Iowa now ranks second to Kentucky in cancer incidence in the United States, and from 2015 to 2019 was the only state where the rate of new cancers increased, according to the National Cancer Institute. Rates of oral cancer, leukemia, non-Hodgkin lymphoma, melanoma, kidney, colon, and breast cancer are among the nation’s highest, according to Charlton.

The state is expected to see 21,000 new cases of cancer this year alone, more than double the number of new cancers recorded for 1973, the year Iowa began keeping records, according to Charlton. Since 1973, the state population has grown only a little over 10%.

“Some cancers in Iowa are rising and others are not falling as quickly as they are in other states,” said Charlton. “We do know that Iowans have a number of environmental exposures that could contribute to our risk of cancer.”

Exposure to nitrate in drinking water is well-recognized by scientists as a risk factor in many of the same high-incidence cancers seen in Iowa – lymphoma, breast cancer, blood, and colon cancer.

Cancer researchers, including a group from the University of Iowa, have linked various cancers to long-term exposure in air and water to trace levels of insecticides and herbicides, as well as nitrates. And Iowa farmers annually spread more pesticides (nearly 54 million pounds) more commercial fertilizer (2 billion pounds) and more animal manure (50 million tons) than in any other state, according to the US Department of Agriculture (USDA) and Iowa State University.

These farm pollutants heavily contaminate surface and groundwater across Iowa, according to state monitoring data, potentially exposing even people who don’t live and work on farms,

Links between farm contaminants and disease have long been studied. In 2001, researchers at the University of Iowa evaluated data from a long-term study of more than 20,000 women in Iowa and found increased risks of bladder and ovarian cancers associated with elevated nitrate levels in public drinking water supplies used by the women.

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