed during incomplete combustion. Sources include diesel vehicles, heating, smoking, certain types of food‐processing, and incomplete combustion in general. 2‐Nitrofluorene (NF) represents a model substance for the nitro‐PAHs. An attempt has been made to estimate the lifetime human cancer risk due to background exposure to nitro‐PAHs by two different models. The first model is based on genotoxic lesions produced by gamma‐irradiation and the second model is based on an earlier published mega study (24,000 animals) on the carcinogenicity of the major metabolite of NF. Both models agreed well‐representing a yearly human cancer risk in the range of 0.15–49 × 10−6 for an urban citizen. The weaknesses and strengths of the models are discussed.
Should Persons with Diabetes Be Licensed to Drive Trucks?—Risk Management
Authors: Lave Lester B. , Songer Thomas J. , LaPorte Ronald E.
Published: May 2006

How should a regulatory agency interpret a risk analysis that concludes there is a small increase in risk? The agency must decide on behalf of society whether the increased risk is large enough to justify banning the risky activity or taking some other step to lessen the risks. In a companion paper (Songer et al.), we conclude that licensing insulin using persons to drive commercial motor vehicles in interstate commerce would result in 42 additional crashes each year. Here we address risk management issues by interpreting the number of additional crashes and the relative risks of the prospective handicapped drivers. Are the number of additional crashes (42) significant? Is the increase in the annual crash risk (from 0.00785 to 0.032 for non‐insulin dependent and 0.048 for insulin dependent persons) significant? Are the relative risks significant for all insulin using drivers (4.7)? For drivers with a history of severe hypoglycemic reactions (19.8)? How should society tradeoff risk increases for increases in opportunity for these handicapped persons? We review other social decisions concerning highway safety: Accepting the increasing risks of letting 16 year olds drive, allowing extremely light cars, allowing some unsafe highways, and allowing extremely unsafe driving conditions at some times of day. We conclude that the additional risks from insulin using persons are well within the current accepted range of risks. Currently, 70% of states permit insulin using persons to drive trucks within their state. Nonetheless, the social cost, due to fatalities, injuries, and property damage from allowing a person with a history of severe hypoglycemic reactions to drive is more than $19,700 per year.
An Investigation of Indoor Air Contamination in Residences Above Dry Cleaners
Authors: Schreiber Judith S. , House Stanley , Prohonic Elizabeth , Smead Gregory , Hudson Charles , Styk Michael , Lauber Jack
Published: May 2006

An investigation of residences located above dry cleaning facilities was conducted to determine whether indoor and outdoor air concentrations of the dry cleaning solvent tetrachloroethene (perchloroethylene, PCE) were elevated compared to residences not near a dry cleaning facility. Data were also collected on the dry cleaners' operating conditions and equipment. Significantly elevated levels of PCE were found in the indoor air of each of six apartments located above dry cleaners compared to control residences for both day and night samples. The PCE concentrations in outdoor air near the dry cleaners were also significantly elevated compared to control locations and were lower than the concentrations measured indoors. The type of dry cleaning machine was significantly associated with the concentration of PCE found in the apartment above. A strong correlation was also found between the day and night PCE levels in the study apartments.
A Distributional Approach to Characterizing Low‐Dose Cancer Risk
Authors: Evans John S. , Graham John D. , Gray George M. , Sielken Robert L.
Published: May 2006

Since cancer risk at very low doses cannot be directly measured in humans or animals, mathematical extrapolation models and scientific judgment are required. This article demonstrates a probabilistic approach to carcinogen risk assessment that employs probability trees, subjective probabilities, and standard bootstrapping procedures. The probabilistic approach is applied to the carcinogenic risk of formaldehyde in environmental and occupational settings. Sensitivity analyses illustrate conditional estimates of risk for each path in the probability tree. Fundamental mechanistic uncertainties are characterized. A strength of the analysis is the explicit treatment of alternative beliefs about pharmacokinetics and pharmacodynamics. The resulting probability distributions on cancer risk are compared with the point estimates reported by federal agencies. Limitations of the approach are discussed as well as future research directions.
Assessing Health Risks Associated with DDT Residues in Soils in California: A Proposition 65 Case Study
Authors: Lowe John A. , Jamall Ijaz S.
Published: May 2006

