Atrazine Weed Killer Linked to Birth Defect: Study

A study by University of Washington (Seattle) researchers indicates that a certain type of birth defect may be linked to the weed killer atrazine.

The study is to be presented at the annual meeting of the Society of Maternal-Fetal Medicine in Chicago, and indicates that atrazine may cause some cases of a birth defect known as gastroschisis, an abdominal wall defect which causes some of an infant’s organs, usually intestines, to develop outside of the body. Syngenta Corporation, which manufactures the herbicide, vehemently reject the study’s findings, despite the fact that it is at least the third such study to link atrazine to birth defects in recent years.

Atrazine (ethylamine and isopropylamine) is a widely used herbicide, with more than 70 million pounds used in agriculture every year in the U.S. The weed killer has been banned by the European Union due to how easily it contaminates waterways and drinking water supplies. It has also been held in suspicion by critics due to its effects on species such as amphibians, and the growing body of evidence that it causes a variety of birth defects.

Researchers looked at 805 cases of children born with gastroschisis between 1987 and 2006, and 3,616 infants born without defects were used as a control group. They found that gastrochisis was more common among infants born to mothers who lived within 15.5 miles of a water body that was found to have high levels of atrazine contamination. They also found that the closer the mother lived to the contaminated water source, the more likely the risk of a birth defect, and that the defects were more prevalent among mothers who conceived in the spring, when atrazine use is at its highest.

Syngenta Corp. released a statement dismissing the link between atrazine and birth defects, claiming that the study results are not credible. “A large number of rigorous scientific animal studies have consistently shown that atrazine does not cause birth defects and does not cause reproductive effects,” the company said in a statement.

However, critics point out that the new study is the latest in a series of studies by different groups that have found links between atrazine use and the rate of birth defects. Even the U.S. Department of Health and Human Services’ Agency for Toxic Substances and Disease Registry indicates that atrazine at high levels causes birth defects in animals.

A 2007 study by Indiana researchers published in the Journal of Pediatric Surgeryfound that gastrochisis and other defects occurred at a higher rate in Indiana in locations where atrazine was heavily used. Another study published in 2009 in Acta Paediatricafound that the risk of nine different types of birth defect nationwide could be linked to atrazine.