GENERIC CASE STUDY: Simplified Approach for Spatially Explicit … … · 2 April 26 2018, Risk Solution Expo. Hydrogeological Setting and Water Use DW DW + AW Sub-set of GW COC 3

GENERIC CASE STUDY:Simplified Approach for Spatially Explicit Human Health & Ecological Risk Assessment

April 26 2018, Risk Solution Expo

Craig Harris, M.Sc., P. Geo., R.P. Bio.

Mike Sanborn, M.Sc., R.P. Bio.

Mike Rankin, M.Sc., R.P. Bio.

David Tiplady, P. Eng.

Introduction & Outline

• Generic Case Study: Use of Spatially Explicit Exposure &

Effects

• Industrial Activities• Early 1900’s Industrial Activities on 37 ha Site

• Replaced and Redeveloped early infrastructure through mid 1900’s

resulted in overlapping APECs

• Cessation of original 1900’s activities in 2000 with multiple leased

industrial activities

• Access and Surroundings• Fenced Industrial Site

• Adjacent to riparian area and freshwater body

• Vegetated area along margins amounts to 8 ha

• Underlain by productive provincially mapped aquifer

• Presentation Outline• Problem Formulation Components

• Spatial Explicit Computational Components

• Results & Schedule B Conditions

April 26 2018, Risk Solution Expo2

Hydrogeological Setting and Water Use

DW

DW + AW

Sub-set of

GW

COC


Shallow aquifer – fill (sand, gravel, wood waste & debris)

overlying silt. Unconfined and recharged by infiltrating

precipitation. Gradient is dominantly downward.

Deep aquifer – Provincially mapped sand & gravel aquifer.

Recharged from upgradient zone and from downward

infiltration. Gradient predominantly horizontal and discharge to

surface water body.

Terrestrial Habitat Mapping


Land Use, Human Receptors and

Pathways

Current & Future Industrial Land Use – Multiple

industrial leased areas with expectation that this could

continue in future. Exposure differs depending on the

area. Triggered need for spatially explicit approach

Future Construction/Trench Worker – Calculated Prior to

October 2015 MoE Notification Regrading CW/ TW

Assessment. Retained as it provides value for eventual

future land development

Pathways of Exposure• Direct Soil Ingestion, Dermal Contact & Dust

Inhalation

• Vapour Indoor (current & future)

• Vapour (future trench)

• Dermal Groundwater (future trench)April 26 2018, Risk Solution Expo5

Terrestrial Ecological Receptor

SelectionPotential for presence onsite: Yes No

Habitat size Connectivity

of fragmentsQuality

Move to

ecological risk

assessment

Yes

YesNot applicable Yes

Not applicable Yes

NoYes Yes

No No

No

YesYes Yes

No No

NoNot applicable No

Not applicable No

Habitat Suitability: Raptors/ Marsh Waders

Habitat Suitability: Songbirds

Protocol 1 – List of potential receptors

Biogeoclimatic zone.

Reduce list of potential receptors based on

land use

Protocol 13 – Opportunity to refine potential

receptors based on habitat quality,

connectivity and species preferences

Listed and otherwise protected species are

considered

** Rationale for all decision regarding

final receptors excluded and included.

• Western Toad (listed)

• American Robin

• Deer Mouse

• Vegetation and Soil Invertebrates


Observed onsite or potential for presence onsite: Yes No

Habitat size Connectivity of

fragmentsQuality

Move to

ecological risk

assessment

Yes

Yes

Not applicable Yes

Not applicable Yes

NoYes Yes

No No

No

YesYes Yes

No No

NoNot applicable No

Not applicable No

Contaminant Screening (1 of 2)

Inorganic

Schedule 4 3Schedule 5 Human Health 1 Schedule 5 Ecological 2 and 3

AntimonyNickelMolybdenumSeleniumTin

Arsenic (intake & DW)Barium (DW)Cadmium (DW)Chromium (DW)Copper (DW)Lead (intake & DW)Zinc (DW)

Arsenic (soil contact & AW)Barium (soil contact)Cadmium (AW)Chromium (soil contact & AW)Copper (soil contact & AW)Lead (soil contact & AW)Zinc (soil contact & AW)

Organic

Schedule 4 3Schedule 5 Human Health 1 Schedule 5 Ecological 2

LEPHHEPHVPH

Benzene (DW)Trichloroethylene (DW)Pentachlorophenol (DW)

Pentachlorophenol (AW)

Inorganic

Schedule 6 (DW) Schedule 6 (AW)

Antimony Arsenic CopperMagnesium

CadmiumCobaltCopperZinc 1

Organic

Schedule 6 (DW) Schedule 6 (AW)

Ethyl benzene 1

Toluene Xylene Benzene 1

Benzo[a] anthraceneBenzo[a] pyrene 1

TetrachloroetheneTrichloroethylene 1

1, 1, 2 trichloroethylene cis 1,2 dichloroethylene 1

Vinyl chloride 1

1,2 dichlorobenzene 1

LEPHw 1

Naphthalene 1

Phenanthrene 1

Pyrene 1

Acridine, anthracene, chrysene, Fluoranthene 1

Soil Contaminants Groundwater Contaminants

1 Soil DW only addressed if the substance was discovered above Sch. 6 DW in shallow or deep GW

2 Soil AW addressed if the substance was discovered above Sch .6 AW n the deep aquifer

3 1.5 m depth cut off1 Observed in the deeper aquifer above its schedule standard. Deeper = well

screens beginning at or below 5 m below ground. All other dissolved substances are considered to meet risk-based standards by virtue of not being observed in the deeper aquifer.


