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

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ONTARIO APPROVED MODEL for TIER 3 ASSESSMENT IN SASK

• 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

Outline

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

Where does it come from?

Background to Approved Model

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• Ontario Regulation 153/04 governs the assessment and cleanup
• f 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

Where does it come from?

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

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Why use it?

Advantages / benefits

• 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

Why use it?

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

• 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)

Built-in Risk Management Measures

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

Receptor Exposure Pathways

Known as ‘components’

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Components

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Component nent Definit nitio ion

GW1 Groundwater for drinking water purposes. GW1 Odour Odour from groundwater for drinking water purposes (aesthetic, not health consideration). 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. S1 Component for direct exposure to soil via soil ingestion and dermal contact appropriate for a residential scenario (toddler). S2 Soil for protection from direct soil contact for a lower frequency and intensity exposure than residential surface soil, such as for commercial or industrial scenarios where children are not frequently present. S3 Soil for direct soil contact for a low-frequency, high-intensity, human health exposure scenario without children present that is protective of a worker digging in the soil. S-IA Soil for protection of movement to indoor air and human exposure. S-OA Soil for protection of movement to outdoor air and human exposure. 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.

SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Primary Inputs

And other variables you may like to change

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Primary Model Inputs

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

Notes on Primary Inputs

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Primary Model Inputs – Risk Management Measures

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Other Variables

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Project Examples

Undisclosed Site

Shield Area of Northern Saskatchewan

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Scope

Phase II ESA for future remediation of PHC impacts 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

SUSTAINTECH, 22 MARCH 2018, SASKATOON, SK

Full table

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

Full table

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

Co-op Gas Station

Commercial Intersection in a Sask. City

19 A presentation by Wood.

Scope

Data recast in light of new SEQG with comparison to Approved Model criteria and additional subslab vapour monitoring for PHC impacts. 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.

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

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• 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

Shortcomings

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

• 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.

Shortcomings

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

• 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

Final Notes

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

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