August 15, 2012
Keith Solomon, University of Guelph
Criteria for the identification of POPs were developed from the properties of the so-called “dirty dozen” (DDT, etc.) that had been observed to be persistent (P), bioacumulative (B), toxic (T), and transported over long distances (LRAT). The quantitative criteria for identification of POPs are deterministic values for P and B and qualitative for T and LRAT. The objective of these regulations is to avoid the use of chemicals that, over time, will increase in concentration in environmental compartments to the extent that they cause harm to organisms, including humans. Thus, the combined properties that drive P, B, and T must have, or will, result in accumulation to harmful levels. This was the case for some of the legacy POPs, but not necessarily for compounds that have properties close to the criterion values. These compounds are “on the cusp” and present scientific challenges that will be discussed using endosulfan as a case example.