Fish consumption advisories in Colorado

Eating fish is good for your heart and children’s growth

The FDA recommends eating two or three servings of fish per week. Fish are a source of lean protein, contain vitamins and minerals, and are the primary food source for omega-3 fatty acids. However, some fish from some waterbodies may also contain high levels of mercury or perfluorooctane sulfonate (PFOS), and you should eat less of those fish.

Colorado issues fish consumption advisories to balance the benefits of eating fish with the risks of consuming pollutants. Colorado’s fish consumption advisory program isn’t designed to prevent you from eating fish; instead, it is designed to help you make informed choices about how much fish you eat, what species and sizes of fish you eat, and what waterbodies you eat fish from.

Understanding pollutants in fish

Mercury is a metal that is naturally released into the environment from soils, rocks, and volcanoes. It is also released as a result of human activity, like coal combustion. Mercury released into the air can travel long distances and be deposited into water. Fish take in mercury from the water and their food. The mercury builds up in their tissues over their lifespan. As a result, nearly all fish have at least small amounts of mercury in them. If pregnant people eat fish with high levels of mercury, it can interfere with fetuses’ developing nervous systems. Larger amounts of mercury in fish can also harm older children and adults. Usually, the harmful effects can be corrected if a person stops eating fish with high mercury levels.

PFOS is one in a large group of human-made chemicals called per- and polyfluoroalkyl substances (PFAS). PFAS have been manufactured since the 1940s for use in many products, like non-stick cookware, firefighting foams, and food packaging. PFAS do not break down easily and can stay in the environment for a long time. Certain PFAS, like PFOS, can build up in fish muscle tissue. Eating fish with high levels of PFOS over a lifetime can cause higher cholesterol, affect the immune system and liver function, and lead to lower infant birth weights.

How mercury and PFOS build up in fish

The amount of mercury in fish depends on its age and diet. Bigger, older fish may have more mercury, especially if they eat other fish with mercury. Some fish may be safe to eat when they are small, but unhealthy when they are large.

The amount of PFOS in a fish depends primarily on how close the water is to the source of the pollutant. Fish from waterbodies closer to PFOS sources generally contain more of the pollutant, while fish from waterbodies not near PFOS sources generally contain lower or no PFOS.

Advisories for safe fish consumption

Cooking and cleaning fish do not remove mercury or PFOS.

The site-specific and statewide guidelines in the links below only apply to fish caught in Colorado. Fish from restaurants and stores may also contain pollutants. The FDA has guidelines for safely eating these fish at www.fda.gov.

PFAS in fish

With EPA-provided funding, the department partnered with Colorado Parks and Wildlife to learn more about the levels of PFAS in fish in Colorado waterbodies.

For the first time, the department added site-specific advisories for PFOS for certain types of fish in the waterbodies: Chatfield Reservoir, Runyon Lake, and Barr Lake. PFOS is one chemical in the group of PFAS that research shows tends to build up in fish. Anglers who eat the fish they catch in Colorado can find the advisories on the department’s fish consumption dashboard.

The department selected six waterbodies by evaluating their proximity to known PFAS contamination, proximity to disproportionately impacted communities, and fish species in the water bodies. The department did not detect measurable levels of PFAS in Corn Lake, Gypsum Ponds, or Vega Reservoir.

The most recent testing builds upon the 2020 pilot fish sampling project that collected and analyzed fish from three waterbodies with known or suspected PFAS contamination.

We will continue to test fish and waterbodies as resources allow.

Statewide guidelines

The default guidelines are for the general population, people who are pregnant or may become pregnant, and children ages six and younger. If there are no site-specific guidelines for the water body where you are fishing, follow these guidelines.