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PROTOCOL 27, SOIL LEACHING ASSESSMENT FOR USE IN DERIVING SITE SPECIFIC STANDARDS CSR STAGE 11 AMENDMENT WEBINAR #5 NOVEMBER 28, 2017 Lavinia Zanini, P.Geo. Contaminated Sites Officer
This PowerPoint presentation and a recording of the audio will be posted on the web following the webinar
OBJECTIVE OF P27
• Establishes procedures for using approved soil leaching tests in the development of site-specific numerical soil standards (SSSs) under Protocol 2 “Site-Specific Numerical Soil Standards”.
• Allows modification of matrix numerical soil standards for the site-specific factors protective of the groundwater pathway in the Contaminated Sites Regulation (CSR), Schedule 3.1 Part 1, based on soil leaching test results at a contaminated site.
• Outlines the requirements, leachate methods and processes to establish a leachate concentration that can be used in Protocol 2.
2
BC ENV/CSAP WORKING GROUP
• A task group was established to research and aid in the development of the protocol.
• Jointly funded by BC ENV and the CSAP Society of BC.
3
Working group: Tony Gillett (facilitator) George Szefer, Lavinia Zanini (ENV reps) Patricia Carmichael, Bob Beck, Robert McLenehan (Industry reps) Will Gaherty (SAB rep) Barry Loescher (Lab rep)
Methods Evaluated: TCLP - US EPA 1311 SPLP - US EPA 1312 LEAF - USEPA 1313 LEAF - USEPA 1316
LEACHATE TEST METHODS
Saturated Paste Extraction for Soils Approved for the following inorganic substances which have matrix numerical soil standards: chloride and sodium The approved method of evaluation under the CSR is the saturated paste extraction method. The regulated standards are considered the leachable fractions of these substances.
4
NEW !
LEACHATE TEST METHODS
The Liquid-Solid Partitioning (Leachability) of VOCs – Prescriptive (BC VOC Soil Leachate Test) Approved for the following organic substances which have matrix numerical soil standards: benzene; ethylbenzene; toluene; xylenes; tetrachloroethene (PCE); trichloroethene (TCE); and naphthalene.
5
LEACHATE TEST METHODS
BC VOC Soil Leachate Test • US EPA Method 1311 TCLP Zero Head Extractor (ZHE) – with modification • TCLP and SPLP ZHE leachate extraction are currently the only available
leachate test for soil contaminated with volatile organics • Leaching results for the listed VOC’s are generally not pH-dependant • The test is conducted with reagent water as the extraction fluid • Field sampling methods - minimize losses due to volatilization
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Modifications: Holding times: Samples must be extracted within 48 hours from the time of sampling, or within 14 days if frozen within 48 hours of sampling – NEW! Sample collection: exclude large particles (>9.5 mm), no particle reduction
LEACHATE TEST METHODS
Liquid-Solid Partitioning (Leachability) as a Function of pH (Metals, Inorganics, and SVOCs) – Prescriptive - BC Soil Leachate Test Approved for the following substances that have matrix numerical soil standards:
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Organic substances: diisopropanolamine (DIPA); ethylene glycol; methanol; nonylphenol and nonylphenol ethoxylates; pentachlorophenol (PCP); perfluorooctanesulfonic acid (PFOS); phenol; and sulfolane.
Inorganic substances: arsenic; barium; beryllium; cadmium; chloride; chromium; cobalt; copper; lead; manganese; molybdenum; nickel; selenium; sodium; thallium; uranium; vanadium; zinc.
NEW !
LEACHATE TEST METHODS
BC Soil Leachate Test • pH sensitive: 3 parallel batch extractions on soil at pH 5, 7 and 9 • 4th batch extraction is done at soil’s natural pH if < 4.5 or > 9.5 • Extraction run at liquid-solid ratio (L/S) of 20 mL/g-dry • Nitric acid or sodium hydroxide is added to each vessel to obtain
specified final pH value • The vessels are tumbled 48-hrs • Samples are filtered and preserved for chemical analysis • Constituent concentrations [mg/L] reported as a function of eluate
pH Note: Some substances tested using this method are not pH sensitive and therefore require only one leach test (at natural pH).
8
LEACHATE TEST METHODS
9
Vanderbilt University Webpage
LEACHATE TEST METHODS
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pH modification for pH sensitive substances: from 2 to 13 (US EPA) to 5 to 9 (BC): • The BC Soil Leachate Test was developed to best predict the
leaching and mobility of substances in various soil pH settings. • pH range spans reasonable variations in pH that could occur
[>90% of B.C. soil samples fall within pH 5 to 9] • Future changes in site conditions (e.g. the deposit of organic or
alkaline fill) would be captured by this range.
REDOX SENSITIVE INORGANIC SUBSTANCES
• In reducing conditions, the BC Soil Leachate Test may under predict actual field concentrations for certain redox sensitive species (literature review).
