Risk Assessment and Life-Cycle Impact Assessment (LCIA) for Human Health Cancerous and Noncancerous Emissions: Integrated and Complementary with Consistency within the USEPA

The historical parallels, complementary roles, and potential for integration of human health risk assessment (RA) and Life-Cycle Impact Assessment (LCIA) are explored. Previous authors have considered the comparison of LCA and risk assessment recognizing the inherent differences in LCA and risk assessment (e.g., LCA's focus on the functional unit, and the differences in perspective of LCA and risk assessment), and also the commonalities (e.g., the basis for the modeling). Until this time, however, no one has proposed a coordinated approach for conducting LCA and risk assessment using models consistent with the U.S. Environmental Protection Agency's (USEPA's) handbooks, policies, and guidelines. The current status of LCIA methodology development can be compared to the early days of human health RA when practitioners were overwhelmed with the model choices, assumptions, lack of data, and poor data quality. Although methodology developers can build on the shoulders of the giant, LCIA requires more innovation to deal with more impact categories, more life-cycle stages, and less data for a greater number of stressors. For certain impact categories, LCIA can use many of the guidelines, methodologies, and default parameters that have been developed for human health RA, in conjunction with sensitivity and uncertainty analysis to determine the level of detail necessary for various applications. LCIA can then identify “hot spots” that require the additional detail and level of certainty provided by RA. A comparison of the USEPA's Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI) and the USEPA's Risk-Screening Environmental Indicators (RSEI) will be explored.