Be careful eating local fish caught in certain parts of the Arkansas River and other waterways around Wichita.
The Kansas Department of Health and Environment and the Kansas Department of Wildlife issued what has become an annual warning about potentially toxic fish in rivers around the state.
The culprits appear to be polychlorinated biphenyls (PCBs) and mercury in fish, and lead and cadmium in shellfish showing up in annual tests.
PCBs showed up in Arkansas River fish from Hutchinson to Wichita and in the Kansas River near Lawrence.
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PCBs were produced from the 1920s to the 1970s and used in paints, waterproofing and cements. They also were used in florescent lights and other discarded materials.
Improper trash disposal by past generations could account for the toxic levels of PCBs in fish today.
"They came from a lot of different products, so it's hard to pinpoint a source, but they could be from old landfills," said Maggie Thompson of the Kansas Department of Health and Environment.
Despite not being used for decades, PCBs are difficult to get out of the environment, experts say.
PCBs have potential cancer-causing effects and have been linked to immune system deficiencies and harm to the reproductive system, according the Environmental Protection Agency.
Mercury warnings have been issued for the Little Arkansas River in the Wichita area and the Blue River in Johnson County.
Too much mercury can cause brain damage to unborn babies and slow development in children, the EPA says.
The good news is data from most long-term monitoring sites show a decrease in PCB levels and no significant change in mercury concentrations since 2004.
Limits on these rivers
People are advised to limit their intake to one 8-ounce serving per month of fish from the following areas of the Arkansas River due to PCB contamination:
* From the Lincoln Street dam in Wichita downstream to the confluence with Cowskin Creek near Belle Plaine.
* Cow Creek in Hutchinson and downstream to the confluence with the Arkansas River.
Because of mercury contamination, the state suggests limiting diets to one 8-ounce serving per month for adults and one 4-ounce serving per month for children ages 12 and younger for the following:
* Predatory fish, including bass, crappie, walleye from the Little Arkansas River, from the Main Street Bridge west of Valley Center to where it meets the Arkansas River in Wichita.
* All species of fish in the Blue River in Johnson County from U.S. 69 to the Kansas-Missouri state line.
Catches to avoid
Test reports advise avoiding eating fish and other aquatic life from several waterways outside the Wichita area.
In Douglas and Leavenworth counties:
* From the Kansas River from Lawrence (below Bowersock Dam) downstream to Eudora at the confluence of the Wakarusa River — bottom-feeding fish (carp, blue catfish, channel catfish, flathead catfish, freshwater drum, bullhead, sturgeon, buffalo, carpsuckers and other sucker species) because of PCB levels.
In Cherokee County:
* Horseshoe Lake in units 22 and 23 of the Mined Lands Wildlife Area — all forms of aquatic life including fish because of perchlorate levels. Perchlorates have been used fireworks and rocket fuels. Too much exposure can cause thyroid problems.
* The Spring River from the confluence of Center Creek to the Kansas-Oklahoma border for shellfish (mussels, clams, and crayfish) because of lead and cadmium levels.
* Shoal Creek from the Missouri-Kansas border to Empire Lake — shellfish because of lead and cadmium.