• Test for inorganics must not be used for the following redox-sensitive substances, unless it can be demonstrated that oxidizing conditions are present in the soil of interest:
arsenic; chromium; copper; manganese; and vanadium.
11
REDOX SENSITIVE INORGANIC SUBSTANCES
Oxidizing conditions are assumed to be present in: • Unsaturated mineral soil that is not organic soil; and • Saturated soil, provided that: pH + pE ≥ 13 where: pH = pH of water; pE (electron activity) = Eh/59; and Eh (oxidation-reduction potential of groundwater or porewater) is expressed in mV. • Measurement of pH and Eh in the field must be carried out in
accordance with standard industry practice (BC Field Manual)
12
MINIMUM REQUIREMENTS FOR USE OF P27
• The presence and extent of soil and groundwater contamination in each Area of Environmental Concern (AEC) to be characterized by leachate testing has been investigated in accordance with ministry guidance and procedures and standard professional practice such that maximum concentrations of contaminants of concern (COCs) in soil have been identified; and
• Substance concentrations in groundwater in or below the AEC where soil has been leachate tested are less than or equal to the concentrations measured in the soil leachate determined using the leachate testing procedure presented in this protocol.
13
SAMPLING PROGRAM
The collection and analyses of soil samples must be conducted to determine the following site-specific parameters: • Maximum concentration(s) of the substance(s) investigated in
soil for which leachate testing is to be performed • Maximum concentration(s) of the corresponding substance(s) in
groundwater in or below the soil for which leachate testing is to be performed
• Soil pH range, if applicable • Soil redox conditions, if applicable
14
SAMPLING PROGRAM – LEACHATE SAMPLES
• Leachate testing must be performed on a minimum of three soil samples collected within each AEC
• Leachate testing must be performed on samples that have soil concentration(s) equal to or greater than the 90th percentile of the maximum measured concentration(s) of substance(s) to be tested
15
SAMPLING PROGRAM – REMEDIATION SCENARIO
• Where an AEC is planned to be, or has been remediated (e.g. hot spot removal or risk assessment), leachate testing can be performed on the remaining contaminated soil.
• Leachate testing must be performed on a minimum of three remaining soil samples that have soil concentration(s) equal to or greater than the 90th percentile of the maximum measured concentration(s) for substance(s) tested.
16
SAMPLING PROGRAM – EXAMPLE REMEDIATION
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SAMPLING PROGRAM
The number of leaching tests must be proportionate (i.e. more than three samples) with : • Large areas or volumes of contaminated soil (e.g. an area
greater than 300 m2 or a volume greater than 900 m3) • Contamination that contains randomly distributed substances,
such as in contaminated fill
18
INTERPRETATION OF LEACHATE RESULTS
Determination of Leachate Test Concentration (CL test) For substances that have at least three reported leachate concentrations (pH sensitive substances), obtained at pH leach values of 5, 7 and 9, and potentially a fourth corresponding to the “natural” site soil pH, select the highest reported leachate concentration. The substance concentration in soil leachate = the arithmetic mean of the highest leachate results measured for each soil sample tested. For all other substances that require a single leachate test (not pH sensitive), the substance concentration in soil leachate = the arithmetic mean of the leachate results measured for each soil sample tested. Note: A correction for highly soluble substances is required
19
INTERPRETATION OF LEACHATE RESULTS - EXAMPLE
20
Sample 1: pH 5 pH 7 pH 9
Sample 2: pH 5 pH 7 pH 9
Sample 3: pH 5 pH 7 pH 9
Test CL = ( sample 1 + sample 2 + sample 3)/3
Highest Result Highest Result
BC Soil Leachate Test : pH Sensitive - 3 pH values
INTERPRETATION OF LEACHATE RESULTS
NEW! – correction of test leachate concentrations • For substances that are highly soluble and have a low
distribution coefficient or organic carbon partitioning coefficient (Kd< 5 or a Koc <1000) a correction to the substance concentration in soil leachate is required
• For highly soluble substances, leachate concentrations
measured in the ministry approved tests are not equivalent to those that would be observed under field conditions because the relative amounts of soil and water used in the leachate tests are larger than what exists in natural soils
21
INTERPRETATION OF LEACHATE RESULTS
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Model (literature values ) of Kd Field (model) vs Lab (method) Liquid and Air/Solid ratios Field : 0.36 : 1 (field porosity) Lab: 20 : 1 (lab method)
INTERPRETATION OF LEACHATE RESULTS
Substances that require a correction to leachate concentrations measured in test leachate are: benzene diisopropanolamine [DIPA] Ethylbenzene ethylene glycol methanol pentachlorophenol [PCP] phenol sulfolane tetrachloroethylene trichloroethylene toluene xylenes, total
23
INTERPRETATION OF LEACHATE RESULTS
Substance concentrations in soil leachate for these substances are corrected using one of the following methods: 1. Multiply the substance concentration in soil leachate by 20 to
obtain a final estimate of the substance concentration in soil leachate; or
2. Calculate a test specific partition coefficient (Kdtest) for each soil sample. Using these results, calculate a field estimate of substance concentration in leachate (CLfield).
