Public Reactions to Risk Messages Communicating Different Sources of Uncertainty: An Experimental Test

There is an abundant literature on the challenge of integrating uncertainties in experts’ risk assessments, but the evidence on the way they are understood by the public is scarce and mixed. This study aims to better understand the effect of communicating different sources of uncertainty in risk communication. A causal design was employed to test the effect of communicating risk messages varying in type of advisory warning (no risk and suggests no protective measure, or risk and recommends a protective measure) and sources of uncertainty (no uncertainty, divergence between experts, contradictory data, or lack of data) on public reactions. Participants from the general public (N = 434) were randomly assigned to read and react to variants of a fictitious government message discussing the presence of a new micro-organism found in tap water. Multiple analysis of variance showed that to report uncertainty from divergence between experts or from contradictory data reduced the adherence to the message, but not to mention the lack of data. Moreover, the communication of diverse sources of uncertainty did not affect trust in the government when the advisory warning stated there was a risk and recommended a protective measure. These findings have important implications for risk communication.     

Ecology,Environmental Impact Statements,and Ecological Risk Assessment: A Brief Historical Perspective

Ecological risk assessment will continue to increase in importance as a conceptual and methodological basis for evaluating environmental impacts as required by the National Environmental Policy Act. Understanding the historical strengths and limitations of more traditional environmental assessments performed in support of the NEPA can facilitate the effective incorporation of ecological risk assessment into the NEPA process. Such integration will also benefit from a knowledge of the historical and continuing development of the ecological risk assessment process, as well as from a recognition of the contri butions from modern quantitative ecology and ecosystem science. Adopting a risk-based approach can improve the NEPA process by providing a framework for consistent and comprehensive ecological assessment and by providing a conceptual and methodological basis for addressing the varied uncertainties attendant to environmental assessments. The primary concern in integrating ecological risk assessment into the NEPA process is that ecological risk assessment not merely become a new name for traditional environmental impact assessments. While the integration of ecological risk assessment into the NEPA process occurs, it is important to begin to outline the next transition in environmental assessment capabilities. Operationally linking ecological risk assessment methods with formal decision models appears as a worthwhile objective in beginning this transition.     

Uncertainty Analysis of Pesticide Residues in Drinking Water Risk Assessment

Pesticide residues in drinking water can vary significantly from day to day. However, water quality monitoring performed under the Safe Drinking Water Act (SDWA) at most community water systems (CWSs) is typically limited to four data points per year over a few years. Due to this limited sampling, likely maximum residues may be underestimated in risk assessment. In this work, a statistical methodology is proposed to study two types of uncertainties in observed samples and their propagated effect in risk estimates. The methodology was demonstrated using data from 16 CWSs that have three independent databases of atrazine residue to estimate the uncertainty of risk in infants and children. The results showed that in 85% of the CWSs, chronic risks predicted with the proposed approach may be two- to four-folds higher than that predicted with the current approach, wheras intermediate risks may be two- to three-folds higher in 50% of the CWSs. In 12% of the CWSs, however, the proposed methodology showed a lower intermediate risk. A closed-form solution of propagated uncertainty was developed to demonstrate the number of years (seasons) of data and sampling frequency needed to reduce the uncertainty of risk estimates. In general, this methodology provided good insight into the importance of addressing uncertainty of observed water quality data and the need to predict likely maximum residues in risk assessment.     

Quantitative Risk Assessment in Epidemiological Studies Investigating Threshold Effects

In this paper a method for quantitative risk assessment in epidemiological studies investigating threshold effects is proposed. The simple logistic regression model is used to describe the association between a binary response variable and a continuous risk factor. By defining acceptable levels for the absolute risk and the risk gradient the corresponding benchmark values of the risk factor can be calculated by means of nonlinear functions of the logistic regression coefficients. Standard errors and confidence intervals of the benchmark values are derived by means of the multivariate delta method. The proposed approach is compared with the threshold model of Ulm (1991) for assessing threshold values in epidemiological studies.     

Risk Perception and Energy Production

Mean risk magnitude judgments expressed by Belgian and French students on 107 items combining a particular energy domain (wood and biomass, coal, gas, oil, nuclear, water, wind, geothermal and solar) and a particular aspect of the energy production process (obtaining raw materials, storage of raw materials, transport of raw materials, energy production, waste products related to energy production, energy transport, waste products transport, waste products storage, utilization of energy) are reported, and analyzed. Questions were of the form: What is the level of risk (for health and the environment) associated with the item “Electrical energy production by thermodynamic conversion”? Concerning energy domains, nuclear energy received the highest ratings, almost regardless of the aspect of the energy production process considered (from the extraction of raw materials to the storage of production wastes). This was followed by oil, obtaining the next highest ratings after those for nuclear energy, then gas, considered more risky than biomass and coal. The brand image of these two latter energy sources would be almost as positive as that of water, solar, geothermal and wind energy if a solution could be found to the problem of atmospheric emission of carbon monoxide. Concerning production process aspects, waste products (as well as the transport and storage of waste) received the highest ratings. This is not unrelated to the fact that the vast majority of studies devoted to a particular area or particular aspect have concerned nuclear waste. In contrast, no very high degree of concern was found regarding the energy (electrical) transport aspect.     

