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Ontario risk assessments currently in the system at any stage, including re-submissions, may require significant revisions, based on a new Technical Update released by the Ministry of the Environment (MOE) in March.

Instrinsik Environmental makes an excellent point about an unadvertised consequence of O. Reg. 511/09. The new Site Condition Standards (SCS) for contaminated sites are dated July 27, 2009, but are scheduled to come into effect July 1, 2011.  In some ways, however, they are already in force. Intrinsik says:

When developing these generic SCS, the MOE established a number of risk-based values intended to protect sensitive receptors from exposure via specific exposure pathways, termed “component values”.  The numerically lowest value from all of the component values was used by the MOE to establish the generic SCS.  Since the component values provide a benchmark to screen potential risk for specific exposure pathways, they are commonly used in O. Reg. 153/04 risk assessments as part of a secondary screening step which refines the chemicals and exposure pathways considered in the quantitative risk assessment.

On March 22nd, the MOE released a Technical Update (http://www.ene.gov.on.ca/publications/7454e.pdf) entitled “Use of MOE Component Values in Risk Assessments Submitted under the Record of Site Condition Regulation (O. Reg. 153/04)”. The Technical Update is intended to inform all QPRAs that any risk assessment currently under review or being prepared for submission must use the revised 2009 component values for all secondary screening steps as part of the risk assessment, rather than those used to develop the 1996/2004 SCS.  While the MOE does permit the continued use of the 1996/2004 component values until July 1, 2011, the QPRA must provide an adequate justification as to why the older component values would be protective of human health and the environment, on a chemical-by-chemical basis.  This would be very difficult given that most of the changes in the component values between 1996/2004 and 2009 are a result of improved exposure models and toxicological knowledge, and inclusion of receptors and pathways that were not considered previously.  Past experience suggests that the Ministry will accept continued use of the outdated component values only on very rare occasions.

Why is this important for you to know?

Virtually every risk assessment conducted under O. Reg. 153/04 contains some form of component value screening.  This Technical Update will likely invalidate most risk assessments already submitted to the MOE, if they used the 1996/2004 component values.  If the risk assessment has not already been accepted by the MOE, changes will likely have to be made to ensure it conforms with the elements of the new Regulation (O. Reg. 511/09) immediately.

Further Information:

If you require additional information to better understand the potential impacts of this Technical Update, or if you would like to discuss what options may be available to your clients, please contact one of the Intrinsik risk assessment team at (905) 364-7800 or visit our website at www.intrinsikscience.com“.

Thanks, Instrinsik! This is one of many factors complicating the transition from the old to the new standards under Ontario Regulation 153/04.

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