Comparing the disrupting effects of short-, medium- and long-chain chlorinated Paraffins on cell viability and metabolism

With the phasing out of short-chain chlorinated paraffins (SCCPs), the production and emissions of medium- and long-chain chlorinated paraffins (MCCPs and LCCPs) are expected to increase. In this study, cell viability assay and pseudotargeted metabolomics approach were adopted to define and compare the toxic effects induced by SCCPs, MCCPs and LCCPs. The dose response curves indicated that three CP mixtures with comparable chlorine contents produced similar inhibitory effects on cell viability. At exposure concentration of 100 μg/L, three CP mixtures all induced significant increases in levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and a significant reduction in level of adenosine triphosphate production (ATP), and produced similar impact intensities on overall metabolism. A stronger perturbation in phospholipid and fatty acid metabolism was observed in all CP exposure groups. In comparison with SCCPs and MCCPs, LCCPs produced a stronger suppressive effect on amino acid transport across cell membrane and induced an opposite effect on purine metabolism. Furthermore, the toxicity mechanism and possible health risks of the three types of CPs were discussed. MCCPs shared the most similar cytotoxicity and metabolic perturbation with SCCPs, suggesting that there should be concern about using MCCPs as alternatives to SCCPs.