Chemical Contaminants from Plastics in the Animal Environment

Accidental exposure of our mice to bisphenol A (BPA) from damaged polycarbonate cages 20 y ago provided some of the first evidence of the harmful effects of exposure to this common chemical. Recently we found that housing mice in damaged polysulfone cages resulted in similar harmful effects due to exposure to bisphenol S (BPS). This problem was unexpected for 2 reasons. First, polysulfone is a far more chemically resistant polymer than polycarbonate. Second, BPS is not a component in the manufacture of polysulfone. We report here our efforts to verify the source of the BPS and eliminate the exposure. Our analysis of new polysulfone caging materials confirmed that BPS is a breakdown product of damaged polysulfone plastic. Furthermore, we found that BPS can cross-contaminate new or undamaged cages in facilities that process damaged caging materials. Neither the use of disposable cages nor replacement of caging materials used solely for our colony was sufficient to eliminate exposure effects. Only the replacement of all cages and water bottles in the facility corrected the problem and allowed us to resume our studies. Taken together, our previous and current findings underscore the concern that chemicals from plastics are harmful environmental contaminants for both humans and animals. Furthermore, our results provide strong evidence that the presence of damaged plastic in a facility may be sufficient to affect research results and, by extension, animal health.