Decision making in environmental projects can be complex and seemingly intractable, principally because of the inherent trade-offs between sociopolitical, environmental, ecological, and economic factors. The selection of appropriate remedial and abatement strategies for contaminated sites, land use planning, and regulatory processes often involves multiple additional criteria such as the distribution of costs and benefits, environmental impacts for different populations, safety, ecological risk, or human values. Some of these criteria cannot be easily condensed into a monetary value, partly because environmental concerns often involve ethical and moral principles that may not be related to any economic use or value. Furthermore, even if it were possible to aggregate multiple criteria rankings into a common unit, this approach would not always be desirable because the ability to track conflicting stakeholder preferences may be lost in the process. Consequently, selecting from among many different alternatives often involves making trade-offs that fail to satisfy 1 or more stakeholder groups. Nevertheless, considerable research in the area of multicriteria decision analysis (MCDA) has made available practical methods for applying scientific decision theoretical approaches to complex multicriteria problems. This paper presents a review of the available literature and provides recommendations for applying MCDA techniques in environmental projects. A generalized framework for decision analysis is proposed to highlight the fundamental ingredients for more structured and tractable environmental decision making.

Acute lethal dose/concentration estimates are the most widely used measure of toxicity and these data often are used in ecological risk assessment. However, the value of the lethal concentration (LC50) as a toxicological endpoint for use in ecological risk assessment recently has been criticized. A question that has been asked frequently is how accurate is the LC50 for prediction of longer-term effects of toxicants on populations of organisms? To answer this question, Daphnia pulex populations were exposed to nominal concentrations equal to the 48-h acute LC50 of 6 insecticides, Actara, Aphistar diazinon, pymetrozine, Neemix, and Spinosad; and 8 agricultural adjuvants, Bond, Kinetic, Plyac, R-11, Silwet, Sylgard 309, Water Maxx, and X-77; for 10 d. None of the D. pulex populations exposed to the acute LC50 of these insecticides were 50% lower than the control populations at the end of the study; exposure to diazinon resulted in populations that were higher than expected (91% of the control). Exposure to Actara and Aphistar resulted in populations that were <1 and 29% of the control, respectively. Exposure to Fulfill, Neemix, and Spinosad resulted in extinction. Extinction occurred after exposure to all of the adjuvants, except Silwet L-77 where the population was 31% of the control. These results corroborate other studies that indicate that the LC50 is not a good predictor of effects on population growth. Although lethal concentration estimates have their place in toxicology, namely to compare intrinsic toxicity of chemicals among species or susceptibility of a species to different chemicals over short time periods, population growth and growth-rate studies are necessary to predict toxicant effects on populations.

In this study, 9 chemicals were chosen from a recent report on surface water concentrations of a variety of xenobiotics to test the hypothesis that the toxicity of chemical mixtures could be estimated using a model based on the toxicity of the individual chemicals. Concentration-response curves for the endpoints of lifespan, growth rate, and fecundity were generated for each chemical experimentally using the crustacean, Daphnia magna. From this data, a mathematical model for the combined toxicity of these chemicals was generated that merged the concepts of concentration addition and independent joint action. Toxicity of a mixture was modeled at various levels at which the ratio of the chemicals within the mixture was maintained at that reported for median detected environmental levels. Toxicity of the mixture was then determined experimentally and compared to model predictions. The model accurately predicted the most sensitive endpoint, as well as the lowest toxic effect level of the mixture. Results demonstrated that, for this mixture of chemicals, toxicity was not influenced significantly by interactions among the chemicals and a single constituent dominated toxicity. According to model predictions and experimental results, the median detected environmental concentrations of chemicals constituting this mixture provided no margin of safety.

This study addresses the potential risks to the aquatic ecosystem posed by pesticides currently used in The Netherlands. The study used a novel method to predict aquatic exposure to pesticides based on a geographic information system (GIS) map of agricultural land use, comprising 51 crops used in open-canopy areas. Through the application of species-sensitivity distributions for aquatic organisms, in combination with rules for mixture-toxicity calculation, the modeled exposure results were transformed to risk estimates for aquatic species. The majority of the predicted risks were caused by pesticides applied to potato cropland, and approximately 95% of the predicted risk was caused by only 7 of the 261 pesticides currently used in The Netherlands. For risk verification, local toxic-risk estimates were compared with observed species composition in field ditches. The field verification study was not able to draw firm conclusions regarding the predicted impact of pesticide use on overall biodiversity. A toxicity-related shift from sensitive to more tolerant or opportunistic species could be observed for a few species.

A comprehensive indoor air–quality (IAQ) investigation was conducted at a state correctional facility in New Jersey, USA with a lengthy history of IAQ problems. The IAQ investigation comprised preliminary indoor air screening using direct readout instrumentation, indoor air/surface wipe sampling and laboratory analysis, as well as a heating, ventilation, and air-conditioning system evaluation, and a building envelope survey. In addition to air sampling, a human health risk assessment was performed to evaluate the potential for exposure to site-related air contaminants with respect to the inmate and worker populations. The risk assessment results for the prison facility indicated the potential for significant health risks for the inmate population, possibly reflecting the effects of their confinement and extended exposure to indoor air contaminants, as compared to the prison guard and worker population. Based on the results of the risk assessment, several mitigation measures are recommended to minimize prison population health risks and improve indoor air quality at prison facilities.

Tissue residue-based toxicity benchmarks (TRBs) have typically been developed using the results of individual studies selected from the literature. In the past, TRBs have been developed using a point estimate (e.g., LC50 value) reported in a study on a single species deemed to be most closely related to the receptor of interest. Despite attempts to maximize the protectiveness and relevance of TRBs, their relationship to specific receptors remains uncertain, and their general applicability for use in broader ecological risk assessment contexts is limited. This article proposes a novel framework that establishes benchmarks as distributions rather than single-point estimates. Benchmark distributions allow the user to select a tissue concentration that is associated with the protection of a specific percentage of organisms, rather than linked to a specific receptor. A methodology is proposed for searching, reviewing, and analyzing linked, tissue residue effect data to derive benchmark distributions. The approach is demonstrated for contaminants having a dioxin-like mechanism of toxic action and is based on residue effects data for 2,3,7,8-tetrachlorodibenzo- p-dioxin (2,3,7,8-TCDD) and equivalents in early life stage fish. The calculated tissue residue benchmarks for 2,3,7,8-TCDD toxic equivalency (TEQ) derived from the resulting distribution could range from 0.057- to 0.699-ng TCDD/g lipid depending on the level of protection needed; the lower estimate is protective of 99% of fish species whereas the higher end is protective of 90% of fish species.

As a member of the group of diseases known as transmissible spongiform encephalopathies (TSEs), bovine spongiform encephalopathy (BSE) has been causally associated with a new variant of Creutzfeldt-Jakob disease (vCJD) in humans. Given the many uncertainties on the transmission and persistence of TSE pathogens in the environment, quantitative assessment of risks to humans and animals continues to remain a public health issue. This paper reviews quantitative BSE risk assessments undertaken in the United Kingdom since 1997 to address the potential for human exposure and theoretical health risks through environmental pathways. The review focuses on how model assumptions and methodology may influence the results.