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Human Health Effects of Biphenyl: Key Findings and Scientific Issues
Citation:
Li, Jenny, K. Hogan, Christine Cai, AND S. Rieth. Human Health Effects of Biphenyl: Key Findings and Scientific Issues. ENVIRONMENTAL HEALTH PERSPECTIVES. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, 124(6):703-712, (2015). https://doi.org/10.1289/ehp.1509730
Impact/Purpose:
Biphenyl exists naturally as a component of crude oil and coal tar. Biphenyl is currently used as a chemical synthesis intermediate (including in the synthesis of the sodium salt of 2-hydroxybiphenyl, a pesticide known as Dowicide 1), as a dye carrier in polyester dyeing, and as a component in heat transfer fluids (consisting of 26.5% biphenyl and 73.5% diphenyl oxide). Biphenyl has been used as a fungistat, most commonly to preserve packaged citrus fruits or in plant disease control (as reviewed by HSDB 2014; IPCS 1999); U.S. registration of biphenyl as a pesticide (fungistat and antimicrobial agent) was cancelled [U.S. Environmental Protection Agency (EPA) 1998].
Description:
Background: In support of the Integrated Risk Information System (IRIS), the U.S. Environmental Protection Agency (EPA) has evaluated the human health hazards of biphenyl exposure. Objectives: We review key findings and scientific issues regarding expected human health effects of biphenyl. Methods: Scientific literature from 1926 through September 2012 was critically evaluated to identify potential human health hazards associated with biphenyl exposure. Key issues related to the carcinogenicity and noncancer health hazards of biphenyl were examined based on evidence from experimental animal bioassays and mechanistic studies. Discussion: Systematic consideration of experimental animal studies of oral biphenyl exposure took into account the variety of study designs (e.g., study sizes, exposure levels, and exposure durations) to reconcile differing reported results. The available mechanistic and toxicokinetic evidence supports the hypothesis that male rat urinary bladder tumors arise through urinary bladder calculi formation but is insufficient to hypothesize a mode of action for liver tumors in female mice. Biphenyl and its metabolites may induce genetic damage, but a role for genotoxicity in biphenyl-induced carcinogenicity has not been established. Conclusions: The available health effects data for biphenyl provides suggestive evidence for carcinogenicity in humans, based on increased incidences of male rat urinary bladder tumors at high exposure levels and on female mouse liver tumors. Kidney toxicity is also a potential human health hazard of biphenyl exposure.
