Oct. 20, 2000 (Omaha World-Herald)—Agriculture, a driving force of Iowa's economy, is also a chief polluter of its water resources.
Siltation from farm runoff is a threat to state reservoirs, which otherwise have good-quality water, and farm pesticides are threatening southern Iowa's Rathbun reservoir, the source for one of the largest rural water systems in the country, a report by the U.S. Environmental Protection Agency said.
Sediment, nutrients and bacteria are common contaminants. Several studies have detected low levels of pesticides in Iowa's groundwater, according to the report, which was based on 1998 water quality assessments.
"The concern is not the use of more pesticides or practices, but the using of surface water and reservoirs, which are much more susceptible to runoff," said Susan Heathcote, research director at the nonprofit Iowa Environmental Council.
Groundwater - water found below ground - supplies about 80 percent of Iowa's drinking water. But the trend is toward surface water, which is available in large quantities, said Bernard Hoyer, a geologist who works with water monitoring for the state.
Nearly all of Iowa's land is used for agriculture. A 1995 survey by Iowa State University Extension found that 99 percent of the state's corn and soybean acres were treated with at least one pesticide. Iowa led the nation in planted acres for two crops this year.
"Certainly, with the amount of chemicals used, Iowa has quite a bit of chemicals in its streams, at least seasonally," said Dana Kolpin, a water quality researcher with the U.S. Geological Survey.
Spring rainstorms, for example, can wash more chemicals from a field. Lawn and garden chemicals used in urban areas also contribute.
Herbicides and insecticides in shallow groundwater in an eastern Iowa urban study area were in the upper 25 percent of groundwater sampled across the nation. The detection frequency of herbicides in groundwater in an agricultural area fell in the top 25 percent of groundwater. Research was conducted as part of the geological survey's National Water Quality Assessment Program.
Overall, eastern Iowa streams have lower pesticide concentrations than streams in agricultural parts of Illinois and Nebraska. Insecticide concentrations are in the lowest 25 percent of streams sampled across the United States, said Bob Gilliom, chief of the geological survey's national pesticide synthesis team.
Some studies have suggested a link between the herbicide atrazine, a common chemical sprayed on corn, and stunted fetal development and cancers.
Red-flag alerts for pesticides were issued for five cities - two of which were flagged twice - after maximum contaminant levels for pesticides were exceeded in public drinking water supplies from 1995 to 1998.
The alerts were issued by the nonprofit environmental council based on U.S. Environmental Protection Agency standards. Because of reporting requirements, which may vary because of the source's history, the high levels didn't necessarily mean there was a violation, Heathcote said.
A 1998 state report, the most recent available, found 90 percent of the nearly 2,000 public drinking water systems in Iowa in compliance.
Jack Riessen, chief of the water quality bureau for the Iowa Department of Natural Resources, said the public is aware of the issue and farmers are participating in conservation programs.
Landfill rules in Iowa require annual inspections and permit renewals every three years. The state also regulates construction in floodplains to minimize erosion and effects on aquatic life, the EPA report said.
Monitoring has been limited in Iowa, largely because of the lack of funding. The Legislature allocated $2 million to expand efforts this year, Hoyer said. That includes looking at water quality upstream and downstream from selected cities and sampling surface water for pesticides, which he said has not been part of a routine statewide monitoring program.
"Pesticides have always been of concern, and everybody knows they're powerful," he said.
Iowa contributes about 25 percent of the total nitrate-nitrogen runoff that reaches the Gulf of Mexico, Heathcote said. The so- called "Dead Zone" is an 8,000-square-mile area just beyond the mouth of the Mississippi River where no plankton, shrimp, crabs or fish live.
Farmers are interested in water quality and in doing their best to improve it, said Rick Robinson, who works on environmental issues for the Iowa Farm Bureau.
"There is a lot of evidence farmers do embrace a number of best management practices that protect water quality," Robinson said.
Better products are on the market, and other chemicals can be used with atrazine to reduce its level of application, he said.
He also notes that Iowa leads the nation in planting buffer strips, areas of farmland along streams and lakes that are taken out of production to catch agricultural runoff. There have also been efforts to restore wetlands and reduce soil erosion, he said.
"We're talking 10 years and 20 years for these efforts to help clean up," he said. "We didn't get into the situation we are in in a few years."Iowa Water QualitySurface Water Quality good at Saylorville, Red Rock, Coralville and Rathbun reservoirs; siltation threatens uses. Pesticides a concern at Rathbun.GroundwaterSupplies about 80 percent of state's drinking water.Contaminants: agricultural chemicals and drainage wells, under-ground storage tanks, livestock waste and improper management of hazardous substances.Studies: low levels of agricultural pesticides and synthetic organic compounds detected in treated and untreated water.ImpairmentImpaired aquatic life in 19 percent of assessed rivers and 35 percent of assessed lakes; impaired swimming use in 54 percent of 913 surveyed river miles and 26 percent of assessed lakes, ponds and reservoirs.Environmental Protection Agency 1998 water quality assessment report.
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