Atrazine — Second Most Common Used Herbicide in U.S.

US Herbicide

Story at-a-glance -

  • The Environmental Protection Agency’s (EPA) risk assessment for atrazine found the chemical could cause reproductive harm to mammals, fish and birds, with the level of concern already surpassed by nearly 200-fold using real-world scenarios for mammals
  • Atrazine’s primary use is to control weeds in corn crops that cover much of the Midwest; Monsanto even recommends farmers mix atrazine with Roundup to control glyphosate-resistant weeds
  • Atrazine is the most commonly detected pesticide in U.S. waters, so I recommend filtering your tap water to remove it

By Dr. Mercola

Glyphosate, the active ingredient in Monsanto's Roundup herbicide, has been making headlines recently not only because it's the most used agricultural chemical in history, but also because the International Agency for Research on Cancer (IARC) determined it is a probable carcinogen.

Lurking somewhat below the radar, however, is atrazine, the second most commonly used herbicide in the U.S. Though it hasn't yet achieved the notoriety of glyphosate, it is equally disserving.

Atrazine's primary use is to control weeds in corn crops that cover much of the Midwest. This might sound strange, since that's what glyphosate is used for too. Most of the corn crops are genetically engineered (GE) to survive Roundup for that very purpose.

But because so much Roundup has been used, weeds are growing resistant. Bring in atrazine, a known hormone-disrupting chemical manufactured by Syngenta AG. It's already been banned in Europe, but in the U.S. about 70 million pounds are used every year.1

In fact (and quite ironically), Monsanto recommends farmers mix atrazine with Roundup to control glyphosate-resistant weeds.2

They may soon have to come up with a new recommendation, however, as a risk assessment released by the Environmental Protection Agency (EPA) may lead to tighter regulatory limits and possibly an eventual ban.

EPA: Atrazine Dangerous to Animals and Fish

The EPA's risk assessment for atrazine found the chemical could cause reproductive harm to mammals, fish and birds, with the level of concern already surpassed by nearly 200-fold using real-world scenarios for mammals.

For fish and birds, atrazine exceeded the level of concern by 62- and 22-fold, respectively.3

An EPA "level of concern" describes the threshold above which a chemical may be expected to cause harm. The chemical, which has previously been linked to birth defects and cancer, was banned in the European Union for its potential to contaminate water and ecosystems.

The EPA specifically cited research by Tyrone Hayes, Ph.D., an integrative biologist at the University of California, Berkeley, which found atrazine may be chemically castrating male frogs, essentially turning them into female frogs.

Former Syngenta Researcher Found Atrazine Causes Hermaphroditism in Frogs

Hayes used to conduct research for Novartis, which eventually became Syngenta, but he resigned his contractor position after the company refused to allow him to publish the results of studies they had funded.

After resigning, he obtained independent funding to repeat the research, which was subsequently published and found that atrazine causes hermaphroditism in frogs. Since then, he's built an educational website dedicated to informing the public about atrazine.4

Syngenta attempted to discredit Hayes after the damaging research was released, but now he's received well-deserved vindication. Mother Jones further reported:5

"As for amphibians like frogs, the report found 'potential for chronic risk' from atrazine at real-world exposure levels — not rapid death, like what a roach might experience after a blast of Raid, but long-term, subtle damage, like an impeded ability to reproduce.

… 'The science has been settled for a long time,' Hayes [said] … 'Now it's politics and economics.'"

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Environmental Groups Urged the EPA to Take Action Against Atrazine Years Ago

The EPA's risk assessment is up for public comment and is not expected to be finalized until 2017.

The pesticide and agriculture industries are already up in arms over the findings, with the Iowa Corn Growers Association (ICGA) noting that if the report is finalized, it would "effectively ban the product from most uses."6

Such a move is long overdue, as environmental groups have been pushing the EPA to take action against atrazine for years.

The National Resources Defense Council (NRDC) put out a report in 2009 that showed widespread atrazine contamination in drinking water, posing a "dangerous problem" that was not communicated to the people most at risk. They continued:7

"Some scientists are concerned about exposure for children and pregnant women, as small doses could impact development of the brain and reproductive organs.

Research has also raised concerns about atrazine's 'synergistic' affects, showing potential for the chemical having a multiplier affect to increase toxic effects of other chemical co-contaminants in the environment.

… Under the Safe Drinking Water Act (SDWA), EPA has determined that an annual average of no more than 3 parts per billion (ppb) of atrazine may be present in drinking water.

One of the chief findings of the report was that this reliance on a 'running annual average' allows levels of atrazine in drinking water to peak at extremely high concentrations.

