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(81-03) Development of ecological toxicity potentials (ETPs) for the US EPA TRACI model. McKone, Thomas*,1,2, Bare, Jane3, 1 University of California, Berkeley, CA2 Lawrence Berkeley National Laboratory, Berkeley, CA3 U.S. Environmental Protection Agency, Cincinnati, OH ABSTRACT- The ecological toxicity potential (ETP) has been developed as a quantitative toxic equivalency potential (TEP) that expresses the potential ecological harm of a unit quantity of chemical released into an evaluative environment. The goal of the ETP is to establish for life cycle impact assessment (LCIA) a rank measure of potential ecosystem harm for a large set of toxic industrial and agricultural chemicals. The ETP includes two components--a generic concentration-to-source relationship (CSR) for pollutant emissions and an impact to concentration ratio (ICR). The CSR can be applied at multiple scales--i.e. local (critical habitat scale), urban, regional, continental, and global. The ICR provides exposure-response functions that serve as an index of potential harm for terrestrial and aquatic ecosystems. The current ETP set includes 161 chemicals. We use the CalTOX model to provide CSRs in soil and surface water attributable to continuous emissions to air or surface water. The ICR is derived from an ecosystem-based toxicity benchmark. Currently we use the potentially affected fraction of species (PAF) as to define a benchmark measure of harm for ecosystems. Among the advantages of the PAF are simplicity and transparency. For emissions to air and surface water, we calculate an ETP based on potential terrestrial ecosystem impacts (related to soil concentration) and potential aquatic ecosystems impact so that we end up with four ETP values. We use weighting factors to select a single ETP measure. For normalization we use 2,4-dichlorophenoxy-acetic acid (2,4-D, CAS ID 94-75-7). The current set of ETPs is being developed for the US EPA Tool for the Reduction and Assessment of Chemical Impacts (TRACI) program. TRACI is a state-of-the-art impact assessment tool for the implementation of pollution prevention, LCA, and Sustainability programs. Key words: life cycle impact, ecological toxicity, multimedia model, pollution prevention |
