The use of biomonitoring equivalents for interpreting blood concentrations in population studies: a case for polychlorinated biphenyls

A number of exposure guideline values for environmental contaminants are established by various agencies for risk assessment purposes. Biomonitoring equivalents are conversions of external guideline values to internal doses, against which biomonitoring data can be directly compared. Several biomonitoring equivalents have been developed for the interpretation of blood concentrations of environmental contaminants, but none has yet been developed for polychlorinated biphenyls (PCBs). In this paper, we describe information needed to develop biomonitoring equivalents for PCBs and discuss anticipated challenges. We provide a broad overview of PCB absorption, distribution, metabolism and excretion, PCB guideline values, and PCB pharmacokinetic modeling efforts in animals and humans. We also provide strategies to address anticipated challenges in deriving biomonitoring equivalents for this complex contaminant. Biomonitoring equivalents will be useful for the interpretation of the PCB biomonitoring data that is currently available for populations around the globe through national surveys and research of specific populations.