A new report concludes state and federal water quality policies are too lax and have let a certain kind of harmful “scum” build up in the state’s lakes and rivers.
Andrea Heffernan, the Iowa Policy Project researcher who conducted the study, says the level of blue-green algae in Iowa waterways indicates there may be harmful bacteria in the water.
“They also can cause difficulty in water treatment when source water is contaminated,” Heffernan says.
According to Heffernan, that means some of the drinking water systems in the state cannot filter out some of that bacteria, called cyanobacteria.
“Iowa waters have proven to be a hospitable environment for cyanobacteria,” Heffernan says. “Common agricultural practices such as the application of synthetic fertilizers to corn and soybean fields as well as the application of nutrient-rich animal manure to farm fields have provided an abundant nutrient source for cyanobacteria. To a lesser extent, urban sources have also contributed to nutrients in Iowa waterways.”
The chemicals Iowans use to keep their lawns green and free of weeds contribute to the problem, too, according to Heffernan. Heffernan says when you see blue-green algae or “pond scum” growing in a lake, that can signal there’s a lot of this cyanobacteria that can harm people, causing skin irritation or even stomach and intestinal ailments if you swallow the water. She says that means water treatment plants use more chemicals — and spend more money — to try to eliminate that bacteria from the water that’s piped into your homes and offices.
“Ultimately these excess nutrients are adding a cost burden to water customers,” Heffernan says. “…In reality, we really don’t know the extent of the problem as cyanobacteria are not a regulated contaminant and therefore little or not monitoring takes place.”
Heffernan and another researcher from the Iowa Policy Project say it’s time for the state and federal governments to establish new rules for farmers and for those who apply chemicals on lawns to address run-off issues. But Rick Robinson of the Iowa Farm Bureau points to an Iowa Department of Natural Resources estimate that concludes less than five percent of the fertilizer applied to Iowa farm fields winds up running off.
“I think most reasonable people would understand that given 35 inches of rainfall a year in Iowa, that’s really pretty good news,” Robinson says. “It’s unfortunate that there are groups out there continually trying to find problems, I think, with Iowa agriculture and probably don’t realize the good job that Iowa farmers are already doing.”
The estimate that four to five percent of the manure and commercial fertilizers and herbides applied to Iowa farm fields runs off into waterways was developed before new state rules restricting manure application on frozen ground went into effect, which could reduce that run-off estimate.
“There’s been a number of regulations put in place,” Robinson says. “So all those things, over time, have contributed to less and less nutrients leaving the landscape.”
Robinson says commercial fertilizers and herbicides cost money, so farmers use only what’s necessary.