While pesticides are often designed to protect crops, these chemicals can extend their influence beyond their intended targets, affecting biodiversity, water sources and human health. With news of the risks of atrazine circulating around the world, this pesticide is no exception.
The results of a study published May 6 in JAMA Network Open indicate that atrazine—the second-most used herbicide in the United States—has been linked at county levels to infant diagnosis of gastroschisis, a birth defect where, as described by the Cleveland Clinic, 'your baby’s intestines (stomach, large or small intestines) exit their body from a two to five-centimeter hole beside their belly button during fetal development.'
The documented risks of atrazine is not new. The New York Times reported in 2009 that an estimated 33 million Americans had been exposed to atrazine through their tap water, whereas , the Natural Resources Defense Council—also in 2009—found that atrazine has contaminated “all of the watersheds monitored by the EPA,” with 90% of drinking water samples testing positive for this chemical. The New York Times reports that an estimated 33 million Americans have been exposed to atrazine through their tap water, emphasizing its widespread impact.
Despite being banned in the European Union for its persistence in water sources, atrazine continues to be used extensively in the United States and other parts of the world. It is known among researchers for its ties to the disruption of hormonal systems and the adverse impacts on aquatic life, underlining the complex and often negative effects of its continued usage.
Atrazine’s wide reach: Health and environmental repercussions
According to the U.S. Environmental Protection Agency (EPA) - Pesticides Industry Sales and Usage 2008-2012 report, Atrazine is the second-most widely used herbicide in the United States. The U.S. Geological Survey (USGS) reported in 2012 that over 70 million pounds are applied annually. Its use is widespread, particularly on crops like corn, soybeans and sugarcane, as well as on golf courses and residential lawns. The U.S. Department of Agriculture (USDA) notes that over 65 percent of all corn acreage is treated with atrazine.
Further underscoring atrazine's environmental impact, a fact sheet from the Natural Resources Defense Council (NRDC) highlights significant contamination in six U.S. states—namely Iowa, Illinois, Indiana, Minnesota, Nebraska and Ohio. These states experience elevated levels of atrazine in their water sources, posing ongoing risks to ecosystems and public health.
Enduring presence: Atrazine in our ecosystems
Banned in the European Union since 2004 due to its persistence in water sources, atrazine remains, according to the EPA, one of the most common contaminants in U.S. groundwater and public drinking water systems. A USGS report found that atrazine was one of the most frequently detected herbicides in domestic water wells. Moreover, according to the Seattle Times, atrazine is consistently detected in tap water across various regions. Furthermore, the Seattle Times wrote that legal actions have been taken against atrazine’s manufacturers, with 43 water systems in six states — Illinois, Indiana, Iowa, Kansas, Mississippi and Ohio — suing to recover costs for removing the herbicide from drinking water.
Health concerns: Atrazine as an endocrine disruptor
Atrazine is widely recognized as an endocrine disruptor. According to the EPA, "The endocrine system, made up of all the body's different hormones, regulates all biological processes in the body from conception through adulthood and into old age. This includes the development of the brain and nervous system, the growth and function of the reproductive system, as well as the metabolism and blood sugar levels." Major constituents of this system include the female ovaries, male testes and the pituitary, thyroid and adrenal glands.
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Intrauterine growth retardation (IUGR): This condition occurs when babies grow slower than expected in the womb, often leading to smaller size at birth. Beyond immediate size concerns, these infants may face long-term challenges such as developmental delays and an increased risk of chronic conditions like diabetes and heart disease, depending on the severity and timing of the growth restriction.
- Small-for-gestational-age (SGA) births: This condition involves babies born with a weight in the lowest 10th percentile for their gestational age, indicating significant underdevelopment. These infants are at a higher risk of facing developmental challenges and chronic health issues later in life, such as cardiovascular disease and impaired glucose tolerance.
- Spontaneous abortion: Research indicates an increased risk of miscarriages among pregnant women exposed to higher levels of atrazine, particularly in agricultural areas where this chemical is frequently used.