Population growth in California has increased the pressure to convert agricultural land to commercial, industrial, or residential uses. In the ensuing property transactions, buyers and sellers must address the presence of toxic materials in soils such as pesticides, several of which are known to the State of California to cause cancer under Proposition 65. While this statute does not specifically address soil contaminants, the potential scope of its enforcement is sufficiently broad that owners of former agricultural properties may be obliged to provide warning of exposure to potential buyers, occupants, or construction workers about exposure to residues in soil from pesticide applications. However, Proposition 65 provides no guidance on how to assess exposures to chemicals in soil. The U.S. EPA Risk Assessment Guidance for Superfund (RAGS) provides a method for assessing soil‐related exposure pathways that is consistent with the intent of Proposition 65. Using this approach, we have calculated the lifetime average concentrations of DDT in soil corresponding to the no‐significant‐risk level stipulated under Proposition 65 (1 × 10−5) for a hypothetical residential exposure scenario. The concentration of DDT in soil corresponding to a no‐significant‐risk ranges from 7.9‐18.8 mg/kg, depending upon which exposure pathways are deemed to be complete for residential land use. It is argued that Proposition 65 forces the assessment and possible cleanup of such a situation through the threat of creating a health risk perception that could affect the market value of a property.
The Benefits of Probabilistic Exposure Assessment: Three Case Studies Involving Contaminated Air, Water, and Soil1
Authors: Finley Brent , Paustenbach Dennis
Published: May 2006

Probabilistic risk assessments are enjoying increasing popularity as a tool to characterize the health hazards associated with exposure to chemicals in the environment. Because probabilistic analyses provide much more information to the risk manager than standard “point” risk estimates, this approach has generally been heralded as one which could significantly improve the conduct of health risk assessments. The primary obstacles to replacing point estimates with probabilistic techniques include a general lack of familiarity with the approach and a lack of regulatory policy and guidance. This paper discusses some of the advantages and disadvantages of the point estimate vs. probabilistic approach. Three case studies are presented which contrast and compare the results of each. The first addresses the risks associated with household exposure to volatile chemicals in tapwater. The second evaluates airborne dioxin emissions which can enter the food‐chain. The third illustrates how to derive health‐based cleanup levels for dioxin in soil. It is shown that, based on the results of Monte Carlo analyses of probability density functions (PDFs), the point estimate approach required by most regulatory agencies will nearly always overpredict the risk for the 95th percentile person by a factor of up to 5. When the assessment requires consideration of 10 or more exposure variables, the point estimate approach will often predict risks representative of the 99.9th percentile person rather than the 50th or 95th percentile person. This paper recommends a number of data distributions for various exposure variables that we believe are now sufficiently well understood to be used with confidence in most exposure assessments. A list of exposure variables that may require additional research before adequate data distributions can be developed are also discussed.
Can Long‐Term Exposure Distributions Be Predicted from Short‐Term Measurements?
Authors: Wallace Lance A. , Duan Naihua , Ziegenfus Robert
Published: May 2006

A method for estimating long‐term distributions of exposure based on repeated short‐term measurements within the same population is developed. If the short‐term measurements span seasonal variation, and if the distributions are log‐normal or nearly so, then long‐term distributions can be estimated from as few as two visits to the same population. The method is illustrated using examples drawn from EPA's TEAM Study of exposures to volatile organic compounds.
Exposure to Chlorination By‐Products from Hot Water Uses
Authors: Weisel Clifford P. , Chen Wei Jie
Published: May 2006

Exposures to chlorination by‐products (CBP) within public water supplies are multiroute in water. Cold water is primarily used for ingestion while a mixture of cold water and hot water is used for showering, bathing others, dish washing, etc. These latter two activities result in inhalation and dermal exposure. Heating water was observed to change the concentration of various CBP. An increase in the trihalomethanes (THM) concentrations and a decrease in the haloacetonitriles and halopropanones concentration, though an initial rise in the concentration of dichloropropanone, were observed. The extent of the increase in the THM is dependent on the chlorine residual present. Therefore, estimates of total exposure to CBP from public water supplies need to consider any changes in their concentration with different water uses. The overall THM exposures calculated using the THM concentration in heated water were 50% higher than those calculated using the THM concentration present in cold water. The estimated lifetime cancer risk associated with exposure to THM in water during the shower is therefore underestimated by 50% if the concentration of THM in cold water is used in the risk assessment.
Awareness of Bad News, Environmental Attitudes, and Subjective Estimates of Coastal Pollution
Authors: Eiser J. Richard , Reicher Steven D. , Podpadec Tessa J.
Published: May 2006

Questionnaires distributed to 154 holiday‐makers on beaches in Southwest England assessed awareness of local hazards or incidents associated with either the electricity supply industry or the water and sewage industry and examined the relationship between awareness and evaluations of the industry, current and future levels of pollution on the beach in question, and general levels of concern about environmental pollution. With respect to electricity, those respondents who were more aware of reports claiming a higher incidence of childhood leukemia in the vicinity of a nearby nuclear plant evaluated the electricity industry as less competent or trustworthy, showed higher levels of environmental concern, and were more pessimistic in their estimates of present and future levels of specific pollutants on their beach. With respect to the water industry, similar effects were associated with greater awareness of an accident at a water treatment plant and agricultural pollution of a nearby estuary. These findings are interpreted as suggesting a cyclical relationship between risk awareness and concern. On the one hand, reports about environmental hazards may lead to generalized concern across specific contexts; on the other hand, greater levels of concern may sensitize individuals to such reports.
Risk Decision Making in Operational Safety Management– Experience from the Nordic Benchmark Study
Authors: Holmberg Jan , Pulkkinen Urho , Pörn Kurt , Shen Kecheng
Published: May 2006

