Mississippi River in Hastings, Minnesota (Credit: Michael Hicks, via Wikimedia Commons)
Minnesota researchers found 158 million pounds of nitrates leave the state through the Mississippi river each year on average, according to a report from National Water Quality Monitoring News.
Scientists from the Minnesota Pollution Control Agency initiated the study. They analyzed 50,000 samples from 700 stream sites across with the help of scientists from the U.S. Geological Survey and University of Minnesota.
Analysis showed 70 percent of nutrient pollution was due to runoff from agricultural operations. Fertilizer drains through channels in farmed soil and enters ground and surface water bodies nearby.
The other 30 percent of nitrate pollution was from sources such as fertilized residential lawns, wastewater treatment plants and natural sources.
MPCA will use the data to identify sources of nitrates and to determine strategies to reduce runoff.
Image: Mississippi River in Hastings, Minnesota (Credit: Michael Hicks, via Wikimedia Commons)