Posted: Thursday, January 03, 2013 12:00 PM
Dan Wheat/Capital Press
Thousands of milk and manure producers at George DeRuyter and Sons Dairy, Sunnyside, Wash., in October. DeRuyter, Cow Palace and Liberty dairies are among five the EPA believes are contributing to nitrate pollution of groundwater in the Lower Yakima Valley. DeRuyter and Cow Palace are involved in a $13.5 million digester project to convert biogas from manure into renewable natural gas and reduce nitrate loads.
Officials, scientists argue over accuracy of EPA report
By DAN WHEAT
SUNNYSIDE, Wash. -- Veterinarian pharmaceuticals, ionic signatures and nitrate concentrations along with hydrogeologic information all indicate dairies are contributing to groundwater contamination in the Lower Yakima Valley, the state Department of Ecology says.
"Veterinarian pharmaceuticals are an indicator of an animal source and several of the pharmaceuticals tested are specific to dairy cows," Robert Duff, manager of Ecology's Environmental Assessment Program, wrote to the U.S. Environmental Protection Agency, which performed the testing.
Duff's Dec. 20 letter was a comment on EPA's study, released Sept. 27, that identified five dairies near Sunnyside as likely sources of nitrate pollution to groundwater.
The federal Natural Resources Conservation Service has said the EPA study is "filled with considerable errors" and can't be "scientifically defended to derive at the stated conclusions."
Tom Eaton, director of EPA's Washington Operations Office in Olympia, agreed his agency assumed dairy lagoon leakage rates because the EPA was unable to get design and construction information about the lagoons from the dairies. Any errors in the EPA report will be corrected, he said, as the agency gathers data soon from new monitoring wells.
In his letter, Duff said numerous sources and transformations in the environment make it extremely difficult to pinpoint the source of nitrate contamination. But, he said, the EPA report indicates dairies are discharging nitrates into groundwater. He said EPA's further testing should be more definitive.
Duff's letter resulted from review of EPA's report by Ecology's Environmental Assessment Program, said Joye Redfield-Wilder, an Ecology spokeswoman in Yakima.
EPA's report indicates the dairies are contributing to the pollution but "the main thing is how much," Redfield-Wilder said.
"We support additional information being gathered and it should clarify the sources of nitrates and reduce uncertainty in the findings," she said.
A year ago, Ecology provided $300,000 and authorized Yakima County to develop a groundwater management program to address nitrate pollution in an area of about 512 square miles from Union Gap to Benton City. The Lower Yakima Valley Groundwater Management Area, led by the county, was formed and a citizen advisory panel was named with local, state, federal and tribal representation to work to implement strategies to protect drinking water and prevent further contamination to soil and groundwater.
The group is expected to make recommendations early in 2013.
"We want to move forward with solutions and look at all the potential of how to address it and get away from the finger-pointing," Redfield-Wilder said. "People are drinking water that is above standards for nitrates and we all want safe water."