Increased exposure to lead-contaminated drinking water in Washington, DC, is a possible cause for a sharp increase in fetal deaths and somewhat lower birth rates in the region in 2000 to 2003 and again from 2007 to 2009, according to a new study published online by the journal Environmental Science and Technology.
The study attributes the spike in fetal deaths from 2001-2003 to a switch in drinking water disinfectant from chlorine to chloramine, which caused an unintended release of lead from plumbing material into drinking water.
DC fetal death rates declined from 9.7 to 7.9 per thousand births in the years immediately before chloramine was used in the water and when lead levels were low, but increased as much as 63 percent by 2001. Fetal death rates did not drop below the levels prior to the use of chloramine until public health officials intervened in 2004 and limited the exposure of pregnant women to water with high levels of lead.
The second spike, from 2007 to 2009, was associated with partially replacing lead plumbing transporting water from the main into homes. It was later discovered that partial replacements increase lead in water levels for a period of time and the associated incidence of childhood lead poisoning. Fetal death rates rose by as much as 42 percent in 2007-2008 when the risk of high lead levels in water were the highest for homes that had partial lead service line replacements, according to the article.
The study compared rates in DC with those of Baltimore City, which has a number of regional similarities but had relatively low water lead levels during the study period.
"Through the comparisons with Baltimore City and the rest of the US, we see that adverse pregnancy events were anomalously high in DC when there was high risk of lead in water exposure," explains study author Marc Edwards, professor of Civil and Environmental Engineering at Virginia Tech. Edwards received funding from the Public Health Law Research program of the Robert Wood Johnson Foundation to complete this study.
The paper also revisits a case from 1987 in which workers in on certain floors of an office building in Rosslyn, Va., experienced a 100 percent miscarriage rate at the time of office renovations. The study determined that very high levels of lead could have been in the water, due to renovations causing short-term spikes in levels of water lead.
Exposure to lead was previously been associated with still birth and high rates of infant mortality, and recent research had indicated that every 5 micrograms per deciliter increase in maternal blood lead levels doubled miscarriage rates.
"Tests of the water showed lead levels in DC homes that were 10, 100 or even 1,000 times over the Environmental Protection Agency action level of 15 ppb," says Edwards. "Consuming even a small amount of that water exceeded the lead dose used in 1900s lead-based abortion pills, creating an expectation of adverse pregnancy outcomes."
The study reinforces the basis for health concerns and warnings associated with lead spikes arising from disturbing old lead plumbing. The research notes that there currently no requirements to notify or protect consumers as to health risks from voluntary partial lead service replacements.
When these replacements are unavoidable, Edwards recommends that health service providers clearly notify consumers of the health risks, and provide lead filters or advise use of bottled water.