Introduction

This case study considers a federal property located in Southern Ontario, consisting of multiple industrial piers used for cargo shipping, handling, and storage. AEL was retained to conduct Phase One and Phase Two Environmental Site Assessments (ESAs) on three of the piers in support of an upcoming lease of the property. A Limited Phase One and Phase Two ESA was conducted by others in 2010 at two of the piers and a baseline Phase Two ESA was completed for soil and groundwater conditions at a third pier in 2020.

Executive Summary

The first goal of this project was to identify any data gaps from the Limited Phase One and Phase Two ESAs conducted on two of the piers by others in 2010, determine if environmental conditions of the two piers had changed since 2010, and establish a new baseline for groundwater conditions at the two piers. Since a baseline had previously been established by others in 2020 at the third pier, the second goal of this project was to confirm groundwater conditions and to delineate and further characterize known impacts on the site. The environmental conditions of the site would then be compared to both provincial and federal guidelines to determine the areas and magnitude of contamination.

Problem

The site had been in use for industrial operations since the early 1910s and therefore, had the potential for environmental impacts to be present in soil and groundwater due to the longevity of its operations, including metal fabrication, mechanical maintenance, and historical and current chemical and fuel tank farms. The site was located in an area of industrial land use and was located hydraulically downgradient of neighbouring properties (e.g. manufacturing, rail lines) so there was also a potential for off-site contaminant migration onto the site.

Contaminants of Concern (COCs) identified in soil during the 2020 investigation by others included zinc, Polycyclic Aromatic Hydrocarbons (PAHs), Petroleum Hydrocarbons (PHCs), electrical conductivity, and sodium adsorption ratio. COCs identified in groundwater included PAHs, sodium, and chloride.

Solution

Based on observations made during site reconnaissance, interviews with key personnel, and review of historical records, areas of potential concern (APECs) at the site were identified by AEL in 2023 as part of the Phase One ESA.

To address these environmental concerns, a total of sixteen (16) overburden boreholes were advanced on-site by AEL in 2023, fifteen (15) of which were completed as monitoring wells. Soil and groundwater samples were collected from the newly advanced boreholes/monitoring wells as well as existing wells installed by others. Using comparative analysis of current and historical analytical results as well as AEL’s Geographic Information System (GIS) mapping tools, AEL provided the client with figures to visualize the lateral extent of soil and groundwater contamination on-site, and compared the analytical results to both provincial (Ontario Ministry of the Environment, Conservation and Parks) and federal standards (Canadian Council of Ministers of the Environment).

Results

Due to close communication with the client throughout the duration of the project, the qualifications and experience of the engineers, scientists, and technicians on the AEL team, and clear project goals, the Phase One and Phase Two ESAs were completed and a baseline for soil and groundwater conditions was established for the site. Project managers ensured that client goals and timelines were met and that the project was completed within initial proposed budget. Conclusions were made for the site based on the analytical results and a groundwater monitoring program was recommended in order to characterize the long-term groundwater contaminate levels.