Weed Killer Ingredient Found in U.S. Urine Samples

Here's how we're being exposed to glyphosate, why it matters, and how to steer clear of it in our food, gardens and lawns.

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A recent study suggests many Americans have a common weedkiller in their bodies linked to cancer and problems in reproductive health. That’s glyphosate, an active ingredient in many herbicides commonly used on residential and commercial lawns. One popular brand: Roundup.

“It’s probably the No. 1 selling herbicide for the last 20-plus years,” says Mark Highland, president of Organic Mechanics Soil Company. “Many don’t want to disparage a tool that has been widely used for so long. But glyphosate is on the way out.”

Curiously, the primary way glyphosate enters in our bodies isn’t from lawn care. It’s in our food, says Alexis Temkin, Ph.D. and a toxicologist for health nonprofit The Environmental Working Group (EWG).

“Testing by EWG and other groups has found glyphosate in many different types of food sources, especially oats and oat-based products commonly consumed by children,” she says.

Glyphosate Weed Killer Study Findings

The report, released by the U.S. Centers for Disease Control and Prevention (CDC), found more than 80 percent of urine samples in children and adults contained glyphosate. Other studies reported similar findings, demonstrating how widespread it is in our environment, and that children are often more exposed than adults.

The prevalence of glyphosate in our bodies has steadily increased since the 1990s, when Monsanto introduced genetically engineered crops designed to be sprayed with Roundup. Today more than 200 million pounds of glyphosate are used on U.S. crops like wheat, oats, spinach and almonds, plus genetically engineered corn and soybeans.

The U.S. Environmental Protection Agency (EPA), along with Monsanto and its parent company Bayer, maintain glyphosate products are safe. However, many scientists disagree, including researchers at the World Health Organization’s International Agency for Research on Cancer. They classified it as a probable human carcinogen in 2015.

In 2019 the U.S. Agency for Toxic Substances and Disease Registry also released an analysis suggesting the connection between glyphosate and non-Hodgkin lymphoma. Bayer has announced that it will stop selling glyphosate for residential lawn and garden care in 2023.

How to Minimize Your Exposure to Glyphosate

Avoiding glyphosate products will help limit your risk. But because our largest exposure comes from our food, that’s also a vital part to address, Temkin says. One EWG study found glyphosate in more than 90 percent of non-organic hummus and chickpea samples.

“One way to reduce exposure to glyphosate can be choosing organic options for foods where glyphosate is found, like oats, hummus and other beans,” says Temkin. “EWG testing has shown organic products have much lower or non-detectable levels of glyphosate.”

Alternatives To Glyphosate Weed Killer

Our understanding of specific chemicals continues to evolve. What we think is safe today may turn out to be harmful with additional study. So the safest bet is avoiding synthetic chemicals altogether. Here are a few ways:

  • Manual weeding: “The best alternative to using any herbicide is two gloved hands and a good weeding tool,” says Highland. “My favorite weeding tool is a hori-hori style knife.”
  • DIY weed killer: “White vinegar is a great DIY weedkiller on its own, and mixing it with dish soap makes it even more successful at penetrating leaves and stems,” says Rupa Mehta, an outdoor home expert at Angi. Add two tablespoons of liquid dish soap to a gallon jug of white vinegar, shake, then spray it onto the leaves and stems of the weeds. “Be careful not to spray your wanted plants,” she says. “Your weeds should wither in about 48 hours.”

Pro tip: Avoid homemade recipes with salts. “At high doses, salt or a cocktail mixture of salts plus soap can be even more toxic to our environment than glyphosate alone,” says Highland.

  • Flame weeding. “Literally a small flamethrower to burn weeds to a crisp,” says Highland. “Personal Protective Equipment (PPE) required!” Also, take precautions not to start a wildfire or home fire; keep ample water nearby and never attempt it on a windy day. Also wear leather gloves, work boots, a mask, eye protection and long pants. And don’t burn poison ivy or similar noxious plants.
  • Talk to a local pro: They’ll know the tricks of tackling specific weeds and can answer questions about product ingredients and potential health risks. “They’ll also be a great resource for making sure you’re killing off weeds while allowing your grass and desired plants to continue to thrive,” says Mehta.

If you’d rather purchase an alternative weedkiller at the store, inspect labels carefully for warnings or environmental hazards. “Specifically, keep an eye out for an EPA registration number to ensure it’s a registered product,” says Mehta. She also recommends staying clear of any solutions that contain the following ingredients, which can be toxic to animals:

  • Glyphosate;
  • Pyridine;
  • Dinitroaniline;
  • Disulfoton;
  • Sodium arsenite;
  • Metaldehyde;
  • Ammonium sulfamate;
  • Borax;
  • Benzimidazole;
  • Chlorophenoxy herbicides (2,4-Dichlorophenoxyacetic acid; 2,4-D);
  • Benzoic acid herbicides.

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Karuna Eberl
Karuna writes about wildlife, nature, history and travel for magazines, newspapers and websites including National Geographic, National Parks, Discovery Channel, Atlas Obscura and the High Country News. She's also produced a number of independent films and directed the documentary The Guerrero Project, about the search for a sunken slave ship. She and her husband, Steve, wrote an award-winning guidebook to the Florida Keys and are currently completely renovating an abandoned house in a ghost town. She holds a B.A. in journalism and geology from the University of Montana. Member of OWAA, SATW.