UPDATES TO PROVINCIAL VAPOUR STANDARDS AND POLICY

CSR STAGE 11 AMENDMENT WEBINAR #3 NOVEMBER 23, 2017

Peter Kickham and Heather Osachoff Managers, Risk Assessment and Remediation

This PowerPoint presentation and a recording of the audio will be posted on the web following the webinar

OVERVIEW

1. Stage 10/11 amendments to the CSR (Peter)

2. Updated document: Technical Guidance 4 version 2 (TG4) (Heather)

3. Newly released document: Protocol 22 version 1 (P22) (Heather)

4. Future vapour policy directions (Peter)

Question break after each section

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STAGE 10 & 11 CSR AMENDMENTS

• The Stage 11 (Housekeeping) amendments to the Stage 10 (Omnibus) amendments to the Contaminated Sites Regulation (CSR) and related consequential amendments to the Hazardous Waste Regulation (HWR) and Organic Matter Recycling Regulation (OMRR) were approved October 31, 2017.

• The amendments made to the regulations are summarized in the October 31, 2017 Update entitled “Stage 10 (Omnibus) and Stage 11 (Housekeeping) Amendments to the Contaminated Sites Regulation” on the Site Remediation website.

• These changes came into legal force on November 1, 2017.

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EVOLUTION OF GENERIC NUMERICAL VAPOUR STANDARDS

• Originally derived in 2006-2007 as the “Interim Air Concentration Criteria”

• Formally adopted in 2008 Stage 6 Amendment to the Contaminated Sites Regulation (CSR)

• Apply in the breathing zone • Application of the soil vapour standards may be adjusted depending on

the site specific contaminant configuration and building design. (Technical Guidance 4)

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VAPOUR STANDARDS UPDATE

• “Vapour” means any gaseous emissions from soil, sediment or water.

• Volatile substances give rise to gaseous emissions: • Henry’s Law Constant > 1.0x10-5 atm-m3/mol, and • Vapour Pressure > 0.05 Torr (at 1 atm, 25oC)

• CSR 11(1)(c.1) defines a site as contaminated if “the concentration of any

substance in vapour at the site is greater than the applicable generic numerical vapour standard”.

• Vapour standards applied to soil vapour may be adjusted for depth dependent attenuation as specified in new Protocol 22.

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UPDATE SUMMARY

• Derivation of Schedule 11 Standards fairly recent (< a decade). • BC was the first jurisdiction in Canada to set standards for the vapour

pathway.

• Scope of the Stage 10 (omnibus) was limited to the following:

• Update of existing CSR Schedule 11 Generic Vapour Standards to reflect current (as of October 2015) inhalation Toxicity Reference Values,

• Derivation of a new category of generic numerical vapour standards for application in “Parkades”.

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TRV SELECTION

• Preference given to TRVs specific to inhalation pathway • Selection according the Hierarchy identified in Technical Guidance 7

• USEPA Integrated Risk Information System, • Health Canada, • World Health Organization, • Any of (i.e. no order of preference):

– ATSDR – ORNL (RAIS) – Netherlands – Cal EPA – Region 9 RSLs/PRGs – Other Canadian Province’s or US State Agencies

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DERIVATION PROTOCOL – NON CARCINOGENS

For non-carcinogenic substances: VS = (HQT x RfC) / ET where: VS = Generic Numerical Vapour Standard (µg/m3) HQT = Target Hazard Quotient for substance = 1.0 ET = Exposure Term (unitless) RfC = Reference Concentration (µg/m3): if RfC unavailable for substance, then RfC = RfCcalc

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DERIVATION PROTOCOL – NON CARCINOGENS

• Where no inhalation TRV’s available, used oral TRV as follows: RfCcalc = (RfD x BW) / IR where: RfD = Oral Reference Dose (mg/kg/d): substance specific BW = Body weight (kg): age specific, adult = 70.7 kg, toddler = 16.5 kg IR = Inhalation Rate (m3/d): age specific, adult =16.6 m3/d, toddler = 8.3 m3/d

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DERIVATION PROTOCOL – CARCINOGENS

