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Environmental health delves into Carlsborg groundwater
As the Clallam County Public Utility District sends Carlsborg residents a letter assuring them nothing is set in stone regarding a proposed sewer system, county environmental health staff continue to try to educate them on septic systems and nitrates.
In well samples collected for building permits or submitted for analysis, there is a clear upward trend in nitrate levels, said Ann Soule, a hydrogeologist with Clallam County Environmental Health.
A nitrate test of water samples submitted for water availability permits in 1999-2001 showed a median nitrate level of 0.9 milligrams per liter. The same tests performed on samples from 2008-2010 showed a median nitrate level of 2.13 mg/L.
“More wells than not have evidence of degradation,” Soule said.
If the pollution were from one source, such as a farm or mill, the evidence would be seen in a plume, not in a lateral spread such as they are finding in Carlsborg, she said.
In a newsletter recently mailed to county residences utilizing on-site septic systems, Soule wrote an article specifically addressing the issue of nitrogen waste in Carlsborg septic systems turning into nitrates and contaminating local water supplies.
“Septics are one of the contributors for sure,” she said.
But some against the proposed sewer system staunchly deny her claim.
Citizens refute nitrate claims
At a June 7 public hearing, Brian Frazier, president of Citizens for the Preservation of Carlsborg, said claims by the county and PUD that septic systems are causing elevated nitrate levels are “self-serving.”
He wrote in a November 2010 letter to Sen. Maria Cantwell that “the assertion by the Clallam County Commissioners, planners that the on-site septic systems in the Carlsborg UGA are responsible for nitrate pollution in the Dungeness Bay cannot and have not been proven. The more likely culprits in the pollution of the Dungeness Bay are the City of Sequim sewer out fall, the cattle ranch at the mouth of the bay or the fact that our Canadian neighbors dump thirty million gallons of raw sewage into the Strait of Juan De Fuca each year.”
The data presented by Soule at a January 2011 meeting of the Carlsborg Community Advisory Council shows nitrate pollution within the Carlsborg UGA, as well as north of it, following the flow of groundwater.
At the June public hearing numerous other residents also refuted and criticized the idea that septic systems were failing or contributing to nitrate pollution.
Stacey Hopkins said claims that septics are polluting the water seem ridiculous to her. Hopkins said a sewer system would destroy the rural lifestyle of Carlsborg.
Soule said she thinks sometimes people overlook the pockets of more intense development.
“It looks like the ideal countryside but there are these pockets of urban densities that could be putting more in the ground than the ground can handle,” she said.
Board of Health hears report
In a June 21 presentation to the Clallam County Board of Health, Environment Health director Andy Brastad pointed out that the soil in Carlsborg lacks the organic material necessary to treat human waste adequately.
Septic tanks provide minimal treatment, septic drain fields provide some treatment and disposal but the real treatment occurs in the soil as the effluent moves through the layers and ultimately lands in the aquifers, he said.
“The soil in Carlsborg doesn’t treat waste well,” he said.
Once nitrate levels reach 10 mg/L, they poses a risk to human health and a personal treatment system must be installed or a deeper well must be dug, as occurred in 2001 at Carlsborg Mobile Estates, according to county data. The trigger level is 4 mg/L. Even some community wells are inching toward this level.
While the data strongly suggest septics are contributing to the elevated nitrate levels, Soule said in order to conclusively prove septics are a source of nitrates there must be another substance from human waste to trace, such as caffeine.
Elevated nitrate levels sometimes are found in sewered areas if people are over-fertilizing, she said.
“We have to be careful with all our activities,” she said.
To read the Clean Water Herald, Septics Edition, published by the county, go to www.clallam.net/HHS/
Reach Amanda Winters at firstname.lastname@example.org.