Proposed Revisions to the Polychlorinated Biphenyl Criteria for Human Health and Wildlife for the Water Quality Guidance for the Great Lakes System

Résumé

EPA is proposing revisions to the polychlorinated biphenyl (PCB) ambient water quality criteria for human health and wildlife for the final Water Quality Guidance for the Great Lakes System (the Guidance). The Guidance was published on March 23, 1995. Following publication, several industries and trade associations challenged the human health and wildlife criteria for PCBs in the Guidance. Among the issues they raised was the equation used to calculate the weighted geometric mean baseline bioaccumulation factor (BAF) for PCBs. EPA re- examined the issue, and decided that a different approach for calculating a composite baseline BAF would be preferable because it would be more consistent with the definition of bioaccumulation factors since it more appropriately relates the concentrations of the PCB congeners in tissue to the concentrations of the PCB congeners in water. The proposed revisions are limited to the method for deriving a composite BAF for PCBs and for deriving a composite octanol-water partition coefficient (K ow) for PCBs. The human health cancer criteria for PCBs would change from 3.9 E-6 ug/L to 6.8 E-6 ug/L. The wildlife criteria for PCBs would change from 7.4 E-5 ug