http://www.timesrepublican.com/news/todays-news/2018/07/study-iowa-nitrogen-pollution-in-the-water-is-getting-worse/

"DES MOINES — Nitrogen pollution flowing out of Iowa to the Gulf of Mexico has grown by close to 50 percent over nearly two decades, a new report shows, despite hundreds of millions of dollars spent to stem nutrients entering the state’s waterways."

which leads to:
“We’re not headed in the right direction. … We need to follow the lead of other states and pass some environmental laws that will actually reduce loads and result in cleaner water,” Terry said.