Trace metals and persistent organic pollutants contamination inbatoids (Chondrichthyes: Batoidea): A systematic review

Abstract

Atoids (Chondrichthyes: Batoidea; e.g. stingrays, skates, and guitarfish) comprise more than 55% ofelasmobranch taxa and represent ecologically important predators in benthic and pelagic habitats.Although overexploitation and habitat degradation are the two biggest threats to batoid populations,coastal and oceanic pollution is also a pervasive potential threat. In this systematic review, we compilepublished scientific literature on trace metals and persistent organic pollutants (POPs) contamination inelasmobranch species of the Batoidea superorder and present contamination patterns, exposure effects,and potential human exposure risks to most reported contaminants. We found batoids to accumulate awide range of trace metals, including mercury (Hg), arsenic (As), lead (Pb), copper (Cu), cadmium (Cd)and zinc (Zn). Accumulation of POPs is reported for chlordanes, dichlorodiphenyltrichloroethane (DDT),polychlorinated biphenyl (PCB), dieldrin, Heptachlor epoxide, hexachlorobenzene and perfluoroalkylsubstances (PFAS). Hg levels in muscle tissue were significantly different among oceanic basins andhabitats, consistent with previous global assessments of Hg oceanic background levels. Some batoidspecies presented Hg levels higher than large pelagic teleostfishes and comparable to sharks. Ecologicaltraits such as, bottom feeding, upper trophic position and elasmobranch-specific physiology and meta-bolism are discussed as potential factors associated with Hg uptake and accumulation in batoids. Somespecies exceeded USEPA's maximum contamination safety limits in edible tissues for Hg, As andSPCBs.For most trace metals and POPs, there is a lack of studies focusing on contamination levels in batoids. Werecommend future research increasing reporting on POPs and trace metals besides Hg in batoids tofurther investigate the role of Elasmobranch as a bioindicator for marine pollution