Chemicals released during natural gas extraction may harm reproduction, development

"We examined more than 150 peer-reviewed studies reporting on the effects of chemicals used in UOG operations and found evidence to suggest there is cause for concern for human health," said Nagel. "Further, we found that previous studies suggest that adult and early life exposure to chemicals associated with UOG operations can result in adverse reproductive health and developmental defects in humans."

The "weight of evidence" review of scientific literature and peer-reviewed publications, where studies are examined thoroughly for patterns and links, included international studies that focused on UOG chemicals. Reviewers say these chemicals have been measured in air and water near UOG operations, and have been associated with harmful effects in both animals and humans.

The reviewers concluded that exposure to air and water pollution caused by UOG operations may be linked to health concerns including infertility, miscarriage, impaired fetal growth, birth defects and reduced semen quality.

"There are far fewer human studies than animal studies; however, taken together, the studies did show that humans can be harmed by these chemicals released from fracking," Nagel said. "There is strong evidence of decreased semen quality in men, higher miscarriages in women and increased risk of birth defects in children. There is a striking need for continued research on UOG processes and chemicals and the health outcomes in people."

Nagel, an associate professor of obstetrics, gynecology and women's health in the School of Medicine, and adjunct associate professor of biological sciences in the College of Arts and Science at MU, conducted the review with colleagues from the University of Missouri as well as researchers at the Institute for Health and the Environment and the Center for Environmental Health.