Nitrogen is a key, high-volume pollutant in state waters and its concentrations in both surface and groundwater have been increasing over time. The MPCA released a report on nitrogen pollution in 2013, indicating that agricultural fields using artificial subsurface drainage (drain tile) are a key source of nitrogen pollution. Nitrate (a form of nitrogen) in lakes, rivers, and streams is toxic to fish and other aquatic life; in drinking water, it's potentially harmful to humans. Proposed reductions in nitrogen will benefit both Minnesota waters and water downstream from us, particularly the oxygen-depleted “dead zone” in the Gulf of Mexico.