Parachute Creek spill: Day 96

water-soil-vaporThe benzene is back. Williams testing results from June 8-10 showed trace levels of benzene at sampling site 6.

In a June 10 update, Company Response Continuing to Show Progress in Protecting Parachute Creek, Recovering Increasing Volumes of Hydrocarbon Fluids, Williams provides an overview of the remediation and response since March 8. Regarding air sparging, Williams states: “It is a U.S. Environmental Protection Agency-accepted method for effectively reducing concentrations of certain hydrocarbons from water.”

But is the air sparging actually working?

Williams is pretty cagey on that front saying [emphasis added]: “Surface water samples from Parachute Creek indicate that Williams’ remediation efforts to remove benzene from a defined area of Parachute Creek have proven effective.”

After years of listening to the industry, you learn it’s what they don’t say that counts. And what they don’t say is how effective is the air sparging in removing benzene from the groundwater and other areas of the creek near the release site – only “a defined area of Parachute Creek.”

According to the EPA, there advantages and disadvantages to air sparging. Let’s look at the disadvantages:

  • Cannot be used if free product exists (i.e., free product must be removed prior to air sparging).

According to Williams, they continue to extract hydrocarbons from the site. According to the CDPHE, there are hydrocarbons floating on the groundwater near the release site. So that means “free product exists.”

The EPA says: “Air sparging can create groundwater mounding which could potentially cause free product to migrate and contamination to spread.”

  • Cannot be used for treatment of confined aquifers

According to the USGS (page 156), upper and lower Parachute Creek are considered “generally confined aquifers.”

  • Stratified soils may cause air sparging to be ineffective.

According to a 2001 Garfield County Survey of Critical Biological Resources (page 270): “Parachute Creek and its tributaries cut through sedimentary rocks of the Tertiary period, leaving a geologic timeline exposed from cliff top to valley bottom. Going from top to bottom, found exposed are the lower part and Parachute Creek member of the Green River formation; Wasatch formation claystone, mudstone and sandstone; and finally there are unconsolidated gravel and alluvial deposits of the Quaternary period along Parachute Creek.”

In other words, there are stratified soils along Parachute Creek.

Remaining disadvantages:

  • Some interactions among complex chemical, physical, and biological processes are not well understood.
  • Lack of field and laboratory data to support design considerations.
  • Potential for inducing migration of constituents.
  • Requires detailed pilot testing and monitoring to ensure vapor control and limit migration.

Sort of begs the question – with so many variables seemingly against them, why did they go with air sparging?

Not a lot of choices, I guess.

Another concern has plagued me throughout this “air sparging” process. They are using air, or oxygen, to release bubbles of benzene from the water into the air. We’re talking about huge quantities of benzene here, especially in the groundwater. Benzene is heavier than air. So when it rains, the benzene will be in the rain. That’s obvious. But what happens when it doesn’t rain? Do we then wind up with clouds of vaporized benzene?

I’m not very smart but I know that benzene doesn’t just disappear. So I looked to the EPA again for further explanation.

If benzene is released to the atmosphere, it will exist predominantly in the vapor phase. Gas-phase benzene will not be subject to direct photolysis but it will react with photochemically produced hydroxyl radicals with a half-life of 13.4 days calculated using an experimental rate constant for the reaction. The reaction time in polluted atmospheres which contain nitrogen oxides or sulfur dioxide is accelerated with the half-life being reported as 4-6 hours. Products of photooxidation include phenol, nitrophenols, nitrobenzene, formic acid, and peroxyacetyl nitrate.

Benzene is fairly soluble in water and is removed from the atmosphere in rain. The primary routes of exposure are inhalation of contaminated air, especially in areas with high traffic, and in the vicinity of gasoline service stations and consumption of contaminated drinking water.

That doesn’t sound very good. Perhaps that’s why there’s been no mention of air quality monitoring or data on air quality monitoring. When you look from Silt in the direction of Parachute, there’s a permanent blue-gray haze. On some days, the clouds look weird out here. Like wisps of vapor. I wonder what’s up with the air quality.


New! Improved! Updated numbers at CDPHE Parachute Creek

Follow-Up Questions from Journalists and Others; Answers from CDPHE Staff
(If the link doesn’t work click on the CDPHE link, go to the drop down menus and click on Media)

Plume size:
The maximum estimated size of the plume is approximately 1,500 feet long, 308 feet wide and 10 feet thick. This equals an area of approximately 462,000 square feet or 10.6 acres in area; roughly 34,595,000 gallons.

Chemical composition of plume:
Benzene; toluene; ethylbenzene; all three xylenes (M, O and P); cyclohexane; hexane; methylcyclohexane;  isopropylbenzene; acetone; bromoform; heptanes; 1, 2 , 3-trimethylbenzene; 1, 2, 4-trimethylbenzene; 1, 3, 5-trimethylbenzene and tetrachloroethene.

Amount of hydrocarbons extracted as of May 31:
173 barrels or 7,266 gallons

Amount of contaminated water brought up with the hydrocarbons as of May 31:
Approximately 225,000 gallons

Amount of contaminated sand and soil brought up with the above, same time frame:
Approximately 1,500 cubic yards

Groundwater benzene levels in mid-May from selected monitoring wells:
“Williams has draft groundwater results that show a significant decrease in benzene concentration in groundwater down-gradient of the aeration trench. The concentration of benzene in monitoring point TMP-48 dropped from 670 ppb on April 29 to 100 ppb on May 13 to 4 ppb on May 15. The benzene concentration in monitoring point TMP-52 dropped from 360 ppb on April 29 to 170 ppb on May 12 (the last sample collection date for TMP-52). Furthermore, the benzene concentration in the down-gradient air sparge trench and vertical well points efficacy monitoring location, SPT1-4, has decreased from 760 ppb on May 12 to 140 ug/L on May 15, 2013.”

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2 Comments on “Parachute Creek spill: Day 96”

  1. Anita Sherman Says:

    Most county commissioners would immediately work toward protecting the public’s health and safety, during a disaster like this. Not ours. They’re too busy removing all the 1041 regulations in land use codes to make it easier for the industry to access ancillary surface permit approvals, as fast as COGCC can write drilling permits.

    Plus, we have “Big Oil” Bob Rankin, and his wife, lobbying for the industry in House District 57; helping our frackaholic Governor eliminate any oversight over industries that pillage, poison, and pollute for profit with our public funds. Someone needs to explain the word “impact” to our BOCCs, state district representatives, and the Governor, because “impact” means to “the public” – the one’s they’re supposed to represent – not to the industries bottom line profits, or their future campaign coffers and perks.

  2. Anita Sherman Says:

    Nobody cares until its their ox that is being gored. Well folks, our ox is bleeding profusely! Our residents, land, property values, health, safety, and the environment we cherish, are all being sacrificed in the global game of profit for a few off the backs of many. How long will we stand for our rights being removed by industry lobbyists and corporate profiteers under the auspices of “economic development” code for “economic devolvement” on our our dime?

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