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

Abstract

BackgroundBisphenol 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 toxicokinetic studies.ObjectiveWe examined several possibilities for why biomonitoring and toxicokinetic studies could come to seemingly conflicting conclusions.Data sourcesWe examined > 80 published human biomonitoring studies that measured BPA concentrations in human tissues, urine, blood, and other fluids, along with two toxicokinetic studies of human BPA metabolism.Data extraction and synthesisThe > 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, toxicokinetic studies proposed that humans are not internally exposed to BPA. Some regulatory agencies have relied solely on these toxicokinetic models in their risk assessments.ConclusionsAvailable 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 toxicokinetic 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.

Low‐Dose Bisphenol A Exposure: A Seemingly Instigating Carcinogenic Effect on Breast Cancer

“…In neonatal rhesus monkeys gestationally exposed to BPA via food, a significantly higher density of mammary buds and an overall greater development of mammary epithelium was observed in newborns (Table 1). 27 Although the treatment dose of 400 µg kg –1 BW day –1 was high, the mean concentration of unconjugated BPA in maternal serum was 0.68 ng mL –1 , similar to what is measured in humans 98. A study in Wistar‐Furth rats revealed that fetal exposure to BPA (2.5, 25, 250, 1000 µg kg –1 BW day –1 ) via an implanted osmotic pump resulted in a 3–4 fold increase in the number of hyperplastic ducts at postnatal day (PND) 50 at all doses, and led to a significantly elevated number of these structures at PND90 at only the lowest dose 25.…”

Chlorination by-products of bisphenol A enhanced retinoid X receptor disrupting effects

“…Among the frequent human exposed EDCs, bisphenol A (BPA) is one of the highest production volume chemicals worldwide [6]. BPA is widely used to produce polycarbonates and epoxy resins, which are in the raw materials of buckets, feeding bottles, food cans and packaging [7], resulting in various opportunities for human exposure.…”

Estimating bisphenol A exposure levels using a questionnaire targeting known sources of exposure

“…Conclusions: Known dietary sources of BPA exposure explained less than half the variability in uBPA levels, regardless of diet assessment method. Findings suggest that a questionnaire approach may be insufficient for ranking BPA exposure level and additional important sources of BPA exposure likely exist.Bisphenol A (BPA), used in the manufacture of polycarbonate plastics and epoxy resins, is one of the highest-volume chemicals produced worldwide (1,2) and production is predicted to reach more than 4·09 Mt (9 billion lb) by 2020 (3) . Biomonitoring data indicate widespread, chronic low-level exposure to BPA (2,(4)(5)(6) .…”

“…Bisphenol A (BPA), used in the manufacture of polycarbonate plastics and epoxy resins, is one of the highest-volume chemicals produced worldwide (1,2) and production is predicted to reach more than 4·09 Mt (9 billion lb) by 2020 (3) . Biomonitoring data indicate widespread, chronic low-level exposure to BPA (2,(4)(5)(6) .…”

“…The use of polycarbonate plastics in the production of food and beverage storage containers has been largely phased out in the USA. However, BPA is still used in epoxy resin linings of metal cans and lids (1,2,6,51) . BPA has been measured in numerous canned (metal) food products (42,43,(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68) .…”