Benzene is detected in grounds near creek
Three monitoring wells between an oil and gas leak site and Parachute Creek showed “significant groundwater impacts” from benzene, Colorado Department of Natural Resources spokesman Todd Hartman said Thursday.
The wells are about 30 feet from the creek, but numerous samples of creek water, including ones taken by the Colorado Oil and Gas Conservation Commission, show no evidence of contamination, he said in an e-mail update to reporters.
An investigation into the source of an unidentified liquid hydrocarbon found in a pipeline corridor continues, and investigators are working around a valve box for a pipeline carrying natural gas liquids away from Williams’ nearby Parachute Creek Gas Plant.
Some 6,000 gallons of the hydrocarbon and more than 176,000 gallons of tainted groundwater have been removed from the site.
Hartman said the monitoring wells show benzene at levels from 5,800 parts per billion to 18,000 ppb, with the 18,000-ppb reading coming from the well closest to a recovery trench and the area being investigated as the possible leak source. The state health standard for benzene in water is 5 ppb.
“Operators are currently drilling another set of monitoring wells roughly 10 feet from Parachute Creek to further delineate groundwater impacts,” Hartman said.
Investigators believe the creek recharges nearby groundwater, rather than the groundwater feeding the creek, which is helping protect the creek from contamination.
The contamination was first discovered March 8. The site is about four miles northwest of Parachute.