Iowa is grappling with water quality and cancer rates, bringing these issues to the forefront of state politics. These topics have typically been politically sensitive due to Iowa's powerful agricultural industry. Chemical fertilizers and animal waste contain nitrates and phosphorus that can get washed with rain or snowmelt into the state’s rivers. That affects Iowa’s more liberal urban centers which rely on rivers and lakes for drinking water. Some studies suggest a link between nitrates in water and cancer, but this remains debated. The state has invested in water infrastructure, but criticism over slow progress continues. Candidates from both parties are addressing growing public concern, with events and advertisements focusing on water quality, conservation and cancer.