“People in rural communities are getting sick. Cancer is just everywhere,” said Kerri Johannsen, senior director of policy at the Iowa Environmental Council, a non-profit focused on improving the environment that is helping to lead the project. “Every person I talk to knows somebody that has [recently] had a cancer diagnosis,” she said. “It’s just a constant drumbeat. It’s scary.”
Kentucky, the only state with a higher cancer incidence than Iowa, historically has also ranked first in adult smoking, which is considered to play a major role in the state’s high cancer rates.
In Iowa, the cause has been less clear. Last year, a state report cited alcohol consumption as a key factor. Higher-than-average levels of radon, a naturally occurring, colorless gas known to cause cancer, is also a concern.
But many residents blame the insecticides, herbicides and other pesticides widely used on farms as well as the state’s persistent problem with high levels of hazardous nitrates that wash off farm fields into the state’s water supply.
As a key US farm state, Iowa has long been known for the leafy green stalks of corn that stretch seemingly endlessly across the horizon. With nearly 87,000 farms, the state ranks first not only for corn production but also for pork and egg production, and is within the top five states for growing soybeans and raising cattle.
Of Iowa’s 35.7m acres of total land, roughly 31m is devoted to farming.
Many of the pesticides routinely used are linked to a range of diseases, including the popular herbicide glyphosate, which is classified as a probable human carcinogen by cancer experts at the World Health Organization. Nitrates are also tied to cancer, particularly when consumed in drinking water or other dietary sources.
Agricultural fertilizers and manure from large-scale livestock operations are key sources for nitrates, which are known to contaminate surface water and groundwater.
In addition to looking at pesticides and nitrates, the research will also look at cancer links to per- and polyfluoroalkyl substances (PFAs).
Earlier this year, the Environmental Protection Agency (EPA) warned of elevated cancer risks related to such farm fertilizer contaminated with PFAs.
The work will also include a deeper look at the state’s high levels of radon as a key cancer cause, said Elise Pohl, former community health consultant for the Iowa department of health who is the lead researcher for the project. Radon, a leading cause of lung cancer, is particularly high across Iowa, with approximately 50% of homes facing radon levels above federal regulatory action levels.
“We really want to find out why these cancers are increasing,” Pohl said. “We’re homing in on the agriculture side of things.”