Technical Research Centre of Finland (VTT) and Studsvik AB, Sweden, have simulated decision making of the Swedish Nuclear Power Inspectorate and a power company by applying decision models in a benchmark study. Based on the experience from the benchmark study, a decision analysis framework to be used in safety related problems is outlined. By this framework both the power companies and the safety authorities could be provided with a more rigorous, systematic approach in their decision making. A decision analytic approach provides a structure for identifying the information requirements of the problem solving. Thus it could serve as a discussion forum between the authorities and the utilities. In this context, probabilistic safety assessment (PSA) has a crucial role of expressing the plant safety status in terms of reactor core damage accident probability and of risk contributions from various accident precursors. However, a decision under uncertainty should not be based solely on probabilities, particularly when the event in question is a rare one and its probability of occurrence is estimated by means of different kinds of approximations.
Estimating Upper Confidence Limits for Extra Risk in Quantal Multistage Models
Authors: Bailer A. John , Smith Randall J.
Published: May 2006

Multistage models are frequently applied in carcinogenic risk assessment. In their simplest form, these models relate the probability of tumor presence to some measure of dose. These models are then used to project the excess risk of tumor occurrence at doses frequently well below the lowest experimental dose. Upper confidence limits on the excess risk associated with exposures at these doses are then determined. A likelihood‐based method is commonly used to determine these limits. We compare this method to two computationally intensive “bootstrap” methods for determining the 95% upper confidence limit on extra risk. The coverage probabilities and bias of likelihood‐based and bootstrap estimates are examined in a simulation study of carcinogenicity experiments. The coverage probabilities of the nonparametric bootstrap method fell below 95% more frequently and by wider margins than the better‐performing parametric bootstrap and likelihood‐based methods. The relative bias of all estimators are seen to be affected by the amount of curvature in the true underlying dose‐response function. In general, the likelihood‐based method has the best coverage probability properties while the parametric bootstrap is less biased and less variable than the likelihood‐based method. Ultimately, neither method is entirely satisfactory for highly curved dose‐response patterns.
Derivation of a Target Level of Lead in Soil at Residential Sites Corresponding to a De Minimis Contribution to Blood Lead Concentration1
Authors: Stern Alan H.
Published: May 2006

Inability to define either a clear toxicologic threshold or a stochastic all‐or‐nothing (cancer‐type) response model for the noncarcinogenic effects of lead (Pb) in young children has posed difficulties for derivation of risk‐based target levels of Pb in residential soil. Approaches based on empirical relationships between Pb levels in blood (PbB) and Pb in soil suffer from inability to specify the numerous variables which mediate between these two quantities. Approaches based on achieving a toxicologically de minimis target PbB level (e.g., 10 μg/dl) are subject to large uncertainty in estimating the distribution of existing PbB levels in a specific exposed population and in estimating the relative contribution from nonsoil sources of Pb. The multisource contribution to the distribution of PbB makes this approach unsuited for determination of a target Pb level in a single medium. An alternative approach is presented based on achieving a de minimis contribution to PbB (ΔPbB) from soil. Contributions to Pb exposure from outdoor soil and indoor soil‐derived dust (ISDD) are modeled and appropriate values are suggested for input parameters. This analysis predicts that chronic exposure of young children to 200 μg Pb/g (ppm) in residential soil will result in a ΔPbB of 2 μg Pb/dl blood. This concentration of Pb in soil may provide an appropriate target level for residential soil when other significant sources of Pb exposure are present. In other cases, this approach can be used to predict a soil concentration of Pb corresponding to an appropriate non‐de minimisΔPbB.
Design of Developmental Toxicity Studies for Assessing Joint Effects of Dose and Duration
Authors: Scharfstein Daniel O. , Williams Paige L.
Published: May 2006

In the assessment of developmental and reproductive effects, the timing and duration of exposures to chemical compounds or other environmental contaminants are of particular interest, as the gestational cycle is known to have periods of increased sensitivity. The goal of this research is to identify optimal experimental designs for conducting developmental toxicity studies when the effects of both exposure level and duration of exposure are of interest. The elements of the study design considered in this evaluation are the allocation of animals to dose‐duration exposure groups and the determination of the most efficient intermediate exposure levels. The optimality of various designs is assessed via the accuracy of the estimated excess risk as well as testing criteria. Simulation studies are conducted to compare these criteria and determine optimal design strategies under various underlying dose‐response patterns. Asymptotic results are also derived to lend support to the simulation studies.
Mechanistic Insights Aid the Search for CFC Substitutes: Risk Assessment of HCFC‐123 as an Example
Authors: Jarabek Annie M. , Fisher Jeffrey W. , Rubenstein Reva , Lipscomb John C. , Williams R. Joel , Vinegar Allen , McDougal James N.
Published: May 2006

