DES MOINES, Iowa (AP) — Last year’s drought combined with the wettest April in Iowa in more than 140 years is causing a significant washing out of fertilizer from farmland and it’s ending up in the rivers used by many cities for drinking water.
The Des Moines Register reports the Des Moines and Raccoon rivers have reached record nitrate levels forcing the city Water Works to switch on its $4 million nitrate removal equipment for the first time since 2007. The Environmental Protection Agency allows up to 10 milligrams per liter in drinking water. Untreated, the Raccoon River is running at 24 and the Des Moines River at 18.
The problem is worse because drought-stunted crops absorbed less nitrogen fertilizer last fall leaving it in soil. This spring’s heavy rain washed it into rivers.