Scientists are concerned that toxic mix of endocrine disrupting chemicals could pose more harm to humans than exposure to single chemical alone.

Currently in the USA, over 15 million people reside within a mile of unconventional oil and gas extraction sites that utilize a combination of directional drilling and 'fracking' methods to release natural gas contained within the underlying rock. There is growing concern over the health impacts resulting from exposure to chemicals used during these operations, particularly the effect on human development, but until now scientific studies have been inconclusive.

Now, after reviewing current studies on the health effects linked to unconventional oil and gas operations, a team of researchers led by scientists from the University of Missouri have concluded that these activities have the potential to release a complex mix of endocrine disrupting chemicals into the environment, which in combination with each other have the potential to form a toxic cocktail that could be detrimental to both human reproduction and human development.

Fracking Wastewater Pond - credit: flickr.com/photos/arimoore/

The researchers reviewed over 100 peer-reviewed scientific research studies, examining them closely for links and patterns associated with chemicals used in unconventional oil and gas extraction and human development. They conclude that available studies suggest that exposure to these chemicals results in adverse health conditions, but point out that there is a lack of evidence-based studies related to unconventional oil and gas extraction processes.

"We recommend a process to examine the total endocrine disrupting activity from exposure to the mixtures of chemicals used in and resulting from these operations in addition to examining the effects of each chemical on its own," said co-author, Susan Nagel, an associate professor of obstetrics, gynecology and women's health in the School of Medicine at the University of Missouri. "Studying these complex mixtures of chemicals released during fracking is necessary since the chemical identities used in oil and natural gas operations are not always known. Additionally, there is strong evidence of endocrine disrupting chemical mixtures having additive effects, so this approach also may be more sensitive."

Chemicals used during hydrofracking operations to extract natural gas from underground rock can penetrate fissures in the rock or leach through soil and contaminate underground aquifers -- a vital source of freshwater that supplies drinking water for much of the nation. Furthermore, tainted wastewater can also seep through soils to contaminate groundwater sources, or chemicals can contaminate other freshwater sources, such as rivers and streams, during the disposal process if not treated or disposed of appropriately.

If you are one of the 15 million US residents who live near an unconventional oil and gas site, you may want to consider taking extra precautions to remove any toxic industrial chemicals that may be present in your drinking water. A good quality home water filter that is capable of removing industrial chemicals and other toxins offers a sound investment for your long-term health.

Journal Reference: Christopher D. Kassotis, Donald E. Tillitt, Chung-Ho Lin, Jane A. Mcelroy, and Susan C. Nagel. Endocrine-Disrupting Chemicals and Oil and Natural Gas Operations: Potential Environmental Contamination and Recommendations to Assess Complex Environmental Mixtures. Environmental Health Perspectives, 2015 DOI: 10.1289/ehp.1409535