Meeting the challenge of identifying persistent pollutants at the state level

In 2007, the State of Oregon enacted legislation aimed at identifying persistent pollutants that could pose a threat to waters of the State and then reducing their discharge by means of a comprehensive pollution prevention program. This legislation defined a persistent pollutant as one that is toxic and persistent or bioaccumulative; a broad definition that required evaluation of an extensive number and variety of chemicals. The Oregon Department of Environmental Quality, in consultation with a science workgroup, implemented a 12-step process for identifying and prioritizing persistent pollutants consistent with this definition. This process is characterized by (a) maximum overall transparency in its conduct, including extensive public involvement, (b) 3 levels of objective and predefined criteria for categorization of a chemical as a persistent pollutant, (c) full disclosure of values and sources for all physicochemical data used for comparison with these criteria, and (d) clear acknowledgement when a chemical was identified as a persistent pollutant for reasons other than these criteria alone. This process was used to identify those chemicals relevant as persistent pollutants and to then prioritize them in terms of their relative ability to adversely impact waters of the state, with special emphasis on impacts to aquatic receptors. An initial list of 2130 chemicals was compiled from existing lists. Criteria for toxicity, persistence, and bioaccumulative potential were defined and then used with 2 different chemical property evaluation models (PBT Profiler and EPISuite) to produce a final list of 118 chemicals. The final list includes several legacy pollutants but also contains numerous current-use pharmaceuticals, personal care products, and pesticides, approximately half of which appear only once or not at all on lists compiled by others. Although it drew from the experience of others, assembling this list proved to be an exemplar of science in the service of policy.