An international consensus on the need to reduce the use of chlorofluorocarbons (CFCs) and other ozone‐depleting gases such as the halons led to the adoptions of the 1987 Montreal Protocol and Title VI of the 1990 Clean Air Act Amendments, “Protecting Stratospheric Ozone.” These agreements included major provisions for reducing and eventually phasing out production and use of CFCs and halons as well as advancing the development of replacement chemicals. Because of the ubiquitous use and benefits of CFCs and halons, an expeditious search for safe replacements to meet the legislative deadlines is of critical importance. Toxicity testing and health risk assessment programs were established to evaluate the health and environmental impact of these replacement chemicals. Development and implementation of these programs as well as the structural‐activity relationships significant for the development of the replacement chemicals are described below. A dose‐response evaluation for the health risk assessment of the replacement chemical HCFC‐123 (2,2‐dichloro‐1,1,1‐trifluoroethane) is also presented to show an innovative use of physiologically based pharmacokinetic (PBPK) modeling. This is based on a parallelogram approach using data on the anesthetic gas halothane, a structural analog to HCFC‐123. Halothane and HCFC‐123 both form the same metabolite, trifluoroacetic acid (TFA), indicative of the same metabolic oxidative pathway attributed to hepatotoxicity. The parallelogram approach demonstrates the application of template model structures and shows how PBPK modeling, together with judicious experimental design, can be used to improve the accuracy of health risk assessment and to decrease the need for extensive laboratory animal testing.
Modeling for Risk Assessment of Neurotoxic Effects
Authors: Gaylor David W. , Slikker William
Published: May 2006

The regulation of noncancer toxicants, including neurotoxicants, has usually been based upon a reference dose (allowable daily intake). A reference dose is obtained by dividing a no‐observed‐effect level by uncertainty (safety) factors to account for intraspecies and interspecies sensitivities to a chemical. It is assumed that the risk at the reference dose is negligible, but no attempt generally is made to estimate the risk at the reference dose. A procedure is outlined that provides estimates of risk as a function of dose. The first step is to establish a mathematical relationship between a biological effect and the dose of a chemical. Knowledge of biological mechanisms and/or pharmacokinetics can assist in the choice of plausible mathematical models. The mathematical model provides estimates of average responses as a function of dose. Secondly, estimates of risk require selection of a distribution of individual responses about the average response given by the mathematical model. In the case of a normal or lognormal distribution, only an estimate of the standard deviation is needed. The third step is to define an adverse level for a response so that the probability (risk) of exceeding that level can be estimated as a function of dose. Because a firm response level often cannot be established at which adverse biological effects occur, it may be necessary to at least establish an abnormal response level that only a small proportion of individuals would exceed in an unexposed group. That is, if a normal range of responses can be established, then the probability (risk) of abnormal responses can be estimated. In order to illustrate this process, measures of the neurotransmitter serotonin and its metabolite 5‐hydroxyindoleacetic acid in specific areas of the brain of rats and monkeys are analyzed after exposure to the neurotoxicant methylene‐dioxymethamphetamine. These risk estimates are compared with risk estimates from the quantal approach in which animals are classified as either abnormal or not depending upon abnormal serotonin levels.
Why Rules for Risk Communication Are Not Enough: A Problem‐Solving Approach to Risk Communication
Authors: Rowan Katherine E.
Published: May 2006

Current work on risk communication offers practitioners helpful guidelines and rules such as “speak clearly” and “speak with compassion.” While important, these guidelines have limitations. They offer practitioners and scholars little aid in determining why a communication encounter failed. Also, they do not help practitioners anticipate and overcome likely difficulties in future risk situations, nor can they help locate information about how to reduce these difficulties. To overcome the limitations of rule‐based approaches to risk communication, this paper describes a diagnostic or problem‐solving approach. This approach maintains that instead of rules, people need bases for anticipating likely obstacles to effective communication and selecting approaches that reduce these difficulties. Research on building trust, increasing awareness, deepening comprehension, gaining agreement, and motivating action is available in fields such as communication, educational psychology, science education, marketing, counseling, negotiation, and disaster response. This paper describes a framework that assists scholars and practitioners in: (a) identifying communication goals; (b) determining principal obstacles to those goals; and (c) selecting research‐based methods for overcoming or minimizing these difficulties and achieving communication objectives.
Lognormal Distributions for Fish Consumption by the General U.S. Population
Authors: Ruffle Betsy , Burmaster David E. , Anderson Paul D. , Gordon Henry D.
Published: May 2006

