The Importance of Pre-Remediation Delineation
Property owners in Ontario that go through the process of conducting a Phase 1 and/or 2 Environmental Site Assessment (ESA), may be faced with the overwhelming conclusion that their property is not in compliance with the Ministry of the Environment, Conservation and Parks (MECP) Site Condition Standards. These conclusions are made if chemical exceedances are found within the soil, ground water, and/or sediment on your property during the Phase 2 ESA. As a property owner, finding contamination can be devasting as it may reduce your property value, increase your environmental risk, or delay your land development plan because in many cases your next steps are to remove the contamination.
Traditionally, contamination found on your property may have had its boundaries assumed based on the findings of a Phase 1 ESA or worse, may have been left in place to break down or dilute over time, exposing the owner to potential off-Site migration and expensive future remediation costs. To better understand the extent and migration pathways of the contamination found on your property, a Supplementary Phase 2 ESA may be recommended. A Supplementary Phase 2 ESA also known as delineation, entails the drilling of additional boreholes and/or installation of additional ground water monitoring wells in the vicinity of the formerly identified impacted areas in an attempt to isolate boundaries both horizontally and vertically. Identifying more accurate horizontal boundaries for the contamination is performed by sampling similar depth profiles radially around the former impacted boreholes to reduce the distance of unknown soil and/or ground water quality between impacted and non-impacted boreholes. Similarly, to identify the extent to which the contamination has migrated vertically within the soil and/or ground water column, samples can be collected outside the known contamination depth profile at the upper and lower limits. Adequately quantifying the 3-dimensional profile of the contamination plume prior to conducting remedial activities through a Supplementary Phase 2 ESA can provide many benefits to the property owner with both time and cost savings.
Conducting a Supplementary Phase 2 ESA prior to initiating remedial activities on your property can provide many economical benefits to the property owner. The most common remedial solution in removing contamination from the upper fill layer on a property is known as a “dig and dump” where the soils can be excavated to the known boundaries of the contaminated area, transported off-Site and disposed at a licensed landfill facility. Typically, the excavation pit will require to be back-filled with fill materials of known quality to meet your property’s MECP Site Condition Standards. This can be one of the most cost-effective methods of remediating impacted surficial soils yet, far exceeds the previous costs of the Phase 1 and 2 ESAs. By conducting a Supplementary Phase 2 ESA, the property owner can better define the contamination area by reducing the assumed impacted area to only remediate what needs to be remediated.
Properly performing a Supplementary Phase 2 ESA can also reduce the time of the site remediation process by reducing the trial and error process of testing soil remedial boundaries or assuming ground water treatment quantities. Overall, a Supplementary Phase 2 ESA may be an additional step in the ESA process but can reduce the entire duration and cost of Site remediation. Property owners should be aware of this option to prevent overinflated remedial activities and lengthy sampling events.