(Some) of the nasty effects caused by a chronic exposure to a dirty cocktail

Persistent Organic Pollutants (POPs) have been widely described as major health threats. Most of the research on them has focused on single compounds, while the environment and individuals are continuously exposed to a variety of substances. Here, we tested a synthetic version of a POP mixture consisting of 29 compounds (Total Mix) that is based on environmentally relevant concentrations found in the blood of Scandinavian people. In addition, we tested sub-mixtures of each separate class of compounds (perfluorinated, chlorinated, and brominated compounds) of such Total Mix. Zebrafish larvae were exposed to seven different mixtures for 4 days and then monitored for their movement behavior, heart rate, cartilage and bones deformations, inflation of swim bladder, and gene expression. Their responses varied significantly depending on the mixture used. The most remarkable effects were seen in those fish treated with the Total Mix, suggesting a distinctive synergistic effect. The perfluorinated-containing class of compounds induced the most remarkable defects in all the assessed endpoints. Our results add up to the already existing catalogue of toxic effects described for POPs, paving the way to a much deeper understanding on how POP mixtures may affect wildlife and humans.