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INTERPRETATION OF LEACHATE RESULTS
25
Kdtest = is the test specific distribution coefficient (L/kg) Ct = the total concentration of the substance in the soil sample tested (mg/kg) Ms = the total weight of the soil sample used in the leachate test (0.05 kg) Ctest = the substance concentration determined in soil leachate test(mg/L) V = the volume of the eluent used in the leachate test (1 L)
Kdtest = is the test specific distribution coefficient (L/kg) θw = water-filled porosity (0.119) θa = air-filled porosity (0.241) H’ = the dimensionless Henry’s law constant ρb = dry bulk density of the soil (1.7 Kg/L) CLfield = estimate of substance concentration in field leachate (mg/L)
The final estimate of substance concentration in soil leachate is the arithmetic mean of the calculated field leachate results (CLfield) for each soil sample tested.
QUESTIONS ? LAVINIA ZANINI
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.
PROTOCOL 2 SITE-SPECIFIC NUMERICAL SOIL STANDARDS
CSR STAGE 11 AMENDMENT WEBINAR #5 NOVEMBER 28, 2017
Annette Mortensen and Amy Sloma Senior Contaminated Sites Officers
This PowerPoint presentation and a recording of the audio will be posted on the web following the webinar
UPDATED PROTOCOL 2
Highlights • Total rewrite to increase usability • User-friendly framework to derive
site-specific numerical soil standards (SSSs) • Derive SSSs under AP
- Modified Groundwater Protection Model (GPM) method
- Leachate Test method • Option for Director’s decision • Flowcharts to help navigate document • Developed with assistance from:
- CSAP working group - Core 6 Environmental contract
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SUPPORTING DOCUMENTS
Protocols and Technical Guidance • Protocol 27, Soil Leaching Tests for Use in Deriving Site-Specific Numerical Soil Standards • Technical Guidance 24, Site-Specific Numerical Soil Standards, Model Parameters • Technical Guidance 13, Groundwater Protection Model • Protocol 28, Chapter 4, Derivation of Soil to Groundwater Protection Matrix Soil Quality Standards
Other documents (available on ministry webpage) • Results of a Sensitivity Analysis for the Omnibus Groundwater Model, Core 6 Environmental • Estimation of Regional Infiltration Rates in British Columbia, Core 6 Environmental • Defining the Contaminant Source Zone, Core 6 Environmental
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PROTOCOL 2 INTRODUCTION
Protocol 2 purpose • Procedure to derive site-specific numerical soil standard (SSS) • SSS can replace the corresponding numerical matrix soil standards in Schedule 3.1 Part 1
SSS can be derived for the site-specific factors protective of groundwater use: • Groundwater used for drinking water (DW) • Groundwater flow to surface water used by aquatic life (AW) • Groundwater used for livestock watering (LW) • Groundwater used for irrigation (IW)
Protocol 21
SSS cannot be derived for the following site-specific factors: • Intake of contaminated soil • Toxicity to soil invertebrates and plants • Livestock ingesting soil and fodder • Major microbial functional impairment
Mandatory
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PROTOCOL 2 INTRODUCTION
The numerical soil standard is determined as the lowest value of: • the derived SSSs protective of the groundwater pathway(s) • the mandatory matrix numerical soil standards site, i.e. “intake of contaminated soil”
and “toxicity to soil invertebrates and plants” • other applicable matrix standards
When a SSS represents the lowest applicable numerical standard, the SSS can be use to determine if: • a site is contaminated • a contaminated site has been satisfactorily remediated • soil is considered acceptable for deposit at a receiving site
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SUBSTANCES IN SCHEDULE 3.1 PART 1
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Mandatory SSS
SSS
SSS SSS
Mandatory
SUBSTANCES IN SCHEDULE 3.1 PART 1
Substance DW AW LW IW Arsenic x x x x Barium x x NS NS Beryllium x x x x Cadmium x x x x Chloride x x x x Chromium (3+) x x x x Chromium (6+) x x x x Cobalt x x x x Copper x x x x Cyanide (CN-) x x NS NS Lead x x x x Manganese x NS NS x Mercury (inorganic) NS NS NS NS Molybdenum x x x x Nickel x x x x Selenium x x x x Sodium x NS NS NS Uranium x x x x Vanadium x NS x x Zinc x x x x
