Toxicological profile of bisphenol F via comprehensive and extensive toxicity evaluations following dermal exposure

Identification of the allergenic sensitizing potential of bisphenol A substitutes used in the industry

BACKGROUND

Bisphenol (BP-)A is a chemical used in Europe to produce polycarbonate plastics and epoxy resin or as colour developer in thermal paper. Due to its toxicity, BPA presence was restricted by European regulations. Therefore, substitute chemicals are replacing BPA.

OBJECTIVE

To assess the allergenic sensitizing potential of 27 substitutes to BPA used in the industry.

METHODS

The expression of two costimulatory molecules and six cytokines were analysed by flow cytometry in mouse bone marrow-derived dendritic cells (BMDCs) exposed to the chemicals.

RESULTS

All substances except one induced overexpression of at least one receptor and were thus identified as having allergenic sensitizing potential. Based on the BMDC model, they were classified as extreme (1 out of 27), strong (20 out of 27) and moderate (5 out of 27) sensitizers. BPA was classified as a moderate sensitizer and BPF was the only substitute classified as a non-sensitizer. The more potent substitutes induced more than 2-fold secretion of CCL3, CCL4 and/or CCL5 by dendritic cells.

CONCLUSION

Most of the BPA substitutes tested in this study have an allergenic sensitizing potential; 24 of them being more potent than BPA itself. Only BPE, BPF and 2,4-BPS appeared to be weaker sensitizers than BPA.

Development of human dermal PBPK models for the bisphenols BPA, BPS, BPF, and BPAF with parallel-layered skin compartment: Basing on dermal administration studies in humans

Risk assessment of human exposure to bisphenols (BPs) including bisphenol A, S, F and AF (BPA, BPS, BPF and BPAF) have suggested that except for ingestion, health risk resulting from dermal contact is not negligible. However, the absorption kinetics of BPA substitutes in humans following dermal exposure have been poorly studied. This study aimed to address the knowledge gap in physiologically based pharmacokinetic (PBPK) modeling of BPA and its high-concerned substitutes (BPS, BPF and BPAF) following dermal administration. Parallel-layered skin compartmental model for dermal absorption of BPs was for the first time proposed and human dermal administration studies were conducted to determine dermal bio-accessibility of BPS from thermal paper (TP) (n = 4), BPF (n = 4) and BPAF (n = 5) from personal care products (PCPs). Further, pharmacokinetics of BPS and its metabolites following human handling TP were investigated and the dermal PBPK models for BPA and BPS were validated using the available human biomonitoring data. Overall, 28.03 % ± 13.76 % of BPS in TP was transferred to fingers followed by absorption of 96.17 % ± 2.78 % of that. The dermal bio-accessibilities of BPs in PCPs were 31.65 % ± 2.90 % for BPF and 12.49 % ± 1.66 % for BPAF. Monte Carlo analysis indicated that 90 % of the predicted variability fell within one order of magnitude, which suggested that the developed PBPK models had medium uncertainty. Global sensitivity analysis revealed that the model uncertainty is mainly attributed to the variabilities of dermal absorption parameters. Compared with the previous models for BPs, the developed dermal PBPK models were capable of more accurate predictions of the internal dose metric in target organs following human dermal exposure to BPs via TP and PCPs routes. These results suggested that the developed human dermal PBPK models would provide an alternative tool for assessing the risk of human exposure to BPs through dermal absorption.

Determination of 20 Endocrine-Disrupting Compounds in the Buffalo Milk Production Chain and Commercial Bovine Milk by UHPLC-MS/MS and HPLC-FLD

Simple Summary

The restriction of the use of bisphenol A (BPA) in industrial production has led manufacturers to employ several BPA analogues. The endocrine-disrupting activity of these substitutes has been proven, and some of them are already widespread in the environment. The intake of these endocrine-disrupting chemicals through diet represents a public concern, and food contamination data are still scarce in scientific literature. To investigate the levels of BPA and its analogues in the production chain of buffalo milk, we developed and validated two analytical methods based on UHPLC–MS/MS and HPLC–FLD. The methods were used to analyse feed and feed additives, raw milk, drinking water, and blood serum samples from buffalo farms in the Campania region, Southern Italy. BPA was found to be the most abundant contaminant, proving that the presence of this compound is still significant and should be monitored.

Abstract

Bisphenol A (BPA) and some of its analogues are well known as endocrine-disrupting chemicals (EDCs), i.e., compounds that can affect the physiological hormonal pathways in both animals and humans, causing adverse health effects. The intake of these substances through diet represents a public concern, compounded by the scarce data in the literature about contamination levels in food. In the framework of a research project, funded by the Italian Ministry of Health, we determined the contamination levels of BPA and 19 EDCs in the production chain of buffalo milk, analysing feed, drinking water, buffalo milk, and blood sera. Overall, 201 feed, 9 feed additive, 62 drinking water, 46 milk, and 190 blood serum samples were collected from 10 buffalo farms in the Campania region, Southern Italy, between 2019 and 2020, and analysed. Moreover, 15 retail bovine milk samples packaged both in Tetra Pak and in PET were analysed to further evaluate consumers’ exposure to EDCs. The results of our work showed no contamination by EDCs in drinking water samples, whereas in 43% of all of the other samples from the farms at least one bisphenol was detected. The most abundant bisphenol detected was BPA (32% of the samples from the farms and 80% of the retail milk samples), thus proving that this compound is still widely used for plastic production.