Missouri's most recent list of impaired waters left out 135 water bodies that contain pollutants above the levels permitted by the U.S. Environmental Protection Agency under the Clean Water Act, according to a proposed decision announced Wednesday by the federal agency.

The EPA did approve Missouri's listing of 61 waters as impaired, and the delisting of 42 water bodies, but says the state did not identify any waters impaired by mercury, low dissolved oxygen, bacteria, chloride, metals, sediments, and unknown pollutants.

EPA Region 7 Administrator John Askew said, "After an extensive and exhaustive review of the relevant and available data, EPA believes that Missouri should have identified more waters on its impaired waters list."

"Identifying impaired waters is a critical step in fulfilling the objective of the Clean Water Act, which is to restore and maintain the chemical, physical and biological integrity of the nation's waters," Askew said.

The Missouri Department of Natural Resources submitted its 2004-2006 impaired waters list to the EPA for review and approval, as required by the Clean Water Act. EPA made a partial decision on Missouri's list in September 2007.

EPA is required by law to list waters that are not meeting their designated uses - this evaluation is made by comparing the state's criteria to its monitoring data.

Wednesday, the federal agency said that in its 2004-2006 list, Missouri did not identify waters as impaired by mercury. EPA found data indicating that 19 waters are impaired by mercury and is proposing to add these waters to Missouri's list.

While reviewing Missouri's bacteria data, EPA found multiple assessment errors and, in many cases, found that Missouri had assessed its waters that are designated for whole-body contact against an E. coli criterion that has not been approved by EPA for Clean Water Act purposes.

After reevaluating Missouri's data against the state's only approved E. coli criterion, EPA is proposing to add 23 waters as impaired by bacteria.

In its public notice of the state's final 2004-2006 impaired waters list, the Missouri Department of Natural Resources explained that numerous waters were not listed because there were "no apparent pollutant sources."

But the EPA says 50 of those waters should be added to Missouri's list as impaired by low dissolved oxygen.

Full Story: http://www.ens-newswire.com/ens/sep2008/2008-09-24-093.asp