14 out of 20 wells tested in Town of Colfax contaminated with nitrate
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By LeAnn R. Ralph
COLFAX — Out of 20 wells tested in the Town of Colfax, 14 were contaminated with nitrate, at least to some degree, and out of the 14 wells, three tested above the drinking water standard of 10 milligrams per liter.
Six of the 20 wells (30 percent) tested at 1 mg/L or lower, which is considered a “natural” level of nitrate, according to a letter sent to the test participants by Dean Logslett, chair of the Colfax Town Board.
Out of the 20 wells, seven (35 percent) tested between 1.1 and 4.9 mg/L, and four of the wells (20 percent) tested between five and 10 mg/L.
The three wells that tested above the unacceptable nitrate level of 10 mg/L represent 15 percent of the sample size.
“Water with greater than 10 mg/L of nitrate-nitrogen should not be consumed by infants less than six months of age, pregnant women and women who are trying to become pregnant. This includes baby formula made with this water. This guidance is based on concerns related to methemoglobinemia, also called blue-baby disease, a condition in infants which inhibits the blood’s ability to carry oxygen. If not caught early and treated, this condition can be fatal. Some studies suggest that high nitrate water may be linked to birth defects and miscarriages,” according to “Interpreting Well Water Quality Results,” a publication by the Center for Watershed Science and Education, College of Natural Resources, UW-Stevens Point and Extension UW-Madison.
Sources of nitrate-nitrogen in well water include fertilizers, septic systems, animal waste and land spreading of bio-solids, according to “Interpreting Well Water Quality Results.”
“Elevated nitrate levels can be an indicator of other potential contaminants. If nitrate levels are elevated, you may want to consider testing for pesticides if you know they are used nearby,” the publication states.
Two of the Town of Colfax tests also indicated coliform bacteria in the well water.
Coliform bacteria is always present in the digestive tracts of animals, including humans.
“Due to the sensitivity of tests to any presence of coliform, we are asking those who have had a positive coliform sample to retake their tests in case there may have been a sampling error,” the letter to the Town of Colfax residents states.
Dunn County
Water quality information available from Dunn County indicates that wells in the southeastern part of the county have the highest nitrate contamination.
In the Town of Dunn, out of 22 samples, the average nitrate level is 8.59 mg/L, with 31.82 percent of the samples being above 10 mg/L.
In the Town of Spring Brook, out of 17 samples, with an average nitrate level of 8.02 mg/L, 35.29 percent of the samples are above 10 mg/L.
In the Town of Peru, out of 13 wells tested, the average nitrate level is 7.93, with 30.76 percent of samples above 10 mg/L.
In the Town of Rock Creek, out of 24 wells tested, the average nitrate level is 8.03 mg/L, with 37.5 percent of the samples above 10 mg/L.
The Town of Colfax results showing 15 percent of the wells tested are above 10 mg/L is not as high as those in southeastern Dunn County, but “15 percent still represents people drinking water that is not safe for them. Although individual citizens whose wells have been found unacceptable may not be able to change their groundwater quality, there are other actions they can take to mitigate the danger to their health,” said Kathy Stahl, Town of Colfax resident and a member of the Dunn County Groundwater Ad-Hoc Committee as well as the Healthy Environment Action Team.
The Healthy Environment Action Team (HEAT) was one of the citizen groups that formed after a Dunn County survey on health needs in the county. Other citizen groups that were formed focus on alcohol, nicotine and drugs; chronic disease prevention; housing; and mental health.
Critical
“There are two critical points from this township study. One is everyone who gets their drinking water from a private well should have their water tested. Research is showing that drinking high levels of nitrates over time is a health hazard for adults as well as babies,” Stahl said.
“The second critical point is that nitrate levels can change over time. I’ve not yet reached the third citizen whose well water had unacceptable level of nitrate, but two of the three told me their well water nitrate levels had gone up since their last study. It’s important to track each well over time,” she said.
Cost of testing
The money to test the 20 wells in the Town of Colfax was donated, and there is no fund with money available for private well testing, Stahl said.
Be that as it may, the cost of testing for coliform and nitrate is not out of reach for the ordinary homeowner, she said.
Commercial Testing in Colfax charges $40 for the coliform and nitrate tests, and the UW-Stevens Point Water and Environmental Analysis Lab charges $44 for both tests, Stahl said.
Commercial Testing and the UW-Steven Point lab will not share results with townships or counties without permission to release the information, she noted.
Stahl encourages homeowners in this area with private wells to get their water tested for nitrates and coliform bacteria.
“There are areas in other localities where nitrate levels have been trending higher over time and some that have decreased. To assure that your drinking water maintains a safe drinking level, we encourage you to test your water on an annual basis,” states the letter from the Town of Colfax to the residents who participated in the water study.
Corrective action
There are several corrective actions that homeowners with high nitrate levels in their well water can take to reduce or eliminate nitrate contamination.
According to “Interpreting Well Water Quality Results,” if possible, homeowners should eliminate the contamination source.
Nitrate contamination can result from farming practices that took place decades ago or it can come from more recent farming operations.
The amount of nitrate contamination also will be affected by the soil type in the area where you live. Sandy soils allow nitrogen to reach the groundwater more quickly than heavier soils.
Eliminating the contamination source “may take years to to observe any reduction in nitrate levels and short-term solutions are usually necessary,” according to “Interpreting Well Water Quality Results.”
The publication lists three short-term solutions to help reduce nitrate levels in well water:
• Extending the depth of the casing, or drilling the existing well deeper, or drilling a new well, may result in water with lower nitrate contamination. (The publication puts an emphasis on “may.”)
• Use bottled water for drinking and cooking.
• Use a water treatment device effective at reducing nitrate such as Reverse Osmosis (RO), distillation and anion exchange. (The publication states that when purchasing a water treatment device, you should only purchase those approved by the Wisconsin Department of Safety and Professional Services and that dealers should be able to provide a copy of the product approval letter.)
“Interpreting Water Quality Results” does not talk about the cost of any of the mitigation strategies, including Reverse Osmosis systems, but according to online sources, an RO system for the whole house can cost between $15,000 and $20,000.
Homeowners in the Town of Emerald in St. Croix County near Emerald Sky Dairy, where there are a number of wells that test above the recommended standard of 10 mg/L for nitrate, including the well at the Emerald Town Hall, have reported at town board meetings covered by the Colfax Messenger/Tribune Press Reporter that the cost of a Reverse Osmosis system is around $15,000.
More info
The letter from the Town of Colfax indicates that if people would like more information about the Dunn County water quality program, they can contact Heather Wood, Dunn County Land and Water Conservation Specialist, by e-mail at hwood@do.dunn.wi.us.
For more information about groundwater quality and water quality testing in general, you can contact Kevin Masarik, Groundwater Education Specialist with the Center for Watershed Science and Education at UW-Stevens Point, by e-mail at kmasarik@uwsp.edu.
