Urinary, Circulating, and Tissue Biomonitoring Studies Indicate Widespread Exposure to Bisphenol A

Background: Bisphenol A (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous.Thus, there are concerns that the amount of BPA to which humans are exposed may cause adverse health effects.Importantly, results from a large number of biomonitoring studies are at odds with the results from two toxico kinetic studies.oBjective: We examined several possibilities for why biomonitoring and toxico kinetic studies could come to seemingly conflicting conclusions.data sources: We examined > 80 published human biomonitoring studies that measured BPA concentrations in human tissues, urine, blood, and other fluids, along with two toxico kinetic studies of human BPA metabolism.data extraction and synthesis: The > 80 biomonitoring studies examined included measurements in thousands of individuals from several different countries, and these studies overwhelmingly detected BPA in individual adults, adolescents, and children.Unconjugated BPA was routinely detected in blood (in the nanograms per milliliter range), and conjugated BPA was routinely detected in the vast majority of urine samples (also in the nanograms per milliliter range).In stark contrast, toxico kinetic studies proposed that humans are not internally exposed to BPA.Some regulatory agencies have relied solely on these toxicokinetic models in their risk assessments.conclusions: Available data from biomonitoring studies clearly indicate that the general population is exposed to BPA and is at risk from internal exposure to unconjugated BPA.The two toxico kinetic studies that suggested human BPA exposure is negligible have significant deficiencies, are directly contradicted by hypothesis-driven studies, and are therefore not reliable for risk assessment purposes.