City officials are hopeful that a chemical treatment will get rid of any poisonous, common chemicals in the soil at the city service garage left over from a 2004 excavation, ending a 20-year-old problem.
Tomorrow, employees from the Columbus-based engineering firm Burgess & Niples will inject chemicals into the ground at the garage, 387 W. State St., to break down a harmful chemical commonly found in oil and paint, said Street Department Director Andy Stone.
The contamination was originally found in 1985. The EPA sued and fined the city, ordering they remove the tetrachloroethylene, also known as PCE, which the city did in 2004. After a series of groundwater tests to make sure the PCE was removed, another hit of PCE was found, requiring the new treatment.
Exposure to high concentrations of PCE can cause dizziness, headaches, sleepiness, confusion, nausea, difficulty in speaking and walking, unconsciousness and death, according to the U.S. Agency for Toxic Substances and Disease Registry's Web site. Mayor Paul Wiehl said that the amount of PCE found at the garage was not enough to cause symptoms.
The total cost for this portion of the project ' which includes treatment, testing, monitoring and other consultant services ' is about $150,000, said Deputy Auditor Ray Hazlett. Hazlett began working on the project in 2000 while he was the city's assistant service safety director. The city will pay $95,000 this year and pay the $55,000 balance over the next two years, he said.
1985: Contamination
The original contamination was caused by years of old oil and solvents seeping into the protected ground around the city's water wells where the garage is located, Stone said.
In that protected zone, the city pays close attention to all possible sources of contamination and tries to minimize and prevent contamination, said Dina Pierce, spokeswoman for the Ohio Environmental Protection Agency.
In 1985, the Ohio EPA fined the city less than $100,000 and sued to get the contamination removed, Hazlett said.
The total cost of removing the contaminants and paying fines before 2002 was $887,000. The contamination from oil and paint spills was first removed in 2004 through the Resource Conservation and Recovery Act (RCRA) closure project, which required digging a hole in the service garage, removing the contaminated soil and filling the hole with clean dirt, Hazlett said. The city has paid Burgess & Niples an additional $421,000 since 2002 to remove the contamination, not including the $150,000 it will receive for the latest treatment.
Monitoring for PCE
After the removal of the contaminated soil in 2004, the city had to construct monitoring wells and go through about two years of ground water testing to make sure the contamination was removed, Pierce said. In 2006, during the last of these eight tests, PCE was found.
The city filed a first draft of a plan with the Ohio EPA to remove the chemical in 2006; the plan was finalized in 2007.
City officials had to decide between using a chemical plan or a biological plan for treating the soil for the leftover contamination. The biological plan would put bacteria into the soil to dissolve the PCE, and the chemical plan would put chemicals into the soil.
Employees for Burgess & Niples found a large buildup of sodium chloride in late 2006 while determining which plan would be best for the site, said Scott Dailey, the Hydrogeology Section director of the firm.
The sodium chloride buildup was the result of road salt seeping into the ground from around the city's salt storage bin,
Hazlett said.
Burgess & Niples determined that the salt might have interrupted natural bacteria dissolving the PCE and would interfere with a biological treatment, Dailey said.
Completing treatment
One benefit to the chemical plan compared to a biological plan is that the chemicals should be broken down and out of the soil in a matter of weeks, Hazlett said. The biological plan would have taken months to be effective, he said.
Hazlett said the road salt, though a concern, was a periphery problem for the RCRA closure project.
We have to do something about the salt bin to make sure no more salt seeps into the ground
but that is a separate issue for the closure project Hazlett said. That can impact water quality but that is not what we are concerned about with the RCRA closure project.
Dailey said that though it might take more than one treatment to remove the residual PCE from the soil, he didn't anticipate it coming back. He added that this was typical and had been figured into the budget for the project.
Once the contamination is removed, the city must to go through two more years of groundwater monitoring to make sure the contamination does not come back, Pierce said. If more contamination is found, it will have to go through the process again. Once the RCRA closure project is complete, the monitoring wells will be filled and capped, Hazlett said. The city has been following all procedures to remove hazardous materials from the site to prevent another contamination, he said.
Wiehl said the city is also looking at ways to keep the salt bin contained or move it out of the wellhead protection area so that it does not add to the buildup of sodium chloride in the wells.
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