U study: Wetlands key to keeping harmful nitrates out of waters

A new University of Minnesota study found wetlands are providing a significant water quality benefit by keeping nitrates from crop fertilizer out of rivers. The study from the U's St. Anthony Falls Laboratory and the College of Biological Sciences found that when stream flows are high, wetlands are actually more effective at removing nitrates than conventional land conservation practices."What our study shows is that multiple wetlands in the watersheds are having a measurable effect on the nitrate concentration in the river said Amy Hansen, a research associate at the university and the study's lead author. Hansen said past studies haven't demonstrated that wetlands reduce nitrate concentrations on a watershed scale. That's probably because other Midwest states like Iowa and Illinois don't have enough remaining wetlands to measure an impact, she said. The study found the basin's wetlands are on average five times more effective at reducing nitrate pollution than other conservation methods such as taking land out of production, Hansen said.