Advancing the Use of Nitrate and Neonicotinoids Findings to Inform Groundwater Protection and Improvement Strategies

Background/Need: Nitrate and neonicotinoids are two types of pollutants that can be found in groundwater. Nitrate contamination can occur naturally or as a result of human activities such as agricultural practices and waste disposal. Neonicotinoids, on the other hand, are a type of pesticide that is widely used in agriculture to protect crops from insects. Both nitrate and neonicotinoids have been linked to negative impacts on the environment and human health. The Central Sands region of Wisconsin is an area with high susceptibility to groundwater contamination and a high percentage of land use devoted to agricultural procedures. Since many residents of the Central Sands rely on groundwater resources for their drinking water, it is a priority for federal and state agencies and local governments to assess the state of groundwater contamination and reduce the levels of nitrate and neonicotinoids in groundwater.

To better coordinate efforts, in 2018 six counties in the Central Sands region of Wisconsin (Adams, Juneau, Marquette, Portage, Waushara, and Wood) decided to form the Central Sands Groundwater County Collaborative (CSGCC). While nitrate and neonicotinoids data points have been continuously collected for decades in the CSGCC region, no compilation of such data has been ever attempted. Creating a comprehensive and accessible database will help stakeholders in decision-making for protecting both the environment and public health.

Objectives: The main objective of our work was to compile nitrate and neonicotinoids data collected in groundwater of the Central Sands region of Wisconsin in a unique GIS database. We also aimed to identify spatial and temporal gaps in the data and evaluate which factors are primarily affecting groundwater contamination in the area.

Conclusions/Implications/Recommendations: Due mostly to data incompleteness, data inconsistency, and lack of data accuracy, we found data merging extremely challenging. We recommend that each entity invested in data collection performs data validation before storing and sharing the data. Overall, neonicotinoids and nitrate data compilation are ongoing and continuous processes that require collaboration between various stakeholders. We believe that the database produced by this study will be extremely valuable to the researchers, policymakers, and members of the public for understanding and mitigating the impacts of groundwater contamination, and for protecting the quality and availability of groundwater resources. In addition to data compilation, we also focused on effective communication and dissemination of information on nitrate and neonicotinoids contamination. To this aim, we created the Groundwater Quality Resource Guide- Focus on Nitrate and Neonicotinoids document (Appendix D of this report) with a detailed compilation of all available online resources on the matter. This tool will assist in the development of educational materials, which can help raise public awareness and knowledge about groundwater contamination issues.