From The Grand Junction Daily Sentinel (Dennis Webb):
Weekend tests continue to show the presence of benzene in Parachute Creek downstream of a natural gas liquids leak, but at what the state Department of Natural Resources said are trace amounts. In fact, while the detections were somewhat below the standard of 5 parts per billion for drinking water, they are far under what’s allowable for the creek, agency spokesman Todd Hartman said in a press release. “Since Parachute Creek has not been designated as a drinking water supply by the state Water Quality Control Commission, the actual benzene standard on the creek is 5,300 ppb to protect aquatic life,” he said.
The creek does supply the irrigation system for the town of Parachute and its residents. However, there continue to be no benzene detections at the diversion point for that system, 2.7 miles downstream from where the leak is believed to have occurred.
Thousands of gallons of hydrocarbons leaked in a pipeline corridor near Williams’ gas processing plant up the creek valley. Williams says the source was a faulty pressure gauge on a natural gas liquids pipeline leaving the plant. High benzene levels have been found in groundwater since early in an investigation that started in March, but the first detection of benzene in the creek wasn’t until last Thursday.
On Saturday, benzene was detected 1,800 feet downstream from the pipeline corridor at 3.1 parts per billion, a level slightly higher than previous readings. That detection site is where groundwater is believed to be introducing benzene into the creek. No benzene was found at that location Sunday, and 3 ppb was detected Monday. Saturday and Sunday readings at monitoring points 2,500 and 3,700 feet from the pipeline area ranged from 1.5 to 1.1 ppb, with no results available for Monday.
Work continues on installation of an interceptor trench to strip benzene from groundwater above the creek contamination point, and to remove benzene at two locations in the creek. “Operators have drilled several additional monitoring wells to determine the extent of impacted groundwater. These new monitoring wells are not detecting benzene, an indication that delineation of the affected groundwater continues to improve,” Hartman said.
Also over the weekend, Bob Arrington, a retired engineer in Battlement Mesa and member of Garfield County’s Energy Advisory Board, wrote Gov. John Hickenlooper, urging him to have the Colorado Department of Public Health and Environment rather than Colorado Oil and Gas Conservation Commission lead the leak investigation. Arrington wrote that Williams has struggled with its own leak response, initially even doubting that the burst pressure gauge could leak that much fluid, and he argued that the commission doesn’t have the staff or training to oversee remediation.
From the Glenwood Springs Post Independent (John Colson):
According to a report on Monday from the Colorado Oil and Gas Conservation Commission, benzene was detected during last weekend at the same three sites where it was first found on April 18. The water sampling and analysis is being conducted by personnel working for Williams Midstream, the company that owns a natural gas processing plant and some of the pipelines running underground in the area of the leak. The sampling sites, according to COGCC spokesman Todd Hartman, are at locations 1,800 feet, 2,500 feet and 3,700 feet, respectively, downstream from an above-ground valve set believed to be the source of leaking natural-gas liquids first discovered on March 8.
According to Hartman’s report on Monday, the concentration of benzene at the closest point to the valve set, 1,800 feet away, on Saturday was three parts benzene per billion parts water. In the subsequent two days, according to Hartman’s report, no benzene was detected at that location on Sunday, and 3 ppb was reported by Williams on Monday.
Analysis of samples taken at the more distant sites showed the concentration of benzene decreasing at each site and decreasing as samples were taken farther from the supposed source of the leak. At the 2,500-foot distance, according to results supplied to the COGCC by Williams, analysis detected 1.5 ppb on Saturday, and 1.4 ppb on Sunday. Results from Monday’s sampling were not available on Monday. At the site furthest from the leak, 3,700 feet downstream, samples tested out at 1.1 ppb on Saturday, and 1.2 ppb on Sunday. No results were available from Monday’s sampling…
Hartman’s report stated that Williams is working to build an “interceptor trench to strip benzene from the ground water prior to the point where it’s believed ground water enters the stream,” along with other efforts to clear the toxic chemical from the water.
From the Associated Press via KGWN.tv:
Aerators have been set up on Parachute Creek to flush out cancer-causing benzene that has been detected downstream from a hydrocarbon spill in western Colorado. Williams energy company crews also expanded their pumping of hydrocarbons from trenches dug along the creek.
“It is of great concern to see” benzene in #COriver trib #ParachuteCreek.Well, yeah, that seems reasonable… gjsentinel.com/news/articles/…
— Doug Pflugh (@dpflugh_ej) April 22, 2013