The rate of fish consumption is a critical variable in the assessment of human health risk from water bodies affected by chemical contamination and in the establishment of federal and state Ambient Water Quality Criteria (AWQC). For 1973 and 1974, the National Marine Fisheries Service (NMFS) analyzed data on the consumption of salt‐water finfish, shellfish, and freshwater finfish from all sources in 10 regions of the United States for three age groups in the general population: children (ages 1 through 11 years), teenagers (ages 12 through 18 years), and adults (ages 19 through 98 years). Even though the NMFS data reported in Ref. 14 are 20 years old, they remain the most complete data on the overall consumption of all fish by the general U.S. population and they have been widely used to select point values for consumption. Using three methods, we fit lognormal distributions to the results of the survey as analyzed and published in Ref. 14. Strong lognormal fits were obtained for most of the 90 separate data sets. These results cannot necessarily be used to model the consumption of fish by sport or subsistence anglers from specific sites or from single water bodies.
Uses of Probabilistic Exposure Models in Ecological Risk Assessments of Contaminated Sites
Authors: Macintosh David L. , Suter Glenn W. , Hoffman F. Owen
Published: May 2006

Food web models have two uses in assessments of environmental contaminants. First, they are used to determine whether remediation is needed by estimating exposure of end‐point species and subsequent effects. Second, they are used to establish cleanup goals by estimating concentrations of contaminants in ambient media that will not cause significant effects. This paper demonstrates how achievement of these goals can be enhanced by the use of stochastic food web models. The models simulate the dynamics of PCBs and mercury in the food webs of mink and great blue herons. All parameters of the models are treated as having knowledge uncertainty, due to imperfect knowledge of the actual parameter values for the site, chemicals, and species of interest. This uncertainty is an indicator of the potential value of additional measurements. In addition, those parameters that are responsible for variance among individual organisms are assigned stochastic uncertainty. This uncertainty indicates the range of body burdens that are expected when the end‐point species are monitored. These two types of uncertainty are separately accounted for in Monte Carlo simulations of the models. Preliminary monitoring results indicate that the models give reasonably good estimates of heron egg and nestling body burdens and of variance among individuals.
Principles of Good Practice for the Use of Monte Carlo Techniques in Human Health and Ecological Risk Assessments
Authors: Burmaster David E. , Anderson Paul D.
Published: May 2006

We propose 14 principles of good practice to assist people in performing and reviewing probabilistic or Monte Carlo risk assessments, especially in the context of the federal and state statutes concerning chemicals in the environment. Monte Carlo risk assessments for hazardous waste sites that follow these principles will be easier to understand, will explicitly distinguish assumptions from data, and will consider and quantify effects that could otherwise lead to misinterpretation of the results. The proposed principles are neither mutually exclusive nor collectively exhaustive. We think and hope that these principles will evolve as new ideas arise and come into practice.
Estimated Distributions for Average Daily Consumption of Total and Self‐Caught Fish for Adults in Michigan Angler Households
Authors: Murray Donald M. , Burmaster David E.
Published: May 2006

Fish consumption rates play a critical role in the assessment of human health risks posed by the consumption of fish from chemically contaminated water bodies. Based on data from the 1989 Michigan Sport Anglers Fish Consumption Survey, we examined total fish consumption, consumption of self‐caught fish, and consumption of Great Lakes fish for all adults, men, women, and certain higher risk subgroups such as anglers. We present average daily consumption rates as compound probability distributions consisting of a Bernoulli trial (to distinguish those who ate fish from those who did not) combined with a distribution (both empirical and parametric) for those who ate fish. We found that the average daily consumption rates for adults who ate fish are reasonably well fit by lognormal distributions. The compound distributions may be used as input variables for Monte Carlo simulations in public health risk assessments.
Development of a Standard Soil‐to‐Skin Adherence Probability Density Function for Use in Monte Carlo Analyses of Dermal Exposure
Authors: Finley Brent L. , Scott Paul K. , Mayhall Douglas A.
Published: May 2006

