YSI contaminants still linger
- Published: September 11, 2008
Several vigilant groups of environmentalists received satisfactory news last week when they met with the team leading the bioremediation of contaminants spilled at the YSI campus on Brannum Lane in the early 1990s. According to data collected over a period of three years, due to remediation measures, contaminant levels on and around the facility dropped off significantly in the first two years, but have now begun to creep back up. YSI is preparing this month to begin a second round of soil and groundwater treatment to get rid of pollutants in the source area and will continue to monitor areas that no longer show contamination.
YSI’s remediation consulting firm, BHE Environmental, Inc., presented an update report of the cleanup process to the Source Water Protection Committee, a group of Yellow Springs residents who were charged with overseeing the cleanup process. The source water committee, including Suzanne Patterson, Chris Mucher and Dawn Falleur, has retained its own firm, Bennett & Williams Environmental Consulting, to help evaluate the plans. The source water committee used the Green Environmental Coalition as fiscal agent to receive a technical assistance grant in 2002 from YSI when the Ohio Environmental Protection Agency issued an administrative consent order to YSI to clean up the contamination.
After drilling 36 monitoring wells on the campus and as far out as East Enon Road and east of Dollar General to determine the extent of the contamination plume, YSI implemented its initial bioremediation plan in 2005. The process involved injecting CAP18 (a vegetable oil-based product) into the areas of concern to create a soil environment where microbes could grow and metabolize toxic chlorinated hydrocarbons that had leached into the soil and water.
The contaminated areas are both near the Brannum East building located east of Brannum Lane and abutting Xenia Avenue. In the current dock area, situated west of and below Brannum East, the primary pollutants are 1,1,1-trichloroethane and 1,1-dichloroethene. In the former dock area, situated just north of Brannum East, the primary pollutants are carbon tetra chloride and chloroform.
According to data from the wells, the remediation process did shrink the size of the plume and reduce contaminants in the ground water from 2005 to 2007. But since mid-2007, the breakdown of certain contaminants appears to be slowing. For instance, according to BHE’s report, 1,1,1-trichloroethane in the current dock area went from 600 parts per billion in 2006 to 76 ppb in 2007, but increased again to 133 ppb in February 2008. Similar data was found for carbon tetrachloride and other volatile organic compounds in the former dock area, indicating insufficient levels of CAP18 to break down the contaminants completely.
According to YSI’s Social Responsibility Director Lisa Abel, the data indicated that the contaminants had not yet leached entirely out of the soil.
“From 2005 to 2008 we did see a decline in the chemicals we were trying to get rid of, but it leveled off and then started to go back up — it was an indication that the chemicals bound to the soil were still there and were coming back into the ground water,” she said. “It was also an indication that the oils from the CAP18 had been used up.”
YSI’s remediation team has proposed to inject 6,000 additional pounds of a reformulated version of CAP18 (CAP18-ME) into the contaminated areas to promote the continued breakdown of pollutants in the soil and water in the source areas.
While the source areas of contamination are being treated, 1,1-dichloroethene was found outside the source area in the residential well at 1793 Xenia Avenue (a property just north of and owned by YSI), and YSI plans to conduct further tests to determine whether there could possibly be an additional source area for the contaminant on the YSI campus. If a source area is found, it will be treated like the others, according to a report from YSI.
Following the addition of CAP18-ME, YSI will continue to test 11 of its monitoring wells quarterly, as well as some secondary outlying wells, to track treatment results, Abel said.
At the request of the Source Water Protection Committee, Bennett & Williams reviewed YSI’s proposal for additional remediation and reported three concerns regarding the integrity of testing for contaminant levels, sampling of all the wells on and around YSI campus, and establishing a plan for additional monitoring after remediation has ceased, to ensure that no further action is necessary. The consultant also encouraged the continued monitoring for vinyl chloride, a potential toxic break-down product of the current contaminants.
According to Abel, testing in the outer limits of the plume show that the plume has shrunk to within the source area on the YSI campus, and only two of the contaminated wells show pollutants that are above the safety limits. All the soil and water contamination currently occurs 10 to 20 feet below the ground surface, and because residents in the immediate area are using Village water, there is no pathway for human contamination, she said.
“The plume has been shrinking back quite a bit, so now we’re dealing with the source area primarily, and we’ll continue to monitor the down gradient wells [outside the source area],” Abel said.
In its report, Bennett & Williams stated, “Probably the most important question that was raised in the beginning and is still not answered is, “When is the site clean?”
The timing of the new remediation plans depends on approval from the Ohio EPA to inject CAP18-ME, followed by additional testing by YSI to locate any additional remediation needs. According to Abel, this second wave of treatment is expected to take approximately two years, after which the Ohio EPA has asked to see four consecutive quarters of acceptable contamination levels for all the wells that are still being monitored.
According to Bennett & Williams, while it could take longer than originally anticipated for contaminants to leach out of the soil for biodegration, the treatment process that YSI is engaging in is a reasonable bioremediation approach.
Falleur, from the Source Water Protection Committee, also has confidence in YSI’s approach so far, though she is surprised at how long the process is taking.
“Lisa presented what was going on, and she said Bennett & Williams was very thorough,” Falleur said. “It’s not horrible, but we thought it would be done by now. This could go on until 2011.”
The most recent reports from YSI, Bennett & Williams, and the Ohio EPA, as well as questions, comment and response documents, will be available in the Yellow Springs Community Library sometime this fall between October and November.
“We all hoped we’d only need to do this once and be done. We saw great improvement from the first injection, but it was not enough,” Abel said. “That’s okay, we’ve learned a lot, and we got some good results from the first trial, and everyone feels good about that.”