title: Impact of natural gas extraction on PAH levels in ambient air.
abstract: Natural gas extraction, often referred to as "fracking," has increased rapidly in the U.S. in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. PAH levels were highest when samplers were closest to active wells. Additionally, PAH levels closest to natural gas activity were an order of magnitude higher than levels previously reported in rural areas. Sourcing ratios indicate that PAHs were predominantly petrogenic, suggesting that elevated PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. Closest to active wells, the risk estimated for maximum residential exposure was 2.9 in 10 000, which is above the U.S. EPA's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest. This work suggests that natural gas extraction may be contributing significantly to PAHs in air, at levels that are relevant to human health.
authors: †Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States.
authors: L Blair
authors: LB
authors: Paulik
authors: †Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States.
authors: Carey E
authors: CE
authors: Donald
authors: †Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States.
authors: Brian W
authors: BW
authors: Smith
authors: †Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States.
authors: Lane G
authors: LG
authors: Tidwell
authors: †Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States.
authors: Kevin A
authors: KA
authors: Hobbie
authors: ‡College of Public Health and Human Sciences, Oregon State University, Corvallis, Oregon 97331, United States.
authors: Laurel
authors: L
authors: Kincl
authors: §Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio 45267, United States.
authors: Erin N
authors: EN
authors: Haynes
authors: †Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States.
authors: Kim A
authors: KA
authors: Anderson
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D059206:Natural Gas; D009820:Ohio; D000066388:Oil and Gas Industry / Q000379:methods*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D011634:Public Health; D018570:Risk Assessment / Q000379:methods; D014481:United States
chemical_list: D000393:Air Pollutants; D059206:Natural Gas; D011084:Polycyclic Aromatic Hydrocarbons