Atrazine, Health and Water
The NRDC May 2010 report summarizes scientific information that has emerged since the publication of the initial report and includes more recent monitoring data. http://www.nrdc.org/health/atrazine/
The report revealed “approximately 75 percent of stream water and about 40 percent of all groundwater samples from agricultural areas tested in an extensive U.S. Geological Survey study contained atrazine. In the 2010 report atrazine was found in 80 percent of drinking water samples taken in 153 public water systems. All twenty watersheds sampled in 2007 and 2008 had detectable levels of atrazine, and sixteen had average concentrations above the level that has been shown to harm plants and wildlife.”
According to the CDC, liver, kidney, and heart damage has been observed in animals exposed to atrazine; we do not know if this would also occur in humans. Atrazine has been shown to cause changes in blood hormone levels in animals that affected ovulation and the ability to reproduce. These effects are not expected to occur in humans because of specific biological differences between humans and these types of animals. A few studies are available that suggest that atrazine could affect pregnant women by causing their babies to grow more slowly than normal or by causing them to give birth early. However, the women in these studies were also exposed to other chemicals that may have caused or contributed to these effects. In pregnant animals, exposure to atrazine causes a decrease in fetal growth and birth defects. Exposure to high levels of atrazine during pregnancy caused reduced survival of fetuses. It is unclear whether or at what level of exposure this might occur in humans.
http://www.atsdr.cdc.gov/tfacts153.html#bookmark05
Dr. Tyrone Hayes, an endocrinologist at the University of California at Berkeley, maintains that atrazine is an endocrine disruptor. Dr. Hayes writes that "atrazine inhibits production of testosterone (the male sex hormone) and induces production of estrogen (the female sex hormone), upsetting the balance between these two hormones." The result is a decrease in sperm counts and an increase in impaired fertility. Dr. Hayes states that atrazine also causes immune collapse in amphibians and rodents, most likely due to atrazine-induced increases in corticoids, the hormones, which cause stress responses, as cited in the journals Toxicology, Toxicological Science and Toxicology and Applied Pharmacology.
Research published in the journals Neoplasma and Toxicology Science, reports that atrazine-induced estrogen production is associated with prostate cancer and breast cancer. A 2007 study by researchers at U.C. Berkeley, together with researchers from the Graduate School of Medical Science, Kyusha University, Japan, also concluded there is a correlation between atrazine and reproductive cancers in humans.
Additional studies in animals reported in the journal Toxicology and others found that atrazine can cause miscarriage in laboratory rodents and reduces production of prolactin, a hormone necessary for maternal behavior in mammals. Dr. Hayes writes, "the mechanisms underlying the detrimental effects of atrazine in amphibians and rodents are common to all animals, including humans."
More scientists are questioning whether the government's acceptable levels of the chemical are truly safe, especially for expectant mothers.
"We found that women who conceive their babies in the months between April and July, June, are the most likely to have birth defects," said Dr. Paul Winchester, an Indiana neonatologist with St. Francis Hospital and the Indiana University School of Medicine.
Winchester said research shows that the rate of birth defects correlates with spikes of atrazine in the drinking water during the summer growing season; so much so, it’s been called the June effect.