Implementation of Remedial Measures to Contain a PCB Spill

A large spill of Polychlorinated Biphenols (PCB\u27s) occurred at Federal Pioneer Limited\u27s Regina Plant in 1976. The City of Regina is underlain by a relatively shallow aquifer which supplies a significant proportion of its drinking water. A remedial measures plan was developed to contain this spill within the boundaries of the site and clean up any contamination which had spread to adjacent property. The remedial measures plan developed involved limiting or reversing the normal downward hydraulic gradient. The three principle measures introduced to accomplish this reversal included the construction of a cutoff wall around the site, installation of a thick surface seal over the entire surface and active dewatering. The performance of these measures was monitored by an extensive network of piezometers and sampling well. Monitoring over the past seven years has produced no evidence of further downward migration of PCB\u27s