Habitat-based assessment of potential toxic elements and human health risks in deep-sea bycatch fishes from the Arabian Sea

Growing utilization of deep-sea bycatch fishes as food sources necessitates the preliminary assessment of potential toxic elements contamination to safeguard consumers and guide regulatory frameworks. This baseline study evaluates the concentrations of potential toxic elements including arsenic, cadmium, copper, nickel, lead, selenium, manganese, iron and zinc levels in the muscle tissues of marine fishes occupying benthopelagic, demersal and bathydemersal habitats in the Arabian Sea. The fish were obtained as bycatch from deep-sea demersal shrimp trawlers and the research provides novel insights into their toxicant levels and associated health risks. Arsenic levels exceeded the permissible safety limits in two demersal species, with the highest concentration recorded in Grammoplites scaber (1.4330 mg/kg wet weight) followed by Callionymus gardineri (1.2570 mg/kg ww). Cadmium levels surpassed safety thresholds in all demersal and bathydemersal species examined, with Pterygotrigla macrorhynchus recording the highest concentration (0.1484 mg/kg wet weight). Human health risks delineated that estimated daily intake was dominated by iron and zinc across all species, though these posed negligible toxicological concern. Arsenic drove non-carcinogenic risk, with target hazard quotient exceeding 1 individually in six species and hazard index surpassing the safety threshold in seven of nine species. The target cancer risk exceeded the USEPA acceptable limit in all the species. Mean metal pollution index values showed a pattern of demersal > bathydemersal > benthopelagic. These findings indicate a potential cumulative health risk from regular consumption of certain bycatch species, warranting continued monitoring to refine food-safety guidance for communities dependent on bycatch fishes.