BY SAMANTHA OHLSON
A bill signed by Gov. Kim Reynolds in January could help reduce phosphorus pollution in Iowa.
The bill, SF 512, appropriates funds expected to total $282 million from an infrastructure fund and a water tax to allocate money towards projects designed to improve water quality.
Phosphorus is an element that is essential to life and is used as an important fertilizer for crops, but it can also be toxic and cause algae blooms detrimental to freshwater sources.
According to a recent study published in the journal Water Resources Research, nearly 38 percent of Earth’s freshwater bodies are overloaded with phosphorus. In Iowa, most lakes and streams have two to ten times the level of phosphorus they should have, according to the Iowa Department of Natural Resources (DNR) in 2005, the last available data.
The algae blooms caused by phosphorus can cause freshwater bodies to turn green.
“Lots of people are using our rivers and lakes and whatnot for recreation, and it’s not as fun to recreate in water … full of algae,” said Jeremy Klatt, an environmental specialist at the DNR.
Iowa phosphorus use affects the environment more broadly as well, as the streams in Iowa lead to the Mississippi River, which dumps the excess phosphorus into the Gulf of Mexico.
“Nitrogen and phosphorus getting in the Gulf are a concern,” said Matthew Helmers, a professor and extension agricultural engineer at Iowa State University. Helmers said that algae can consume so much of the oxygen in the water that the Gulf can no longer support aquatic life.
In Iowa, as in other parts of the world, the problem is largely caused by sewage and surface water runoff.
“All cities have a discharge pipe (for sewage treatment plants), most likely, and that will have phosphorus in it,” Klatt said.
Klatt said surface water runoff is a major contributor in Iowa because of the state’s focus on agriculture. When soil erodes, it takes nutrients like phosphorus, which have been applied to the soil through fertilizer and manure, with it.
Antonio Mallarino, professor of soil fertility and nutrient management and extension specialist at Iowa State University, said controlling phosphorus in the soil gets tricky in Iowa because of the humid climate and dependency on animal production.
“We need to do something with the animal manure, and the best way is utilizing animal manure to (apply it) to the soils,” he said.
Iowa has been working to control phosphorus loss for some time, implementing both the Iowa Phosphorus Index and Iowa Nutrient Reduction Strategy in the last 20 years, with the new voluntary water quality bill being the latest legislative step.
Strategies for controlling phosphorus loss include terrace farming, no till farming and cover crops for farmers. Buffer strips along rivers, or anything that increases vegetation before the water to allow sediment to settle out, is helpful. Wastewater treatment plants are also working to filter out as much phosphorus as possible before dumping sewage into rivers.
Despite the increased funding for these projects from SF 512, critics argue the bill does not do as much as it needs to, as it lacks benchmark improvement goals and does not mandate water quality monitoring.
Mallarino said patience is needed to see results. “It may be years before we can see a dramatic impact in the reduction of problems in streams or some lakes,” he said.
