Environmental group distills Iowa ag runoff pollution into clickable map

By: - August 31, 2021 12:01 am

The Raccoon River, a major source of drinking water, has chronic, severe runoff pollution. (Photo by Perry Beeman/Iowa Capital Dispatch)

A national environmental group has developed a clickable map that describes some of Iowa’s most pressing pollution problems in fine detail. 

The Environmental Working Group’s “water atlas” shows what Iowans have long known in a broad sense — the state is awash in manure and commercial fertilizers.

That fact affects every Iowan. Residents pay more for tap water because utilities must manage levels of nitrate, which has been associated with a variety of cancers and other illnesses. Recreation is limited by algae blooms, some of them toxic, and high levels of fecal bacteria.

Nitrate and phosphorus, the other algae-popping fertilizer component detailed in the new report, are common ingredients in runoff from Iowa’s hallmark corn and soybean fields.

Fertilizer practices detailed

The Environmental Working Group map details fertilization statewide and the nitrate and phosphorus pollution associated with the practices in Iowa, Illinois, Minnesota and Wisconsin. All four states are giants of agriculture. 

In an interview, Soren Rundquist, the organization’s director of spatial analysis, said the idea was to make thousands of data points easily accessible in a way people could quickly understand. 

“I think the main takeaway is to have accessibility into these hundreds of thousands of records in one place, which can enable policymakers, citizens and advocates to get a better lay of the land with data being recorded in and around their area,” Rundquist added.

Plenty of Iowans are concerned about agriculture-related water pollution, which experts have said would take $5 billion to address in Iowa alone.

Des Moines Water Works CEO Ted Corrigan has declared the Des Moines River “essentially unusable” for tap water at times due to algae toxins associated with farm runoff. He also said recently that the utility will face a “catastrophe” unless farm pollution is reduced in the Raccoon River, which American Rivers this year included on its list of the nation’s most endangered rivers

Algae toxins, nitrate and other farm-related pollution issues led the utility, which has nearly 500,000 customers, to study a $50 million expansion that would include shallow aquifer wells north of the city. 

Water Works drew national attention when it sued upstream drainage districts to force them to address pollution, but a federal judge threw the case out. A Des Moines Register Iowa Poll in 2015 found 63% of Iowans supported the lawsuit, which heightened debate and caused tensions among some rural and urban interests.

Nitrogen from farm fertilizers easily washes away when it rains, forming nitrate along the way. Phosphorus tends to hitch a ride on soil as it washes off of crop fields. 

Iowa has relied mostly on farmers’ voluntary efforts based on the Iowa Nutrient Reduction Strategy. That document, which relies on years of research by Iowa State University scientists and others, has been praised by ag groups and derided by environmentalists. 

Environmental groups have said the document is more a list of options and not really a strategy at all. One Drake University professor who has studied Iowa’s water quality for decades called the state’s approach “magical thinking.” 

Plan for water quality projects evaporates

Iowa Agriculture Secretary Mike Naig, who called the American Rivers report on the Raccoon River “propaganda,” had joined agriculture groups to support the Nutrient Reduction Strategy as the most promising path to progress without falling into a long legal battle over regulations.

Naig co-chairs the federal Hypoxia Task Force charged with reducing pollution, much of it from Iowa and other Upper Midwestern states, blamed for a large “dead zone” in the Gulf of Mexico.

A plan by Gov. Kim Reynolds to use a sales tax increase in part to boost spending on water quality was abandoned as the coronavirus pandemic rattled the economy, and its future is highly debatable. Iowa voters in 2010 overwhelmingly approved a state trust fund to pay for conservation and outdoor recreation projects, but the account remains empty. Any sales tax increase would send money to the account, created by a constitutional amendment.

EWG drew from thousands of monitors

EWG drew nitrate and phosphorus data from 8,200 state and federal water monitors. Also included was nitrate data from 3,794 community water systems that have a combined 19 million customers in the four states.

The study found that more than 80% of monitors showing high phosphorus levels were in counties in which more than 70% of cropland was fertilized. In Iowa, phosphorus is one of the chief pollutants behind algae blooms that cause swimming advisories at beaches. Manure runoff is another.

Nitrate problems tied to farms, county by county

In the four states EWG studied, 86% of the water systems treating water with nitrate levels at half or more of the federal limit came in counties where at least 70% of cropland is fertilized.

The U.S. Environmental Protection Agency requires water systems to keep nitrate under 10 milligrams per liter for health reasons, but some studies have suggested illnesses may be caused by lower concentrations.

The study found that 29% of Iowa’s water systems detected nitrate at or above the federal limit at least once between 2012 and 2019, the years for which data was analyzed. That was second only to Minnesota at 31%. Wisconsin had 22% and Illinois, 17%.

County by county data show troublesome pollution trends

In many ways, the EWG water atlas shows in great deal what we already knew — agricultural runoff is one of the chief reasons Iowa’s water quality is poor in many ways. 

For example, Hardin County had one of the highest percentages of fertilized land, and an average nitrate level well above federal drinking water limits.

The study found 78% of Hardin County’s acres were treated with synthetic fertilizers, and 23% were fertilized with animal manure. 

The average nitrate level in the south fork of the Iowa River near New Providence was 12.39 milligrams per liter, compared to the federal drinking water standard of 10 mg/l. Readings in the river samples were as high as 34.8 milligrams per liter.

In Polk County, home of the state capital of Des Moines and Des Moines Water Works, which has nearly 500,000 customers, 79% of the acres are fertilized with synthetic chemicals and manure is spread on 4% of the acres. Average nitrate levels ranged from 2 milligrams per liter to close to 12 mg/l depending on the stream, based on Polk County Conservation Board data.

The average reported by the Polk County Conservation Board was 4.13 milligrams per liter. 

Sioux County was the only one with manure applications on as much as 35% of the acres. All but Mills County had at least 2% of acres fertilized with manure.

The map shows that all but Winnebago, Ringgold and Clarke counties had at least 63% of acres treated with commercial fertilizer. Hardin, Lyon, Sioux, Washington, Delaware and Dubuque counties were among those with the highest percentage of acres receiving manure applications, all above 22.5%. 

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Perry Beeman
Perry Beeman

Perry Beeman has nearly 40 years of experience in Iowa journalism and has won national awards for environmental and business writing. He has written for The Des Moines Register and the Business Record, where he also served as managing editor. He also is former editorial director of Grinnell College. He co-authored the recently published book, "The $80 Billion Gamble," which details the lottery-rigging case of Eddie Tipton.