Certain biomarkers for industrial chemicals also showed up at higher levels in people who live closer to fracking wells, including 4-methylhippuric acid, which is produced when the body breaks down xylenes, and phenylglyoxylic acid, which is produced when the body breaks down ethylbenzene and styrene. Exposure to xylenes, ethylbenzene and styrene are linked to skin, eye, and respiratory issues, gastrointestinal illness, organ damage with chronic exposure, hormone dis- ruption, and increased risk of cancer.
Some of these biomarkers have sources other than these chemicals. For example, trans, trans-muconic acid is a biomarker for benzene, but eating sorbic acid (a common food preservative) also produces trans, trans-muconic acid. Hippuric acid is a biomarker for toluene, which can damage the nervous system or kidneys, but it's also formed when the body processes tea, wine, and certain fruit juices.
As a result, we expect to see a certain amount of these compounds in everyone —which is why, throughout this series, we compare our data against the levels of these breakdown products in the average American using U.S. Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey.
Data analysis is ongoing, but so far we have not found chemicals in our air or water samples that were more likely to show up among people who live near fracking sites than they are among people who live further away. As additional data analyses become available through our scientific advisors and partners, we will continue to publish updates on our findings.
Parent compounds screened for in urine samples.
For reference, here are comprehensive lists of the compounds we looked for in air, water, and urine samples:
View full list
to view compounds
Have you been impacted by fracking? We want to hear from you. Fill out our fracking impact survey and we'll be in touch.
We'd like to thank the following people for helping EHN setup our study and/or
understand our data:
• Chung-Ho Lin - Research Associate
Professor at the Center for Agroforestry
at University of Missouri
• Susan Nagel - Associate Professor,
University of Missouri School of
Medicine
• Shu-Yu Hsu - Graduate Research
Assistant School of Natural Resources,
University of Missouri
• Mohamed Mohamed Bayati - M.Sc
Civil - Environmental Engineering Ph.D.
Candidate - Civil & Environmental
Engineering, University of Missouri
• Joan Casey - Assistant Professor,
Columbia University Mailman School of
Public Health
• Krish Bhatt - Research Coordinator at
the Spatial Epidemiology Lab,
Columbia University
• Jamie Ponmattam - Master of Public
Health candidate at Columbia University
• James Fabisiak - Associate Professor,
Environmental and Occupational Health
at the University of Pittsburgh Graduate
School of Public Health, Director,
Center of Healthy Environments and
Communities, Environmental and
Occupational Health
• Dave Brown - founder, public health
toxicologist, director of public health
toxicology for environmental and human
health, Southwest Pennsylvania
Environmental Health Project
• Alison Steele - Executive Director, Southwest
Pennsylvania Environmental Health Project
• Raina Rippel - former Executive Director,
Southwest Pennsylvania Environmental
Health Project
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