Screening for persistent organic pollutants: Techniques to provide a scientific basis for POPs criteria in international negotiations

The United Nations Environment Programme (UNEP) is currently coordinating n egotiations to develop a binding global agreement by late in the year 2000 to prohibit, restrict, or reduce the production, use, or release of certain persistent organic pollutants (POPs). POPs are a small subset of organic c hemicals whose characteristics of persistence in the environment, accumulat ion in biological organisms, and toxicity make them priority pollutants and environmental risks to humans and ecosystems. Under the UNEP negotiation, representatives are developing criteria and procedures for the addition of substances, guided by the initial list of 12 substances or substance groups selected for global action. It is therefore timely to investigate the scie ntific foundation for POPs screening criteria that have been used in other international, regional, and national programs, focusing on the properties of persistence, bioaccumulation, toxicity, and long-range transport in a po licy context. The theoretical, empirical, and multimedia modeling approache s used reveal that guidance for setting POPs screening criteria can be deve loped using a combination of science and policy input. These approaches sug gest that criteria adopted under regional PDPs agreements in North America and Europe are reasonable and tend to isolate a limited number of clearly h azardous POPs from the majority of organic chemicals, while not being so st ringent that the ability to respond to as yet unidentified risks is serious ly compromised.