AEL Environment
Unit 3, 1705 Argentia Road, Mississauga, Ontario, Canada

Risk Assessment

Manage Your Site's Unique Challenges, Protect Human Health and the Environment, and Reduce Cost

In some instances, completing a property remediation to generic standards becomes practically impossible, either due to prohibitive costs or practical challenges that cannot be overcome. When this becomes apparent on a project during the assessment or remedial phase, a further option to overcome these barriers and allow development to proceed is available in risk assessment. 

By following the approach used in the MOECC generic criteria, an owner can develop site-specific criteria that is equally protective of human health and the environment and is accepted by the MOECC for use at the site. It also avails the owner of all the protections under the generic approach including meeting the appropriate standard of care, and indemnification from the MOECC upon acknowledgement of a risk-based RSC.

About Environmental, Groundwater, and Soil Risk Assessments

Risk assessment calculates the probability that a hazard (like environmental contamination in the soil or groundwater) will cause harm to humans, plants, wildlife and the natural environment under specific conditions of exposure to a contaminant. The purpose of a risk assessment is to develop property-specific standards that will protect the uses that are being proposed for the property, so it is important to consider the client’s end use goals when choosing risk assessment options.

The Groundwater & Soil Risk Assessment Process

The QP initially prepares information on the property and how people would be exposed to contaminants. Human health risk assessment (HHRA) is the evaluation of the risk of adverse health effects to humans caused by exposure to a contaminant at a given property. Ecological risk assessment (ERA) evaluates the risk that adverse ecological effects may occur as a result of exposure to contaminant(s). Many contaminants may be present together in different media such as food, air, water, soil and dust. These contaminants reach receptors through multiple exposure pathways such as ingestion, dermal contact in inhalation.

This information is submitted and reviewed by the Ministry of Environment (MOE) using a Pre-Submission Form (PSF). This review allows the ministry to comment on the scope and approach of the RA. This helps the property owner to decide the best way to proceed with completing the RA and if any additional investigations are required prior to undertaking the RA. A PSF can save the owner time and money!

An owner can submit a Modified Generic Risk Assessment (MGRA) or Tier 2 RA. The MOE has developed an “Approved Model” which allows users to modify some of the generic assumptions used in creating the standards. The MOE’s review time for a MGRA is approximately eight weeks. This approach is intended to be timelier and more cost effective. The “Appoved Model can result in less stringent standards while maintaining the same target level of protection as a generic standard.

The Approved Model can be used in either a MGRA (Tier 2 RA) or a full (Tier 3) RA. For an RA to be considered an MGRA, the RA must have used only the Approved Model and used only RM measures as stipulated in the model. For a full Tier 3 RA, the approval times range from 4 months to 18 months (excluding external delays). There is also a Streamlined Tier 3 RA. This is a hybrid approach which incorporates many aspects of the Modified Generic RA but deviates from the MGRA in areas such as exposure limits and the derivation of property-specific standards other than those produced by the Approved Model. The use of this approach is acceptable by the MOE but its application should be reviewed with the MOE’s Streamlined Risk Assessment Coordinator prior to submission. This approach has a timeline typically longer than a MGRA but much shorter than a full Tier 3 RA.

The MOE will review the completed RA and will decide to accept or reject the risk assessment. If the risk assessment is not accepted, the property owner can revised the risk assessment and resubmit it or choose to remediate the site to generic standards.

RA Risk Management Measures

Risk assessment can often lead to recommendations to utilize risk management to provide protection to human health and the environment. In this situation, risk management measures must be maintained to achieve the same target level of risk as the site conditions standards. Risk management is a process to control or reduce the level of risk estimated by the risk assessment. Risk management integrates the results from the other components of risk assessment with information about technical resources, socio-economic factors and control options in order to reach decisions about the best way to manage a property.

If risk management measures are required, the ministry may issue a certificate of property use (CPU) to ensure that over time the property owner maintains the measures. Local stakeholders may be consulted when considering risk management measures. An MOE order may also be required so that the CPU is registered on the title to the property.