Substance DW AW LW IW Anthracene NS NS NS NS Benzene x x NS NS Benzo[a]pyrene NS NS NS NS DDT NS NS NS NS Diisopropanolamine x x NS NS Ethylbenzene x x NS NS Ethylene Glycol x x NS NS Fluoranthene NS NS NS NS Methanol x NS NS NS Naphthalene x x NS NS Nonylphenol x x NS NS Pentachlorophenol x x x x PFOS x x NS NS Phenol x x NS NS PCB NS NS NS NS PCDD/PCDF NS NS NS NS Sulfolane x x x x Tetrachloroethylene NS x NS NS Toluene x x NS NS Trichloroethylene NS x x NS Xylene x x NS NS
Inorganics Organics
33
SUBSTANCES IN SCHEDULE 3.1 PART 1
Substance DW AW LW IW Arsenic x x x x Barium x x NS NS Beryllium x x x x Cadmium x x x x Chloride x x x x Chromium (3+) x x x x Chromium (6+) x x x x Cobalt x x x x Copper x x x x Cyanide (CN-) x x NS NS Lead x x x x Manganese x NS NS x Mercury (inorganic) NS NS NS NS Molybdenum x x x x Nickel x x x x Selenium x x x x Sodium x NS NS NS Uranium x x x x Vanadium x NS x x Zinc x x x x
Substance DW AW LW IW Anthracene NS NS NS NS Benzene x x NS NS Benzo[a]pyrene NS NS NS NS DDT NS NS NS NS Diisopropanolamine x x NS NS Ethylbenzene x x NS NS Ethylene Glycol x x NS NS Fluoranthene NS NS NS NS Methanol x NS NS NS Naphthalene x x NS NS Nonylphenol x x NS NS Pentachlorophenol x x x x PFOS x x NS NS Phenol x x NS NS PCB NS NS NS NS PCDD/PCDF NS NS NS NS Sulfolane x x x x Tetrachloroethylene NS x NS NS Toluene x x NS NS Trichloroethylene NS x x NS Xylene x x NS NS
Inorganics Organics
No soil to GW standard 34
SUBSTANCES IN SCHEDULE 3.1 PART 1
Substance DW AW LW IW Arsenic x x x x Barium x x NS NS Beryllium x x x x Cadmium x x x x Chloride x x x x Chromium (3+) x x x x Chromium (6+) x x x x Cobalt x x x x Copper x x x x Cyanide (CN-) x x NS NS Lead x x x x Manganese x NS NS x Mercury (inorganic) NS NS NS NS Molybdenum x x x x Nickel x x x x Selenium x x x x Sodium x NS NS NS Uranium x x x x Vanadium x NS x x Zinc x x x x
Substance DW AW LW IW Anthracene NS NS NS NS Benzene x x NS NS Benzo[a]pyrene NS NS NS NS DDT NS NS NS NS Diisopropanolamine x x NS NS Ethylbenzene x x NS NS Ethylene Glycol x x NS NS Fluoranthene NS NS NS NS Methanol x NS NS NS Naphthalene x x NS NS Nonylphenol x x NS NS Pentachlorophenol x x x x PFOS x x NS NS Phenol x x NS NS PCB NS NS NS NS PCDD/PCDF NS NS NS NS Sulfolane x x x x Tetrachloroethylene NS x NS NS Toluene x x NS NS Trichloroethylene NS x x NS Xylene x x NS NS
Inorganics Organics
No soil to GW standard
Tox standards ≤ soil to GW standard (except CL, IL)
Tox standards ≤ soil to GW standard 35
PROTOCOL 2 METHODS
Methods to derive SSSs under an AP
1. Modified Groundwater Protection Model (GPM) Method
2. Leachate Test Method
• If using both methods, the highest derived SSS may be applied • If a derived SSS is lower than the corresponding matrix standard, the matrix standard applies
Obtain Director’s decision for SSSs if using alternative methods • Change parameters outside ranges provided in protocol • Change parameters not included in protocol
36
MODIFIED GPM METHOD
SSSs derived using the Modified GPM method
• Ministry’s Groundwater Protection Model (GPM) • Used to derive the matrix soil standards protective of groundwater use: (AW, DW, IW, LW) • Default model parameters (simulate flow and transport in a Fraser River sand aquifer setting)
• Modified GPM method • Modify model parameter to adjust for site-specific conditions • Calculate a SSS protective of the applicable groundwater uses
37
GROUNDWATER PROTECTION MODEL - GPM
• Protocol 28, Chapter 4 Derivation of Soil to Groundwater Protection Matrix Soil Quality Standards
38
GROUNDWATER PROTECTION MODEL - GPM
39
GROUNDWATER PROTECTION MODEL - GPM
Soil Leachate Partitioning
Saturated fate and transport
Leachate/ groundwater mixing
Unsaturated fate and transport
40
GROUNDWATER PROTECTION MODEL - GPM
1. Water use standard at point of compliance, Cx
2. Groundwater concentration below source, Cgw
3. Leachate concentration at water table, Cz
4. Leachate concentration at source, CL
5. Soil concentration at source, Cs 6. Adjusted soil concentration, Cc
= soil standard protective of respective water use
Deriving soil standards protective of groundwater use using the GPM
Saturated fate and transport
Leachate/groundwater mixing
Unsaturated fate and transport
Soil Leachate Partitioning
41
GROUNDWATER PROTECTION MODEL - GPM
Category Model Parameter Symbol Unit Default value
Source dimensions
Source length X m 10 Source width Y m 30 Source depth Z m 3
