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Increase in nitrate levels in Rock County wells worries health officials

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Gina Duwe
July 1, 2013

— Rock County health officials are concerned about a nitrate level spike in drinking water found during an expanded effort to test more rural wells.

Typically, 25 to 30 percent of wells tested have had unsafe nitrate levels of 10 parts-per-million or higher, said Rick Wietersen, sanitarian at the Rock County Health Department.

This year, nearly 50 percent of wells tested were unsafe.

In some parts of the county, such as the town of Harmony, 80 percent of the wells were higher than 10 ppm, he said.

Anything over 10 is a health concern for infants and pregnant women because it can cause blue baby syndrome, Wietersen said. Beyond those high-risk groups, drinking water high in nitrates can, over a long period of time, cause certain types of cancer.

These results are from about 500 wells, which puts the health department on pace to double the number of tests it will conduct this year.

Test results

Health officials offered the special testing program to local town officials at a towns association meeting in January. Any town can participate, and each one that attended the meeting has since called independently to sign up.

Health officials drop well kits off at the participating town halls, then collect samples voluntarily filled by participating residents a few days later. Results are explained to residents a few days after that.

Due to the volume of tests being conducted, the health department is able to reduce the normal $44 charge for nitrates and bacteria testing to $35.

The department already has conducted tests in Bradford, Porter, Lima and Harmony, and it plans to do even more in several other towns.

Aside from the nitrate spike seen in private wells, officials also have seen increases in dozens of community wells at places such as parks, churches and restaurants. The department tests about 150 of those wells annually, and about 88 of those consistently for the last 19 years.

"Those are kind of our indicator wells," Wietersen said.

Last year, nitrate rates spiked to their highest levels in 19 years. Wietersen expects they will go up sharply this year, as well.

Results for bacteria remain status quo with about one of every seven tests being positive for coliform bacteria, Wietersen said. He noted that this is more of an indication of maintenance issues.

None of the tests have been positive for E. coli, which is great, he said.

Janesville Utility Director David Botts said the city has not seen "a real increase" in nitrates in public wells.

The city continuously tests its water, and in 2012 water averaged 6.6 parts-per-million in nitrates.

Why?

Many theories attempt to explain the nitrate spike, but county health officials think the best answer comes out of last year's drought.

Because crops in farm fields around the county didn't grow to their potential, a lot of fertilizers applied to the fields were not used, Wietersen said.

"So there was a greater potential for that nitrogen to leach into the groundwater," he said.

Nitrates actually decreased a bit after floods in 2008 lifted the groundwater table to record-high levels, he said.

"Then last year with the drought, the water table just bottomed out very dramatically, and we're thinking that may have played a factor in pulling down some of that nitrogen in the upper soil profile, bringing it down into some deeper wells," Wietersen said.

"If we're correct (about the drought), and that's where the spike has come from, then it's already in the water table, so it's not going to go away as quickly as it arrived."

Officials hope nitrates will level off or decrease over time.

"Time will tell," Wietersen said.

Rock County UW Extension Ag Agent Jim Stute confirmed one of Wietersen's suspicions: More corn is being planted in Rock County, which means more fertilizer applications are taking place.

Stute said the area has seen an upsurge in corn acreage because the crop is more profitable than others, such as soybeans. Unlike soybeans, however, corn requires nitrogen to grow.

Stute guessed that in addition to the drought, "more corn and maybe over-fertilization" has contributed to the rise in nitrate levels.

A soil test specific for corn can advise farmers how much nitrogen to apply based on how much remains in the soil. But all the spring moisture helped nitrates seep beyond the root zone, making the test pointless, Stute said.

While the health department's test results in Bradford show high nitrate levels, Wietersen said it can't be attributed to the Rock Prairie Dairy, which opened in December 2011 with a capacity for 5,200 cows.

"We're not really seeing a trend (around the dairy) that would be out of the ordinary from anywhere else," he said. "Some have jumped up, some have gone down."

What should you do?

Rock County Health Department officials advise residents to have their wells tested annually for bacteria and nitrates.

Test kits can be picked up at the health department, 3328 N. Highway 51 in Janesville or 61 Eclipse Center, Beloit. The cost is $44 for bacteria and nitrates, but participation in a town-wide program brings the cost to $35. Testing for nitrates or bacteria only is $22. For more information, call 608-757-5440.

The county has 13,000 wells, but only 1 to 2 percent is sampled each year, said Rick Wietersen, health department sanitarian.

Homeowners with high nitrates can:

-- Use bottled water for drinking, cooking, etc.

-- Install a treatment system. The most common of these is a reverse osmosis system, which can remove more than 95 percent of nitrates. A small household system can run $500 to $800, Wietersen said, along with filter changes needed every six months to a year.

Janesville water system companies say they have been taking increased calls and selling more reverse osmosis systems in recent weeks.

-- Dig a deeper well, which could cost more than $10,000. There's no guarantee, though, that you won't have the same problem or worse, said Scott Hembrook, sales manager at Culligan of Janesville.

Terry Addie, owner of Addie Water Systems, said his office has taken more than a dozen calls in the last week from concerned residents.

"A lot of people are being made aware, and being made aware gets people to do something," he said.

Hembrook recommends owners test their water before and after installing a system to make sure it's performing as expected. Some systems might bring a well with 34 parts-per-million down to 20 ppm, but that's still above the 10 needed for safe drinking water, he said.

"That doesn't do any good," he said. "It's still contaminated water."



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