For carcinogenic substances VS = ILCRT / (UR x ET) where: VS = Schedule V, Generic Vapour Standard (mg/m3) ILCRT = Target Incremental Lifetime Cancer Risk = 1.0x 10-5 ET = Land use specific exposure term (unitless) UR = Cancer Unit Risk (mg/m3)-1: if UR unavailable for substance, then UR = URcalc

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DERIVATION PROTOCOL – CARCINOGENS

Where no inhalation UR’s available, used oral Slope Factors as follows: URcalc = (SF x IR) / BW where: SF = Cancer Slope Factor (mg/kg/d)-1: substance specific IR = Inhalation Rate (m3/d): age specific, adult =16.6m3/d, toddler= 8.3 m3/d BW = Body weight (kg): age specific, adult = 70.7 kg, toddler= 16.5 kg

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EXPOSURE TERMS

ET Exposure Term: land-use specific

AL/RL/UPL ET = 1.0 (24hr/24hr x 7d/7d x 52wk/52wk x 70 yr/70yr)

CL ET = 0.33 (12hr/24hr x 5d/7d x 48wk/52wk x 70 yr/70yr)

IL ET = 0.11 ( 8hr/24hr x 5d/7d x 48wk/52wk x 35 yr/70yr)

PK ET = 0.125 ((1hr/24hr x 5d/7d)+( 8hr/24hr x 2d/7d)) x 52wk/52wk x 70yr/70yr

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PARKADE EXPOSURE TERM

• A parkade exposure term was proposed in a 2009 white paper prepared for the Science Advisory Board for Contaminated Sites

• During weekdays (5 days/week 52 weeks/year) – a total of 1 hour per day based on four 15 minute exposures to parkade air,

• During weekends (2 days/week, 52 weeks/year) – a total of 8 hours per day.

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NEW PARKADE DEFINITION

“parkade” means an enclosed building, storey of a building or other construction used for the parking of multiple motor vehicles, but does not include the parking of motor vehicles associated with a single residence.

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RESIDENTIAL GARAGE IS NOT A PARKADE

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APPLICATION OF PARKADE STANDARDS

• Parkade Vapour Use, is not a defined Land Use under CSR.

• Vapour standards are intended to apply in the “breathing zone”.

• For sites where there is a combination of building design features, the vapour investigation will need to support application of appropriate standards to various breathing zones.

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APPLICATION OF PARKADE STANDARDS

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NOTES ON THE ERRATA

• As mentioned in webinar #1, there are known errors in the Stage 11 amendment. An errata will likely be issued in the new year for the Stage 11 amendment.

• (e.g.) VPH is listed in Schedule 3.3 as VPH and not VPHv

• Please bring these to our attention by notifying site@gov.bc.ca

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UPPER CAP CONCENTRATIONS (PROTOCOL 11)

• Some jurisdictions have incorporated ‘alert levels’ for the carcinogenic and toxic substance: trichloroethylene (TCE)

• To protect the development of the fetus in pregnant women, a sensitive exposure route to consider in HHRA

• The ministry reviewed the available science and decided the course of action to take under the omnibus amendment was to reduce the multiplier for TCE for the calculation of upper cap concentrations (UCCs) from a value of 10 to 3 (Protocol 11) • Note, most substances have an UCC multiplier of 10; however, that does

not necessarily mean that the UCC is 10 times the standard due to detection levels or other factors. See the footnotes in the vapours table of Protocol 11 (page 91).

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TCE IN PROTOCOL 11

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14 In consideration of US EPA 2014 Memorandum: “EPA Region 9 Response Action Levels and Recommendations to Address Near-Term Inhalation Exposures to TCE in Air from Subsurface Vapor Intrusion“, upper cap concentrations were derived by application of a 3x upper cap multiplier for vapour exposure to the corresponding CSR Schedule 3.3 vapour standards for the substance and vapour use.

