Well here is an update on the situation. I'm keeping an eye on this case and hopefully raising awareness in the town about getting screened for cancer.
What's up on the G-P mill site
Of the Advocate
Activity on the former Georgia Pacific mill site has definitely picked up this summer, since the city's Redevelopment Agency approved an interim remedial action plan that will allow bioremediation of petroleum contaminated soil. That sounds complicated, but it's not.
Essentially, by adding water and air to soil, Mother Nature has the ability to eat oil, grease and diesel fuel in dirt, releasing more microbes, water and carbon dioxide back into the soil and water.
Several people have asked me what has been taking place on the site in recent weeks, and I had the opportunity to tour the site and talk with Judy Nedoff, senior scientist with Arcadis, G-P's environmental consulting agency.
Those who worked at the mill likely remember the mobile equipment shop, fueling area and compressor house, where trucks and other equipment were repaired and refueled there. Over the years, a significant amount of petroleum products leaked or spilled from trucks, equipment and underground pipes and soaked into the surrounding dirt. According to Nedoff, the mobile equipment shop also featured a bay, like an in-ground swimming pool, that allowed mechanics to stand while working on the underside of trucks and equipment. That also leaked a lot of oil, grease and diesel fuel into the soil.
Subcontracted crews, overseen by Arcadis staff, removed the foundations of the building in June and began digging below. The level of diesel and oil in the soil was obvious to nearby businesses as wind carried the smell over the city. I could smell it myself in some areas, especially where excavated dirt was being prepared for bioremediation.
Nedoff said crews dug downward and outward from the building until they reached clean dirt. The process left a rather large "puddle" as groundwater flowed into the hole.
Landfarming made easy
The landfarm, as officials are calling the area being used for bioremediation, covers most of the paved area east of the planer building. Nedoff said that the bottom foot of the landfarm is sand, dredged from the Noyo Harbor, which prevents equipment from scraping the pavement as it tills the dirt.
I asked her if Arcadis had tested the sand for pollutants. She said Arcadis had not, but the sand came with a clean bill of health from the Environmental Protection Agency and the Army Corps of Engineers. For the next four months, a large tiller will be turning the 18-inch-thick layer of dirt and adding water.
"Throughout the summer, the population of microbes will grow quite a bit, and breakdown the hydrocarbons," said Nedoff.
She said the soils will be tested repeatedly and it is expected that the process should fully clean the soil of petroleum pollutants by October. The dirt will then go back in the holes it came from.
The landfarm contains about half of the petroleum-impacted dirt on the site. The rest will be dug up and placed on the landfarm next year.
Air monitors
At almost all times when I was on the site, I could see a tanker truck spraying water on all roads used by the dump trucks and other equipment. Nedoff said that keeps the dust down. Tilling the soil also created some dust. Nedoff said moveable air monitoring stations are placed downwind of the work site. If the monitors pick up a certain level of dust, work is stopped. Work is resumed after additional dust control measures are taken and levels drop, she said later by phone.
Groundwater treatment
Biosparging is a scientific term for something that looks very similar to the bubbler in a fish aquarium. Since petroleum hydrocarbons soaked down far enough to reach groundwater, it was determined they needed to be removed as soon as possible.
She said it was necessary to clean those areas first, because petroleum contamination threatened to infect groundwater below the site. The most "upstream" underground water is being treated first, to cut off the spread of contamination as it slowly moves west toward the ocean. It also ensures that previously-treated areas won't be re-contaminated.
The process will not use purified oxygen or filtered air, but just the same coastal air we all breathe, pushed into the water with a compressor.
The bubbling will both add oxygen to the groundwater and mix added nutrients to allow microbes that are already there to thrive, said Nedoff. When soils are put back into the holes, an oxygen-releasing compound will be added, so that underground bioremediation will continue after the project is done.
According to Arcadis reports, the process should take about three months. Several groundwater wells have been placed between the excavation area and the ocean, and scientists will continue to test water samples to ensure the treatment is successful.
Nedoff said this type of bioremediation is a common way to treat petroleum-impacted areas and that petroleum levels have been "about what we expected."
"We're just taking advantage of what happens naturally," she said.
She said about four truckloads of dirt and hazardous metals were taken from the site's electrical shop to Kettleman Hills waste facility in Kings County in early June. Mixed with dirt were shavings of lead and copper, Nedoff said, which are considered hazardous and have to be disposed of at a licensed handling facility.
More information can be found on the state Department of Toxic Control Website by clicking the envirostor link on the left and entering Fort Bragg in the search field. More specific information about current projects can be found online at fortbraggmillsite.com and the City of Fort Bragg's Website also has a link to mill site-related information on its Website, ci.fort-bragg.com.ca.us/.
More photos of the site can be seen by clicking the DotPhoto link on our Website, www.advocate-news.com.
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1 comment:
Interesting story. It's always scary to think that so many of us are exposed to such a multitude of chemicals and harmful substances by seemingly innocuous operations and activities.
One can't help but wonder...
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