Toxins in wastewater and fracking fluids.

• Position: Your Life

In an analysis of more than 1,000 chemicals in fluids used in--and created by--hydraulic fracturing, researchers at the Yale University School of Public Health, New Haven, Conn., found that many of the substances have been linked to reproductive and developmental health problems, and the majority have undetermined toxicity due to insufficient information. Further exposure and epidemiological studies are needed to evaluate potential threats to human health from chemicals found in fracking fluids and wastewater created by fracking, the study maintains.

The research team evaluated available data on chemicals used in fracking, a process that involves drilling into the earth--as deep as two miles--and releasing a high-pressure mixture of water, sand, and chemicals that fracture the rock and release the gas trapped inside. The process creates significant amounts of wastewater and fractures the bedrock, posing a potential threat to surface water and underground aquifers that supply drinking water, note the researchers.

While they lacked definitive information on the toxicity of the majority of the chemicals, the...