QUESTION BREAK

PLEASE TYPE YOUR QUESTION

NEXT SECTION: UPDATES TO TG4

UPDATES TO TECHNICAL GUIDANCE 4

TG4 Scope: Vapour Investigation and Remediation • Information from version 1 largely retained

• Updates included in version 2 (effective Nov. 1, 2017):

• Reference to Schedule 3.3 “Generic Numerical Vapour Standards” in Stage 10/11 CSR amendments in force Nov. 1, 2017

• Addition of “aerobically biodegradable substances lateral exclusion distance” of 10 m

• Refinement of risk management via mechanical ventilation

• Stakeholder comments received (summer of 2017) were incorporated

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REFINEMENT STEP RETAINED

• Select substances (in Table 1 of TG4 v2) for an area of potential environmental concern (APEC) for which there are no detectable concentrations of the substance at or near the site in soil, sediment or water, may be removed from the vapour potential contaminants of concern (PCOC) list:

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Substance Substance Substance

benzene isopropylbenzene trimethylbenzene, 1,2,4-

butadiene, 1,3- MTBE toluene

dibromoethane, 1,2- methylcyclohexane xylenes, total

dichloroethane, 1,2- n-hexane VPHv

n-decane naphthalene

ethylbenzene trimethylbenzene, 1,3,5-

Page 2 of TG4 v2

10 M LATERAL EXCLUSION DISTANCE

• Select substances that are considered to be aerobically biodegradable have a low potential for vapour intrusion in buildings that are more than 10 m (laterally) away from detectable concentrations:

• 30 m lateral exclusion distance applies for all other PCOCs, including butadiene, 1,3-, dibromoethane, 1,2-, dichloroethane, 1,2-, and MTBE.

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Substance Substance Substance

benzene methylcyclohexane trimethylbenzene, 1,2,4-

n-decane n-hexane toluene

ethylbenzene naphthalene xylenes, total

isopropylbenzene trimethylbenzene, 1,3,5- VPHv

Page 3 of TG4 v2

UPDATES TO TECHNICAL GUIDANCE 4

• New language included for separate categories of risk management for vapours.

• This provides relief for situations where mechanical ventilation

systems have been relied upon.

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Page 6 of TG4 v2

PARTS OF TG4 V1 PORTED TO PROTOCOL 22

• Default vapour attenuation factors (VAFs) listed in Table 2 of TG 4 v1 were ported to Table 1 of Protocol 22 (and parkade vapour use added)

• Adjustment of the default VAFs to account for biodegradation using a 10 fold factor (αbio) has been incorporated into P22 Section 4.1 and renamed to: Biodegradation Attenuation Adjustment Divisor (BAAD)

More on these items coming up in the next Section …

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QUESTION BREAK

PLEASE TYPE YOUR QUESTION

NEXT SECTION: PROTOCOL 22

OVERVIEW OF PROTOCOL 22

• New CSR protocol from the ministry, created in collaboration with CSAP, came into force Nov. 1, 2017

Contents, Major Sections:

• Vertical Vapour Attenuation Factors (VAFs)

• Vapour Attenuation Adjustment Divisors (AADs): 1. Biodegradation AAD (BAAD) 2. Parkade AAD (PAAD) 3. Lateral AAD (LAAD)

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VAFS – PARKADES ADDED

• Parkade use column added, Parkade VAFs equal to AL/UP/RL

• Precluding conditions (revised):

Groundwater is in contact with the foundation slab at any time of the year, or there is active pumping or drawdown of groundwater at the site, with the exception of parkades built to equivalent or better: 2012 or later BC Building Codes.

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Page 4 of P22

USE OF VERTICAL VAFS RETAINED

Use of Vertical VAFs:

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To estimate vapour substance concentrations in the breathing zone vertically above vapour concentrations determined in subsurface or subslab vapour: CV-I = CV-SS * αI CV-O = CV-SS * αO Where CV-I and CV-O (µg/m3) are the estimated substance concentrations in

indoor and outdoor vapour, respectively; CV-SS (µg/m3) is the measured or estimated substance concentration in subsurface or subslab vapour; and αI and αO (unitless) are the default indoor (I) and outdoor (O) vertical VAFs.