It has recently been suggested that “standard” data distributions for key exposure variables should be developed wherever appropriate for use in probabilistic or “Monte Carlo” exposure analyses. Soil‐on‐skin adherence estimates represent an ideal candidate for development of a standard data distribution: There are several readily available studies which offer a consistent pattern of reported results, and more importantly, soil adherence to skin is likely to vary little from site‐to‐site. In this paper, we thoroughly review each of the published soil adherence studies with respect to study design, sampling, and analytical methods, and level of confidence in the reported results. Based on these studies, probability density functions (PDF) of soil adherence values were examined for different age groups and different sampling techniques. The soil adherence PDF developed from adult data was found to resemble closely the soil adherence PDF based on child data in terms of both central tendency (mean = 0.49 and 0.63 mg‐soil/cm2‐skin, respectively) and 95th percentile values (1.6 and 2.4 mg‐soil/cm2‐skin, respectively). Accordingly, a single, “standard” PDF is presented based on all data collected for all age groups. This standard PDF is lognormally distributed; the arithmetic mean and standard deviation are 0.52 ± 0.9 mg‐soil/cm2‐skin. Since our review of the literature indicates that soil adherence under environmental conditions will be minimally influenced by age, sex, soil type, or particle size, this PDF should be considered applicable to all settings. The 50th and 95th percentile values of the standard PDF (0.25 and 1.7 mg‐soil/cm2‐skin, respectively) are very similar to recent U.S. EPA estimates of “average” and “upper‐bound” soil adherence (0.2 and 1.0 mg‐soil/cm2‐skin, respectively).
Summary of the Workshop on Issues in Risk Assessment: Quantitative Methods for Developmental Toxicology
Authors: Mattison Donald R. , Sandler J. David
Published: May 2006

This report summarizes the proceedings of a conference on quantitative methods for assessing the risks of developmental toxicants. The conference was planned by a subcommittee of the National Research Council's Committee on Risk Assessment Methodology4 in conjunction with staff from several federal agencies, including the U.S. Environmental Protection Agency, U.S. Food and Drug Administration, U.S. Consumer Products Safety Commission, and Health and Welfare Canada. Issues discussed at the workshop included computerized techniques for hazard identification, use of human and animal data for defining risks in a clinical setting, relationships between end points in developmental toxicity testing, reference dose calculations for developmental toxicology, analysis of quantitative dose‐response data, mechanisms of developmental toxicity, physiologically based pharmacokinetic models, and structure‐activity relationships. Although a formal consensus was not sought, many participants favored the evolution of quantitative techniques for developmental toxicology risk assessment, including the replacement of lowest observed adverse effect levels (LOAELs) and no observed adverse effect levels (NOAELs) with the benchmark dose methodology.
Tests for Trend in Developmental Toxicity Experiments with Correlated Binary Data
Authors: Fung K. Y. , Krewski D. , Rao J. N. K. , Scott A. J.
Published: May 2006

In this article, the operating characteristics of recently proposed tests for trend in correlated binary data arising in laboratory studies of developmental toxicity are examined using both computer‐generated and experimental data. Specifically, we consider adjusted Cochran‐Armitgc tests based on the Rao‐Scott transformation which are of the same general form as that for uncorrelated data. In addition, generalized score tests based on generalized estimating equations allowing for extra‐binomial variation in the data are discussed. Specific forms of these statistics demonstrating favorable type I and type II error rates are identified and recommended for use in practice. The application of these tests is illustrated using data from studies of developmental toxicity that have been reported in the literature.
Risk Perception and Communication Unplugged: Twenty Years of Process1
Authors: Fischhoff Baruch
Published: May 2006

Over the past twenty years, risk communication researchers and practitioners have learned some lessons, often at considerable personal price. For the most part, the mistakes that they have made have been natural, even intelligent ones. As a result, the same pitfalls may tempt newcomers to the field. This essay offers a personal (even confessional) history of the field over this period. It identifies a series of developmental stages. Progress through the stages involves consolidating the skills needed to execute it and learning its limitations. Knowing about their existence might speed the learning process and alert one to how much there still is to learn.
The Significance of Socioeconomic and Ethnic Diversity for the Risk Communication Process
Authors: Vaughan Elaine
Published: May 2006

Risk communication is being characterized as one way of facilitating more effective, democratic and participatory risk management strategies. An emphasis on formal communication approaches as a means to improve decisions and decrease conflict will highlight the challenge of managing hazards within a culturally heterogeneous society. Communication and participatory strategies will be considered successful only if diverse communities can be engaged as partners in the policy process. Because responses to risks are embedded and evolve within broader social environments, achieving the promise of risk communication across a diverse society may not be possible absent an understanding of how sociocultural variables and past experiences shape the exchange of ideas or information in any particular situation. This paper considers the implications of ethnic and socioeconomic variability for the risk communication process, summarizing theoretical perspectives and empirical evidence on the link between sociocultural features and risk responses. Specifically, the factors that define the context of communication may influence: the initial framing of a risk issue, particularly, the adoption of an environmental justice vs. scientific/economic perspective; the perceived importance of various aspects of the decision problem; and prior beliefs about environmental hazards and agencies involved in risk management. Two examples of situations requiring communications about risk are presented and illustrate how these principles could operate in minority or lower‐income communities. A significant challenge for health and regulatory officials will be to engage in an interactive process of information and opinion exchanges that is reasonable and effective within vastly different socioeconomic and cultural contexts.
The Sizes, Shapes, and Mineralogy of Asbestos Structures that Induce Lung Tumors or Mesothelioma in AF/HAN Rats Following Inhalation1
Authors: Berman D. Wayne , Crump Kenny S. , Chatfield Eric J. , Davis John M.G. , Jones Alan D.
Published: May 2006

