GEOCHEMICAL ANALYSIS OF SURFACE WATER QUALITY IN RICE COUNTY, MINNESOTA

Rice County, located in southeastern Minnesota has a complex water system that ultimately drains into the Mississippi River. The eastern half of the county is predominantly farmland cut up by rivers and streams, while the western half, which was more recently glaciated, is covered with lakes. Water samples were collected from 74 sites around the county and tested for conductivity, nitrate, chloride, calcium, and trace metals using ICP-MS. Using ArcGIS, maps were created to show the spatial variance of these cations and anions to see if there were patterns or clues indicating why certain areas of the county had higher levels of ions. The goal of our study is to provide a report of the surface water quality of Rice County at this time and to examine the source of its pollutants, as well as to see if the water quality has changed in the last few years. The higher frequency of dissolved ions and especially of nitrate in the eastern half of the county indicate that agricultural practices may be impacting the surface water quality. Research in the last four years found similar results, which implies that little has been done to improve the water quality or to stop the leeching of nitrogen from fertilizers. Nitrogen pollution has been proven to cause harmful ecological effects such as anoxic zones. Therefore, our findings should encourage residents and policy makers in the county to attempt to improve its water quality. Further studies should be done on the specific ecological impacts of Rice County’s surface water quality and on the ground water of the county to show the extent of the anthropogenic pollutant’s impacts.