Page 3 of P22

ADJUSTMENT OF CALCULATION USING AAD

Use of Vertical VAFs Modified by AAD:

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To estimate vapour substance concentrations in the breathing zone from vapour concentrations measured in subsurface or subslab vapour: CV-I = CV-SS * αI / AAD CV-O = CV-SS * αO / AAD Where CV-I and CV-O (µg/m3) are the estimated substance concentrations in

indoor and outdoor vapour, respectively; CV-SS (µg/m3) is the measured or estimated substance concentration in subsurface or subslab vapour; αI and αO (unitless) are the default indoor (I) and outdoor (O) vertical VAFs; and AAD is the attenuation adjustment divisor (unitless).

Page 6 of P22

AADS

3 Attenuation Adjustment Divisors (AADs):

1. Biodegradation AAD (BAAD)

2. Parkade AAD (PAAD)

3. Lateral AAD (LAAD)

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BIODEGRADATION AAD (BAAD)

The ministry permits a 10-fold adjustment of the vertical VAFs for biodegradation for select aerobically biodegradable substances listed in Table 2 of Protocol 22:

• BAAD = 10

• Limited list of substances, considers 2015 US EPA OUST [reference 6 in P22]. Note, same list as 10 m lateral exclusion zone in TG4.

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Substance Substance Substance

benzene methylcyclohexane trimethylbenzene, 1,2,4-

n-decane n-hexane toluene

ethylbenzene naphthalene xylenes, total

isopropylbenzene trimethylbenzene, 1,3,5- VPHv

Pages 6-7 of P22

RESTRICTION: BIOLOGICALLY ACTIVE SOIL

• The BAAD may only be used when “biologically active soil” underlies the entire extent of the breathing zone(s) under evaluation.

• Definition based on 2015 US EPA OUST [reference 6 in Protocol 22]; found in Procedure 8:

biologically active soil means soil that has the capability to support the growth and survival of aerobic microorganisms such that aerobic biodegradation of contaminants can occur. Biologically active soil must not contain detectable concentrations of substances listed in CSR Schedule 3.3. The following geologic materials do not qualify as biologically active:

1. coarse sand and gravel with low silt, clay and organic matter content, and a moisture content that is less than two percent;

2. fractured, faulted, or jointed consolidated rock; or consolidated rock with solution channels (i.e., karst).

Soil samples must be collected and analyzed for soil moisture, which must be greater than two percent to indicate a biologically active soil.

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Pages 6-7 of P22

EXAMPLE OF USE OF BAAD

• The vertical separation distance between the vapour source and the building foundation is either 2 m or 5 m of biologically active soil depending on source strength:

• 2 m = VHw6-10 is < 15,000 μg/L and EPHw10-19 is < 5,000 μg/L, and NAPL is not present;

• 5 m = VHw6-10 is > 15,000 μg/L and EPHw10-19 is > 5,000 μg/L, or NAPL is present.

Please see this restriction as well as others in Protocol 22

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Dissolved phase Contamination

Predicted indoor air

Vapour sample

> 2 m

CaI

Pages 6-7 of P22

AADS

3 Attenuation Adjustment Divisors (AADs):

1. Biodegradation AAD (BAAD)

2. Parkade AAD (PAAD)

3. Lateral AAD (LAAD)

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PARKADE AAD (PAAD)

The ministry permits a 50-fold adjustment of the subslab vertical VAF (0.02) for parkades in consideration of increased air exchange in parkades:

• PAAD = 50

• Use of the PAAD constitutes reliance on an engineered system to increase air exchange within the parkade. Therefore, use of the PAAD constitutes risk management for vapours and only a risk-based contaminated sites legal instrument can be obtained.

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Contamination

Predicted indoor air in parkade

Subslab vapour sample

Cap Apply PAAD

Page 7 of P22

AADS

3 Attenuation Adjustment Divisors (AADs):

1. Biodegradation AAD (BAAD)

2. Parkade AAD (PAAD)

3. Lateral AAD (LAAD)

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LATERAL AAD (LAAD)

• Protocol 22 permits adjustment of the vertical VAFs where the target breathing zone is offset laterally from the vapour sampling point, subject to conditions.

• Based on a review of modelling studies and empirical data showing that current vertical VAFs could also be applied in the lateral direction and are predicted to be conservative.

