Contamination of polychlorinated biphenyls in fishes leading to toxicity in fish consuming population
The pollution of rivers and streams with chemical contaminants has become one of the most critical environmental problems. Similar to humans and other species of animals, fish have also been found to be polluted with a large number of pollutants/contaminants. Unintentionally added chemicals causing fish toxicity include organochlorine pesticides, polychlorinated biphenyls (PCBs) and other persistent chemicals in feed, chemicals in construction materials, and metabolites and degradation products of intentionally added chemicals. High levels of PCBs have been reported in farmed fishes. The fishes caught in highly polluted water could cause cells of some kinds of cancers to multiply rapidly. The PCBs are persistent environmental contaminants that are ubiquitous in the environment due to intensive industrial use. Many PCB congeners persist in ambient air, water, marine sediments and soil at low levels throughout the world. Humans may be exposed to detectable quantities of PCBs when they eat fish, use fish oils in cooking, or consume meat, milk or cheese. The general population is exposed to PCBs by inhaling contaminated air and ingesting contaminated water and food. The toxic responses to PCBs are dermal toxicity, immunotoxicity, carcinogenicity, and adverse effects on reproduction, development and endocrine functions. Epidemiological studies indicate that consumption of background levels of PCBs may cause slight but measurable impairments in physical growth and learning behaviour in children.