Drinking Water in Des Moines Is Nearing Danger Levels

Local officials warned more than a half-million Iowans in the state's capital city and suburbs on Thursday that near-record level of pollutants in its rivers could make drinking water dangerous if immediate steps are not taken to reduce demand. But the officials declined to say what has caused the surge in nitrate levels, which has historically been tied to runoff from farmland draining into Des Moines-area rivers. The water utility, Central Iowa Water Works, issued a first-ever ban on lawn watering for the region after seeing the highest levels of nitrates in the river water since 2013. Federal regulations set a maximum nitrate level of 10 milligrams per liter. The current level being provided to 600,000 customers is 9, the AP reports.

• The concerns: "If we end up in a space where we're well over that … threshold, we're really going to start worrying about our pregnant women and our children under the age of 6 months," said Juliann Van Liew, public health director for Polk County. Van Liew warned that drinking water with high levels of nitrate could cause birth defects and a condition in which an infant's blood doesn't have enough oxygen, commonly known as blue baby syndrome. Officials made clear that the water currently meets regulations and is safe to drink now. But while the utility works to treat the water to reduce nitrate pollutants to a safe level, Des Moines-area residents' demand is higher than the amount that can be treated. The utility said it has been treating water for 55 days, at a cost of $14,000 to $16,000 a day.

• The source: The root cause of the nitrate problem is runoff from fertilizer and manure from agricultural operations, said Chris Jones, a retired University of Iowa research engineer trained as an analytical chemist. Two new treatment plants have helped, but Jones suggested changes in agriculture are required. "Although the idea that lawn watering is an aesthetic and maybe not needed," he said, "the fact that they're telling people not to use water in this way is a real red flag about the situation with water quality."

(More Des Moines stories.)