Evaluating Chemical Interaction Studies for Mixture Risk Assessment

We describe a set of criteria to evaluate the quality of data and interpretations in chemical interaction studies. These criteria reflect the consensus of the literature on interaction analysis developed over decades of research in pharmacology, toxicology, and biometry; address common pitfalls in published interaction studies; and can be easily applied to common methods of interaction analysis. The criteria apply broadly to interaction data for drugs, pesticides, industrial chemicals, food additives, and natural products and are intended to assist risk assessors who must evaluate interaction studies for use in component-based mixture risk assessments. The criteria may also assist researchers interested in conducting interaction studies to inform mixture risk assessment. The criteria are also intended to serve larger scientific goals, including increasing the repeatability of results obtained in chemical interaction studies, enhancing the reliability of conclusions drawn from interaction data, providing greater consistency of interpretations among various analysts, and decreasing uncertainty in using interaction data in risk assessments. We describe the basis for each criterion and demonstrate their utility by using them to evaluate interaction studies from the recent toxicological and pharmacological literature, which serve as examples of different types of data sets that the risk assessor may encounter.     

Perceptions of Mercury Risk and Its Management

Anthropogenic activities, such as coal burning for electricity generation, release mercury (Hg), a toxic, bioaccumulative pollutant with potential health impacts primarily borne by specific population groups such as women of child-bearing age and subsistence fishers. Current Hg risk communication efforts and much of the extant research on Hg risk perceptions focus on these groups most at-risk. Little is known about the perceptions of Hg risk among the general public, although their support is required for implementing Hg emissions mitigation policies. We report results from two surveys—one a U.S. nationally representative Internet survey and the other a mail survey of New England residents—on a range of perceptions of the general population regarding Hg risk and its management. Our analysis of quantitative and qualitative data from the surveys point toward some gaps in public understanding of Hg risk, on aspects such as sources of mercury release, agencies responsible for mercury information, and products that contain mercury. Our results suggest that agencies responsible for providing Hg information should go beyond fish advisories and enhance their efforts at wider dissemination of information on Hg risk and its management.     

Approaches for Integrated Risk Assessment

Recognizing the need to enhance the effectiveness and efficiency of risk assessments globally, the World Health Organization's International Programme on Chemical Safety, the U.S. Environmental Protection Agency, the European Commission, and the Organization for Economic Cooperation and Development developed a collaborative partnership to foster integration of assessment approaches used to evaluate human health and ecological risks. The objectives of this effort included: improving understanding of the benefits of integration, identifying obstacles to the integration process, and engaging key agencies, organizations, and scientific societies to promote integration. A framework with supporting documentation was developed to describe an approach for integration. Four case studies were constructed to illustrate how integrated risk assessments might be conducted for chemical and nonchemical stressors. The concepts and approaches developed in the project were evaluated in an international workshop. The goal of this effort was international acceptance of guidance for integrated risk assessment.     

The Role of Convictions and Trust for Public Protest Potential in the Case of Carbon Dioxide Capture and Storage (CCS)

For the public to accept new technologies, trust and convictions play an important role. In the present research, we used structural equation modeling to examine an extensive causal model of the role of convictions and trust for the public's protest potential against carbon dioxide capture and storage (CCS) among a large sample of the general population (N = 769). Trust, convictions, perceived benefits, and risks were included in the model. Our model fitted the data well. Convictions regarding emission reduction, decentralization of energy production, and tampering with natural structures in the deep subsurface influenced the perception of benefits and risks. Trust, in contrast, was barely influential. Perceived benefits were more prominent for public protest potential than perceived risks. However, perceived benefits did not dominate perceived risks as much as earlier studies found for acceptance. We argue that trust can become fully effective as a determinant of perceived risks and benefits only when the public perceives the distinct positioning of the stakeholders involved. Until then, laypeople are likely to draw on their own convictions and intuitive mental concepts for making decisions about accepting a new technology or protesting it.     

