One of the litany of problems with industrialized agriculture, particularly concentrated animal feeding operations (CAFOs), is the huge quantity of wastes produced and how it’s managed. There’s no easy way to deal with the staggering amounts of urine and manure produced by these facilities, which approach that produced by small cities, reaching over 335 million tons annually (and that’s just for dry matter).¹

Some CAFOs treat animal feces in open air — often unlined lagoons — and “dispose” of the waste by spraying it onto nearby fields.²Although the creation of new CAFO lagoons and the spray systems were banned in 2007, older farms are still allowed to use them. While reasonable amounts of manure from healthy cows can, in fact, make excellent fertilizer, covering farm fields in the waste from diseased CAFO cows is another matter entirely, especially because it’s used in excess quantities.

The liquefied waste often leaches into groundwater and wells, poisoning drinking water, and runs off into waterways, turning once pristine bodies of water into veritable toilets. The resulting damage includes an excess of nutrients that lead to algae overgrowth, depleting the water of oxygen and killing fish and other marine life in expansive dead zones.

This, combined with the excess fertilizers applied to monocrops like corn and soy, sends a steady stream of nitrogen and phosphorus to both surface and groundwater, spreading potentially disease-causing organisms and unsustainable amounts of nutrients along the way. The dead zone in the Gulf of Mexico is the largest recorded dead zone in the world, beginning at the Mississippi River delta and spanning more than 8,700 square miles — and industrial agricultural pollution is primarily to blame.

Iowa CAFOs Are Ruining the Mississippi River

According to the U.S. Environmental Protection Agency (EPA), manure from industrial agriculture is the primary source of nitrogen and phosphorus in waterways.³ So, it’s not surprising that areas with an abundance of agriculture, like the state of Iowa, would contribute more than their share of this environmentally devastating pollution. Indeed, a study published in PLOS One set out to quantify Iowa’s contribution of nitrogen pollution to the Mississippi River,⁴ which was named the second-most polluted waterway in the U.S. in 2012.⁵

There are well over 14,000 CAFOs in Iowa, primarily medium and large in size and housing pigs.⁶ Genetically engineered corn and soy crops are also prolific. In the 2016 State of the River Report by the Mississippi National River and Recreation Area, the greatest source of chemical contamination to the river was found to be agricultural runoff. For the featured study, stream nitrate and discharge data were collected from 1999 until 2016 at 23 Iowa stream sites near watershed outlets.

The results confirm that much of the nitrates devastating the Mississippi River are coming from the state of Iowa. Iowa contributes an average of 29 percent of the nitrate load to the Mississippi-Atchafalaya Basin, 45 percent to the Upper Mississippi River Basin and 55 percent to the Missouri River Basin.

Cindy Lane, water program director for the Iowa Environmental Council, told The Gazette, “This paints a clear picture that our state is a main contributor to the nitrate loads … It’s a huge push for us to say ‘Iowans need to do our part. We need to be accountable.’”⁷

The amount of nitrates Iowa contributes to the Mississippi is larger than would be expected for the amount of water flowing into rivers in the area. While Iowa is one of 12 states that committed to a nutrient-reduction strategy to try to stop the Gulf of Mexico dead zone from worsening, the study notes, this “will be very difficult to achieve if nitrate retention cannot be improved in Iowa.”⁸

Meanwhile, an AP investigation revealed alarming trends throughout the U.S., including that levels of nitrogen and phosphorus from fertilizer runoff are getting higher in lakes and streams.

Despite government agencies spending billions of dollars to help farmers prevent fertilizer runoff and circumvent the problem, algae blooms are getting worse instead of better.⁹ Overall, the EPA states that about 15,000 water bodies have been identified that have “nutrient-related problems,”¹⁰ and many more probably have yet to be identified.

CAFOs: The Real Reason for Romaine Lettuce Poisonings

In the spring of 2018, nearly 200 people spanning 35 states became sick from eating romaine lettuce contaminated with Shiga toxin-producing E. coli O157:H7. Nearly 90 people were hospitalized and five deaths were reported. More than two dozen of those affected suffered from hemolytic uremic syndrome, a potentially life-threatening complication of this type of E. coli infection, which can lead to kidney failure.

The U.S. Centers for Disease Control and Prevention (CDC) stated only that the suspect lettuce likely came from the Yuma, Arizona, growing region,¹¹ but because salad packaging rarely labels where it’s grown, there was no way for consumers to determine if the lettuce on store shelves was potentially contaminated, even after the outbreak began picking up speed. So what’s causing romaine lettuce — an ordinarily healthy food — to turn into a vector for deadly bacteria like E. coli O157:H7?

Perhaps a lesson can be learned from 2006, when there was an outbreak of E. coli in fresh spinach. The bacteria were traced back to the feces of wild pigs that supposedly invaded the fields, but it was also found in manure from CAFO cattle.¹² While E. coli deposited by wild pigs in a field likely wouldn’t survive for long out in the hot sun, CAFOs are a hotbed for bacterial growth. Dust from CAFOs can also contain E. coli, which can easily be blown onto neighboring fields.

To reduce the potential for contamination, some produce associations require fields to be at least 400 feet from a CAFO, but studies have shown the dust can easily travel beyond this distance. In Yuma, where cattle CAFOs are plentiful, some farmers plant their fields as little as 1 mile away from the feedlots. Michele Jay-Russell, research microbiologist and manager for the Western Center for Food Safety at the University of California-Davis, who was closely involved in the 2006 spinach investigation, told Food Safety News:¹³

“The growers in the Yuma [area] are very aware of potential issues with CAFOs … There is a much higher density of cattle in the Yuma area than in Salinas Valley where so much of the California leafy greens are grown. In Salinas, there are mostly cow-calf operations … you see them grazing on the hillsides.”

Aside from the potential of E. coli in dust blowing over onto greens fields from neighboring CAFOs, the feedlots pose another risk factor for the area, as they’re prime feeding grounds for migrating birds. “The migrating birds, as well as resident flocks of crows and other birds, can’t pass up the easy pickings of animal feedlots,” Jay-Russell said. Unbeknownst to many, birds can become carriers for E. coli and their contaminated feces could contaminate agricultural fields.

“You can try to scare the birds away from feedlots, but they get used to the noises and just come back,” Jay-Russell said. “They know when the feed is going to be put out and they show up. Then they fly to the (produce) fields seeking water. They can contaminate the food, the dirt and irrigation water.”¹⁴

Ultimately, the contamination again comes back to CAFOs; if they weren’t raising animals in disease ridden conditions, the birds wouldn’t end up contaminated when they stop for a midday meal. Even a report by the National Institutes of Health singled out the problems of CAFO animal manure as a key contributor to contamination of plant foods:¹⁵

“During the past decade, fruits and vegetables have become leading vehicles of food-borne illness. Furthermore, many plant-based foods and ingredients, not previously considered a risk, have been associated with food-borne disease outbreaks.

Most of the pathogens that have been identified as causative agents in these illnesses or outbreaks are enteric zoonotic pathogens that are typically associated with animal hosts. Transmission of zoonotic pathogens from animals to plant systems occurs by a variety of routes, but the initial contributing factor is the discharge of animal manure into the environment.”