US EPA

Polychlorinated dioxins (PCDDs), furans (PCDFs), and biphenyls (PCBs) are persistent contaminants found widely in the environment. Several of these compounds bioaccumulate in the tissues of fish, birds, and mammals, where they have been demonstrated to cause mortality and adverse effects on reproduction, development, and the immune system. This Framework is intended to assist EPA scientists in using a method known as the toxicity equivalence methodology to assess ecological risks from mixtures of these compounds. The Framework also informs EPA decision makers, other agencies, and the public about this methodology.

This framework is not a regulation nor is it intended to substitute for federal regulations.

U.S. EPA. Framework for Application of the Toxicity Equivalence Methodology for Polychlorinated Dioxins, Furans and Biphenyls in Ecological Risk Assessment (External Review Draft). U.S. Environmental Protection Agency, Risk Assessment Forum, Washington, DC, 630/P-03/002A, 2003.

As announced in the September 22, 2003 Federal Register Notice the public comment period is extended until October 29, 2003. Comments may be submitted electronically, by mail, or in person, as described in the instructions in the Federal Register notice announcing the availability of the document (see Downloads below). The document is undergoing peer review concurrent with the 60-day public comment period.

As a service to reviewers, the 1997 World Health Organization database on relative potencies for PCDDs, PCDFs, and PCBs cited in the draft Framework is also provided below under Downloads. Please note that this is not an EPA database.