• LAAD = three look-up tables (Table 3 of Protocol 22) for:

• outdoor exposure;

• indoor exposure – AL/UP/RL/Parkade;

• indoor exposure – CL/IL.

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EXAMPLE LAAD TABLE 3B

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Page 9 of P22

EXAMPLE LAAD TABLE 3B

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Page 9 of P22

Example with 7 m deep soil vapour well and lateral distance of 20 m to offsite building (RL): LAAD = 3

CONDITIONS OF USING LAAD

• The measured or predicted vapour concentration in indoor or outdoor air at the point of measurement is less than or equal to 10 times the vapour standard of the Regulation;

• The point of application of the LAADs (i.e. the point at which subsurface or sub-slab vapours have been characterized) must in all cases be beyond the vapour source in soil or groundwater (i.e., at the boundary of detectable concentrations in soil and groundwater); and

• The contaminant plume must be stable or decreasing in concentration and extent.

Please see these conditions as well as others in Protocol 22

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Page 8 of P22

EXAMPLE: USE OF LAAD FOR TCE CONTAMINATION

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Site boundary

Actual offsite Building (RL)

Contamination

Predicted indoor air at sample location

Vapour sample

20 m

7 m

Caoff Cav

• TCE residential (RL) Sch. 3.3 standard: 2 µg/m3

• Measured vapour sample concentration at 7 m deep: 5000 µg/m3

• Vertical VAF αI = 8.3E-4 for depth of 7 m (from Table 1, P22)

Cav = 5000 * 8.3E-4 = 4.15 µg/m3 (> Sch. 3.3)

Assess the indoor air in the offsite building 20 m away

EXAMPLE OF USE OF LAAD

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Site boundary

Actual offsite Building (RL)

Contamination

Predicted indoor air at sample location

7 m

Caoff Cav

• For lateral distance of 20 m, LAAD (RL) = 3 (from Table 3B, P22)

Caoff = 5000 * 8.3E-4 / 3 = 1.38 µg/m3 (< Sch. 3.3 std of 2 µg/m3)

• No further delineation required towards offsite building.

20 m

Vapour sample

QUESTION BREAK

PLEASE TYPE YOUR QUESTION

NEXT SECTION: FUTURE VAPOUR POLICY DIRECTIONS

FUTURE VAPOUR POLICY DIRECTIONS

Parkade use column added: Parkade VAFs equal to AL/UP/RL

• Complete derivation of parkade specific VAFs

• Make any necessary adjustments to the Parkade Attenuation Adjustment Divisor (PAAD).

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FUTURE VAPOUR POLICY DIRECTIONS

Expansion of “Refinement Step”:

• If select constituents of gasoline and diesel mixture are below analytical detection limit in soil, sediment and water, they need not be evaluated in soil vapour.

• Determine if evidence would support extending the refinement step to other substance classes (e.g., drycleaning solvents).

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FUTURE VAPOUR POLICY DIRECTIONS

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Use of Biodegradation Attenuation Adjustment Divisor (BAAD) limited by presence of impervious surface cover.

• Evaluate impervious surfaces for their ability to limit gas transport, and differentiate between asphalt and concrete.

• Evaluate adjusting the precluding condition for surface cover

ACKNOWLEDGEMENTS FOR RECENT VAPOUR POLICY DEVELOPMENT CONTRIBUTORS

• CSAP Society

• Dave Williams (MEMS); Jerry Naus (Parsons); Tara Kennedy (SNC-Lavalin); Jim Malick (SLR Consulting); Beth Power (Azimuth Consulting)

• Ian Hers and Parisa Jourabchi (Golder Associates)

• Glyn Fox and Peggy Evans, Ministry of Environment and Climate Change Strategy

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QUESTIONS ? PETER KICKHAM

PETER.KICKHAM@GOV.BC.CA OR (778) 698-4922

HEATHER OSACHOFF HEATHER.OSACHOFF@GOV.BC.CA OR (604) 582-5308

Advice provided during this webinar is based on

information available at the time of recording and may be subject to change.

This PowerPoint presentation and a recording of the audio will be posted on the web. If you do not wish

your question to be on the public record, please email the presenter following the webinar.