Contaminant screening and tissue distribution in the critically endangered Brazilian guitarfish Pseudobatos horkelii

Elasmobranchs are particularly prone to accumulating contaminants due to their life history patterns and relatively high trophic position. However, several compounds, especially contaminants of emerging concern, have still not been well studied in this group. Here, we aimed to determine the occurrence and concentrations of several inorganic and organic contaminants in different tissues of the Brazilian guitarfish Pseudobatos horkelii. This species is a critically endangered species, endemic from the Southwest Atlantic which uses southern Brazilian waters as a nursery habitat. Polycyclic aromatic hydrocarbons (PAHs), emerging pesticides, pharmaceutical and personal care products (PPCPs) and trace metals were determined in five biological tissues in order to assess the accumulation and organotropism of these compounds. Except for chlorothalonil and triclosan, all compounds were detected in, at least, one tissue, mostly in liver samples. All compounds differed among tissues, with liver presenting the higher concentrations of several contaminants, followed by muscle and gills. PAHs and PPCPs were the most detected analytes and presented the highest concentrations among tissues. Diclofenac levels were determined, for the first time in elasmobranchs, and were relatively high, when compared to other fishes. Finally, relatively high concentrations of PAHs, dichlofluanid and octocrylene in muscle might be suggestive of chronic exposure, presenting also human health implications. Regarding trace metals, contrary to most elasmobranch studies, Hg levels were low in all tissues, whereas Cd and Pb here higher in liver, and gills and blood samples, respectively. Our results indicate that P. horkelii is exposed to several organic and inorganic which might affect this species in a long-term scale. Concerning the determination of emerging contaminants, it is likely that other elasmobranchs are also exposed to these compounds and special attention should be given to this issue in order to predict future effects on this group.