Agricultural compounds in drinking water linked to birth defects

One of the most unappreciated luxuries of modern life may be the fact that clean water comes out of the taps on demand, but as the recent lead crisis in Flint, Michigan, reminds us, we shouldn’t take that for granted. However, water need not look or smell wrong to be dangerous, especially to the most vulnerable: embryos in their first few weeks of development.

That’s why Jean D. Brender, R.N., Ph.D., professor emeritus at the Texas A&M Health Science Center School of Public Health, has spent years studying the effects chemicals in water can have on developing fetuses. Based on her work and extensive review of the published literature, she’s found that three contaminants (nitrates, atrazine and arsenic) in drinking water have been associated with birth defects.

“We know what’s in our public water supply, but many people are on private wells for their drinking water, and those wells aren’t routinely tested,” Brender said. Her work and other studies have shown that women who drink primarily from these private sources, especially in rural areas, may be most at risk.

Brender’s previous work, funded in part by the National Institutes of Health (NIH) and published in Environmental Health Perspectives, found that women who had babies with birth defects—such as limb deficiencies, cleft palate and cleft lip—were almost two times more likely than other new mothers (those having babies without major birth defects) to have ingested water with large amounts of nitrate, a component in many common synthetic fertilizers, during their pregnancies. Now, she has looked at various studies of other compounds and found that atrazine and arsenic may also be linked to birth defects. The findings of her and co-author Peter Weyer, Ph.D., of the University of Iowa, were recently published in Current Environmental Health Reports.

Atrazine is commonly used to grow corn, and it can then leech into the soil and then into drinking water sources. Arsenic is also a problem in drinking water in Texas, even in municipal systems, but that may be due to naturally occurring sources in the bedrock, rather than agricultural use. Still, it may cause problems, especially because the current “safe” levels of arsenic have been computed for cancer risk, not reproductive harms.

Another unclear aspect of the science, as it stands now, is what happens when two or more of these substances get into the water. “One thing that needs to be studied more fully is the effects of mixtures of these chemicals,” Brender said. For example, nitrate and atrazine often occur together as contaminants in drinking water, and these two chemicals can react together to form a compound called N-nitrosoatrazine. In a recent study of animal models exposed to N-nitrosoatrazine, investigators at the University of Nebraska Medical Center observed numerous birth defects, including heart, neural tube, abdominal, eye and other defects.

That’s why Brender cautions women to find out what’s in their water even before becoming pregnant.

“People who live in rural areas and who use private wells need to have their well water tested, particularly if they are thinking about becoming pregnant,” Brender said. “If testing shows the water does exceed acceptable limits for any of these chemicals, they would want to use an alternative source of water.” Women whose drinking water source is from a private well should consult with their local health department to determine a water testing facility or call the federal Safe Drinking Water Hotline at 800-426-4791.

Those who are on city water can easily find reports of contaminants. Suppliers are required to periodically test their water for these compounds and must make the results available. Women who are still worried can filter their water or buy bottled.

“When we were working on our NIH-funded study of nitrate and birth defects, we were missing information about nitrate levels in the bottled water,” Brender said. “We traveled all over Iowa and Texas, to the grocery stores within a few miles of where the women in the study lived, and collected samples to test,” Brender said. “We found, without exception, that the nitrate levels in the bottled water were well below the Environmental Protection Agency (EPA) standard for drinking water, so we are fairly confident that nitrate levels in bottled water are low.”