Infiltration Infiltration I m/yr 0.55 Hydrogeology Total porosity n - 0.36
Water filled porosity nw - 0.119 Effective porosity ne - 0.25 Dry bulk density ρb g/cm3 1.7 Fraction of organic carbon foc - 0.005 pH of soil pHsoil - 6.5 pH of groundwater pHwater - 6.5 Hydraulic conductivity K m/s 3E-5 Hydraulic gradient I - 0.008 Average linear velocity v m/yr 30.3 Aquifer thickness da m 5 Depth to water table d m 3 Distance to point of compliance x m 10
Substance Half-life t1/2s X Substance Distribution coefficient Koc/Kd X Substance Henry’s Law constant H X Substance Solubility S X Substance
Default model parameters • Used for deriving the matrix numerical soil standards in Schedule 3.1 Part 1
42
MODIFIED GPM METHOD
Category Model Parameter Symbol Default Look-up table Literature Site-specific
Source dimensions
Source length X X X Source width Y X X Source depth Z X X
Infiltration Infiltration I X X Director Hydrogeology Total porosity n X X X
Water filled porosity nw X X Effective porosity ne X X X Dry bulk density ρb X X X Fraction of organic carbon foc X X pH of soil pHsoil X X pH of groundwater pHwater X X Darcy flux (K and i) V X X Aquifer thickness da X X Depth to water table d X X Distance to point of compliance x X X
Substance Half-life t1/2s X Director Distribution coefficient Koc/Kd X Director Henry’s Law constant H X Director Solubility S X Director
SSSs derived using the Modified GPM method • Determine site-specific model parameters
43
MODIFIED GPM METHOD
Category Model Parameter Symbol Default Look-up table Literature Site-specific
Source dimensions
Source length X X X Source width Y X X Source depth Z X X
Infiltration Infiltration I X X Director Hydrogeology Total porosity n X X X
Water filled porosity nw X X Effective porosity ne X X X Dry bulk density ρb X X X Fraction of organic carbon foc X X pH of soil pHsoil X X pH of groundwater pHwater X X Darcy flux (K and i) V X X Aquifer thickness da X X Depth to water table d X X Distance to point of compliance x X X
Substance Half-life t1/2s X Director Distribution coefficient Koc/Kd X Director Henry’s Law constant H X Director Solubility S X Director 44
SSSs derived using the Modified GPM method • Determine site-specific model parameters
MODIFIED GPM METHOD
Infiltration Rate: I = P – (ET+RO)
45
Infiltration table and map • Map constructed based on 44 climate
stations • Most recent five years of climate data
used and averaged • Minimum value of 80 mm/year • Further details in “Estimation of
Regional Infiltration Rates in British Columbia”, Core 6 Environmental
MODIFIED GPM METHOD
Category Model Parameter Symbol Default Look-up table Literature Site-specific
Source dimensions
Source length X X X Source width Y X X Source depth Z X X
Infiltration Infiltration I X X Director Hydrogeology Total porosity n X X X
Water filled porosity nw X X Effective porosity ne X X X Dry bulk density ρb X X X Fraction of organic carbon foc X X pH of soil pHsoil X X pH of groundwater pHwater X X Darcy flux (K and i) V X X Aquifer thickness da X X Depth to water table d X X Distance to point of compliance x X X
Substance Half-life t1/2s X Director Distribution coefficient Koc/Kd X Director Henry’s Law constant H X Director Solubility S X Director 46
SSSs derived using the Modified GPM method • Determine site-specific model parameters
MODIFIED GPM METHOD
Source definition under Protocol 2
Petroleum hydrocarbon sources • Defined by the greater of the horizontal and vertical extent of either:
• NAPL presence, as defined in Protocol 16 or • soil concentrations of:
- VHs6-10 greater than 100 µg/g; or - EPHs10-19 greater than 1000 µg/g; or - EPHs19-32 greater than 1000 µg/g
No source: Matrix standards protective of applicable groundwater use(s) does not apply
All other sources • Defined by the horizontal and vertical extent of soil concentrations:
• greater than the applicable matrix standard; or • greater than the local/regional background soil quality; or • greater than a SSS derived modifying one or more of the following model parameters:
I, n, nw, ne, ρb, foc, pH, K, i, da
• Further details in “Defining the Contaminant Source Zone”, Core 6 Environmental
47
MODIFIED GPM METHOD
Hydrogeological parameters Site-specific source dimensions are required to modify: • Depth to water table • Distance to point of compliance