Contaminant Screening (2 of 2)

o Trichloroethylene

o 1,2 dichloroethene


o 1, 2, 4 trimethylbenzene

o VPH

o Xylene (total)

Vapour Contaminants :

Future Buildingso Trichloroethylene


o cis 1,2 dichloroethylene

o 1,2 dichloroethane

o Vinyl chloride

o Methyl cyclohexane

o n-hexane

o VPH



o Benzene

o Xylene (total)

Vapour Contaminants:

Future Trench

o Trichloroethylene

Vapour Contaminants :

Current Buildings


Conceptual Site Model: Humans


Conceptual Site Model: Ecological


Ecological Assessment and

Measurement Endpoints

Receptor Assessment Endpoint and Effects

Level

Measurement Endpoint

Plants &

Invertebrates

Sustain populations based on EC50 levels Estimated direct exposure relative to

benchmark

Mammalian &

Avian

Sustain populations based on median

non-lethal effects levels

Estimated dose relative to wildlife TRV

Amphibian

(listed)

Sustain population based on low effects

(IC20 or EC20) on larval stage

Tiered Approach:

(i) Early life stage habitat present?

(ii) Water & Sediment Benchmarks

(iii) Developmental Bioassays


Import From Matrix

Calculate Doses

Calculate Risk Estimates

Export to Results Matrix

Input Matrix[COPCs]

TRVs

Chem. Parameters

Result

MatrixHQs

ILCRs

GoldSim Spatially Explicit Computations

• Assessed maximum concentrations

of 8 COPCs in 101 grid cells (808

individual risk estimates)

• Avoids formula and cell reference

errors common in large

spreadsheets.

• Static parameters are held within the

model environment.


Human Health: Direct Soil Contact

– Quadrant-by-Quadrant Risk Evaluation

– 8 contaminants x 101 quadrants – GOLDSIM®

Software

• Red=Risk Management

– In-Situ Hazardous Waste

Area

– Conditions in Certificate

and PVP Related to

Asphaltic Cover


Future Indoor Vapour Intrusion Risk

– Quadrant-by-Quadrant Future Indoor Risk

• Red=Risk Management Quadrants

• Associated with Degreasers and Sump Waste Lines

– Schedule B Conditions

– Slab-on-grade

construction

– No reduction

in grade


Human Health Principle Risk Controls


– Type II Risk – Based Scenario – PVP Required

– General Site Assumptions (Sch. B, Clause 1)

• All buildings must have slab-on-grade construction

• Site grade must remain the same or higher

RP provides written submission to Director if general site assumptions are inconsistent with HHERA

– Specific Risk Management (Sch. B, Clause 2)

Surface asphalt or equivalent must be maintained at In-Situ Hazardous Waste Zone

Annual inspection to verify that surface cover remains intact and is effective at preventing exposure and limiting infiltration

Administrative restrictions to prevent access to groundwater for domestic consumption within property boundary


Terrestrial Ecological: Current Terrestrial Habitat

– Quadrant-by-Quadrant Eco-Screening– Maximum concentrations compared to CSR Eco Matrix

Standards in 108 quadrants (Site Wide).

– Eighty-nine grids met

CSR Standards

– Nineteen exceeded, of these;

– Two Red exceeded in

present and/or potential

future eco habitat.

Statistical Approach: Future Terrestrial Habitat

– Consolidate Possible Future Terrestrial

Habitat

• Upper 90th %ile and 95% CL on Mean

– Acceptable Ecological Risk Concluded

– No Conditions or PVP


Groundwater Model Results

𝐶 𝑥 ,0,0 = 𝐶0 𝑒𝑥𝑝 𝑥 2𝐷𝑥 1 − 1 + 4𝜆𝐷𝑥 𝑣 0.5 𝑒𝑟𝑓 𝑌 4 𝐷𝑦𝑥 0.5

𝑒𝑟𝑓 𝑍 4 𝐷𝑧𝑥 0.5

Naphthalene: Over predicted with P13Vinyl Chloride: Under predicted with BIOCHLOR


Documents

GENERIC CASE STUDY: Simplified Approach for Spatially Explicit … … · 2 April 26 2018, Risk Solution Expo. Hydrogeological Setting and Water Use DW DW + AW Sub-set of GW COC 3