Report: Toxins found in Cedar Lake fish decline to bare traces

CEDAR RAPIDS - A new report shows the level of toxins in fish in Cedar Lake remains on the decline.

The Iowa Department of Natural Resources 2016 Iowa fish tissue monitoring program found minimal traces of chlordane and polychlorinated biphenyls - or PCBs - in fish, which once had advisories against consumption.

'Just like the pattern in Iowa and across the rest of the country, PCB levels have declined in fish,” said John Olson, DNR senior environmental specialist. 'What we are seeing now is the bottom of the decline.”

The fish monitoring program has been in existence for more than 30 years, with a roster of some 30 lakes and rivers, Olson said. The information collected helps determine whether advisories are needed to ban or limit fish consumption.

Cedar Lake has been on the list since 1985, he said.

High concentrations of chlordane, which is a termite control insecticide federally banned in the late 1980s, prompted fish in Cedar Lake to have a consumption advisory until 2008, Olson said.

High concentrations of PCBs - an industrial chemical banned in the 1970s - in Cedar Lake prompted a consumption advisory until 2015, Olson said.

The most recent tissue samples came from five big mouth bass, which are predator fish, and three channel catfish, which are bottom feeders.

The catfish samples showed less than 0.05 parts per million of mercury; less than 0.06 parts per million of PCBs; and 0.05 parts per million of chlordane. The bass were tested for mercury and had a concentration of less than 0.05.

By comparison, in 2014, catfish had a concentration of less than 0.07 parts per million of chlordane and 0.06 parts per million of PCBs.

In 2008, carp had 0.105 parts per million of PCBs, which was below the advisory trigger level, and catfish had 0.39 parts per million of PCBs, which triggered an advisory. Chlordane showed up at 0.034 parts per million in carp and 0.18 parts per million in channel catfish fillets, which were both below the advisory trigger level.

The fish tissue samples were taken in August, and the report was released this month.

Advisory thresholds for Iowa include:

' Mercury: no restriction for less than 0.3 parts per million; advisory for one meal per week for 0.3 to 1 part per million; a consumption ban for higher concentration.

'PCBs: no restrictions for less than 0.2 parts per million; one meal per week for 0.2 to 2 parts per million; a ban for higher concentration.

' Chlordane: no restriction for less than 0.6 parts per million; one meal per week 0.6 to 5 parts per million; a ban for higher concentration.

Unless some special need is specified, Cedar Lake likely wouldn't be sampled again in 2017, Olson said.

Dale Todd, president of Friends of Cedar Lake, viewed the report as good news. The Friends group has been lobbying to restore the lake into a destination for fishing, kayaking and other recreational uses.

'The good news is we've seen these levels for the last four years decrease,” Todd said. 'It helps resolve some of the myths that are out there about how toxic the lake is, and it really reinforces our view that instead of a liability, the lake provides a huge opportunity for the community, especially in terms of recreation opportunities.”

Todd acknowledged the results don't necessarily provide clues into a phase two environmental study, which is underway to evaluate the extent of toxins in the sediment of Cedar Lake. City officials are watching for the results of the environmental study before deciding whether to take ownership of the lake, which is critical to the fundraising plan, officials from the city and the Friends group have said.

Todd said he expects preliminary findings from the phase two study in a couple of weeks.