Bioaccumulation of Mercury, Cadmium, Lead, and Arsenic in Whiting and Tub Gurnard From the Sea of Marmara: Implications for Human Health

Abstract

Toxic trace elements tend to accumulate in the Sea of Marmara, a semi-enclosed body of water, exacerbating pollution and posing a threat to human health through the consumption of bottom-dwelling fish. Mercury, cadmium, lead, and arsenic concentrations in two commercially important species, whiting (Merlangius merlangus euxinus) and tub gurnard (Chelidonichthys lucerna), were investigated from eight different locations. Considering the regulatory limits (EU Regulation 2023/915), Hg levels in whiting surpassed the safety threshold, while in tub gurnard the concentrations were higher than 0.30 g/kg at three sampling sites. None of the samples reached the limit values set for Cd and Pb. Although no official limit has been established for As in fish, its concentrations were found to be notable in both species. Overall, whiting presented a higher level of toxicological risk compared to tub gurnard. Total target hazard quotients (TTHQs) exceeded the safety threshold of 1 for individuals weighing 50 kg—typically adolescents or young adults—at all whiting sampling locations, indicating potential health risks for this sensitive population. In tub gurnard, TTHQ values surpassed 1 at only three locations. Notably, the highest TTHQ for Hg was recorded in samples from the western region of the sea, exceeding 1 for all individuals, further underscoring the potential risk associated with consumption. The carcinogenic Target Risk (TR) for inorganic As was found to be unacceptable in whiting captured from this location for all body weights and from the southern location for 50 kg people. Individuals with lower body weight are more susceptible to the risks associated with consuming demersal fish. To mitigate the risks of bioaccumulation, it is advisable to diversify frequently consumed foods.