Strategy key to close-out of challenging site in San Francisco Bay area | 22nd Feb 2011
A strong working relationship between WSP and the San Francisco Regional Water Quality Control Board (RWQCB) has secured closure of site investigation and remedial action at a 20-acre site in Pittsburg, CA. The site has high levels of TCE in groundwater but we have been able to prove that it poses no threat to human health in the area, and in-conjunction with our interpretation of a recent new regulatory policy we have secured a No Further Action declaration for our client at this site.
Our client manufactures heavy duty items for both consumer and industrial purposes. The issue they assigned to us in the San Francisco Bay area was complex involving the presence of elevated levels of chlorinated solvents at one of their former manufacturing facilities. The primary chemical of concern, a degreaser called trichloroethene (TCE), had migrated from the industrial area into a neighbourhood consisting of both residential and industrial uses. Although the contaminant concentrations of TCE had been decreasing, they still were present in groundwater at a concentration greater than 50 times the default standard. Because the potential cost to cleanup the contaminated groundwater was prohibitive, our client was faced with the possibility of being unable to feasibly close the site.
At WSP, we developed a strategy to follow a relatively new regulatory policy issued by the San Francisco Regional Water Quality Control Board. The policy requires responsible parties to demonstrate adequate characterization of contamination, control and mitigation of contaminant sources, and that no current or potential for adverse risks or effects exists. As a result of WSP forging a strong working relationship with the Board, we were able to successfully implement the strategy and obtain a No Further Action determination for the site.
WSP spent 18 months working with the Board to develop a justifiable rationale to close out the project. This involved preparing a comprehensive report articulating all previous investigations and remedial measures and presenting results of further groundwater investigations that took place in 2009. These studies indicate a decrease in TCE concentrations in groundwater. The only potential migration of contaminated groundwater from the original site is to an adjacent railroad yard and our sampling proved there was no existing or potential migration beyond the yard. We also noted the significance of a deed restriction put in place when an adjacent parcel of land was developed for residential use. This prohibited groundwater use or extraction on this particular site. With all these facts we thoroughly evaluated the site conditions and documented in a report to the Board that no risk to human health or the environment is posed by the site.
Only three sites in California have previously been granted closure with TCE concentrations exceeding the contaminant levels at this site. WSP was able to successfully work with the regulators to prove that in this particular case the site conditions pose no risk, and we are delighted that the Board has issued a No Further Action Letter, thereby, alleviating our client from any future expenditures.
For further information please contact Rick Freudenberger on 1 408 453 6100 or at rick.freudenberger@wspgroup.com