An ISU professor is conducting research showing that glaciers that existed in Iowa millions of years ago are still helping to remove nitrates from groundwater, making drinking water safer.

William Simpkins, associate professor of geological and atmospheric sciences, has been researching groundwater quality since 1990 with $260,000 in funding from the United States Department of Agriculture, the Environmental Protection Agency, the Management Systems Evaluation Area Project and the Iowa Department of Natural Resources-funded Till Hydrology project.

About 60 percent of drinking water for Iowa is served through groundwater, according to a 2003 Iowa Public Drinking Water Program report.

Simpkins found in a recent study, which was presented at North-Central Section of the Geological Society of America in May in Minneapolis, that Iowa’s last glacier is contributing to cutting nitrate levels in Iowa groundwater and creating methane gas.

Simpkins has also found other mechanisms that clean nitrate from groundwater.

“Our studies in riparian buffers show that buffers provide a mechanism to remove nitrate from groundwater,” he said.

“I am in the process of re-analyzing the data in light of the tools available through geographic information systems,” Simpkins said. “This coming fall, I will have five graduate students working on various aspects of these topics in Iowa and Missouri.”

Nitrate, one of the most common groundwater contaminants, derives mainly from fertilizers used for agriculture, which in the process of runoff, seeps into the ground.

Ramesh Kanwar, professor and department chairman of agricultural and biosystems engineering, said nitrate concentration in the surface runoff from agricultural fields is usually not very high.

“Many state agencies and Natural Resources Conservations are promoting the use of nutrient management plans for farmers to reduce the contamination of surface and groundwater sources,” he said.

Kanwar said halting the use of nitrogenous fertilizers, however, would cause negative economic consequences.

“Without the use of nitrogen, Iowa farmers will not be able to compete in the global market,” Kanwar said.

Matthew Helmers, assistant professor of agricultural and biosystems engineering, said some nitrogen seeping will take place, regardless of whether farmers cease the application of nitrogen fertilizers, because Iowa soils are very rich in organic nitrogen by nature.

“We need to ensure that we are applying appropriate amounts of nitrogen fertilizer at the right time,” he said.

ISU researchers have been studying this for more than 30 years, Kanwar said.

“We need to educate farmers and provide them with needed tools to manage nitrogen on agricultural lands so that nitrate contamination can be reduced,” he said.