Given the pesticide's limited economic value and the fact that safer agricultural methods can be substituted to achieve similar results, NRDC recommends phasing out the use of atrazine, more effective atrazine monitoring, and the adoption of farming techniques that can help minimize the use of atrazine to prevent it from running into waterways."

What Are Atrazine's Health Effects in Humans?

If atrazine is toxic to mammals, birds and fish, what health risks does it pose to humans? The EPA plans to release a human health assessment for atrazine sometime in 2016. However, independent scientists have previously cited evidence that the chemical may be carcinogenic, noting:8,9

"In summary, the Panel concluded that the cancers for which there is suggestive evidence of carcinogenic potential include: ovarian cancer, non-Hodgkin's lymphoma, hairy-cell leukemia and thyroid cancer."

In addition, research published in Current Environmental Health Reports found higher concentrations of atrazine in drinking water have been associated with birth defects, including abdominal defects, gastroschisis (in which the baby's intestines stick outside of the baby's body), and others.

Past research has also linked atrazine-contaminated drinking water with hormonal irregularities. Women who drank water with even low levels of the chemical were more likely to have irregular menstrual cycles and low estrogen levels.10

Atrazine in drinking water has also been linked to premature birth11 and low birth weight in newborns.12

The results are especially concerning given atrazine's prevalence. Atrazine has been found in a majority of water samples taken from Illinois, Nebraska, Iowa and Minnesota, and the U.S. Department of Agriculture (USDA) found atrazine in 94 percent of drinking-water samples tested.13

Syngenta Paid $105 Million for Contaminating Midwest Drinking Water Supplies

It's no secret that atrazine has infiltrated U.S. drinking water. Syngenta agreed to pay $105 million to settle a class-action lawsuit in which water utilities in the U.S. Midwest claimed atrazine had contaminated their drinking water.14

Nearly 2,000 water utilities were part of the settlement. As part of the settlement agreement, Syngenta was allowed to plea "no liability" and actually went on record saying, "no one ever has or ever could be exposed to enough atrazine in water to affect their health."15

They may soon be eating their words. Even the state of Wisconsin, where the chemical's use has been banned in certain areas, states:

" … [T]he Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) has taken action to reduce atrazine use to prevent any more groundwater contamination … Based on animal feeding studies, atrazine has been classified as a 'possible' cancer-causing agent.

Long-term exposure may increase a women's risk of breast cancer … Animal feeding studies indicate that exposure to high levels of atrazine over a long period of time causes tremors and heart and liver damage."

How to Protect Yourself From Atrazine and Other Pesticide Exposures

According to data from the U.S. Centers for Disease Control and Prevention (CDC), more than 75 percent of the U.S. population has detectable levels of pesticides in their urine, and unless you're a farmer, your diet is one of the most likely routes of exposure, along with your drinking water.16

Eating organic is one of the best ways to lower your overall pesticide burden. The largest study of its kind found that people who "often or always" ate organic food had about 65 percent lower levels of pesticide residues compared to those who ate the least amount of organic produce.17

Research also found that organic produce had, on average, 180 times lower pesticide content than conventional produce.18 That being said, not everyone has access to a wide variety of organic produce, and it can sometimes be costlier than buying conventional.

Remember that eating vegetables, even if they're not organic, is better than not eating vegetables at all. However, when you need to prioritize, refer to the Dirty Dozen list and buy organic as much as possible when you’re choosing foods that are listed as the most-contaminated. If you shop at farmer's markets, which I strongly recommend, you can also ask the farmer directly about pesticide usage.

It's possible to find produce that is not certified organic that may still have a lower pesticide burden than typical conventional produce depending on the farmer. So if you can't find organic produce, look for a local farmer who has eliminated pesticide use (or uses such chemicals only minimally).

Filtering Your Tap Water Is Important to Reduce Atrazine Exposure

Atrazine is the most commonly detected pesticide in U.S. waters, so I recommend filtering your tap water — both for drinking and bathing. If you can only afford to do one, filtering your bathing water may be more important, as your skin absorbs contaminants. To remove atrazine, make sure the filter is certified to remove it. As noted by the (NRDC):19

"Consumers should make sure that the filter they choose is certified by NSF International to meet American National Standards Institute (ANSI) Standard 53 for VOC (volatile organic compounds) reduction and therefore capable of significantly reducing many health-related contaminants, including atrazine and other pesticides."

Finally, if you know you have been exposed to pesticides, eat fermented foods like kimchi. The lactic acid bacteria formed during the fermentation of kimchi may help your body break down pesticides. In addition, there is some evidence that the antioxidant lycopene, found in watermelon, tomatoes, red bell peppers and more, may protect against some of atrazine's toxic effects.20