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Pollutant release and transfer registers (PRTRs) are becoming a popular measure for addressing industrial pollution in many countries. PRTRs require reporting of emissions from specific industrial sectors and making the information publicly available. This article suggests a framework for comparing PRTRs in order to determine whether they attain their declared goals and which factors, if any, influence their effectiveness. The challenges to such a comparison can be divided into three groups. The first refers to changes that are directly linked to the characteristics of PRTRs: both the changes within a specific system over time and variations among different systems. The second refers to parameters that affect the outcomes of the systems without being directly a part of them. The third involves the relations between the emissions reported to the PRTRs and the associated environmental risk. We suggest an approach that relies onrelative comparison,commensurate with the unique characteristics of each PRTR, that compares their actual outcomes. Such an approach is necessary both due to significant variations among current PRTRs as well as for following the unique policy objectives that are manifested in different PRTRs. Application of thiscomparative approachin the United States, England, Canada, and Australia demonstrates significant differences in PRTR systems across countries and suggests that the mere presence of a PRTR may not lead to reduced industrial emissions. The analysis also demonstrates that emission reductions do not correlate with reductions in risk‐related measures. The article proposes several simple modifications to the composition of current PRTR databases that may facilitate more accurate analysis of results and effective oversight of implementation.

AbstractIn this article, we discuss four vexing problems in risk‐based decision making that John Evans has addressed over the last nearly 40 years and has perennially challenged the two of us and others to think about. We tackle the role in decision making of potential thresholds in dose–response functions, how the lack of health reference values for many chemicals may distort risk management, the challenge of model uncertainty for risk characterization, and the yet‐untapped potential for value‐of‐information analysis to enhance public health decision making. Our theme is that work remains to be done on each of these, but that some of that work would merely involve listening to ideas that John has already offered.

Efforts to reduce pesticide‐related risks to consumers and farmworkers often neglect the possibility that measures to reduce the target risk may introduce or enhance countervailing risks. These may arise from substitute pesticides or pest‐control practices, from increased levels of pests or pest‐related hazards, from increased levels of toxic natural pesticides in plants, from increased costs and decreased consumption of health‐enhancing fruits and vegetables, or from direct income effects on consumers and farmers. The effect of the countervailing risks may partially or completely offset the reduction in the target risk. A risk‐trade‐off analysis was conducted of a potential ban on the use of organophosphate and carbamate (OP/Carbamate) insecticides in U.S. agriculture. Although this scenario is extreme, it has the analytic virtue of dispensing with the infinite number of "next‐best" OP/Carbamates that might be substituted for specific combinations of crops and pests should only selected uses be banned. The analysis relies on detailed descriptions of the alternative pesticides and pest‐control measures that would be used for each of 14 major crops. The effects of pest‐control cost changes on prices and consumption and effects on consumer and producer incomes are projected using a general‐equilibrium economic model. Several countervailing risks that may be significant were found, including acute toxicity to farmworkers from substitute pesticides, cancer and noncancer risks from substitute pesticides, and mortality induced by changes in disposable income. Other countervailing risks are more difficult to estimate or weigh. Potential increases in natural plant pesticides following an OP/Carbamate ban are discussed but data are lacking to quantify the effects. Changes in diet following the ban have both positive and negative effects, and the ultimate change is difficult to estimate. Although a net risk cannot be estimated, several approaches were illustrated that would be useful in risk‐trade‐off analyses. Key factors complicating comprehensive analysis of risk/risk trade‐offs for pesticides were also identified, including data gaps and shortcomings of current risk assessment methods.

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.

The North American Free Trade Agreement (NAFTA) and the General Agreement on Tariffs and Trade (GATT) have focused attention on risk assessment of potential insect, weed, and animal pests and diseases of livestock. These risks have traditionally been addressed through quarantine protocols ranging from limits on the geographical areas from which a product may originate, postharvest disinfestation procedures like fumigation, and inspections at points of export and import, to outright bans. To ensure that plant and animal protection measures are not used as nontariff trade barriers, GATT and NAFTA require pest risk analysis (PRA) to support quarantine decisions. The increased emphasis on PRA has spurred multiple efforts at the national and international level to design frameworks for the conduct of these analyses. As approaches to pest risk analysis proliferate, and the importance of the analyses grows, concerns have arisen about the scientific and technical conduct of pest risk analysis. In January of 1997, the Harvard Center for Risk Analysis (HCRA) held an invitation‐only workshop in Washington, D.C. to bring experts in risk analysis and pest characterization together to develop general principles for pest risk analysis. Workshop participants examined current frameworks for PRA, discussed strengths and weaknesses of the approaches, and formulated principles, based on years of experience with risk analysis in other setting and knowledge of the issues specific to analysis of pests. The principles developed highlight the both the similarities of pest risk analysis to other forms of risk analysis, and its unique attributes.

Frontmatter -- Contents -- Foreword -- Preface -- 1 Confronting Risk Tradeoffs -- 2 Estrogen Therapy for Menopause -- 3 Clozapine Therapy for Schizophrenia -- 4 Licensing the Elderly Driver -- 5 Saving Gasoline and Lives -- 6 Eating Fish -- 7 Seeking Safe Drinking Water -- 8 Recycling Lead -- 9 Regulating Pesticides -- 10 Protecting the Global Environment -- 11 Resolving Risk Tradeoffs -- References -- Contributors -- Author Index -- Subject Index