Multi-class contaminants of emerging concern in threatened coastal elasmobranchs: Novel evidence of early-life exposure in southeastern Brazil.

Contaminants of emerging concern (CEC), including pharmaceuticals and illicit drugs, are being increasingly reported in aquatic environments, although data for marine elasmobranchs remain scarce. This study investigated the occurrence of CEC in elasmobranchs from southeastern Brazil through the LC-MS/MS screening of the liver and muscle of Spiny butterfly rays (Gymnura altavela, n = 14) and the liver, muscle, and brain of Scalloped hammerhead (Sphyrna lewini, n = 16) and Smooth hammerhead (Sphyrna zygaena, n = 2) sharks. Detectable residues were found in seven individuals overall, occurring only in a subset of samples. Gymnura altavela showed the greatest diversity of compounds, including benzoylecgonine, cocaine, diclofenac, sulfamethoxazole, fipronil, and piroxicam, with liver presenting a broader profile than muscle. This is the first report on fipronil, sulfamethoxazole and piroxicam in elasmobranchs. Only one juvenile male S. lewini showed contamination, consisting of triclosan in muscle, and no residues were detected in S. zygaena. The co-occurrence of cocaine and benzoylecgonine, with higher concentrations of the former (~4 μg kg-1) compared to the latter (0.5-0.7 μg kg-1) suggests recent sewage-related exposure. All detections occurred in juveniles, indicating early-life exposure. These findings highlight the occurrence of multiple classes of CEC in coastal elasmobranchs from southeastern Brazil and reinforce the need for continued monitoring to clarify exposure routes, tissue distribution, and potential consequences for the health and conservation of threatened marine predators.