This Common Weed Killer Is Also A Dog Killer

Cute dog breed Bulldog relaxing in the grass

The weed killer, atrazine, is so prevalent in the environment that if you or your pets haven’t been exposed to it, you’re the exception, not the rule.


Atrazine is the second most commonly used herbicide in the country, after Roundup. It’s found extensively in the Midwest and the South, where it’s used to control weeds in the regions’ corn, sorghum and sugarcane fields and other agricultural lands. Atrazine is manufactured by Syngenta US. The company states, “Atrazine increases crop yields, reduces soil erosion and improves wildlife habitats,” when faulting the recent EPA document.

Drinking water

Odds are that you’re drinking some atrazine when you quaff down a glass of tap water, or when you’re cooking. The United States Department of Agriculture found atrazine residue in approximately 88 percent of water samples tested in 2012. These are trace amounts, and nowhere near the levels considered toxic for human consumption, in most areas. Still, there is little doubt that atrazine has contaminated major water supplies throughout the country. The EPA notes atrazine is “resistant to natural degradation in water.”

In certain places, atrazine in the water supply is found above the level of one part per billion, the amount at which its presence reduces algae. That’s a major food source for fish and small aquatic animals.

The highest levels of atrazine in water sources were in Nebraska, Missouri, Ohio and Indiana, according to the National Resources Defense Council. It was in Indiana that the highest numbers of possible atrazine-related birth defects were recorded.

Keep in mind that these samples came from treated, public water supplies. Untreated water samples almost certainly contain higher levels of the atrazine.

Canines and atrazine

If your dog is exposed to atrazine, skin issues may develop. Signs of atrazine exposure are often subtle. Your dog — or other animals, including livestock — may become irritable and experience personality changes. Your dog might suffer appetite loss, difficulty walking, rapid breathing and low body temperature. If your pet shows any of these signs, take it to the vet. There is no antidote, but supportive care should help combat side effects.

Most pets exposed to atrazine don’t show any obvious symptoms. It’s what the herbicide may do to their bodies in the long-term that is the major concern. What it does to animals might also occur in people.

Carcinogenic potential

For animals and people, atrazine is bad news. A government panel found “suggestive evidence” that atrazine may contribute to the development of certain forms of cancer, including:

  • Thyroid
  • Ovarian
  • Non-Hodgkin’s lymphoma
  • Hairy cell leukemia

Birth defects

Researchers at Texas A&M and Iowa State University linked high amounts of atrazine in drinking water to birth defects, specifically abdominal defects and gastroschisis. The latter affects the abdominal wall, and the newborn’s intestines stick out of the body from a hole near the navel. In some cases, the liver or stomach may also protrude. Immediate surgery is necessary to save the child’s life, but ongoing issues with food digestion and nutrient absorption are common.

For pregnant women, atrazine exposure during the last trimester of pregnancy appears to pose the greatest risk. Additional reproductive issues linked to atrazine include:

  • Male infertility
  • Miscarriage
  • Low birth weight

Banned in Europe

Europe banned the use of Atrazine 12 years ago, based on the herbicide’s likely ability to harm the environment, especially contamination of drinking water supplies. Even in a best-case scenario, there’s no possibility of that happening in the US until 2017, and whether there’s any chance of a ban depends on who is sitting in the Oval Office and which parties control the legislative branch next year.  

If you’re concerned about the risks of atrazine to your pet and family, the EPA’s public comment period is open until August 6, 2016. When submitting comments, either online or via snail mail, use the docket identification number EPA-HQ-OPP-2015-0794.

—Jane Meggitt

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