Alberta Environment and Park (AEP) has recently released a 2023 update to the Alberta Tier 1 Soil and Groundwater Remediation Guidelines. The changes include a lower Tier 1 threshold for benzene for agricultural and residential coarse soil sites from the previous guidelines.
What is less immediately apparent is that the guidelines also change for the vapour inhalation pathway for all land uses and soil types. These changes will impact sites where the protection of domestic use aquifer (DUA) pathway is eliminated, including sites where the new guidance on excluding the DUA with municipal bylaws is being applied.
Since the change takes effect on January 1, 2023, there remains an opportunity to identify and close sites that will be affected before the new guidelines take effect. After January 1, we believe that site-specific assessment of the vapour inhalation pathway will become more important.
The change in the guidelines is due to a change in the Health Canada toxicity reference value (TRV) used to calculate indoor vapour inhalation guidelines. We expect that provinces using CCME guidelines will also use the Health Canada TRV. As a consequence of this change, we believe that site-specific assessment of the vapour inhalation pathway has become far more critical in Alberta, Saskatchewan and Manitoba.
MEMS has been strengthening our capabilities concerning site-specific assessment regarding vapour inhalation-based guidelines and addressing this pathway.
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