The Nelsonville Water Quality Monitoring Project is a collaboration between the Division of Public Health at Portage County Health and Human Services and the Portage County Planning and Zoning Department. The Village of Nelsonville is an area that is facing potential water quality concerns, similar to those seen across Portage County. This is a confined area with a high density of residential wells that is lacking current water quality data. The intent of this project is to establish a current baseline of water quality data that will help the Village to make decisions regarding water quality in the future. All of the information collected will provide village residents with a better understanding of the safety of their water supply and will increase knowledge of local groundwater resources and land management practices that may influence drinking water quality.
The project in Portage County is one of eight environmental public health projects being funded throughout the state through the Taking Action with Data funding opportunity from the Wisconsin Environmental Public Health Tracking Program, which is housed at the Wisconsin Department of Health Services.
The project was done in two phases. The first round of testing occurred during October and November 2019. Samples were collected by Portage County staff and analyzed by the Water and Environmental Analysis Laboratory at the University of Wisconsin- Stevens Point. The first round of sampling included 60 wells which had a nitrate average of 9.3 mg/L. According to the Wisconsin Environmental Public Health Tracking - 2017 Portage County Environmental Health Profile, complied by the Wisconsin Department of Health Services, Portage County averaged 4.9 mg/L for nitrate-nitrogen; while the state of Wisconsin averaged 1.5 mg/L. The state and federal drinking water standard for nitrate-nitrogen is 10 mg/L. Of the wells tested, 47% exceeded the drinking water standard. The initial round of testing was important to better understand basic water quality across the entire Village.
A second round of testing was conducted during January of 2019. The second round of testing focused on identifying possible sources nitrate-nitrogen through nitrate source testing. Samples were tested for a suite of personal care products, pharmaceuticals, and herbicide breakdown products. The second round of testing sampled 25 of the 28 wells that had elevated nitrate-nitrogen concentrations. In the 25 samples, Eight samples had detects for at least one of the personal care product or pharmaceutical. The positive detects are indicative of some level of septic system influence. There are currently no drinking water standards for any of these products. All 25 samples had a detect for at least one of the herbicide breakdown products. These positive detects are indicative of influences from agricultural land uses. Non of the samples exceeded the drinking water standards for the associated herbicide breakdown products. This information can help guide future management decisions on how to address elevated nitrate-nitrogen concentrations within the Village.