Human and Ecological Risk Assessment - Earthjustice

Section 4.0Risk CharacterizationTable 4-26. Summary of Risk Screening Values for Unmodeled Constituents Using RiskAttenuation Factors—Ecological Risk, Surface Water PathwayWMU/PathwayScreeningHQLandfillHQ withMedianAttenuationHQ with 10thPercentileAttenuationScreeningHQSurface ImpoundmentHQ withMedianAttenuationHQ with 10thPercentileAttenuationChromium VI 18 0.1 0.2 33 0.9 1.9Vanadium 23 0.1 0.3 24 0.6 1.4Beryllium 24 0.1 0.3 - - -Copper 16 0.09 0.2 31 0.8 1.8Silver 110 0.6 1.5 14 0.4 0.8Zinc 16 0.09 0.2 - - -4.2.5 Ecological Damage CasesCases of damages to terrestrial and aquatic organisms from improperly managed CCWare common in the literature. For example, Carlson and Adriano (1993) summarize such damageincidents, including those resulting from alkaline CCW effluent discharge to surface waterbodiesand boron toxicity to plants. Rowe et al. (2002) provide a more comprehensive review,assessment, and meta-analysis of the ecotoxicity of CCW, focusing on aquatic disposal (i.e.,CCW surface impoundments) and tabulating damages from over 20 years of field and laboratorystudies in the published literature. Selenium and arsenic are most commonly associated withCCW damages to terrestrial and aquatic organisms. Cadmium, boron, chromium, and lead arealso associated with CCW ecological risk. Hopkins et al. (2006) show deformities andreproductive effects in amphibians living on or near CCW disposal sites in Georgia, which aremainly attributed to selenium exposure.Table 4-27 summarizes the proven CCW ecological damage cases from U.S. EPA(2007). Most of these cases are from surface impoundments and direct discharge into lakes andother water bodies. Along with the published results discussed in Section 4.1.5, these casesclearly support selenium and arsenic in coal ash as risks to aquatic ecosystems, as well as theadverse impacts of coal ash on terrestrial vegetation.April 2010–Draft EPA document. 4-33