Framework for Metals Risk Assessment

Office of the Science Advisor, Risk Assessment Forum, US Environmental Protection Agency, Washington, DC 20460, USA.
Ecotoxicology and Environmental Safety (Impact Factor: 2.76). 11/2007; 68(2):145-227. DOI: 10.1016/j.ecoenv.2007.03.015
Source: PubMed


EPA recognized that metals present unique risk assessment issues, and saw the need to develop a framework document that puts forth key scientific principles for metals risk assessments to help ensure consistency in metals assessments across EPA programs and regional offices. This framework, called the "Framework for Metals Risk Assessment," is a science-based document that describes basic principles that address the special attributes and behaviors of metals and metal compounds to be considered when assessing their human health and ecological risks. The Risk Assessment Forum oversaw the development of this document, including input from stakeholders and experts throughout the Agency, and obtained through several expert workshops, followed by peer review by the EPA Science Advisory Board (SAB). The Framework for Metals Risk Assessment document is intended to serve as a guide for all EPA programs and regional offices to supplement or update the policies, practices and guidance they currently use in their respective metals assessments. This framework document is not a prescriptive guide on how any particular type of assessment should be conducted within an EPA program office. Rather, it outlines key metal principles and describes how they should be considered in conducting human health and ecological risk assessments to advance our understanding of metals impact and foster consistency across EPA programs and regions. Although the audience for the framework is primarily intended to be Agency risk assessors, it also will communicate principles and recommendations for metals risk assessment to stakeholders and the public. This framework will be used in conjunction with guidance developed by the programs and regions for site-specific risk assessment, criteria derivation, ranking or categorization and other similar Agency activities related to metals. The Framework for Metals Risk Assessment document is intended to serve as a guide for all EPA programs and regional offices to supplement or update the policies, practices and guidance they currently use in their respective metals assessments. EPA assessments can vary in level of detail from simple, screening analyses to complex, definitive assessments. More complex scientific tools and metal specific methods should be applied as the complexity of the hazard assessment or risk assessment increases.

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Available from: Anne Fairbrother, Mar 24, 2014
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    • "For " conventional " metals, the reliance of RA on short-term tests for long-term environmental effect prediction in widely recognised as a potential issue (Fairbrother et al., 2007). This concern has, however, been alleviated to some extent by current understanding of metal " aging " in soil. "
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    ABSTRACT: This study investigated if standard risk assessment hazard tests are long enough to adequately provide the worst case exposure for nanomaterials. This study therefore determined the comparative effects of the aging on the bioavailability and toxicity to earthworms of soils dosed with silver ions and silver nanoparticles (Ag NP) for 1, 9, 30 & 52 weeks, and related this to the total Ag in the soil, Ag in soil pore water and earthworm tissue Ag concentrations. For ionic Ag, a classical pattern of reduced bioavailability and toxicity with time aged in the soil was observed. For the Ag NP, toxicity increased with time apparently driven by Ag ion dissolution from the added Ag NPs. Internal Ag in the earthworms did not always explain toxicity and suggested the presence of an internalised, low-toxicity Ag fraction (as intact or transformed NPs) after shorter aging times. Our results indicate that short-term exposures, without long-term soil aging, are not able to properly assess the environmental risk of Ag NPs and that ultimately, with aging time, Ag ion and Ag NP effect will merge to a common value. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Environmental Pollution 04/2015; 203:191-198. DOI:10.1016/j.envpol.2015.03.033 · 4.14 Impact Factor
    • "The current results show that even when some BAF values were high (as was the case with Ag, Cd, and Zn), these elements presented small percentages of accumulation in oysters compared with the control organisms . Fairbrother et al. (2007) stated that the toxicokinetics of metals are highly dynamic and vary according to the exposure route, metal species and concentration, and type of organism assessed; they also reported that BAFs are sitespecific and should be carefully expressed as a function of the chemistry of the medium and the concentration of metals. "
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    ABSTRACT: This study focuses on the discussion of different lines of evidence (LoEs) applied to a sediment-quality assessment that considered the following: chemical concentrations of metals; polycyclic aromatic hydrocarbons (PAHs) in estuarine waters, sediments, and oysters (native and caged Crassostrea brasiliana); PAHs in semipermeable membrane devices (SPMDs); simultaneously extracted metals-acid volatile sulfides (SEM-AVS); benthic community assessment (the exploratory benthic index and the relative benthic index); chronic toxicity tests with the sea urchin Lytechinus variegatus; and bioaccumulation models. Significantly contaminated sediments from the Santos Estuarine System and the consequent toxicity of tested organisms were measured. Caged oysters presented bioaccumulation rates ≤2,500 % of total PAH content and 200 % of metal content when compared with control organisms from an uncontaminated area. SPMD results presented the same bioaccumulation pattern as caged oysters but at lower concentrations. Benthic communities presented some alterations, and there was a predominance of tolerant species in the inner part of the estuary. According to the SEM-AVS approach, metals should be assumed to be nonbioavailable, but experiments with transplanted C. brasiliana showed metal bioaccumulation, particularly in the cases of chromium, copper, mercury, and zinc. The weight-of-evidence approach was applied to compare and harmonize LoEs commonly used in sediment-quality assessments and to then classify estuary environments according to both their potential for having adverse effects on the biota and their possible ecological risks. All of the results of these approaches (except for SEM-AVS) were found to complement each other.
    Archives of Environmental Contamination and Toxicology 11/2014; 68(1). DOI:10.1007/s00244-014-0099-2 · 1.90 Impact Factor
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    • "They assigned several evidential scores to a certain feature to obtain a distribution function of evidential scores as input probability distribution to support Monte Carlo simulation. This is an effective method for modeling uncertainty where there are some primary reliable historical data for supporting the analyst to obtain a probability distribution of uncertain variables (e.g., Fairbrother et al., 2007; Sari et al., 2009; Mun, 2006). However, the result of Monte Carlo simulation is affected by the probability distribution of the input uncertain variables (e.g., Mun, 2006). "
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    ABSTRACT: Complexities of geological processes portrayed as certain feature in a map (e.g., faults) are natural sources of uncertainties in decision-making for exploration of mineral deposits. Besides natural sources of uncertainties, knowledge-driven (e.g., fuzzy logic) mineral prospectivity mapping (MPM) is also plagued and incurs further uncertainty in subjective judgment of analyst when there is no reliable proven value of evidential scores corresponding to relative importance of geological features that can directly be measured. In this regard, analysts apply expert opinion to assess relative importance of spatial evidences as meaningful decision support. This paper aims for fuzzification of continuous spatial data used as proxy evidence to facilitate and to support fuzzy MPM to generate exploration target areas for further examination of undiscovered deposits. In addition, this paper proposes to adapt the concept of expected value to further improve fuzzy logic MPM because the analysis of uncertain variables can be presented in terms of their expected value. The proposed modified expected value approach to MPM is not only a multi-criteria approach but it also treats uncertainty of geological processes a depicted by maps or spatial data in term of biased weighting more realistically in comparison with classified evidential maps because fuzzy membership scores are defined continuously whereby, for example, there is no need to categorize distances from evidential features to proximity classes using arbitrary intervals. The proposed continuous weighting approach and then integrating the weighted evidence layers by using modified expected value function, described in this paper can be used efficiently in either greenfields or brownfields.
    Computers & Geosciences 11/2014; 74. DOI:10.1016/j.cageo.2014.10.014 · 2.05 Impact Factor
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