• For DW, IW, LW: Distance to point of compliance can be modified to the downgradient property boundary if groundwater on site meets applicable standards • For AW: Distance to point of compliance can be modified to 10 m from aquatic receptor if groundwater meets applicable standards at property boundary
48
MODIFIED GPM METHOD
Category Model Parameter Symbol Unit Default value Acceptable range
Source dimensions
Source length X m 10 ≥ 5 Source width Y m 30 ≥ 5 Source depth Z m 3 ≥ 3
Infiltration Infiltration I m/yr 0.55 ≥ 0.08 Hydrogeology Total porosity n - 0.36 ≥ 0.2 and ≤ 0.4
Water filled porosity nw - 0.119 nw ≤ n Effective porosity ne - 0.25 ≥ 0.1 and ≤ 0.4 Dry bulk density ρb g/cm3 1.7 ≤ 1.9 Fraction of organic carbon foc - 0.005 ≥ 0.001 and ≤ 0.050 pH of soil pHsoil - 6.5 ≥ 5 and ≤ 9 pH of groundwater pHwater - 6.5 ≥ 5 and ≤ 9 Hydraulic conductivity K m/s 3E-5 - Hydraulic gradient I - 0.008 - Average linear velocity v m/yr 30.3 ≥ 5 and ≤ 250 Aquifer thickness da m 5 ≥ 5 and ≤ 20 Depth to water table d m 3 ≥ 1 Distance to point of compliance x m 10 ≥ 10 and ≤ 500
Substance Half-life t1/2s X Substance Distribution coefficient Koc/Kd X Substance Henry’s Law constant H X Substance Solubility S X Substance
49
Site-specific model parameters • Acceptable parameter ranges
MODIFIED GPM METHOD
• Further details in “Results of a Sensitivity Analysis for the Omnibus Groundwater Model”, Core 6 Environmental
Site-specific model parameters • Ranking of model parameters based on sensitivity
MODIFIED GPM METHOD - EXAMPLE
51
Modified GPM method – benzene example • Commercial land use, DW apply • DW water use standard = 5 µg/L • Matrix numerical soil standard protective of DW use = 0.035 µg/g
Site-specific model parameters • Infiltration rate I = 0.212 m/year (Victoria) • SSS = 0.055 µg/g
MODIFIED GPM METHOD - EXAMPLE
52
Modified GPM method – benzene example • Commercial land use, DW apply • DW water use standard = 5 µg/L • Matrix numerical soil standard protective of DW use = 0.035 µg/g
Site-specific model parameters • Unsaturated thickness b = 1 m (depth to water table d = 4 m) • SSS = 0.45 µg/g
MODIFIED GPM METHOD - EXAMPLE
53
Modified GPM method – benzene example • Commercial land use, DW apply • DW water use standard = 5 µg/L • Matrix numerical soil standard protective of DW use = 0.035 µg/g
Site-specific model parameters • Infiltration rate I = 0.212 m/year (Victoria) • Unsaturated thickness b = 1 m (depth to water table d = 4 m) • SSS = 10 µg/g
QUESTION BREAK PLEASE TYPE YOUR QUESTION
NEXT: LEACHATE TEST METHOD PROTOCOL 2 EXAMPLES
LEACHATE TEST METHOD
SSSs derived using the Leachate Test method • Leachate test following Protocol 27 provides: - the max soil concentration - the corresponding soil leachate concentration, CL,test
Max soil concentration
CL,test
Leachate test
55
LEACHATE TEST METHOD
The SSS is determined as the maximum soil concentration if: 1. the soil leachate concentration is ≤ the numerical water use standard or
SSS Cs
Cx
1.
Max soil concentration
CL,test
Leachate test
SSS Cs
Cx
CL,default
2. 3. SSS Cs
Cx
CL,site-specific
2. the soil leachate concentration is ≤ to the modelled leachate concentration CL,default derived using the GPM and default parameters or
3. the soil leachate concentration is ≤ to the modelled leachate concentration CL,site-specific derived using the GPM and site-specific model parameters
56
For substances that don’t degrade, CL,default = 3.3 x water use standard Where 3.3 is the dilution factor obtained by mixing
LEACHATE TEST METHOD - EXAMPLE
Leachate Test method - cadmium example • Commercial land use, DW apply, pH 7.0 - <7.5 (run model at pH=7.3) • DW water use standard = 5 µg/L • Matrix numerical soil standard protective of DW use = 4.5 µg/g
Cmax=25 µg/g
CL,test = 20 µg/L
Leachate test The SSS is determined as the maximum soil concentration if: 1. the soil leachate concentration is ≤ the numerical water use standard;
DW standard = 5 µg/L
57
LEACHATE TEST METHOD - EXAMPLE
Leachate Test method - cadmium example • Commercial land use, DW apply, pH 7.0 - <7.5 • DW water use standard = 5 µg/L • Matrix numerical soil standard protective of DW use = 4.5 µg/g
Cmax=25 µg/g
CL,test = 20 µg/L
Leachate test The SSS is determined as the maximum soil concentration if: 1. the soil leachate concentration is ≤ the numerical water use standard;
DW standard = 5 µg/L
2. the soil leachate concentration is ≤ to the modelled leachate concentration CL,default derived using the GPM and default parameters; CL,default = 3.3 x 5 µg/L = 16.5 µg/L
