AUBURN, Ala. – Alabama has many lakes, rivers and streams. This makes fishing a popular sport and recreational activity. Sometimes certain toxic chemicals find their way into some bodies of water. Fish in these areas may have levels of these chemicals in their system. The Alabama Department of Public Health publishes an annual fish consumption advisory booklet to inform people what bodies of water may present an elevated health hazard.
Dr. Rusty Wright, an Alabama Extension specialist of aquatic resources, said that this list is compiled by testing fish from across the state.
“The department of public health tests fillets, from fish that people typically eat, for potentially harmful contaminants. In 2016, 641 samples were collected at 48 different stations,” Wright said. “This seems like a large number, but it is not when you consider the number of water bodies, the number of species, different sizes of fish, etc.”
In the tests, the department of public health look for contaminants such as mercury and PCBs and PFOs (industrial chemicals and products).
“Coal-fired power plants is the main source of mercury. The mercury gets in the air through smoke and washes into our waters with the rain. Metallic mercury, like in an old style thermometer, is not a big problem until bacteria change it to a different form, methyl mercury,” Wright said. “This happens in swamps and places without a lot of oxygen in the water and the water is acidic. This is why areas like the Mobile-Tensaw Delta often have fish that are high in mercury.”
Mercury and other heavy metals typically bind to the protein of the fish. This is why you can’t just cut the infected pieces away. Mercury is more widespread while PCBs and PFOs are from industrial sources in individual water ways.
Consumption and Risks
Fish on the list have certain levels of contaminants found in the test samples. Consumers should follow the recommendations for each fish explained in the advisory booklet. A species may be on the list for a particular waterbody but is safe to consume elsewhere.
“The people that are most at risk are children, pregnant women and those who are considering pregnancy in the near future,” Wright said. “Most contaminates flush from the body over time. Eating fish with low levels of these contaminants at a low rate won’t cause a buildup in the body.”
This is why the recommendations are to limit consumption for most species, not to stop eating it all together. Typically, problems arise when people consume top predators that are older, like the largemouth bass. Short lived species that eat lower on the food chain like bluegill are almost always safe to eat.
“People should remember that all foods have some low levels of contaminants, even organic foods,” Wright said. “Eating fish is a great way to get low-fat, high quality protein. The health benefits generally outweigh any potential risk as long as one follows the recommendations.”
Wright said that people need to be cautious when eating large amounts of fish from any body of water.
“Just because a species from a certain reservoir is not on the list, doesn’t mean it is free from contaminants,” Wright said. “The Alabama Department of Health may not have tested that species of fish from that source.”
Click here for the 2018 complete list of fish advisories from the Alabama department of public health.
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