Central Illinois: A Cancer Cluster?


Kim Crandall walks her dogs, Roo and Mia, everyday on the streets around her Morton home and in the nearby park bordering corn and soybean fields. The walk gives her time to reflect on an alarming pattern that has only gotten worse the more she looks.

On every street and every block, there are increasing numbers of cancer diagnoses: breast cancer, prostate cancer, brain cancer, colon cancer, non-Hodgkin’s lymphoma . . . .

“I’ve had young friends die of cancer. I remember the day my best friend was diagnosed, and a nurse in the doctor’s office said ‘Oh, we’re charting that area,’” said Crandall, 50.

Morton is a suburban community in Tazewell County with perfect, chemically-treated lawns surrounded by chemically-treated farm fields.

Aza Mohammed, an epidemiologist with the Tazewell County Health Department, said there is no official investigation looking at any region of Tazewell County as a possible cancer cluster.

“Someone must report a suspicion to trigger an investigation and even then it’s very difficult to define a cluster,” Mohammed said.

In a cancer cluster, rates of diagnoses are not just increasing but are greater than the expected number considering the age of the population, time period and type of diagnosis.

“Cancer can take a long time to develop, sometimes 70 years, and people have different risk factors in different geographic areas,” she said. “Breast cancer diagnoses and other cancer diagnoses increase with an aging population. And unless it is a rare cancer due to a specific cause, most of the time there is no specific cause.”

People move multiple times over a lifetime and exposure may be in one region and diagnosis years later in another region, she said.

The U.S. Geological Survey maps pesticide use and shows Morton in the highest use area for atrazine, chlorothalonil, glyphosate and chlorpyrifos, among others.

The U.S. Environmental Protection Agency has labeled atrazine a possible human carcinogen. The World Health Organization has labeled glyphosate, the active ingredient in Roundup, a probable human carcinogen. The EPA has found chlorothalinol a probable human carcinogen. The agency banned chlorpyrifos for residential use in 2000 and issued a proposal two months ago to revoke all food tolerances.

Recently, EPA revoked registration for Enlist Duo, a new Dow AgroSciences’ herbicide combining glyphosate and 2,4-D. (See Community Word OpEd, September 2014: “Roundup Ready Weeds, Brought to You by Monsanto,” by Herman Brockman.)

Greater toxicity than had been originally recognized was cited as the reason for revoking registration for Enlist Duo. Many scientific studies link 2,4-D with cancer. The new herbicide was legally used in Illinois and 14 other states for just one growing season, summer 2015. How much Enlist Duo was used in Morton and central Illinois is unclear.

Jason Rohr, associate professor of integrative biology at University of South Florida, has done extensive research on atrazine, one of the herbicides used widely in central Illinois on corn. The European Union banned atrazine more than a decade ago because of its possible adverse impact on human health.

“Atrazine may be cancer causing. The EPA calls it a ‘possible carcinogen.’ That can be disconcerting especially with children,” Rohr said.

He cautioned that anything applied aerially can be more prone to drift. Because there is a potential cancer risk with these chemicals, he believes the precautionary principle should apply.

The precautionary principle is widely accepted in other countries as justification for banning a pesticide. It allows a chemical to be banned if there is likely risk but not definitively proven risk. The principle is not widely cited in the United States, and agencies generally call for more study and research to prove a definitive risk rather than banning a chemical due to a likely risk.

Rohr said the benefit of chemicals must be balanced with possible human risk.

“Unfortunately, the EPA makes its decisions and can ignore most of the science. With atrazine, most of the science was ignored with the exception of one study. That is a huge problem and a huge issue concerning possible cancer clusters,” he said.

Rohr reviewed atrazine research and documented multiple errors in the single study EPA used to justify re-licensing the pesticide.

Another problem is the EPA makes decisions based on individual pesticide formulations, Rohr said.

“The EPA looks at ecological risk assessment on a single lone chemical and not the known synergism or antagonism,” he said. ”The number of mixtures are infinite. With 100,000 registered chemicals and thousands of new chemicals coming to the market, evaluating mixtures is difficult.”

Rohr has researched toxicity of atrazine and found it is non linear, meaning a small amount of atrazine can result in a big change in endpoints. That indicates small exposures to atrazine can have a big impact.

“I am not against pesticides or pharmaceuticals. Both are designed to deal with pathogens and pests,” Rohr said. “Chemicals can be useful, but the question is whether the costs outweigh the benefits.”

Rohr’s lab is interested in how a two-fold to four-fold increase in global ag chemical applications will affect human health.

Emily Marquez, a scientist with Pesticide Action Network in California, said the global focus on climate change could impact pesticide use because industrial, chemical agriculture is a major contributor of greenhouse gases.

“The climate may force us to curb our use of chemical pesticides,” she said.

She expects a major report will be released in early 2016 on the synergistic affects of multiple pesticides.

Meanwhile, in early November, Crandall was still working on listing cancer diagnoses in her neighborhood. Less than a month later she was reeling from a diagnosis within her household. Her husband, 57, was diagnosed with cancer. The couple was elated to learn just prior to the start of chemotherapy that the disease had not metastasized to his brain as was earlier suspected.

“I would never have believed I’d be thrilled to hear that. It’s still stage 4, but we’re relieved it’s not in his brain,” she said.

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