Human and Ecological Risk Assessment - Earthjustice

Executive SummaryHuman and Ecological Risk Assessment of Coal Combustion WastesHuman and Ecological Risk Assessment of CoalCombustion Wastes – Executive SummaryThe Executive Summary of EPA’s Humanand Ecological Risk Assessment of CoalCombustion Wastes is organized into fourparts. First, it presents Background for theregulation and study of coal combustionwastes. Next, it discusses the RiskAssessment Methodology used to evaluatethese wastes’ potential impact on humanhealth and the environment. The ExecutiveSummary continues with the presentation ofthe report’s Results and Characterization.Finally, it discusses the overall Conclusionsof the report.BackgroundThe U.S. Environmental ProtectionAgency (EPA) is evaluating managementoptions for solid wastes from coalcombustion: fly ash, bottom ash, boiler slag,flue gas desulphurization (FGD) residues, andfluidized bed combustion (FBC) wastes. Inthis report, these five types of coal combustionwastes are referred to as coal combustionwaste (CCW). All coal-fired electric utilityplants in the United States generate at leastone of these wastes, and most generate morethan one. For example, most electric utilityplants generate fly ash and either bottom ashor boiler slag. 1 Some plants also generateFGD residues. 2 Coal-fired electric utilityplants that use FBC technology generate bothbottom ash (bed ash) and fly ash.Depending on the coal-fired power plantboiler and air pollution control technologiesemployed at the power plants, these five typesof CCW might be initially generated either asprimarily dry or primarily wet material.Typically, the dry materials are disposed of inlandfills, while the wet materials are disposed1 U.S. EPA (1999a), Figure 3-2.2 U.S. EPA (1999a), Figure 3-3.of, at least initially, in surface impoundments(the settled solids can be removed periodicallyand disposed of in landfills). Landfills andsurface impoundments are referred to as wastemanagement units (WMUs).Coal-fired power plants typically conductcoal preparation activities before burning thecoal in their boilers. Wastes from these coalpreparation activities (such as coal handlingby conveyor systems, coal washing forremoving mineral matter, and coal “sizing”—for example, reducing particle sizes of coal forfiring in a pulverized coal boiler) are not partof the Bevill exclusion under the federalResource Conservation and Recovery Act.However, in the past, some U.S. coal-firedpower plants have managed CCW togetherwith these coal preparation wastes, or “coalrefuse,” in the same landfills and surfaceimpoundments. Because the chemicalcharacteristics of the coal refuse can affect theamount and behavior of chemical constituentsin the CCW, 3 EPA designed this analysisspecifically to estimate risks from CCWmanagement that is conducted separately fromcoal refuse management, as well as to estimaterisks from CCW that is comanaged with coalrefuse.This report describes the results of anational-scale analysis of groundwaterimpacts of managing CCW in five separatescenarios:• CCW managed alone in landfills• CCW managed alone in surfaceimpoundments• CCW comanaged with coal refuse inlandfills3 U.S. EPA (1999a), page 3-18.April 2010–Draft EPA document.ES-1