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Lack of data drives uncertainty in PCB health risk assessments
Citation:
Cogliano, V. Lack of data drives uncertainty in PCB health risk assessments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH. Ecomed Verlagsgesellschaft AG, Landsberg, Germany, 23:2212-2219, (2015). https://doi.org/10.1007/s11356-015-5157-4
Impact/Purpose:
PCB researchers worldwide have been meeting biannually for about 15 years. I was invited to speak at the Oct 2014 meeting by virtue of longstanding knowledge of PCB health risks and by having chaired the April 2013 IARC meeting that classified PCBs as carcinogenic to humans. Because I had also attended the first biannual meeting, I was asked to give an historical overview of PCB research and how studies were conducted to address uncertainties and knowledge gaps. This paper arose out of that talk.
Description:
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.
