GRANGER, Wash. – A federal agency has concluded that dairies in the Yakima Valley are likely contaminating residential wells. Scientists and other officials presented the information this week to local residents.
The Environmental Protection Agency wanted to link nitrate contamination in residential wells to specific sources: like dairies, croplands or septic tanks.
Scientists sampled more than 300 wells and found up to 20 percent had high nitrate levels. They concluded that dairies were the most likely source of the contamination.
Nitrates come from manure and fertilizers. When they contaminate drinking water, nitrates can be harmful to children and some adults.
Mike Cox is an environmental scientist with the EPA. He says around 25,000 people in the Lower Yakima Valley drink from private wells. He told local residents at a meeting why that’s important.
Cox: “They’re regulated. They’re not monitored. There’s no treatment requirements.”
Some Yakima Valley residents have complained for decades about nitrate contamination in their wells.
The EPA tested five dairies in the Yakima Valley. Dan DeRuyter’s dairy was identified in the study. He says he will work to limit nitrate contamination.
DeRuyter: “My family and many of the employees that work here, they live around the dairy. And I want to make sure they have clean drinking water as well.”
Some farmers at the public meeting questioned the study’s conclusions. They were concerned that EPA scientists only knew the depth of some of the wells. That’s important because deep wells are less likely to be contaminated than shallow ones. Farmers also claimed researchers did not have enough statistical data to back-up their conclusions.
Environmental activist Jan Whitefoot says she thinks this study will spur officials to help clean Yakima Valley’s wells.
Whitefoot: “I hope there’s some enforcement against the polluters, plain and simple. And some relief to the people that do have bad wells.”
The EPA is working with the operators to limit pollution. Officials are discussing a plan with the five dairies studied. Many in the crowd pressed the EPA to explain how it would stop farmers from polluting and who would pay for cleaning up the wells. But officials refused to go into detail.
The study also found fields that grow crops, like hops and mint, are a likely source of nitrate contamination. However, scientists said the link was not as strong to croplands as it was to dairies.
Copyright 2012 Northwest Public Radio