Some wells tested by federal officials returned higher-than-normal levels of nitrates exceeding safe drinking water standards.
However, a federal official said the results don’t necessarily present a health risk.
Seven of 25 wells tested by the U.S. Geological Survey were found to have higher than normal “background” levels of nitrate present, and 12 of the wells exhibited contamination that exceeded Environmental Protection Agency safe drinking water standards.
The information was presented to the Nye County Water District on March 23 by USGS representative Mike Pavelko, who said the results do not necessarily present a health risk.
One sample, Pavelko said, had a contamination level of 22.7 milligrams per liter, more than twice the EPA acceptable level of 10 milligrams per liter. Most of the samples contained a range of 1 to 5 milligrams per liter, tests revealed.
The pre-filtered samples were taken from 22 domestic wells, one utility well, one commercial well and one turf irrigation well, he said. Sulfates, iron and manganese were also detected in some of the samples which affect both the taste and the smell of the water. Pavelko said that water with excessive levels of iron and sulfates do not present a health risk. All but six of the property owners received correspondence from USGS with the test results.
Of the wells tested, Pavelko said that six had detectable waste-water compounds present.
Nye County Water District Chairman John MacLaughlin said he was of the opinion that if water users had a filtration system, it was likely that the contaminants were “probably not making it” to the drinking water.
Darrell Lacy of the Nye County Water District said there are less problems with nitrates now than there were 30 years ago. “We have very little problems in the north end of the valley,” he said. Problem areas, he said, are south of state Route 372. Lacy said that the entire Pahrump Valley has been has been identified as a “nitrogen restricted area” by the Nevada State Department of Environmental Protection. An application to lift that designation to specific areas in Pahrump will be made once more information becomes available, he said.
Baseline values for nitrate levels vary by region, determined by the scientific community by determining a level that is considered “normal.” Pavelko said that value has not yet been established for the Pahrump Valley.
“Naturally occurring” levels of nitrates, he said, are designated at a level 2. While areas that have a level 7 – 20 designation, should determine whether the water is impacted from a nearby or former agricultural operation or a septic system.
Once the results of the remaining six wells have been disclosed to property owners and the county, USGS personnel will ask the Nye County Water District to pay for an additional study to determine the origin of the nitrates.