Human and Ecological Risk Assessment and Life Cycle Assessment: Intersections, Collisions, and Future Directions

摘要

This Debate/Commentary is dedicated to exploring the linkages between Risk Assessment (RA) and Life Cycle Assessment (LCA). The past seven years of my career have been spent conducting and collaborating on LCAs, including more than 100 studies of varying scope and application. I do not consider myself an expert in the field of risk assessment or toxicology to any extent, but it has been incorporated in my work projects over the years. In one particular project a fewyears ago I was presenting the results of a LCA study to a client who is a very astute environmental chemist, very well respected in her field. When the Life Cycle Impact Assessment (LCIA) results for Terrestrial and Aquatic EcoToxicity were presented she nearly choked and said, "That does not pass the laugh test." This outcome required a reexamination of the project. Was it a mistake we had made in the model? Was it an error in the database or characterization factors? It turned out that there were no mistakes in what we had put together. Instead, what we uncovered was that it appeared that the models used to develop the characterization factors for inorganics produced an overestimation of the potential toxicity associated with the emissions. There were two main reasons for this. The first was that the actual distribution and resulting exposure of the emissions could not be appropriately taken into account. That is, a model that uses the same characterization factors, regardless of the fate and exposure of an emission, will often improperly capture the impact. Thus if an emission is released in a highly insensitive environment with relatively low exposure risk, LCIA results will not reflect this. The other reason for the overestimation was because the methods used were based on models derived for organics, which do not work well for inorganics. Thus began a commitment to better educate myself on the models, how they are developed, and how they can be improved.