PITTSBURGH (AP) -- Pennsylvania's Marcellus Shale gas drillers are recycling more and more of their briny, chemical-laden wastewater -- in most cases complying with a state request to keep pollutants from being discharged into rivers that supply drinking water.
But there are still significant quantities of potentially dangerous salty bromides getting into rivers and streams. And experts now wonder if a regulatory loophole is at fault -- or if shale gas drillers are only part of the problem.
Bromides combine with chlorine used in water treatment to produce trihalomethanes, (tri-halo-METH-anes), which can cause cancer if ingested over a long time.
The Associated Press analysis of state data released Friday shows about 97 percent of shale wastewater was either recycled, sent to deep-injection wells, or to a treatment plant that doesn't discharge into waterways.