Heavy metal contamination in fish: sources, mechanisms and consequences

This comprehensive review provides a thorough exploration of a mounting environmental issue: heavy metal contamination in aquatic ecosystems and its far-reaching impacts on fish populations and human health. Starting with the generalized sources of different heavy metals that lead to their entry into the aquatic environment, this review then considers each of the major heavy metals (copper, cadmium, chromium, arsenic, nickel, lead, zinc, and mercury) and ventures deep into the intricate mechanisms governing the uptake, bioaccumulation, and toxicity of heavy metals in fish, shedding light on the profound consequences these processes have for fish health and behavior. A critical aspect emphasized in this article is the activation of antioxidant defense mechanisms and involvement of metallothionein in fish as an adaptive response aimed at mitigating the pervasive oxidative stress triggered by heavy metal exposure. Of utmost concern is the trophic transfer of heavy metals from contaminated fish to humans through consumption, which poses a direct threat to human health regarding various physiological functions. The article underscores the urgency of addressing this issue comprehensively. Given the concerning discoveries at hand, this review fervently supports the enactment of rigorous regulations, the embracing of sustainable management techniques, and the stringent enforcement of pollution containment strategies.