A new study conducted in piglets has revealed that synthetic organic chemical bisphenol S (BPS) persists longer in the body and at much higher concentrations than bisphenol A (BPA).
The results suggest that, the current regulatory advice of replacing BPA with BPS could, therefore, lead to a very significant increase in human exposure to a hormonally active compound. This is worrying given that bisphenols are used in the manufacture of products such as plastic water bottles and cans.
The research was conducted by the Gestation and Endocrine Disrupters team of the Veterinary School of Toulouse and the Toxalim Research Unit in collaboration with the Universities of Montreal and The Royal Veterinary College (RVC). Undertaken with pigs due to their comparable gastrointestinal functions with humans, the study highlights the critical importance of exposure assessment when searching for alternatives to substances of concern.
Bisphenols are a family of synthetic organic chemicals used in the manufacture of polycarbonate-type plastics (e.g. water bottles) and epoxy resins (e.g. cans), as well as developers for most thermal papers (e.g. till receipts). While there are over 20 different types, BPA and BPS are the most commonly used.
Both BPA and BPS are regulated, however the use of bisphenol A is restricted in many countries based on extensive research. Therefore, manufacturers have started to gradually replace BPA with BPS.
Critical research by the team showed the amount of ingested BPS that reaches the general bloodstream is about 100 times higher than that of BPA. Associated with slower elimination from the bloodstream (about 3.5 times lower), this leads to blood concentrations of BPS about 250 times higher than those of BPA, and much higher oral bioavailability of BPS (57%) compared to BPA (0.50%).
Professor Pierre-Louis Toutain, co-author of the study and Honorary Professor at the RVC, said: “In 2017, BPA was classified as a substance of very high concern by the European Chemicals Agency’s (ECHA) who reinforced the use of alternatives, mainly BPS.
“Although toxicological data are still insufficient to assess the associated hazard, these results clearly highlight the importance of exposure estimation in the human health risk analysis process related to the substitution of substances of concern. This is a really important process in helping to avoid regrettable substitution.”