A new study of nearly 14,000 U.S. mothers and babies found that even low levels of arsenic in public drinking water — below what’s currently considered “safe” — may increase the risk of premature birth and low birthweight.
The research, published in JAMA Network Open, was funded by the National Institutes of Health’s Environmental influences on Child Health Outcomes Program. It suggests that current federal standards may not fully protect the most vulnerable: developing babies.
“Most U.S. residents rely on public drinking water, and our findings suggest that further reducing arsenic in public water systems could be an important step to improve infant health across the U.S.,” said Anne Nigra, PhD, an environmental health scientist at Columbia University and lead author of the study.
The researchers estimated prenatal arsenic exposure by combining water quality data with the residential histories of participants. They found that mothers exposed to higher levels of arsenic that were still below the federal limit were more likely to have babies who were born preterm, underweight or smaller than expected for their gestational age.
These risks were seen across a wide range of racial and ethnic groups, with babies born to Black parents facing some of the highest rates of early birth and low birthweight.
Arsenic can enter drinking water naturally from rocks and soil, or through contamination from mining, agriculture and other industrial processes. The U.S. Environmental Protection Agency currently sets the arsenic limit in public drinking water at 10 micrograms per liter.
But this study suggests that even lower exposures may pose health risks, especially during pregnancy.