Click to download online article: From the Des Moines Register – Online
Des Moines Water Works turned on the world’s largest nitrate-removal facility Friday for the first time since 2007 after levels of health-threatening nitrates hit records in both the Des Moines and Raccoon rivers, two main drinking-water sources.
Bill Stowe, the utility’s general manager, said the process will keep nitrates at safe levels in tap water, but he is concerned about the rising costs and difficulty of treating water as nitrate levels climb.
The $4 million nitrate-removal plant, installed in 1992, costs about $7,000 a day to run. So far, the utility is using four of the eight treatment cells where nitrates are stripped from the water. The Environmental Protection Agency had ordered Des Moines to act to remove nitrates after the contaminant exceeded the federal limit in tap water during the early 1990s.
The predicament shows that voluntary conservation efforts on farms aren’t working and do not bode well for the future of the area’s water supply, Stowe said. He added that nitrates, which also occur naturally, primarily come from crop fertilizer. Better field drainage systems have worsened the situation.
Typically, when nitrates rise in the Raccoon River, the Des Moines River remains well within drinking standards. The utility then dilutes the pollution from the Raccoon water with that drawn from the Des Moines.
This time, they are both at record highs — a troubling oddity, Stowe said.
”We are off our playing field,” he said. “We haven’t seen this before.”
Untreated high levels of nitrates in drinking water have been linked to blue baby syndrome, as well as to various cancers and miscarriages. The federal limit is 10 milligrams per liter nitrate in drinking water; both rivers have posted readings in the range of 20 milligrams per liter.
The Raccoon River hit 24 milligrams per liter this week; the previous record was 22. The Des Moines was just under 18; the record was 14.2.
Stowe said some U.S. Geological Survey gauges couldn’t measure the concentrations because they exceeded the meter’s range.
With decades’ worth of data suggesting nitrates are rising in Midwestern rivers, Stowe hopes the situation doesn’t worsen.
Agriculture Secretary Bill Northey said the fact that Water Works didn’t need the removal system for the past six years shows that nitrates have been at manageable levels. He added that nitrates left over from last year, when a smaller than usual corn crop didn’t use as much nitrogen, and the record April rains could have caused a temporary spike.
Northey said strategy now focuses more on reducing nitrogen and phosphorus levels than past efforts, which were targeted mostly on soil conservation.
Laurie Johns, spokeswoman for the Iowa Farm Bureau Federation, said regulations wouldn’t work because farm conditions vary and are best addressed by farmers’ voluntary efforts. No regulation can control record rain, she added.
”With such wild weather swings and 95 percent of Iowa’s land comprised of farmland, there’s not one regulation that would have prevented the current spike in nitrates, short of outlawing crop production in Iowa,” Johns said.
Deborah Neustadt, chairwoman of the Iowa chapter of the Sierra Club, said farmers should be required to have nutrient-management plans featuring specific practices meant to curb runoff. That way, they could be held accountable for pollution from their operations.
“Why does the rate-payer have to pay for actions of farmers?” Neustadt asked.
Susan Heathcote, water program director of the Iowa Environmental Council, took a similar view. “Local pollution-reduction goals are critical to motivating Iowa farmers and landowners to make the significant changes necessary to ensure clean water,” she said.