ONTARIO APPROVED MODEL for TIER 3 ASSESSMENT IN SASK woodplc.com - PowerPoint PPT Presentation

ONTARIO APPROVED MODEL for TIER 3 ASSESSMENT IN SASK woodplc.com

Outline • Where did the Approved Model come from? • Why use it? • Receptor Exposure Pathways (Components) • Site inputs or variables • Project examples from northern and southern Saskatchewan • Shortcomings 2 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Where does it come from? Background to Approved Model 3

Where does it come from? Ontario Regulation 153/04 governs the assessment and cleanup • of brownfield sites Requires the filing of records of site condition in Ontario’s • Environmental Site Registry for changes in land use e.g. from industrial to residential Can file only when property meets soil, groundwater and • sediment standards In order to expedite review and approval of Tier 2 property- • specific standards, proponents may use the Modified Generic Risk Assessment (MGRA) process provided by the Ministry of Environment and Climate Change (MOECC) The MGRA entails use of the Approved Model spreadsheet • which allows limited manipulation of site variables and incorporation of Risk Management Measures to provide custom site criteria 4 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Why use it? Advantages / benefits 5

Why use it? • Fulfills Tier 3 site specific criteria approach provided for by the Saskatchewan Endpoint Selection Standard (2016) – similar to former Tier 2B approach under previous Petroleum Hydrocarbon (PHC) Contaminated Sites Guidelines • Criteria reflect more of the site’s characteristics, not just applicable pathways, instead of a one-size-fits all approach • Comprehensive list of chemicals included, unlike the 2002 CCME spreadsheet tool which allowed calculation of values for PHCs F1 to F4 based on site specific characteristics • Soil vapour screening criteria can be calculated for your site 6 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Built-in Risk Management Measures • Criteria automatically adjust when you select any of these built- in ‘Risk Management Measures’: – Hard cap, fill cap, shallow soil cap – Building, groundwater prohibitions – Passive, active soil vapour intrusion mitigation systems – Building no first floor occupancy – First floor ceiling height minimum – Modified subsurface worker protection – Soil and groundwater management plan (e.g. testing incoming and excavated soil, stockpile protection) 7 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Receptor Exposure Pathways Known as ‘components’ 8

Component nent Definit nitio ion Components GW1 Groundwater for drinking water purposes. Odour from groundwater for drinking water purposes (aesthetic, not health consideration). GW1 Odour GW2 Exposure pathway due to inhalation of vapours in indoor air originating from groundwater. GW2 Odour Odour in indoor air from groundwater (aesthetic, not health consideration). GW3 Exposure pathway to aquatic biota via groundwater discharge to surface water. Component for direct exposure to soil via soil ingestion and dermal contact appropriate for a residential scenario S1 (toddler). Soil for protection from direct soil contact for a lower frequency and intensity exposure than residential surface soil, S2 such as for commercial or industrial scenarios where children are not frequently present. Soil for direct soil contact for a low-frequency, high-intensity, human health exposure scenario without children S3 present that is protective of a worker digging in the soil. S-IA Soil for protection of movement to indoor air and human exposure. Soil for protection of movement to outdoor air and human exposure. S-OA S-Odour Soil for protection from excessive odours (for example, while gardening). S-GW1 Soil for protection from movement to groundwater used for drinking water purposes. S-GW3 Soil for protection from movement to groundwater with subsequent discharge to surface water affecting aquatic life. Plants and Soil Organisms Soil for protection against adverse effects to plants and soil dwelling organisms through direct contact. Mammals and Birds Soil for protection against adverse effects through direct soil contact and food ingestion to mammals and birds. 9 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Primary Inputs And other variables you may like to change 10

Primary Model Inputs 11 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Notes on Primary Inputs 12 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Primary Model Inputs – Risk Management Measures 13 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Other Variables 14 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Project Examples 15

Undisclosed Site Shield Area of Northern Saskatchewan Phase II ESA for future remediation of PHC impacts Scope Tier 3 site specific criteria since Tier 2 not applicable to bedrock. Used soil vapour screening levels - not exceeded provision - to alter VI criteria and input larger impacted soil dimensions to be conservative in bedrock setting. This is not the site but it was near a lake like this! Sand and Clay Overburden Bedrock Aquifer 16 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Full table SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK 17 A presentation by Wood.

Full table 18 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Co-op Gas Station Commercial Intersection in a Sask. City Data recast in light of new SEQG with comparison to Approved Model criteria and additional subslab vapour monitoring for PHC impacts. Scope Used hard capped risk management measure and other site characteristics. More conservative alpha (dilution factor) for assessing vapour intrusion risks. Not the site – a public domain image: photo by David McBee from Pexels https://www.pexels.com/photo/gas-station- 583136. rmission from 123RF Limited Hard capped Fine soils with little to no shallow groundwater. 19 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Full table 20 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

21 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Shortcomings and improvements we’d like to see 22

Shortcomings • While formulas are explicit, it is still taxing to trace them all back through the various spreadsheets • Sensitivity testing is an iterative, manual process but can be made a little easier by hiding irrelevant scenarios, filtering for your COCs • Many of the same limitations as in Tier 2 since uses the same formulas 23 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Shortcomings Rigid conceptual model used for vapour intrusion from soils • doesn’t allow for soil impacts to be at a particular depth below the foundation Source: Ontario Ministry of the Environment, 2011, Rationale for the Development of Soil and Ground Water Standards for Use at Contaminated Sites in Ontario . 24 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Final Notes • Have an experienced Risk Assessor provide review when parameters beyond those allowed by MGRA are changed • A special Qualified Person designation for the Tier 3 site specific approach is needed for submissions to MOE • Thank you to the proponents who graciously allowed us to discuss their sites and to the MOE for facilitating our use of the Approved Model for the Tier 3 site specific criteria approach 25 A presentation by Wood. SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

woodplc.com