Infants born to mothers who lived within 3 km of a hydraulic fracturing (fracking) site had lower birth weight and worse infant health, a study has found. Effects were largest in infants whose mothers lived within 1 km of a fracking site and dissipated at distances greater than 3 km.
“For mothers living within 1 km, we find a 25% increase in the probability of low birth weight (birth weight < 2500 g) and significant declines in average birth weight and in an index of infant health,” the researchers write.
“There are also reductions in infant health for mothers living within 1 to 3 km of a fracking site, but the estimates are about one-third to one-half of the size of those within the 0- to 1-km band. There is little evidence of health effects at further distances, suggesting that health impacts are highly local.”
Janet Currie, PhD, from Princeton University, New Jersey, and the National Bureau of Economic Research, Cambridge, Massachusetts, and colleagues published their findings online December 13 in Science Advances.
The researchers analyzed vital statistics records from more than 1.1 million births that occurred in Pennsylvania during 2004 to 2013. They compared infants of mothers living at increasing 1-km intervals from active fracking sites and infants born both before and after the initiation of fracking at each site, looking at birth weight and an index of infant health outcomes including prematurity (gestation less than 37 weeks) and the presence of any congenital anomalies or other abnormal conditions.
“[O]ur models control for mother fixed effects. Estimates of fracking-independent aspects of maternal health in these models are controlled by comparing the health of fracking-exposed and unexposed siblings born to the same mother,” the researchers note.
Fracking involves forcing water and other chemicals into shale rock to fracture it so that gas or petroleum trapped in the rock can be drawn out. “Whereas much of the previous research has focused on water pollution, several recent studies address the possible effects of chemicals that have been found in both ‘fracturing fluid’ (the fluid that is forced into the shale in order to fracture it) and in air emissions near fractured gas wells,” the authors explain.
The investigators estimate that about 29,000 infants were born in the United States to mothers residing within 1 km of a fracking site between July 2012 and June 2013, or approximately 0.7% of US infants born during that period.
Other research using large administrative databases has consistently found an association between low birth weight and infant mortality, asthma, attention deficit hyperactivity disorder, lower test scores and schooling attainment, lower earnings, and increased rates of social welfare program involvement.
“Hydraulic fracturing provides substantial benefits that are dispersed widely around the entire country — the energy security, the lower energy prices — but ultimately, whether we as a society will have access to those benefits over the long run is going to rest on the shoulders and on the decisions of local communities. And for those local communities, they’re going to be judging whether or not the local benefits exceed the local costs,” coauthor Michael Greenstone, PhD, from the University of Chicago, Illinois, explained in an accompanying video.
Dr Greenstone reports holding more than $10,000 in equities and bonds of various companies, including those within the energy sector. The remaining authors have disclosed no relevant financial relationships.
Sci Adv. Published online December 13, 2017. Full text
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