Data from inhalation studies in which AF/HAN rats were exposed to nine different types of asbestos dusts (in 13 separate experiments) are employed in a statistical analysis to determine if a measure of asbestos exposure (expressed as concentrations of structures with defined sizes, shapes and mineralogy) can be identified that satisfactorily predicts the observed lung tumor or mesothelioma incidence in the experiments. Due to limitations in the characterization of asbestos structures in the original studies, new exposure measures were developed from samples of the original dusts that were re‐generated and analyzed by transmission electron microscopy using a direct transfer technique. This analysis provided detailed information on the mineralogy (i.e., chrysotile, amosite, crocidolite or tremolite), type (i.e., fiber, bundle, cluster, or matrix), size (length and width) and complexity (i.e., number of identifiable components of a cluster or matrix) of each individual structure. No univariate measure of exposure was found to provide an adequate description of the lung tumor responses observed among the inhalation studies, although the measure most highly correlated with tumor incidence is the concentration of structures >20 μm in length. Multivariate measures of exposure were identified that do adequately describe the lung tumor responses. Structures contributing to lung tumor risk appear to be long (>5 μm) thin (0.4 μm) fibers and bundles, with a possible contribution by long and very thick (>5 μm) complex clusters and matrices. Potency appears to increase with increasing length, with structures longer than 40 um being about 500 times more potent than structures between 5 and 40 um in length. Structures <5 μm in length do not appear to make any contribution to lung tumor risk. This analysis did not find a difference in the potency of chrysotile and amphibole toward the induction of lung tumors. However, mineralogy appears to be important in the induction of mesothelioma with chrysotile being less potent than amphibole.
Modeling Human Interindividual Variability in Metabolism and Risk: The Example of 4‐Aminobiphenyl
Authors: Bois Frédéric Yves , Krowech Gail , Zeise Lauren
Published: May 2006

We investigate, through modeling, the impact of interindividual heterogeneity in the metabolism of 4‐aminobiphenyl (ABP) and in physiological factors on human cancer risk: A physiological pharmacokinetic model was used to quantify the time course of the formation of the proximate carcinogen, N‐hydroxy‐4‐ABP and the DNA‐binding of the active species in the bladder. The metabolic and physiologic model parameters were randomly varied, via Monte Carlo simulations, to reproduce interindividual variability. The sampling means for most parameters were scaled from values developed by Kadlubar et al. (Cancer Res., 51: 4371, 1991) for dogs; variances were obtained primarily from published human data (e.g., measurements of ABP N‐oxidation, and arylamine N‐acetylation in human liver tissue). In 500 simulations, theoretically representing 500 humans, DNA‐adduct levels in the bladder of the most susceptible individuals are ten thousand times higher than for the least susceptible, and the 5th and 95th percentiles differ by a factor of 160. DNA binding for the most susceptible individual (with low urine pH, low N‐acetylation and high N‐oxidation activities) is theoretically one million‐fold higher than for the least susceptible (with high urine pH, high N‐acetylation and low N‐oxidation activities). The simulations also suggest that the four factors contributing most significantly to interindividual differences in DNA‐binding of ABP in human bladder are urine pH, ABP N‐oxidation, ABP N‐acetylation and urination frequency.
Correlated Inputs in Quantitative Risk Assessment: The Effects of Distributional Shape
Authors: Bukowski John , Korn Leo , Wartenberg Daniel
Published: May 2006

Application of Monte Carlo simulation methods to quantitative risk assessment are becoming increasingly popular. With this methodology, investigators have become concerned about correlations among input variables which might affect the resulting distribution of risk. We show that the choice of input distributions in these simulations likely has a larger effect on the resultant risk distribution than does the inclusion or exclusion of correlations. Previous investigators have studied the effect of correlated input variables for the addition of variables with any underlying distribution and for the product of lognormally distributed variables. The effects in the main part of the distribution are small unless the correlation and variances are large. We extend this work by considering addition, multiplication and division of two variables with assumed normal, lognormal, uniform and triangular distributions. For all possible pairwise combinations, we find that the effects of correlated input variables are similar to those observed for lognormal distributions, and thus relatively small overall. The effect of using different distributions, however, can be large.
Dioxin–An Analysis of the Major Human Studies: Comparison with Animal‐Based Cancer Risks
Authors: Scheuplein Robert J. , Bowers John C.
Published: May 2006

