Atrazine, an herbicide banned in Europe, is the second-most used weed killer in the US
October 3, 2024
Atrazine, the second most commonly used herbicide after glyphosate (i.e., Roundup), might be lurking in places you’d never expect—like your drinking water.
This human-made herbicide is primarily applied to crops like corn, sugarcane, and sorghum, as well as lawns, golf courses, and municipal areas. It works by disrupting photosynthesis in plants, effectively controlling broadleaf and grassy weeds. However, atrazine is slow to break down in the environment, especially in water. It has a high potential to contaminate groundwater and drinking water as it can be washed from the soil into streams and other bodies of water, especially in agricultural regions. Although it is still widely used in the US, atrazine has been banned in the EU since 2004 due to concerns of exceeding groundwater limits. Atrazine has also been linked to breast cancer, endocrine disruption, and other health issues. Despite these concerns, 60 to 80 million pounds are still applied each year in the US.
Why did the EU ban atrazine?
Similar to their approach to chemical additives in food, the EU also applies the precautionary principle to agricultural product regulation, requiring rigorous evidence to prove a substance is safe before its use is permitted. The EU banned atrazine in 2004 when they found groundwater contamination levels regularly exceeded their regulatory limits. Atrazine’s primary manufacturer, Syngenta, was also unable to prove that these levels were safe or preventable.
In contrast, the US allows chemicals to be used until they are proven harmful, which is why atrazine remains legal despite being a known groundwater contaminant. While the EU set a strict limit of 0.1 µg/L for atrazine in drinking water to prioritize human health and the environment, the US allows up to 3 µg/L, 30 times higher than the EU standard. The EPA continues to review atrazine’s safety, but they still have not imposed a ban despite lawsuits and public health concerns about water contamination and the herbicide’s link to health risks. According to a 2019 Environmental Health study, there are 72 pesticides approved for use in the US but are banned or in the process of being phased out in the EU. The difference in regulatory approaches highlights how Europe prioritizes environmental and public health, while the US utilizes voluntary, industry-initiated cancellation as the primary method of prohibiting pesticides.
How might we be exposed to atrazine?
The EPA sets legal limits on how much pesticide residue is allowed in food and drinking water. Despite these regulations, atrazine remains one of the most commonly detected pesticides in drinking water. People living near agricultural areas, especially farm workers or those involved in applying herbicides, are at greater risk of exposure. Drinking from wells near these areas might also increase the risk of exposure to atrazine. A 2018 report by the Environmental Working Group found that around 30 million Americans in 28 states have some level of atrazine in their drinking water. The report also discovered that drinking water contamination levels exceeded three to seven times more than the legal limit in some locations monitored in the EPA’s Atrazine Monitoring Project, but officials did not inform the residents in those communities about the contamination levels. Levels of this herbicide often peak during the late spring and early summer when farmers spray their crops. However, research has shown that atrazine can remain in soil, groundwater, and surface water for decades.
What are the effects of atrazine on human health?
Breast Cancer Risk
Organizations like the EPA and WHO have said that atrazine is “not likely to be carcinogenic to humans;” however, some studies have found potential links between atrazine and breast cancer. Animal studies suggest that atrazine may disrupt hormone pathways and lead to an increase in mammary tumors. Atrazine has been shown to increase the conversion of testosterone and other androgens into estrogens, especially estradiol, and higher concentrations of estradiol in the body can increase the risk of breast cancer. Exposure to atrazine while taking aromatase inhibitors for treatment of breast cancer could decrease the efficacy of the drug. Moreover, a recent 2023 study found that atrazine promotes the spread of breast cancer tumor cells, particularly in triple-negative breast cancer, which is more aggressive and harder to treat.
Endocrine Disruption and Reproductive and Developmental Issues
Atrazine is widely regarded as an endocrine disruptor, meaning it can interfere with the body’s natural hormonal balance. The endocrine system plays a critical role in controlling biological processes, such as brain development, reproduction, and metabolism. Atrazine has been linked to irregular estrogen levels and menstrual cycles. Researchers compared women living in areas in Illinois where atrazine is heavily used with women living in Vermont where less atrazine is used. They reported that the former group were more likely to report lower estrogen levels and five times more likely to report having irregular menstrual cycles than the latter group.
According to the Agency for Toxic Substances and Disease Registry (ATSDR), one of the primary ways that atrazine can affect a person’s health is “by altering the way that the reproductive system works.” A 2012 study found that pregnant women exposed to atrazine have been linked to an increased risk of giving birth to children with birth defects in their faces and skulls. Other possible birth defects include issues with their hearts, urinary systems, and limbs. There’s also evidence that babies exposed to atrazine in utero may grow more slowly, resulting in smaller head sizes and lower birth weights. Research also indicates a connection between atrazine exposure and preterm delivery, though these findings are complicated because farmers exposed to atrazine are often exposed to other pesticides as well.
General Health Impacts
Atrazine poses significant risks to human health, especially concerning hormonal disruption, reproductive issues, respiratory problems, and potentially cancer. Beyond these risks, long-term exposure to atrazine may also result in other health problems. Studies indicate that it can potentially cause heart, liver, and kidney damage in animals, and researchers suspect similar effects could occur in humans, though this is less certain.
While the EPA has set limits on safe levels of atrazine exposure, there is ongoing debate about whether those limits are truly protective of human health. Some scientists argue that the way chemicals like atrazine are tested underestimates the actual risks to people, especially when it comes to low-dose, long-term exposure.
How can we avoid atrazine?
- Avoid treated areas: Stay away from areas where atrazine is being sprayed, especially fields and lawns.
- Test your water: Ensure your drinking water is free of atrazine or use a filter.
- Steer clear of waterways: Avoid swimming or drinking from rivers, lakes, or streams near farmlands where atrazine has been applied.
- Use protective gear: If you work with atrazine, follow safety instructions and wear proper protection.
- Keep your home clean: Vacuum floors and dust surfaces regularly, especially in the spring and summer months if you live near agricultural areas.
- Avoid lawn chemicals: Skip lawn care products that contain atrazine; use natural alternatives or integrated pest management approaches instead to help control weeds and other pests around your home.
- Buy organic: Choose organic or pesticide-free produce from your local store or farmer’s market to discourage use of dangerous pesticides that can impact our health.
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