During the cleanup of PCBs in the Pottersburg Creek area in the 1980s, a multi-agency committee determined that soils with levels of PCBs less than 20 ppm could be placed safely along the floodplain and capped by a 15 cm layer of soil and grass. Soils in the area with higher concentrations were excavated and secured in vaults for eventual PCB destruction.
The multi agency committee consisted of representatives from the City of London, Environment Canada, the National Research Council, the community and the Ministry of the Environment (MOE). The criteria developed were and remain a safe and effective PCB mitigation process.
As part of its ongoing due diligence, the City and the MOE continue to monitor the area where PCB contaminated soils were capped. Historic sampling results (after clean-up and until 2002) and recent sampling (2008, 2009 and 2010) have been within the expected ppm range. In fact, more than 50 testing samples were taken last year and all have been in the expected range of 20 ppm.
Late last week preliminary results of sampling carried out in preparation for the design of some bank remediation works were received. One soil sample result from a test site beside an eroded area of the creek was found to have levels of PCBs of approximately 112 ppm.
The Middlesex London Health Unit, based on the preliminary test results and its 2009 PCB blood survey, concluded there is no public health concern.
As a precaution and in keeping with normal site work protocol, the City has fenced the area to conduct further sampling to confirm the earlier results and determine the size of the impacted area. Those results should be available within two weeks.
The area is owned by The London Assembly Hall of the Jehovah Witnesses and is located west of Second Ave. north of Dundas Street. The church has been informed of our retesting efforts.
Ongoing management and care of the watershed will always be required to ensure the situation continuously improves and that any identified issues are addressed. It is important for the community to understand that data show the overall situation is much improved along Pottersburg Creek and that the City, Health Unit and MOE will continue to do their due diligence and take action as needed.
