Ecotoxicity of bisphenol S to Caenorhabditis elegans by prolonged exposure in comparison with bisphenol A

Because of increasing concerns about its toxic effects, bisphenol A (BPA) has been gradually replaced in industrial applications by analogs such as bisphenol S (BPS). Few comparative toxicity evaluations of bisphenol analogs have been done. In the present study, 72-h exposure in L1 larvae of the model animal Caenorhabditis elegans was used to evaluate low-concentration BPS toxicity. Multiple indicators at the physiological, biochemical, and molecular levels were tested. At the physiological level, BPS exposure resulted in significantly negative effects at treatments >1 µM, with head thrash being the most sensitive endpoint. At the biochemical level, BPS exposure induced no significant oxidative stress, but significantly increased apoptosis at 1 µM. At the molecular level, BPS exposure induced small but significant variations in most stress-related gene expressions at all doses. In addition, the transgenic nematode TJ375 cell line with the green fluorescent protein-based reporter hsp-16.2 was used to determine stress responses; it was found that TJ375 was not sensitive to BPS exposure. Compared with the effects of BPA shown in our previous 2016 study, the overall results showed that BPS was less noxious to C. elegans than BPA. These toxicity data for BPS could provide a foundation to evaluate the comparative toxicity of BPA alternatives. Environ Toxicol Chem 2018;37:2560-2565. © 2018 SETAC.