Several major epidemiological studies have reported significant mortality rates (SMRs) for both rare cancers (soft tissue sarcoma, non‐Hodgkin's, lymphoma, liver) and the more common cancers (lung, colon, etc), all allegedly caused by TCDD. In this paper, we use the potency of TCDD in animals to establish a plausible worst case cancer risk and ask whether its likely that TCDD is responsible for the epidemiological findings assuming the animal carcinogenic potency is applicable to the conditions of human exposure. Two new features of the technique are the use of measured TCDD blood levels in both animals and humans for dose scale‐up and the calculation of an integrated life‐time exposure for the exposed workers using measured blood levels. On the basis of the stated assumptions it appears unlikely that any of the major epidemiological studies, with the possible exception of the NIOSH study(1)have adequate power to detect the common cancers potentially caused by TCDD.
The Rise and Fall of a Risk‐Based Priority System: Lessons from DOE's Environmental Restoration Priority System
Authors: Jenni Karen E. , Merkhofer Miley W. , Williams Carol
Published: May 2006

This paper presents the history of the Environmental Restoration Priority System (ERPS), a decision aid developed by the U.S. Department of Energy (DOE) to help determine how to allocate funds for cleaning up hazardous waste sites. Although praised in technical peer review, the system was strongly criticized by stakeholders external to the DOE. Ultimately, and in the midst of a National Academy of Sciences review, DOE shelved the system. The rise and fall of ERPS provides useful lessons for analysts hoping to improve risk management in the public sector.
The Effects of Community Pluralism on Press Coverage of Health Risks from Local Environmental Contamination
Authors: Griffin Robert J. , Dunwoody Sharon , Gehrmann Christine
Published: May 2006

Based on the conflict/consensus model of Tichenor, Donohue and Olien, we proposed that mass mediated information signalling that local agents are contaminating the local environment and posing health risks is conflict‐generating information and, therefore, will be controlled in the interest of community stability. We expected such control to vary by community structure. A content analysis of nine months of coverage by 19 newspapers supported the hypothesis that papers in more pluralistic communities were more likely than papers in less pluralistic communities to link contamination from local agents to threats to human health in the community and to frame such stories as problems. Newspapers in less pluralistic communities were more likely to frame local contamination in the context of solutions to the problem and were more likely to link contamination to health risks if the contamination were in a distant community.
A Trichloroethylene Risk Assessment Using a Monte Carlo Analysis of Parameter Uncertainty in Conjunction with Physiologically‐Based Pharmacokinetic Modeling
Authors: Cronin William J. , Oswald Eric J. , Shelley Michael L. , Fisher Jeffrey W. , Flemming Carlyle D.
Published: May 2006

A Monte Carlo simulation is incorporated into a risk assessment for trichloroethylene (TCE) using physiologically‐based pharmacokinetic (PBPK) modeling coupled with the linearized multistage model to derive human carcinogenic risk extrapolations. The Monte Carlo technique incorporates physiological parameter variability to produce a statistically derived range of risk estimates which quantifies specific uncertainties associated with PBPK risk assessment approaches. Both inhalation and ingestion exposure routes are addressed. Simulated exposure scenarios were consistent with those used by the Environmental Protection Agency (EPA) in their TCE risk assessment. Mean values of physiological parameters were gathered from the literature for both mice (carcinogenic bioassay subjects) and for humans. Realistic physiological value distributions were assumed using existing data on variability. Mouse cancer bioassay data were correlated to total TCE metabolized and area‐under‐the‐curve (blood concentration) trichloroacetic acid (TCA) as determined by a mouse PBPK model. These internal dose metrics were used in a linearized multistage model analysis to determine dose metric values corresponding to 10‐6 lifetime excess cancer risk. Using a human PBPK model, these metabolized doses were then extrapolated to equivalent human exposures (inhalation and ingestion). The Monte Carlo iterations with varying mouse and human physiological parameters produced a range of human exposure concentrations producing a 10‐6 risk.
How Dangerous Is Low Level Radiation?
Authors: Cohen Bernard L.
Published: May 2006

Problems in the theoretical basis for the linear‐no threshold theory of radiation carcinogenesis are reviewed, and it is shown that they very strongly suggest that the theory greatly overestimates the risk of low level radiation. A direct test of the theory, based on the radon—lung cancer relationship is described; it strongly reinforces that conclusion. However, it is shown that even if the linear‐no threshold theory is valid, the public's fear of low level radiation, at least in some contexts, is grossly exaggerated.
Perspectives on Cancer Prevention
Authors: Miller Anthony B.
Published: May 2006

Cancer prevention is a major component of cancer control, which also comprises screening, treatment, rehabilitation and palliative care. Preventive approaches need to be congruent with those adopted for other chronic diseases, with a major impact in reduction of incidence and mortality of many common cancers to be expected from smoking control and dietary modification. Increasing interest is now being paid to other environmental causes of cancer, and to gene‐environment interactions. However, one of the major research needs remains the evaluation of better ways to convince people to make the necessary changes in their lifestyle that will reduce their risk of cancer.