Polk County

Scientists discussed pollution, bacteria and other challenges plaguing central Iowa's rivers at an event in Des Moines Monday. The presenters contributed to a two-year assessment of the Des Moines and Raccoon rivers, which includes recommendations at the local, regional and state level.

Nitrates, fecal bacteria, sediment and other pollutants in the Des Moines and Raccoon rivers threaten safe drinking water for 20% of the state’s population. That's one of the findings from a sweeping study commissioned by Polk County supervisors.