• Seafood can contain harmful pollutants.seafood image by AGITA LEIMANE from Fotolia.com
  
  According to the PBS website, "Global consumption of seafood products has doubled over the past 30 years, driven by population growth and rising income levels." Leading seafood consumers are the United States, Japan and the European Union. Unfortunately, the rise in seafood consumption has been accompanied by some discouraging occurrences, such as overfishing and water pollution. Although seafood is an excellent source of many nutrients (such as omega-3 fatty acids), seafood-related illnesses and deaths have increased public awareness of a few harmful seafood pollutants.
  
  

Mercury

• According to the National Resources Defense Council, 30 percent of lakes, estuaries and wetlands are contaminated with mercury, in addition to at least 473,000 miles of rivers and streams. Mercury is released into the air by chemical and power plants. The largest amounts of mercury are found in tuna, shark, swordfish, marlin, orange roughy, king mackerel and tilefish. Fish such as anchovies, salmon, crab, oyster, tilapia and shrimp contain very low mercury levels. Mercury poisoning affects the nervous system, and is especially hazardous for young children and pregnant women.
  
  

PCBs

• Although PCBs (polychlorinated biphenyls) were banned in 1977 in the United States, they continue to persist in the environment. Before they were banned, over 1.5 billion pounds of these hazardous industrial compounds were produced by various industrial factories, and as of 2003, 39 states have issued PCB advisories. Contamination is especially prevalent in the Great Lakes Basin. PCBs affect memory and learning abilities, and may also result in delayed fetal, infant and child development.
  
  

Sewage

• Seafood also may be contaminated with harmful microorganisms found in human sewage. Most sewage treatment plants treat contaminated water and eliminate any harmful bacteria before discharging water into nearby bodies of water. However, in many undeveloped nations, and even in some developed areas, there is little or no sewage treatment, resulting in contamination of water and fish. According to Water Encyclopedia online, sewage water contamination is the leading reason for beach closures. Fishermen and seafood consumers should always consider where the seafood they consume is caught and avoid fishing near sewage treatment plants.