Histopathological Effects of Anthropogenic Toxic Element Pollution in Freshwater Fishes in Their Natural Environments: A Global Review.

Abstract

Potentially toxic element pollution from increasing anthropogenic activities poses a significant threat to freshwater ecosystems. Although many studies have investigated metal toxicity in fish exposed to various toxic elements under laboratory conditions, this review aims to evaluate the histopathological damage caused by potentially toxic element pollution in freshwater fish species within their natural habitats. A thorough literature analysis was performed by examining several scientific databases for papers published from 2011 to 2025. The main keywords used to build the search strategy included anthropogenic pollution, potentially toxic elements, freshwater fish, metal accumulation, toxicity, and histopathology. This review revealed that freshwater resources in many parts of the world are polluted with potentially toxic elements such as copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), lead (Pb), arsenic (As), nickel (Ni), and mercury (Hg) due to various anthropogenic activities and that freshwater fish are highly sensitive to toxic element pollution in their natural habitats, and the resulting histopathological damage is often severe. The present review analyzes the alterations caused by anthropogenic toxic element pollution in the natural habitats of freshwater fish species from a histopathological perspective. It argues that the pollution status in these ecosystems should be monitored with regular research for the global continuity of freshwater resources, fish species, and, in parallel, human life.