Hydraulic fracturing or “fracking” wells used to procure natural gas produce large amounts of wastewater, which may contain toxic and radioactive compounds. The wastewater per well, ranging from 2 million to14 million liters, is most commonly injected underground where it has the potential to contaminate water supplies used by people and animals.
A new study in Ohio led by researchers at the Yale School of Public Health finds that these oil and gas waste disposal wells are disproportionately located in communities that have lower per capita incomes and lower population density compared to areas without these waste sites, after controlling for other sociodemographic and geographic variables.
Specifically, the odds of a census block group containing an injection well were 16 percent lower for each $10,000 increase in median income, and 97 percent lower per 1,000 people/mi2 increase. Race, age, education and voter turnout were not significant predictors of injection well presence.
“Our findings suggest a pattern of environmental inequity and are consistent with findings from a Texas study reporting a greater proportion of disposal wells in high poverty block groups,” said assistant professor Dr. Nicole Deziel, the paper’s senior author. “Further research is needed to determine whether residents in census blocks with injection wells face increased risk of chemical exposures or adverse health outcomes.”
The findings are published in the journal Environmental Health Perspectives.
Potential pathways of water contamination include spills at the surface during the transport or initial injection of the wastewater or underground leakage. In the United States, there is a significant history of disproportionate placement of hazardous facilities, particularly waste disposal facilities, in communities with a lower average income and a higher proportion of minority residents; however, little is known about the characteristics of populations living near injection wells used in fracking.
Dr. Deziel said her team wanted to determine if oil and gas injection wells were disproportionately located in communities with lower income and other social factors as they could be proxies for limited financial resources to fund better medical care, legal representation, and relocation costs, or limited access to resources to advocate on one’s behalf, among other barriers. The sociodemographic variables included were median household income, percentage of the population that is White, population density, educational level, median age and voter turnout.
Other authors on the study include Ms. Genevieve Silva and Dr. Joshua Warren.
This research was funded in part by a National Priority Research Project under the U.S. Environmental Protection Agency Grant Assistant Agreement No. CR839249.