Flood didn't bring 'toxic soup,' environmental expert says

By Rod Boshart
The Gazette
rod.boshart@gazettecommunications.com

DES MOINES — Flooded areas of Iowa faced isolated and short-term water quality and sediment problems, but nothing like the "toxic soup" that some feared, a state environmental expert said Thursday.

Mary Skopec, supervisor of the state Department of Natural Resources' watershed monitoring and assessment section, said elevated bacteria and other potential health risks last June were washed away by record water levels in bloated Iowa streams and rivers.

"The good news is that a lot of the floodwaters helped to dilute contaminants in the water and in the case of sediment we really weren't seeing very high levels," said Skopec, who discussed water quality issues with the Rebuild Iowa Advisory Commission's agriculture and environment task force.

"We really didn't see sediment levels of contaminants that were at a public health risk in any way, shape or form. In most cases we were nowhere near that maximum allowable concentration," she added.

"The media talking about toxic soup was a little overblown," Skopec told task force members. "There was so much water and the dilution was so high that we didn't actually hit levels that were of a public health concern."

The DNR water expert said high levels of bacteria were noted in the Cedar River below the city's flood-impacted wastewater treatment plant, and residents were urged to stay out of the water until the problem subsided.

Skopec said follow-up water testing has indicated bacteria levels statewide are back at normal and acceptable levels.

Throughout the flood monitoring process, she said, only one sample in 22,000 analyte results for sediment found lead at a level that exceeded state guidelines in a non-residential area of the Des Moines River downstream from Des Moines.

Skopec noted there were other "isolated hits" where a few chemicals were detected at levels that exceeded government standards or didn't have state or federal standards, but they were so short-lived they did not pose a public health issue.

"In general things looked pretty OK with respect to exposure through either ingestion or skin contact," she said.

Task force members who are pushing for a complete flood plain mapping of Iowa were told the process likely will cost about $23.3 million and take up to 10 years to complete.

Task force co-chair Brent Halling said a 10-year timeline "isn't going to sell," and Skopec said the process should using risk-based assessments rather than past flood experiences in creating new maps that account for Iowa's changing hydrology.

DNR official Lyle Asell said about 8 percent of Iowa is flood plain. Currently, about one third of Iowa's 99 counties have no flood plain maps for their unincorporated areas, while the remainder have partial to full coverage but the quality and detail of their flood maps are poor.

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