58
Run GPM with default model parameters
59
• Drinking water standard, Cx = 5 µg/L • Modelled leachate concentration, CL,default = 16.5 µg/L • Site-specific soil standard, Cc= 4.5 µg/g
LEACHATE TEST METHOD - EXAMPLE
LEACHATE TEST METHOD - EXAMPLE
Leachate Test method - cadmium example • Commercial land use, DW apply, pH 7.0 - <7.5 • DW water use standard = 5 µg/L • Matrix numerical soil standard protective of DW use = 4.5 µg/g
Cmax=25 µg/g
CL,test = 20 µg/L
Leachate test The SSS is determined as the maximum soil concentration if: 1. the soil leachate concentration is ≤ the numerical water use standard;
DW standard = 5 µg/L
2. the soil leachate concentration is ≤ to the modelled leachate concentration CL,default derived using the GPM and default parameters; CL,default = 3.3 x 5 µg/L = 16.5 µg/L
3. the soil leachate concentration is ≤ to the modelled leachate concentration CL,site-specific derived using the GPM and site-specific model parameters
60
Run GPM with site-specific model parameters • Infiltration I=80 mm/year
61
• Drinking water standard, Cx = 5 µg/L • Modelled leachate concentration, CL,site-specific = 57.3 µg/L • Site-specific soil standard, Cc= 15 µg/g
LEACHATE TEST METHOD - EXAMPLE
LEACHATE TEST METHOD - EXAMPLE
Leachate Test method - cadmium example • Commercial land use, DW apply, pH 7.0 - <7.5 • DW water use standard = 5 µg/L • Matrix numerical soil standard protective of DW use = 4.5 µg/g
Cmax=25 µg/g
CL,test = 20 µg/L
Leachate test The SSS is determined as the maximum soil concentration if: 1. the soil leachate concentration is ≤ the numerical water use standard;
DW standard = 5 µg/L
2. the soil leachate concentration is ≤ to the modelled leachate concentration CL,default derived using the GPM and default parameters; CL,default = 3.3 x 5 µg/L = 16.5 µg/L
3. the soil leachate concentration is ≤ to the modelled leachate concentration CL,site-specific derived using the GPM and site-specific model parameters CL,site-specific = 57.3 µg/L
SSS=25 µg/g 62
DIRECTOR’S DECISION
Director’s decision for derived SSSs • Modified GPM method and Leachate Test method not sufficient
Example of alternative methods applied: • Change parameters outside ranges provided in Protocol 2 • Change parameters not included in Protocol 2
• Submit application to ministry
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QUESTION BREAK PLEASE TYPE YOUR QUESTION
NEXT: PROTOCOL 2 EXAMPLES
EXAMPLE – KAMLOOPS GAS STATION
Kamloops gas station • This is a real site, but identifiers have been removed
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Site Region Interior Land use standards CL Water use standards DW/AW Fresh
Site-Specific Parameter Value Units Source Lenth 10 m Source Width 30 m Source Depth 3 m Fraction of Organic Carbon 0.005 - Infiltration Rate 80 mm/year
Distance to Receptor 10 m Aquifer Thickness 5 m Depth to Water Table 3 m
Groundwater Velocity 9.836112 m/yr Hydraulic gradient (i) c. 0.0017 to c. 0.0035 m/m Hydraulic Conductivity (K) 3.00E-05 m/s
Reported Contaminant in Soil/GW Concentration Range Units benzene (CL soil) 4.3 ug/g ethylbenzene (CL soil) 24.3 ug/g toluene (CL soil) 60.1 ug/g xylene (CL soil) 98 to 153.6 ug/g benzene (GW-DW) 6 to 883 ug/L ethylbenzene (GW-DW) 3.9 to 220 ug/L toluene (GW-DW/AWf) 26 to 482 ug/L xylene (GW-DW/AWf) 305 to 2080 ug/L
EXAMPLE – KAMLOOPS GAS STATION INPUT
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Site-specific model parameters • Infiltration rate • Hydraulic gradient
EXAMPLE – KAMLOOPS GAS STATION OUTPUT
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Model output • Benzene
EXAMPLE – KAMLOOPS GAS STATION OUTPUT
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Model output • Xylene
EXAMPLE – KAMLOOPS GAS STATION STANDARDS
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Substance Stage 10 standard (µg/g) SSS (µg/g)
Benzene 0.035 (DW) 0.2 (DW)
Ethylbenzene 15 (DW) 200 (DW)
Toluene 0.5 (AWf) 55 (AWf)
Xylene 6.5 (DW) 100 (DW)
Reported Contaminant in Soil/GW Concentration Range Units benzene (CL soil) 4.3 ug/g ethylbenzene (CL soil) 24.3 ug/g toluene (CL soil) 60.1 ug/g xylene (CL soil) 98 to 153.6 ug/g benzene (GW-DW) 6 to 883 ug/L ethylbenzene (GW-DW) 3.9 to 220 ug/L toluene (GW-DW/AWf) 26 to 482 ug/L xylene (GW-DW/AWf) 305 to 2080 ug/L
Model results
EXAMPLE – LOWER MAINLAND PULP MILL
