Anglers in area lakes may want to read the newest report from the Oklahoma Department of Environmental Quality (DEQ) before eating their catch.
The DEQ’s newest report, Mercury in Fish - A Guide to Healthy Consumption in Oklahoma, lists lakes in the state that have been tested, and the number of fish by species that are safe to eat. Fish in 73 of Oklahoma’s lakes were found to have some levels of mercury, meaning they could be unsafe for human consumption. That number represents almost half the lakes in the state.
DEQ spokesperson Erin Hatfield, stressed that the mercury advisories in area lakes does not mean the lakes are unsafe, but that people should make informed decisions.
“The DEQ recommends people recreate on Oklahoma lakes, rivers, and streams. The mercury that is in the fish does not affect drinking water and does not make it unsafe to recreate on the lakes that have these advisories,” Hatfield said. “We encourage people to catch fish and eat the fish they catch. Fish are such an important part of a human diet, but we want people to be informed.”
The DEQ broke their advisories into two separate groups: the general population and the sensitive population. Those in the sensitive population comprise women of childbearing age and children up to the age of 15. Those are the people that mercury has the biggest impact on. The general population is everyone else.
Looking at the four lakes in our area, Cleveland Lake, Hominy Lake, Keystone Lake, and Pawnee Lake, all have advisories, but the degree of the advisories varies.
Cleveland Lake had only one advisory. According to the DEQ report, anyone in the sensitive population should consume no more than two servings per month of largemouth bass that are 18 or more inches long. The DEQ gave no advisories for the general population consuming fish from Cleveland Lake and stated that channel catfish and crappie are safe to eat from the lake.
The DEQ listed four advisories for the sensitive population consuming fish from Hominy Lake. They advised those in that population to consume only two meals per month of channel catfish over 21 inches, two meals per month of flathead catfish over 26 inches, and two meals per month of both largemouth bass and spotted bass over 17 inches. No advisories were given for the general population consuming fish from Hominy Lake.
From Keystone Lake, the DEQ advised that the sensitive population should only have only two meals per month of blue catfish over 32 inches and two meals per month of flathead catfish 29 inches and over. In addition, they recommend that population restrict consumption to two meals per month of largemouth bass 18 inches and over, and two meals per month of white bass 15 inches and over. The following fish species were sampled and are safe to eat: black crappie, channel catfish, striped bass and white crappie. No advisories were given for the general population consuming fish from Keystone.
Pawnee Lake, like Cleveland Lake, had only one advisory. The DEQ recommended the sensitive population should restrict consumption of saugeye, 22 inches and over, to only two meals per month. All other fish were tested as being safe. No advisories were given for the general population consuming fish from Pawnee Lake.
Mercury makes its way into fish by first being released into the environment via man-made activities such as mining and manufacturing and coal-fired utilities. It falls from the air as it sticks to dust particles, and it eventually washes into bodies of water. Mercury undergoes changes in the lakes, turning into methyl mercury, an organic form that can accumulate in certain fish, mostly predator species, such as bass and saugeye. It can then be passed on to people who eat these fish. Mercury can affect the brains of developing fetuses and young children.
Some lakes in the Northeast part of the state showed lower levels of mercury, while lakes in the southeast part of the state tended to have more advisories.
“Every lake is different,” Hatfield said. “You tend to have clearer lakes in the southeast because you have more limestone. So, you’re going to have more sunlight that’s able to penetrate the lake and create that process for it to convert to methylmercury.”
If a lake is not listed in the report, Hatfield recommends that women of childbearing age and nursing mothers and pregnant women and children up to the age of 15 consume only one meal per week of predator fish. Predator fish would include flathead catfish, largemouth bass, saugeye, smallmouth bass, spotted bass, striped bass, walleye, and white bass.
Hatfield stressed people should always be informed, but the advisories are not intended to stop people from consuming the fish they catch.
“For the general population, we recommend they continue to eat a variety of fish, including predator fish. Fish is such a significant part of a healthy diet,” she said. “People should look at this advisory so they can be informed, not worried or scared. This information allows people to make good decisions for their families. Oklahomans have been catching and eating fish for as long as we’ve been a state, and we want people to keep doing that just to make good, smart choices.”
Anyone wishing to learn more can download the free booklet at www.deq.ok.gov, or they can call the DEQ at 405-437-8468.