Review on Heavy Metals in Freshwater Fish: Source, Distribution Pattern, Accumulation Levels and Human Health Risk Assessment in Major Rivers in Nigeria

Nigeria's waste management and supervision are very inadequate and of low quality. Usually, human activities pollute rivers by releasing contaminant into them. This study reviewed the various sources, distribution patterns, levels of accumulation, and health risks associated with heavy metals in Nigerian freshwater as compared to marine water (lagoons), as well as the mean concentration of heavy metals in various parts of fish body and any potential negative health effects from consuming fish that are high in heavy metals. It is possible to declare that each session could affect the discharge of heavy metals above the allowable limit, including those related to food processing, industrial waste, pharmaceuticals, and dredging, as well as oil and gas, fertilizer production, batteries, tyres, and pesticides (i.e. Federal Environmental Protection Agency). The aquatic environment could be exposed to these heavy metals by runoff brought on by precipitation. As a result, concentrations of these contaminants have risen in fish tissues and organs over the peak values advised by a number of organizations, including the Food and Agriculture Organization, World Health Organization, and United States Environmental Protection Agency. It is impossible to overstate the harmful effects of heavy metal bioaccumulation in aquatic creatures, thus checkmate should be required. In order to compare the accumulation of heavy metals in fish from both marine and freshwater biomes, this review's conclusion revealed that freshwater fish bioaccumulate heavy metals more than marine fish do, the distribution pattern of heavy metals for both the marine and fresh water fishes was not consistent which suggests that rivers should be properly monitored and waste should be recycled.