Scientists have investigated a link between drilling well density and health care use by zip code from the years 2007 to 2011 in three northeastern Pennsylvania counties, and found those with higher fracking density also had higher rates of hospitalization.
The study of unconventional gas and oil drilling (hydraulic fracturing) comes from the University of Pennsylvania and Columbia University and is published in the open access journal PLoS ONE.
The researchers examined databases of over 198,000 hospitalizations and analyzed the top 25 specific medical categories for these, as defined by the Pennsylvania Health Cost Containment Council.
The team then associated these categories with residents’ proximity to active wells.
Senior author Dr. Reynold Panettieri, a professor of medicine and deputy director of the Center of Excellence in Environmental Toxicology (CEET) at Penn’s Perelman School of Medicine, says:
“This study captured the collective response of residents to hydraulic fracturing in zip codes within the counties with higher well densities.” He adds:
“At this point, we suspect that residents are exposed to many toxicants, noise and social stressors due to hydraulic fracturing near their homes and this may add to the increased number of hospitalizations.
This study represents one of the most comprehensive to date to link health effects with hydraulic fracturing.”
Two of the counties examined – Bradford and Susquehanna – had a significant increase in drilling activity during the study period. Wayne, used as a control county, had no drilling activity since a ban on drilling because of proximity to the Delaware River watershed.
While the study found associations with hospitalization, this link is not proof that hydraulic fracturing is causally related to any health problems.
The results suggest that cardiology and neurologic inpatient prevalence rates – expressed as the proportion of a population hospitalized among every 100 residents each year – were significantly higher in areas closer to active wells. Density was defined by the number of active wells per square kilometer.
Compared with Wayne County, where there is no drilling, there was a 27% rise in cardiology inpatient prevalence rates for the 18 zip codes that had a well density greater than 0.79 wells per square kilometer.
Hospitalizations for skin conditions, cancer and urologic problems were also linked to living near active wells.
The study concludes:
“We posit that larger numbers of active hydraulic fracturing wells would increase inpatient prevalence rates over time due in part to increases in potential toxicant exposure and stress responses in residents evoked by increases in the hydraulic fracturing work force and diesel engine use.”
The authors say the hospitalization rises over the relatively short time observed mean the economic benefits of fracking should factor in any health care costs.
The authors caution that their findings demand more work to determine any effects of specific, individual toxicants or combinations that may increase hospitalization rates.
The rise in cardiology hospitalizations, for example, could be related to diesel exhaust and fine particulate matter but personal monitoring studies will be needed to measure exposure to specific toxicants.
Dr. Panettieri summarizes: “Our findings provide important clues to design epidemiological studies to associate specific toxicant exposures with health end-points.”
The study was supported by the US National Institute of Environmental Health Sciences.