Enhancing Confidence in Drinking Water Quality for Improved Risk Decisions

Reliance is often placed on “indirect” indicators to detect changes in water quality in real time. However, there are challenges in using these indirect indicators, as they cannot replace standardized laboratory tests. As an alternative, reliance on three successive test cases is examined, based on “joint and conditional probabilities” of hazard (contaminant level exceeding acceptable level) that could enhance confidence in monitoring results: (i) a simple and quick screening analysis sensor (primary analyzer, having type-1 error, i.e., α = 0.10 and type-2 error, i.e., β = 0.05), (ii) a repeat of the analysis with the same rapid analyzer is feasible, and (iii) further analysis of the sample with a highly reliable capability is feasible (secondary analyzer with α = 0.05 and β = 0.02). This three-level monitoring protocol for obtaining the posterior probability of hazard is examined and a method is proposed for taking improved risk management decisions by accounting for sensitivity and specificity of monitoring instruments. The revised probability of hazard will ensure that a positive harmful detect is proven false or real with much greater certainty and series of action (or no action) is taken at the earliest.     

An Assessment of Integrated Risk Assessment

In order to promote international understanding and acceptance of the integrated risk assessment process, the World Health Organization/International Programme on Chemical Safety (WHO/IPCS), in collaboration with the U.S. Environmental Protection Agency and the Organization for Economic Cooperation and Development, initiated a number of activities related to integrated risk assessment. In this project, the WHO/IPCS defines integrated risk assessment as a science-based approach that combines the processes of risk estimation for humans, biota, and natural resources in one assessment. This article explores the strengths and weaknesses of integration as identified up to this date and the degree of acceptance of this concept by the global risk assessment/risk management community. It discusses both opportunities and impediments for further development and implementation.

The major emerging opportunities for an integrated approach stem from the increasing societal and political pressure to move away from vertebrate testing leading to a demand for scientific integrated approaches to in vitro and in vivo testing, as well as to computer simulations, in so-called Intelligent Testing Strategies. In addition, by weighing the evidence from conventional mammalian toxicology, ecotoxicology, human epidemiology, and eco-epidemiology, risk assessors could better characterize mechanisms of action and the forms of the relationships of exposures to responses. It is concluded that further demonstrations of scientific, economic and regulatory benefits of an integrated approach are needed. As risk assessment is becoming more mechanistic and molecular this may create an integrated approach based on common mechanisms and a common systems-biology approach.     

Addressing Susceptibility in Microbial Pathogen Risk Assessment

As concern for vulnerable subpopulations has grown, susceptibility has become a more important element in risk assessment and management processes. However, there is little consensus on how to incorporate or model the concept effectively in microbial pathogen risk assessment (MRA). Susceptibility is fundamentally a complex concept. There are many different definitions for it, reflecting the principles and viewpoints of the fields that contribute to risk assessment. Although susceptibility needs to be addressed in every step of the risk management paradigm, it has not yet been fully integrated into risk assessment, one step within the paradigm. Many factors are involved in characterizing and modeling susceptibility, but little is known about the relationships of many of the factors and many cannot be reliably measured. Recent MRA frameworks and case studies were reviewed for their approaches to susceptibility. Themes identified included limited or no explicit conceptualization of susceptibility in the problem formulation, limited data to assess susceptibility, heavy or exclusive emphasis on susceptibility in the health effects portion of the model, primary focus on host characteristics, and little consideration of susceptibility in risk characterization. Recommendations to improve approaches to susceptibility in MRA are presented.     

A Risk Assessment Approach for Policy Evaluation: New Jersey Case Studies

Monitoring environmental policy progress often focuses on contaminant concentrations while policy goals address health. To bridge this gap, we developed policy evaluation case studies applying risk assessment methods to explore population health risks of chemical exposures before and after policy implementation. Beginning in the 1970s the New Jersey Department of Environmental Protection provided some of the United States' first data on contaminants including trichloroethylene in drinking water and polychlorinated biphenyls (PCBs) in fish. These data provide a unique opportunity to evaluate environmental policies. The 1979 PCB manufacturing ban succeeded in reducing exposure and risk, but the persistence of these compounds in local fish requires continued state and local consumption advisories. The positive impact of drinking water standards for trichloroethylene was reflected in declining detection in public water supplies from the late 1970s to 2005, although maximum concentrations in a small percentage of supplies remain above standards. Our case studies show success and progress, and the need for multiple policies in combination when conditions warrant. Tracking specific policies and contaminants using risk assessment methods can be a valuable tool for policy evaluation and can foster population-based environmental health research. Pollution prevention policies are warranted for chemicals that persist in the environment.     

