title: A systematic review of Bisphenol A "low dose" studies in the context of human exposure: a case for establishing standards for reporting "low-dose" effects of chemicals.
abstract: Human exposure to the chemical Bisphenol A is almost ubiquitous in surveyed industrialized societies. Structural features similar to estrogen confer the ability of Bisphenol A (BPA) to bind estrogen receptors, giving BPA membership in the group of environmental pollutants called endocrine disruptors. References by scientists, the media, political entities, and non-governmental organizations to many toxicity studies as "low dose" has led to the belief that exposure levels in these studies are similar to humans, implying that BPA is toxic to humans at current exposures. Through systematic, objective comparison of our current, and a previous compilation of the "low-dose" literature to multiple estimates of human external and internal exposure levels, we found that the "low-dose" moniker describes exposures covering 8-12 orders of magnitude, the majority (91-99% of exposures) being greater than the upper bound of human exposure in the general infant, child and adult U.S. Population. "low dose" is therefore a descriptor without specific meaning regarding human exposure. Where human exposure data are available, for BPA and other environmental chemicals, reference to toxicity study exposures by direct comparison to human exposure would be more informative, more objective, and less susceptible to misunderstanding.
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA 99352, United States. Electronic address: jt@pnl.gov.
authors.forename: Justin G
authors.initials: JG
authors.lastname: Teeguarden
authors.forename: Sesha
authors.initials: S
authors.lastname: Hanson-Drury
mesh_terms: D000328:Adult; D000818:Animals; D001559:Benzhydryl Compounds / Q000008:administration & dosage* / Q000633:toxicity*; D002648:Child; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000008:administration & dosage / Q000633:toxicity; D004781:Environmental Exposure / Q000032:analysis*; D004785:Environmental Pollutants / Q000633:toxicity; D006801:Humans; D008322:Mammals; D010636:Phenols / Q000008:administration & dosage* / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods / Q000592:standards; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D010636:Phenols; C006780:bisphenol A; D000098826:Bisphenol A Compounds
keywords: BPA; Bisphenol A; CHMS; Canadian Health Measures Survey; EFSA; European Food Safety Authority; Exposure; LOAEL; Low-dose; Lowest Observable Effect Level; NHANES; NTP; National Health and Nutrition Examination Survey; National Toxicology Program; Risk; Total BPA; WHO; World Health Organization; the sum of BPA and its metabolites; the unmetabolized Bisphenol A molecule