September 18, 2019
Conceptual Site Model
A conceptual site model (CSM) is a tool used by contaminated sites professionals to help get a clear understanding of contamination at a site. Domtar’s consultants have prepared a detailed CSM of the Greenbelt and Overlanders Community (“the Site”) which Domtar has this month (September 2019) provided to Alberta Environment and Parks.
Based on extensive environmental investigations and remediation at the Site, the contamination at the Site has been thoroughly characterized and the contaminant transport pathways and potential routes of exposure are well understood. Domtar’s most recent environmental work continues to support the conclusion that there is no concern with respect to the quality of the surface soil that people may come into contact with.
Important information with respect to the contamination at the Site that was presented in the CSM can be summarized as follows:
The contamination underneath the Site occurs at significant depth and is stable (in other words, it will not increase or expand over time);
The contamination is not moving; and
Under existing conditions, there is no opportunity for exposure to the contamination because it occurs at significant depth beneath the Site.
The full extent of contamination in soil, groundwater and soil vapour is well understood across the entirety of the Site. Drilling and soil sampling have confirmed the limited lateral extent of potential contamination which, if present, occurs at significant depth. Soil vapour samples collected underneath the basements of some of the homes on Humberstone Road indicate low concentrations of volatile organic compounds (VOCs). These results further support that vapour intrusion into homes north of the former West Pond is not occurring and therefore does not pose a risk to the occupants of those homes.
The primary chemicals of concern at the Site are referred to as non-aqueous phase liquids or “NAPLs”, which are slightly denser than water. Where NAPL has been observed during drilling, it occurs at significant depths below ground surface. There are no active sources of NAPL and the historical discharge of wastewater containing NAPL stopped in the 1970s.
The occurrence of NAPL at significant depth reflects the historical migration pathways of the NAPLs as they accumulated at the base of ditches and ponds, and moved downward through the soil horizon. Vertical migration occurred within fractures, allowing the NAPL to penetrate into inter-till sands and accumulate in geological low points, or to migrate laterally (at depth) along the less permeable till until reaching residual saturation. The geological observations made historically and currently at the Site support the conclusion that NAPL located at significant depth beneath the Site is not mobile. Groundwater monitoring since 1999 supports the conclusion that the groundwater plume is stable and that the NAPL is immobile. Further, soil vapour monitoring indicates that soil vapour concentrations rapidly diminish as they get closer to surface.
Should you have any questions related to the CSM, please don’t hesitate to call us at 780-784-8919 or email us at firstname.lastname@example.org.
Delineation of Contamination
This summer saw a lot of activity in and around the Greenbelt.
In compliance with Section 10 of the Ministerial Order, Domtar has now completed the delineation work on the Greenbelt and in the Overlanders Community. A summary of this work was provided to Alberta Environment and Parks (AEP) on August 9, 2019. The results of the July 2019 soil investigation indicate that there are no exceedances of AEP’s health-based guidelines on the Greenbelt or Overlanders Community. A full discussion of these results will be provided to AEP by
September 9, 2019.
Coupled with the findings of the Intrinsik 2018 soil quality assessment and the 2019 surface soil quality assessment that Millennium EMS prepared for AEP, the results of Domtar’s most recent sampling program continue to show that the surface soils inside and near the fenced area do not pose a threat to the health of the Overlanders residents or recreational users of the Greenbelt.
In that regard, Domtar continues to seek to facilitate the removal of the fencing around the Greenbelt.
August 28, 2019
May 10, 2019
Dust Control Program
In accordance with Section 8 of the Ministerial Order, Domtar has submitted its Dust Control Program for the Greenbelt to Alberta Environment and Parks.
Because the Greenbelt is covered with vegetation with little to no exposed soils, there is limited opportunity for dust to be generated at the Greenbelt. Any dust potentially generated from areas of bare soil would be composed of the clean surface fill material that covers the Greenbelt.
As part of the Dust Control Program, inspections of the Greenbelt will be conducted on a monthly basis. If an inspection identifies an area of the Greenbelt devoid of vegetation, Domtar will work with the City of Edmonton (the owner of the Greenbelt) to implement corrective measures.
Long-term dust control measures will eventually be integrated with the Risk Management Plan for the Greenbelt.
April 8, 2019
EPO-Related Work Conducted to Date
To date, Domtar has submitted a Temporary Dust Control Program for the Greenbelt to the AEP. The Program will remain in place until authorized otherwise by the Approval Director.
March 13, 2019
EAB Report and Ministerial Decision
On March 13, 2019, the Decision of the EAB was made public. The EAB found that the AEP orders should be cancelled and said that the “Board is of the view the Orders should never have been issued.”
The Minister of Environment and Parks accepted the EAB’s recommendations and findings, quashed all of the 2018 orders and, on March 12, 2019, issued a ministerial order to Cherokee and Domtar. Under the 2019 environmental protection order issued by the Minister, Domtar is responsible for completing certain supplementary works at the Greenbelt and the adjacent Overlanders Community.
August 26, 2018
Human Health Risk Assessment of the Greenbelt Near the Former Domtar Wood Treatment Facility, Edmonton, AB
An HHRA that is based on surface soil data and soil vapour data collected from the Greenbelt in the summer of 2018 is submitted to AEP. The HHRA followed a scientific approach that is consistent with guidance provided by AEP and Health Canada.
The findings of the HHRA indicate there was no evidence that the health of the neighbouring residents or Greenbelt users would be adversely affected by exposure to measured chemical concentrations on the Greenbelt.