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Fish Pollutants

Many human activities harm fish in freshwater and ocean environments. Hydroelectricity interferes with the reproductive abilities of fish such as salmon, leading scientists to try to find solutions to the problem. Damage caused by other chemicals is not easily mended. The pollution caused by agriculture, oil refining and residential waste poisons fish and other aquatic life, making them hazardous for human consumption.

DDT
- DDT is found in pesticides, flame retardants and insecticides. When pesticides are sprayed on a field and then the field is watered with sprinklers, the runoff of water goes directly into lakes and streams. According to Science News, breakdown products of DDT have been found in fish and fish oil supplements sold to the public. Though these pollutants cause problems with the development and plasma membrane of fish, the fish also store them within their bodies.
Mercury
- Mercury is a once widely used substance that has since been linked to cancer.
  
  Mercury is a byproduct of coal combustion, which provided 47 percent of the United States power in January of 2011, according to the U.S. Energy Information Agency. The Environmental Protection Agency recommended, in 2004, that people don't eat shark, swordfish, tilefish or king mackerel because of their high mercury content. When consumed by people, mercury poses a threat to the developing nervous systems in children and babies. Large fish contain more mercury because they eat the smaller fish and absorb all the mercury contained within those bodies.
Detergents
- Detergents, plastics and pesticides used around the home can cause damage to fish and their ecosystems. Phosphates and surfactants found in many detergents are poisonous to freshwater fish. They break down the mucus layer that protects the fish from disease, interfere with reproduction and clog the gills of the fish. Detergents containing phosphates have already been prohibited in some states. According to Lenntech, detergent levels of 2 parts per million will kill fish eggs and levels of 15 parts per million will kill most fish.
Toxic Wastes
- Oil makes up a high percentage of the toxic waste that ends up in the ocean.
  
  Toxic waste refers to chemicals and toxic materials that are routinely dumped into the ocean and which cause significant problems in aquatic wildlife. According to Thickquest, toxic wastes are the most harmful pollutant to sea fish and humans. Toxic wastes include spilled oil, boat exhaust, garbage such as plastic, lead and medical waste. Medical waste dumped into the ocean can spread diseases such as hepatitis. Toxic ocean waste reduces the amount of oxygen that is absorbed by ocean waters, choking fish and other sea life.

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