Nitrates in the Upper Mississippi River continue to pose a threat to aquatic life and are associated with a growing number of human health risks including cancer, despite measures taken by state and federal agencies to reduce nutrient loading. Although states like Minnesota, Wisconsin, and Iowa are part of a task force that aims to reduce the size of the hypoxic zone in the Gulf of Mexico, the efficacy of their environmental regulations is unclear. These states are particularly important to compare as they sit on the Upper Mississippi River, where the hypoxic zone starts, and each adheres to a political ideology that impacts its distinct environmental policies. This project used data from the EPA and the USGS to examine nitrate contamination within states, and also to document the number of nitrate contamination violations that are reported to NWIS. Additionally, this project used data from each state's environmental department to compare budgets and enforcement measures by state. Results showed Minnesota had the biggest budget, the strongest measures of enforcement, and the least amount of nitrate contamination, while Iowa had the smallest budget and the greatest area of contamination; although Wisconsin was worse than both Minnesota and Iowa in terms of number of violations, other metrics put Wisconsin ahead of Iowa. These trends also correspond with the political affiliation of state leadership, giving cause to believe that there is a relationship between political ideology and nitrate contamination. Proposed policies to mitigate nitrate contamination in state waterways are to update water quality laws, implement regional water quality trading across states, prioritize transparency in state decision making, and introduce precision agriculture.
Charlotte Weigel (Sat,) studied this question.