Benzene spikes don’t concern health officials
Post Independent Staff
PARACHUTE CREEK — State health officials remain optimistic that recent spikes in the toxic compound benzene in the creek is not a health concern for local residents.
“We just believe that it’s part of the natural fluctuations,” said Dave Walker, an Environmental Protection Specialist with the Colorado Department of Public Health and Environment (CDPHE), on Friday.
A sample of the creek water taken on July 11 showed benzene at concentrations of 5.5 parts per billion (ppb), and a test conducted four days later, on July 15, showed that the benzene levels had jumped to 9.2 ppb, more than twice the typical readings from the creek that have been reported by the CDPHE over the past couple of months.
Those concentrations are higher than the state’s standard for drinking water, which is 5 ppb. But Parachute Creek is not classified as drinking water, and the contamination standard applied to the creek is approximately 5,000 ppb.
The increased benzene levels were not reported immediately because the industry and the state have agreed to ship samples to a Front Range laboratory instead of having them tested at a mobile laboratory on site, at the expense of Williams Midstream, according to Walker.
That means, he said, there can be a delay of a couple of days between taking the samples from the creek and getting results to the public.
Crews have been working to clean up a spill that was first reported in March, along a network of pipelines at a site near a Williams Midstream natural gas processing plant, about four miles upstream from the Town of Parachute.
The spill, blamed on a mechanical failure, released more than 10,000 gallons of hydrocarbon liquids from a broken valve, contaminating soil and groundwater in a plume approximately 1,675 feet long, 435 feet wide and 10 feet thick, stretching downstream.
When the spill was revealed, Williams and its subsidiary, Bargath LLC, along with state and federal agencies, scrambled to protect Parachute Creek, which flows into the Colorado River. Benzene was first detected in the creek itself in early May, at a monitoring point known as CS6, the only point where the plume is believed to come in contact with the bottom of the stream.
About 130 tons per day of contaminated soil, stockpiled as the companies worked to find and clean up the spill, is being shipped from the spill site to a treatment site in Utah. CDPHE expects all of the soil to be removed by the end of July.
To clear up the creek, Williams has been installing special “air sparging” equipment at points along the waterway, which injects air into the groundwater in order to strip the water of chemical pollutants.
A new sparging system went into operation on July 13 near the CS6 monitoring well, which is where the benzene has been detected in the creek, Walker said. He said the elevated levels of benzene found at CS6 may have been due to a shift in the travel pattern of the plume, as the flowing mass tried to get around the vapor extraction equipment that already was in place.
He predicted that the recent high levels should drop back to the pre-July 15 levels.
The state has reported that a new sparging system is to be added to the existing facilities, but further upstream, closer to the leak site, in hopes of cleaning up the contamination of the soils and groundwater at the site itself and perhaps lessening the concentration of benzene and other hydrocarbon contaminants.
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