Unveiling hidden threats: Assessing the risks of potentially toxic elements (PTEs) in contaminated fish of the Anzali Wetland

Abstract

The environmental degradation caused by potentially toxic elements (PTEs) and its consequential health risks to humans and the environment have raised profound concerns. To explore the potential hazards associated with PTEs, we analyzed the total concentration of As, Cd, Cr, Hg, and Pb in the muscle, gills, viscera, and eggs of four fish species Esox lucius Linnaeus, 1758 (Pike), Cyprinus carpio Linnaeus, 1758 (Carp), Vimba vimba Linnaeus, 1758 (Vimba), and Tinca tinca Linnaeus, 1758 (Tinca) collected from the Anzali Wetland. We measured the concentrations of trace metals in the fish samples and calculated the associated human health risks and compared the results with the international standards. Our findings showed the PTEs concentrations in fish samples with Cr > Hg > Pb > Cd >As. We observed Cr, Hg, and Pb concentrations (3.4 ± 1.61, 2.57 ± 1.24, and 1.7 ± 0.48 μg g⁻¹ wet weight (w.w.), respectively) in muscle samples, Cd concentration (1.05 ± 0.53 μg g⁻¹ w.w.) in eggs, and As concentration (0.40 ± 0.13 μg g⁻¹ w.w.) in viscera of Pike. Consequently, Pike exhibited the highest concentrations of these metals across all its sampled tissues. Comparing the results to the standard set by the World Health Organization (WHO) declared that the average heavy metal concentrations exceeded the permissible limits for certain elements. Results also indicated that the concentrations of As and Pb in all fish species posed potential health risks, particularly to children, with a target hazard quotient THQ> 1. Moreover, the presence of As and Pb metals in all human age groups, as well as Cr and Hg metals, indicated a potential risk of cancer for children (Cr > 1E-4). Therefore, the metal pollution status of the Anzali Wetland not only influences the biodiversity of fish but potentially poses health-related issues to the target consumers.