- Reduced semen quality: Exposure to atrazine is associated with lower sperm count and impaired motility, potentially impacting male fertility.
- Increased risk of menstrual irregularities: Atrazine exposure is linked to disruptions in menstrual cycles, potentially causing irregularities such as inconsistent durations or abnormal bleeding patterns.
Case insight: Atrazine's impact on reproductive health
The aforementioned menstrual changes are not only indicators of reproductive issues but are also associated with increased risks of hormonally sensitive diseases such as cancers, osteoporosis, cardiovascular diseases and diabetes.
A specific investigation into these concerns published in Environmental Research examined the effects of atrazine exposure on women's menstrual cycles. Researchers compared data from Illinois and Vermont, finding that in Illinois—where atrazine is extensively used on crops—the concentration of atrazine in public drinking water was twice that of Vermont. Notably, both concentrations were within EPA legal limits.
The findings showed that women in the agricultural areas of Illinois were significantly more likely to experience irregular menstrual cycles—up to five times more than their counterparts in Vermont. Additionally, these women also reported lower estrogen levels, suggesting a disruption in normal hormonal functions.
The study concluded that even atrazine exposure below the established EPA maximum levels could be linked to increased menstrual irregularities and changes in key reproductive hormones.
Case study: Atrazine’s impact on thyroid function and metabolic processes
Furthermore, research by the National Center for Biotechnology Information highlights concerns beyond reproductive health. A particular study examines the implications of atrazine on thyroid function and metabolic processes, revealing:
Thyroid disruption and metabolic changes: In areas with high atrazine usage, such as certain agricultural regions in the Midwest, there is a link between atrazine exposure and altered thyroid hormone levels, which can affect metabolism and overall health.
Widespread health implications: Disrupted thyroid function can lead to a variety of health issues—including changes in energy levels and metabolism—which are crucial for both physical and cognitive development.
Reproductive and developmental effects: The study found that atrazine exposure can lead to several reproductive and developmental issues across different life stages and species, including:
- Delayed development: Exposure during gestation can delay puberty and other developmental milestones.
- Reproductive hormone alterations: Both male and female models show changes in key reproductive hormones, which can affect fertility and reproductive cycles.
- Structural changes in reproductive organs: Animals exposed to atrazine showed altered testicular and ovarian structures, potentially impacting reproductive capabilities.
- Decreased fertility in aquatic life: Anuran and fish models exposed to atrazine experienced reduced spawning events and egg production, alongside hormonal and genetic changes.
Epidemiological Relevance: This study underscores the importance of understanding the reproductive consequences of atrazine exposure, particularly in rural communities where herbicide use is prevalent. Despite ongoing debates over the safe levels of exposure, the continuous widespread use of atrazine in many countries, including the United States, demonstrates the need for investigation into its effects on reproductive health and the environment.
Beyond humans: Atrazine's toll on aquatic and animal life
The effects of atrazine are not limited to humans.
Atrazine's effects reach far beyond human populations, significantly impacting aquatic life and wildlife. Research published in the journal Toxicology has illuminated how even minimal levels of atrazine, commonly found in water bodies, can disrupt the hormonal systems of aquatic species. This disruption is evident in various developmental and reproductive abnormalities observed in fish and amphibians.
To support these findings, research from the University of California, Berkeley, has demonstrated that atrazine exposure can turn male frogs into females, a transformation that occurs at exposure levels as low as 2.5 parts per billion. These feminized males, which develop functional female reproductive organs, are capable of mating and laying viable eggs, profoundly altering natural frog populations.
Concluding reflections: Atrazine's global influence on health and environment
Throughout this exploration of atrazine's use and effects, it becomes apparent that the herbicide's role extends far beyond agricultural utility, influencing both human health and the natural environment significantly. While atrazine remains banned in the European Union due to its enduring presence in water sources and its ecological footprint, its continued use in other parts of the world, including the United States, raises concerns about its safety and environmental compatibility. The diverse studies and findings presented highlight the complex and often hidden consequences of atrazine, suggesting a need for ongoing scrutiny and informed discussion about its role in modern agriculture and environmental management.