Risk Assessment in Navy Deployment Toxicology

The risk assessment process is a critical function for deployment toxicology research. It is essential to the decision making process related to establishing risk reduction procedures and for formulating appropriate exposure levels to protect naval personnel from potentially hazardous chemicals in the military that could result in a reduction in readiness operations. These decisions must be based on quality data from well-planned laboratory animal studies that guide the judgements, which result in effective risk characterization and risk management. The process of risk assessment in deployment toxicology essentially uses the same principles as civilian risk assessment, but adds activities essential to the military mission, including intended and unintended exposure to chemicals and chemical mixtures. Risk assessment and Navy deployment toxicology data are integrated into a systematic and well-planned approach to the organization of scientific information. The purpose of this paper is to outline the analytical framework used to develop strategies to protect the health of deployed Navy forces.     

Axes of Extrapolation in Risk Assessment

Extrapolation in risk assessment involves the use of data and information to estimate or predict something that has not been measured or observed. Reasons for extrapolation include that the number of combinations of environmental stressors and possible receptors is too large to characterize risks comprehensively, that direct characterization is sometimes impossible, and that the power to characterize risk in a particular situation can be enhanced by using information obtained in other similar situations. Three types of extrapolation are common in risk assessments: biological (including between taxa and across levels of biological organization), temporal, and spatial. They can be thought of conceptually as the axes of a 3-dimensional graph defining the state space of biological, temporal, and spatial scales within which extrapolations are made. Each of these types of extrapolation can introduce uncertainties into risk assessments. Such uncertainties may be reduced through synergistic research facilitated by the sharing of methods, models, and data used by human health and ecological scientists     

Machinery Risk Assessment for Risk Reduction

New avenues are reviewed and discussed for preventing industrial machine-related injury by means of realistic risk evaluation and reduction processes at the design and application stages of machinery development and use. U.S. guidelines and European standards on machinery risk assessment procedures are described. Applications of risk assessment for machine-related injury risk management and teaching machine-risk control are discussed.     

Practical Issues in the Use of Probabilistic Risk Assessment

Probabilistic risk assessment (PRA) represents an important step in the evolution of risk assessment methodology to assist decision-making at hazardous waste sites. Despite considerable progress in the development of PRA techniques, regulatory acceptance of PRA has been limited, in part because a number of practical issues in its use must yet be resolved. A recent workshop on PRA identified several areas to be addressed, including the need for: (1) better demonstration of the value of PRA in risk management; (2) PRA training and education opportunities; (3) the development of technical criteria for acceptability of a PRA; (4) policy decisions on acceptable risk distributions; (5) ways to deal with risk communication issues; and (6) a variety of technical issues, including ways to include estimates of variability and uncertainty associated with toxicity values. Solutions to many of these issues will require better dialog between risk assessors and risk managers than has existed in the past.     

Risk Literacy and Risk Perception Among Undergraduates in Mainland China: The Case of BSE

Risk response and cognitive characteristics of different groups are important aspects in risk research. In this article we discuss the general features of risk literacy and perception among undergraduates at Nanjing University and Huaiyin Institute of Technology in China in the case of bovine spongiform encephalopathy (BSE). The results show that: (1) there seem to be no relationships between respondents’ knowledge about BSE and their risk identification; (2) between all contrast samples, the greatest divergence appears in the judgment about probability of risk while the smallest one is the trust in science and technology to avoid BSE; (3) the judgment of hazard probability would be related to gender, family location, and the backgrounds of college and academic specialty. And only gender has impact on the affirmation of hazard with a significant level of 0.05. These findings provide insights into the comprehension of undergraduates’ risk literacy and perception, and can contribute to the improvement of risk communication and management in China.     

Ecological Risk Assessment and the Precautionary Principle

The Precautionary Principle, generated during the late 1980s as a unifying principle for regulating discharge of hazardous material into the North Sea, has been broadened to include a shifting of the burden of proof to the proponent of a proposed activity, adoption of a more holistic assessment process, and encompassing all environmental management decisions, not just pollution prevention activities. We argue that the Precautionary Principle remains a management philosophy, not a substitute for risk assessment. Risk assessment is a tool for organizing information used in environmental management decisions. However, increasing attention to reducing the Type II error of risk assessment studies would significantly reduce the skepticism with which many view the risk assessment process. A critical review of default assumptions used in risk assessments, inclusion of indirect effects within an ecologically relevant spatial/temporal framework, and better communication between risk assessors and risk managers also would enhance the acceptability of the process. Risk assessment can provide a sound basis for management decisions regardless of the underlying philosophies of environmental conservation or utilitarianism, but only if the inherent biases in the risk assessment assumptions are acknowledged explicitly throughout the assessment and management processes.