Development and evaluation of state-specific landscape data sets for multimedia source-to-dose models

The specific aims of this study are (i) to develop for the CalTOX multimedia exposure model landscape data sets for each state in and several regions of the US and (ii) use these data sets to explore the regional variation of risk screening calculations. We develop and evaluate forty-eight state-specific and nine region-specific landscape data sets for use in calculating toxic equivalency potentials (TEPs). TEPs address the information needs of risk management actions that require the comparison and aggregation of releases of several chemicals to a number of environmental compartments. We use state- and region-specific landscape data sets to calculate TEPs for releases to both air and water among a large set of chemically hazardous agents. We compare the TEPs calculated among states having significantly different landscape properties. The purpose of this exercise is to evaluate the extent to which TEPs will vary when applied in different US states or geographic regions. This exercise is also used to explore the premise that a single default US landscape data set is sufficient for making many kinds of LCIA classification. 278 chemicals are used in the analysis. Of these, 230 are on the TRI list, 123 have carcinogen potencies, and 244 have non-cancer allowable daily intakes. The results of the comparison suggest that TEPs can be reliably derived with a single default US landscape data set. As a result, state-specific TEP values may not be needed for assessments within the conterminous US.