Quantity-based and toxicity-based evaluation of the U.S. Toxics Release Inventory

The U.S. EPA Toxics Release Inventory (TRI) represents an extensive, publicly available dataset on toxics and, as such, has contributed to reducing the releases and disposal of toxic chemicals. The TRI, however, reports on a wide range of releases from different sources, some of which are less likely to generate a human or ecological hazard. Furthermore, the TRI is quantity based and does not take into account the relative toxicity of chemicals. In an effort to utilize the TRI more effectively to guide environmental management and policy, this work provides an in-depth analysis of the quantity-based TRI data for year 2007 at industry sector, state, and chemical levels and couples it with toxicity potentials. These toxicity potentials are derived from the U.S. EPA's TRACI (Tool for the Reduction and Assessment of Chemical and other environmental Impacts) characterization factors for cancer, non-cancer and ecotoxicity. The combination of quantity-based and toxicity-based analysis allows a more robust evaluation of toxics use and priorities. Results show, for instance, that none of the highest priority chemicals identified through the toxicity-based evaluation would have been identified if only quantity-based evaluation had been used. As the chemicals are aggregated to the state and industry sector levels, the discrepancies between the evaluation methods are less significant.