Human and Ecological Risk Assessment - Earthjustice

Appendix AConstituent DataA.1 Data SourcesEPA prepared the CCW constituent database in 2002. The 2002 CCW constituentdatabase includes all of the waste characterization data used by EPA in its risk assessments insupport of the March 1999 Report to Congress: Wastes from the Combustion of Fossil Fuels (theRTC) (U.S. EPA, 1999). In addition to the data set from the March 1999 RTC, EPAsupplemented the database with the following data:• Data submitted with public comments to EPA on the 1999 RTC• Data submitted with public comments to EPA concerning the May 22, 2000, FinalRegulatory Determination• Data collected by and provided to EPA since the end of the public comment period on theFinal Regulatory Determination• Data identified from literature searches.The primary sources of these additional data include the electric power industry, state and federalregulatory agencies, and scientific literature. Attachment A-1 is a complete list of the sources ofdata contained in the 2002 CCW constituent database.The additional data represent a significant expansion in the quantity of characterizationdata available to EPA for analysis. For example, the data set used for the risk assessmentssupporting the RTC covered approximately 50 CCW generation and/or disposal sites. With theaddition of the supplemental data, the 2002 CCW constituent database now covers more than160 sites. The 1999 data set included approximately 10,000 individual samples of CCW. The2002 CCW constituent database now includes more than 35,000 individual samples.The additional data also represent an expansion in the scope of characterization dataavailable to EPA for analysis. The 1999 data were obtained exclusively from the electric powerindustry. As shown in Attachment A-1, the 2002 data set includes data from other sources, suchas scientific literature and state and federal regulatory agencies. The 1999 data set includedanalyses of whole waste samples, surface impoundment and landfill porewater analyses, andanalyses of extracts obtained using the Toxicity Characteristic Leaching Procedure (TCLP), theSynthetic Precipitation Leaching Procedure (SPLP), and Extraction Procedure (EP) Toxicityleaching methods. The 2002 data set added analyses of actual landfill leachate (e.g., obtainedfrom leachate collection systems), analyses of extracts obtained using other leaching methods(including higher retention time leaching methods), and porewater analyses.The 2002 CCW constituent database represents CCW characteristics across a broadcross-section of the generating universe. Not only does the database include data from a largenumber of sites, but these sites are distributed throughout the United States, as shown inTable A-2. The database includes data for all major types of CCW (i.e., fly ash, bottom ash, fluegas desulfurization [FGD] sludge, fluidized bed combustion [FBC] fly ash, and FBC bed ash),from mixtures of CCW types that are commonly created during disposal operations (e.g.,combined fly ash and bottom ash), and from CCW mixed with coal refuse (a common disposalpractice). Section A.2 discusses waste types in more detail.April 2010–Draft EPA document. A-2