Article posted Tuesday, December 30, 2014 3:53pm

Wastewater from oil and gas production is contaminating surface waters and sediments in western Pennsylvania, even after the wastewater is processed through a water treatment plant. Wastewater from gas wells in the Marcellus Shale formation was treated this way and samples of water were analyzed upstream and downstream of the plant. Researchers found that although treatment lowered the levels of barium and radium in wastewater, the radioactivity level of radium in downstream river sediments was 200 times greater than background levels. This is well above the regulatory limit. The researchers warned that radioactivity levels may accumulate in wastewater disposal areas, creating a radiation hazard, and that new technologies are needed to reduce contamination in treated wastewater. (Environ. Sci. Technol., Mar. 7, 2013; Nature, Dec. 12, 2013)