Multiple Sites, Hydro Company, Ontario

Executive Summary

The goal of this project was to conduct environmental screening assessments at multiple transformer-housing electrical distribution sites for environmental due diligence. In particular, the client wished to compare site soils to Ontario Regulation 153/04 site standards to evaluate potential site value. Knowing this information would help the client to form a decision regarding future sale, as well as determine the environmental impacts associated with continued use. A thorough review of background information on these sites revealed the potential for impacted soil, specifically the presence of polychlorinated biphenyls (PCBs) from transformer oils, petroleum hydrocarbons (PHCs), arsenic, and other metals. AEL completed phase two environmental site assessments (ESAs) on each of the sites. Samples from shallow soil indicated to have high metal concentrations, including arsenic, zinc, and lead which were sent for confirmation testing. The field program was able to accurately narrow down contaminated areas for timely and effective site remediation.


This case study occurred at multiple transformer-housing electrical distribution sites across Southern Ontario. Phase two ESAs were conducted at each site to determine the potential value and environmental impacts associated with continued use.


Background information was collected on these sites prior to an initial site visit. The background review included past land use, interviews with site owners and employees, and past soil analysis records. This review uncovered the possibility of contaminated soil, i.e., the sites were potentially impacted by the presence of PCBs from the transformer oils, PHCs, arsenic, and other metals


Phase Two ESAs were completed at each of the sites, involving shallow sampling areas on-site. Sampling sites were chosen to capture any potential movement of contaminants and selected if the area had visible staining or was known to have been the location of a historical spill. Using AEL’s x-ray fluorescence (XRF) and ultra-violet fluorescence (UVF) on-site testing devices, soil samples were screened to limit the number of samples that would need to be sent to a certified laboratory for confirmatory testing. Only those samples with high PHC and metal concentrations, (such as arsenic, zinc, and lead) were sent for confirmation. The use of on-site testing allowed our team to quantify areas that were contaminated.


This project was impactful for both our company and the client. The creative use of testing technology on-site enabled AEL to keep the project under budget by reducing the number of samples sent to the laboratory. As a result of our innovative and custom solution, the client was then able to use detailed information from the assessments to make an informed decision regarding the status of their site – definitely a win-win situation!

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