A multi-estuary assessment of pharmaceutical exposure and risk of pharmacological effects in a recreational fishery

Evidence of coastal and marine pharmaceutical pollution is increasing, yet most studies examining pharmaceuticals are conducted in temperate regions, while research in subtropical and tropical regions lags behind. These studies have been conducted at small spatial scales, with a need for larger spatial assessments. We examined pharmaceutical occurrence and pharmacological risk for 94 pharmaceuticals in a coastal recreational fish, the red drum (Sciaenops ocellatus), across nine Florida (USA) estuaries. To evaluate risk of pharmacological effects, we compared plasma concentrations to the one-third human therapeutic plasma concentration (1/3 HTPC) and to the full HTPC. Pharmaceuticals were detected in all estuaries and in 93% of plasma samples analyzed, with an average of 2.1 pharmaceuticals per red drum. A total of 17 pharmaceuticals were detected, and dissimilarity in the pharmaceutical assemblage across estuaries was high. Cardiovascular medications, opioid pain relievers, and psychoactive medications accounted for 90.6% of detections. For pharmacological effects, we observed medium risk in 25.7% and high risk in 15.9% of the red drum sampled. Of the 17 pharmaceuticals detected, five were observed at concentrations above the 1/3 HTPC, with a psychoactive pharmaceutical (flupentixol) showing the highest pharmacological risk. Across estuaries, risk of pharmacological effects was observed in five of nine estuaries, with 33%-60% of the red drum above the 1/3 HTPC threshold, whereas risk was minimal in the other four estuaries (only 0%-7% exceedances). Pharmacological risk was highest on the west coast of Florida and in both large and densely-populated watersheds, as well as small and sparsely populated ones. Our findings highlight the need expand beyond documenting occurrence to estimating toxicological risk, the value of assessing internal concentrations in wild biota, and the importance of expanding the diversity of biota used in pharmaceutical studies to account for pharmacological effects in conservation and management actions, such as recreational fisheries.