Recommendations for the development and application of wildlife toxicity reference values.
ABSTRACT Toxicity reference values (TRVs) are essential in models used in the prediction of the potential for adverse impacts of environmental contaminants to avian and mammalian wildlife; however, issues in their derivation and application continue to result in inconsistent hazard and risk assessments that present a challenge to site managers and regulatory agencies. Currently, the available science does not support several common practices in TRV derivation and application. Key issues include inappropriate use of hazard quotients and the inability to define the probability of adverse outcomes. Other common problems include the continued use of no-observed- and lowest-observed-adverse-effect levels (NOAELs and LOAELs), the use of allometric scaling for interspecific extrapolation of chronic TRVs, inappropriate extrapolation across classes when data are limited, and extrapolation of chronic TRVs from acute data without scientific basis. Recommendations for future TRV derivation focus on using all available qualified toxicity data to include measures of variation associated with those data. This can be achieved by deriving effective dose (EDx)-based TRVs where x refers to an acceptable (as defined in a problem formulation) reduction in endpoint performance relative to the negative control instead of relying on NOAELs and LOAELs. Recommendations for moving past the use of hazard quotients and dealing with the uncertainty in the TRVs are also provided.
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ABSTRACT: To construct informed conservation plans, researchers must go beyond understanding readily apparent threats such as habitat loss and bush-meat hunting. They must predict subtle and cascading effects of anthropogenic environmental modifications. This study considered a potential cascading effect of deforestation on the howler monkeys (Alouatta pigra) of Balancán, Mexico. Deforestation intensifies flooding. Thus, we predicted that increased flooding of the Usumacinta River, which creates large bodies of water that slowly evaporate, would produce increased lead content in the soils and plants, resulting in lead exposure in the howler monkeys. The average lead levels were 18.18 ± 6.76 ppm in the soils and 5.85 ± 4.37 ppm in the plants. However, the average lead content of the hair of 13 captured howler monkeys was 24.12 ± 5.84 ppm. The lead levels in the animals were correlated with 2 of 15 blood traits (lactate dehydrogenase and total bilirubin) previously documented to be associated with exposure to lead. Our research illustrates the urgent need to set reference values indicating when adverse impacts of high environmental lead levels occur, whether anthropogenic or natural, and the need to evaluate possible cascading effects of deforestation on primates.Primates 08/2014; 56(1). DOI:10.1007/s10329-014-0445-z · 1.40 Impact Factor
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ABSTRACT: Information and approaches to evaluating health risks to terrestrial wildlife from fluoride contamination in the environment are few in the literature. We use envi-ronmental field data from a phosphate ore processing site, toxicity reference values (TRVs), and bioaccumulation factors relative to site conditions to develop risk-based concentrations (RBCs) for total fluoride in terrestrial biota and soil. RBCs were de-rived specifically for forage that are protective of terrestrial mammalian and avian ecological receptors through multiple exposure pathways, and which can be used to evaluate site remediation or as environmental monitoring action levels. Following review of the literature, we recommend fluoride TRVs for mammalian and avian wildlife, and bioavailability factors for estimating exposures related to aerial depo-sition of fluoride and fluoride gases. For large ungulates, information on fluoride bioavailability from feed and soil, and related effects thresholds, are summarized from studies on grazing livestock. The resultant RBCs for fluoride in forage range from 14 to 63 mg/kg dry weight, based on no-effect and low-effect concentrations, respectively. These concentrations bracket most state, provincial, and international regulatory standards of vegetation levels for protection of livestock and wildlife.Human and Ecological Risk Assessment 02/2014; 20(4):941-961. DOI:10.1080/10807039.2012.750162 · 1.08 Impact Factor
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ABSTRACT: Ecological soil-screening levels (Eco-SSLs) were developed by the USEPA (United States Environmental Protection Agency) for purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Eco-SSLs for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no observed adverse effect toxicity reference value (TRV). Sensitivity analyses were performed for six avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank Analysis of Variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked second for carnivores and herbivores, but was fourth for invertivores. Different patterns were exhibited depending upon which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with copper as the representative analyte. The underlying assumption that generic body-weight-normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. Environ Toxicol Chem © 2014 SETAC.Environmental Toxicology and Chemistry 10/2014; 33(10). DOI:10.1002/etc.2675 · 2.83 Impact Factor