Lack of data drives uncertainty in PCB health risk assessments.
Health risk assessments generally involve many extrapolations: for example, from animals to humans or from high doses to lower doses. Health risk assessments for PCBs involve all the usual uncertainties, plus additional uncertainties due to the nature of PCBs as a dynamic, complex mixture. Environmental processes alter PCB mixtures after release into the environment, so that people are exposed to mixtures that might not resemble the mixtures where there are toxicity data. This paper discusses the evolution of understanding in assessments of the cancer and noncancer effects of PCBs. It identifies where a lack of data in the past contributed to significant uncertainty and where new data subsequently altered the prevailing understanding of the toxicity of PCB mixtures, either qualitatively or quantitatively. Finally, the paper identifies some uncertainties remaining for current PCB health assessments, particularly those that result from a lack of data on exposure through nursing or on effects from inhalation of PCBs.
U.S. Environmental Protection Agency, 1200 Pennsylvania Ave NW #8601P, Washington, DC, 20460, USA. cogliano.vincent@epa.gov.
Vincent James
VJ
Cogliano
D003625:Data Collection / Q000379:methods / Q000592:standards*; D006801:Humans; D009369:Neoplasms / Q000209:etiology*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D018570:Risk Assessment / Q000379:methods / Q000592:standards*; D035501:Uncertainty
D011078:Polychlorinated Biphenyls
Bioaccumulation; Cancer; Hazard classification; PCBs; Partitioning; Toxicity value; Transformation; Uncertainty