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3 Site Region lower mainland 4 Land use standards IL 5 Water use standards DW/AW Fresh/AW Marine
Site-Specific Parameter Value Units 1 Source Lenth 10 m 2 Source Width 30 m 3 Source Depth 3 m 4 Fraction of Organic Carbon 6.00E-03 - 5 Infiltration Rate 550 mm/year
1 Distance to Receptor 10 m 2 Aquifer Thickness 10 m 3 Depth to Water Table 3 m 4 Groundwater Velocity 25.4916 m/yr 5 Hydraulic gradient (i) 0.05 m/m 6 Hydraulic Conductivity (K) 4.85E-06 m/s
Reported Contaminant in Soil/GW Concentration Range Units 1 arsenic (IL soil) 17.7 to 339 ug/g 2 trivalent chromium (IL soil) 78 to 196 ug/g 3 lead (Il soil) 292 to 3040 ug/g 4 copper (IL soil) 253 to 2580 ug/g 5 cadmium (IL soil) 3.9 to 7.5 ug/g 6 zinc (IL soil) 339 to 2010 ug/g 7 barium (IL soil) 465 to 1950 ug/g 8 benzene (IL soil) ** 0.06 ug/g 9 tetrachloroethylene (IL soil) ** 0.04 ug/g
10 ethylbenzene (GW-DW) 5.7 to 6.6 ug/L 11 lead (GW-DW) 11 ug/L 12 benzo[a]pyrene (GW-DW) 0.023 to 0.03 ug/L 13 uranium dissolved (GW-DW) 25 to 319 ug/L 14 sodium dissolved (GW-DW) 121000 to 688000 ug/L 15 chromium dissolved (GW-DW) 13 to 140 ug/L 16 arsenic dissolved (GW-DW) 12 to 30 ug/L
Lower mainland pulp mill • This is a real site, but identifiers have been removed
EXAMPLE – LOWER MAINLAND PULP MILL INPUT
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Site-specific model parameters • Infiltration rate • Hydraulic conductivity / hydraulic gradient
EXAMPLE – LOWER MAINLAND PULP MILL OUTPUT
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Model output • Cadmium, pH = 5
EXAMPLE – LOWER MAINLAND PULP MILL OUTPUT
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Model output • Cadmium, pH = 9
EXAMPLE – LOWER MAINLAND PULP MILL OUTPUT
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Model output • Lead, pH = 6.5 • Mandatory standards apply
EXAMPLE – LOWER MAINLAND PULP MILL STANDARDS
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Substance Stage 10 standards (µg/g) SSS (µg/g) Concentration Range (µg/g)
Arsenic 10 (DW and AW) 10 (DW and AW) 17.7-339
Barium 350 (DW) 350 (DW) 465-1950
Benzene 0.035 (DW) 0.045 (DW) 0.06
Cadmium 1 (DW)–75 (Tox)* pH is 4.1-10.7 1 @pH 5 – 70 @pH 9
3.9-7.5
Chromium (iii) 250 (Tox) - - 78-196
Copper 75 (AW) -300 (Tox)* 75 (AW) -300 (Tox)* 253-2580
Lead 120 (DW) - 1000 (Tox)* 100 @ pH 5 – 1000 (Tox)*
292-3040
Zinc 150 (AWf) - 450 (Tox)* 150 @ pH 5 - 200 @ pH9 (AWm)
339-2010
PCE 2.5 2.5 0.04
Model results
EXAMPLE FORMER GAS STATION UNKNOWN LOCATION
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Gas station, unknown location • This is a real site, but identifiers have been removed
EXAMPLE – FORMER GAS STATION
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Site-specific model parameters • Benzene in soil • Source dimensions X=20m Y=40m Z=20m d = 22m clean groundwater
EXAMPLE – FORMER GAS STATION INPUT
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Site-specific model parameters • Source dimensions X, Y, Z • Depth to water table
EXAMPLE – FORMER GAS STATION OUTPUT
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Model output • Benzene
EXAMPLE – FORMER GAS STATION
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Model results • SSS for benzene is 3.0 ug/g • All benzene concentrations in soil meet the SSS
TAKEAWAYS ON EXAMPLES USING MODEL METHOD
Understand the hydrogeological system, the substance exceedances and how the GPM sensitivity can work in your favour • PHC contaminated sites in the Interior will likely benefit the most
• Easy to substitute in an appropriate infiltration • Worthwhile to collect foc for these sites • Additional benefit if one determines source dimensions, particularly source depth invokes an
uncontaminated vadose zone
• Inorganic contaminated sites, especially those in the lower mainland, are
unlikely to have significant changes to SSS • Easy to substitute in an appropriate infiltration • Dependent on the pH of the soil • Additional benefit if one determines source dimensions, particularly length – implications on
distance to point of compliance, mainly AW though • May need to consider Protocol 27 and the Leachate Test method
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QUESTIONS ? ANNETTE MORTENSEN
[email protected] OR (778)-698-4869
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.
AMY SLOMA [email protected] OR (778) 698-4866