The Impacts of Unconventional Oil and Gas Development on Drinking Water and Children’s Health

Date of Award

Spring 2022

Document Type


Degree Name

Doctor of Philosophy (PhD)


Public Health

First Advisor

Deziel, Nicole


Unconventional oil and gas development (UOGD) combines horizontal drilling with hydraulic fracturing (the pressurized injection of millions of gallons of water and chemicals) to extract fossil fuels such as natural gas from deep rock deposits. UOGD has led to community concern over environmental hazards, such as water contamination, and health hazards, such as cancer. This dissertation examines the impacts of UOGD on communities in the Appalachian Basin from the perspective of three disciplines: exposure science, environmental justice, and epidemiology (background and overall aims summarized in Chapter 1). Chapter 2 investigates whether UOG exposure through household groundwater is captured by spatial surrogates of exposure (models that predict exposure based on proximity to UOG), including a newly developed metric incorporating groundwater flow paths. We compared the different metrics with detection frequencies and concentrations of 64 organic and inorganic chemicals related to UOG in residential groundwater from 255 homes (94 homes from Pennsylvania [PA], 151 homes from Ohio [OH]). Concentrations of organic chemicals were very low overall, with no exceedances of health-based standards. Several inorganic chemicals exceeded health-based standards but were generally unrelated to UOG exposure potential. In PA, several organic chemicals had greater odds of detection with increasing UOG exposure potential; no inorganic chemicals were associated with any metric. Limited associations between metrics and chemicals may indicate that UOG-related water contamination occurs rarely/episodically, more complex metrics may be needed to capture drinking water exposure, and/or spatial metrics in health studies may better reflect exposure to other stressors. Chapter 3 leverages citizen-initiated oil and gas complaint records from PA to examine UOG impacts on drinking water through an environmental justice lens. Using hierarchical Bayesian Poisson and binomial regression, we evaluated associations between county-level socio-economic and demographic factors, oil and gas drilling, and three outcomes in PA during 2004-2016: number of oil and gas complaints filed, the total number positive determinations (i.e., confirmed water supply impairments), and proportion of state investigations yielding a positive determination. We observed associations between the number of complaints filed and several measures of higher socio-economic status, including income and education. Areas with a higher proportion of underrepresented ethnic and racial groups had both fewer positive determinations and were less likely to have a confirmed impairment after investigation. Our results highlight the high degree of community concern over drinking water and suggest potential procedural and environmental inequities in the complaint and determination process. Chapter 4 presents a population and registry-based case-control study of childhood acute lymphoblastic leukemia (ALL). ALL, the most common type of cancer in children, has been linked to multiple environmental exposures, including chemicals used or produced by UOGD. We conducted a registry-based case-control study of 405 children aged 2-7 diagnosed with ALL in PA during 2009-2017, and 2,080 controls matched on year of birth. We used logistic regression to evaluate the association between residential proximity to UOGD and ALL risk over two windows of exposure (pre-conception to one year prior to diagnosis, pre-conception to birth), adjusting for maternal race, socio-economic status, and density of agricultural land around the home. We used inverse distance squared-weighted well counts and IDups, a newly applied water-specific exposure metric, to assess exposure to UOGD. The selection of these metrics was informed by the project in Chapter 2. Children with at least one UOG well within 2 km of their birth residence during the primary window had 1.98 times the odds of developing ALL as compared to those who did not have UOG wells within the same distance (95% confidence interval [CI]: 1.06-3.69). Children with at least one versus no UOG wells within 2 km during the perinatal window had 2.80 times the odds of developing ALL (95% CI: 1.11-7.05). These relationships were slightly attenuated after adjusting for maternal race and socio-economic status (OR: 1.74 [95% CI: 0.93-3.27] and OR: 2.35 [95% CI: 0.93-5.95], respectively). The ORs produced by the water metric were similar in magnitude to the aggregate metric. This large regional study including a novel UOGD metric found UOGD to be a risk factor for childhood ALL. This work adds to mounting evidence of UOGD’s impacts on children’s health, supporting the need to limit UOGD near residences. In conclusion, UOGD has been a persistent public health issue for nearly two decades. This dissertation provides new and important information on the water exposure pathway, the municipal environmental complaint process, and childhood leukemia outcomes. This work may be used to inform the development of environmental regulations and health policies.

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