Interlaboratory Validation of Leaching
Methods in the Leaching Environmental Assessment
Framework (LEAF) for Acceptance by U.S. EPA
Andrew GARRABRANTS1, David KOSSON1, Rossane DELAPP1,
Hans VAN DER SLOOT2, Leonard STEFANSKI3, Susan THORNELOE4,
Gregory HELMS5, Mark BALDWIN5, and Peter KARIHER6
1
Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, USA
van der Sloot Consultancy, 1721 BV Langedijk, NL
3 Department of Statistics, North Carolina State University Raleigh, NC, USA
4 Office of Research and Development, U.S. EPA, Durham, NC, USA
5 Office of Resource Conservation and Recovery, U.S. EPA, Washington, DC, USA
6 ARCADIS-US, Inc., Durham, NC, USA
2 Hans
Presentation Outline
Motivation
• Materials Testing in the U.S.
• LEAF Methods
• Comparable International Methods
Interlaboratory Validation Program
Comparison to EU Leaching Tests
Conclusions
30 May - 1 June 2012
WASCON, Gothenburg, Sweden
2
U.S. Materials Testing (Historically)
1960s-1990s
Protection from Hazardous Wastes; Waste Minimization/Conservation
• Classification of “Hazardous” Waste (RCRA Subtitle C/D landfills)
• Disposal Criteria for Treated Wastes (Universal Treatment Standards)
• Best Demonstrated Available Treatment (BDAT)
1990s – present
Integrated Materials Management; Environmental Performance Balanced
with Material Costs and Long-term Liability
• Global Economic Policy (Resource Costs, International Trade)
• Changing “Waste” Definition (Dutch Building Materials Decree; U.S. solid waste)
• Applications for Waste Delisting and Alternative Measures of Treatment Effectiveness
• Reuse of Waste Materials (Mine Reclamation, Alternative Construction Materials)
• Revision of Coal Combustion Residue Regulations
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3
Leaching Methods Development
Characterization Leaching Tests
• Release Parameters – pH, liquid-solid ratio, time
• Material Form – granular vs. monolithic
• Applied Release Conditions – improved accuracy, reliable decisions
International Collaboration
• Coordination with Parallel EU Methods Development
Situations where TCLP is Not Required or Best-Suited
• Material Assessment for Beneficial Use
• Evaluation of Treatment Effectiveness (Equivalent Treatment)
• Estimating Potential Release from High-volume Materials
• Corrective Actions (Remediation Decisions)
• Hazardous Waste Delisting
30 May - 1 June 2012
WASCON, Gothenburg, Sweden
4
Leaching Environmental Assessment Framework
LEAF is a collection of …
• Four leaching methods
• Data management tools
• Leaching assessment approaches
LeachXS LiteTM for data management and report support
LEAF facilitates integration of leaching methods
• Identify characteristic leaching behaviors in a wide range of materials
• Provide a material-specific “source term”
More information on LEAF and LeachXS Lite is available at
http://www.vanderbilt.edu/leaching
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LEAF Leaching Methods
Method 1313
Liquid-Solid Partitioning as a Function of Eluate pH using a
Parallel Batch Procedure
Method 1314
Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio
(L/S) using an Up-flow Percolation Column Procedure
Method 1315
Mass Transfer Rates in Monolithic and Compacted Granular
Materials using a Semi-dynamic Tank Leaching Procedure
Method 1316
Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio
using a Parallel Batch Procedure
Note: Incorporation into SW-846 is ongoing; method numbers are subject to change.
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6
WASCON, Gothenburg, Sweden
6
LEAF and EU Methods
Parameter
LEAF Method
EU Method
EU Applications
pH-dependence
Method 1313
CEN/TS 14429
CEN/TS 14997
ISO/TS 14997
waste, mining waste, construction products
waste, mining waste, construction products
soil, sediments, compost, sludge
Percolation
Method 1314
CEN/TS 14405
CEN/TC351/TS-3
ISO/TS 21268-3
waste, mining waste
construction products
soil, sediments, compost, sludge
Mass Transport
Method 1315
CEN/TS 15683
CEN/TC351/TS-2
NEN 7347 (Dutch)
NEN7348 (Dutch)
monolithic waste
monolithic construction products
monolithic waste
granular waste and construction products,
L/S dependence
Method 1316
EN12457-2
waste
Many of These Methods are not yet Standardized Pending Validation
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7
Validation of LEAF Test Methods
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8
LEAF Test Methods Validation
Interlaboratory Validation Program
• EPA “Guidance for Methods Development and Methods Validation for the
RCRA Program”
• ASTM “E691 Standard Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method”
• ISO 5725 “Accuracy (Trueness and Precision) of Measurement Methods
and Results”
Participating Laboratories (minimum of 6)
Study Materials (minimum of 3)
Method Repeatability and Reproducibility
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WASCON, Gothenburg, Sweden
9
Participating Laboratories
Number of labs varied with test method, availability and support
• Method 1313/1316 – targeted 10 laboratories
• Method 1315 – targeted 10 laboratories
• Method 1314 – targeted 7 laboratories
U.S. Government Laboratories

Oak Ridge National Lab
 Pacific Northwest National Lab
 Savannah River National Lab
Academic Laboratories


ARCADIS-US, Inc.
 Test America, Inc.
 URS Corporation, Inc.
International Laboratories
Ohio State University
 University of Wisconsin (Madison)
 Missouri Univ. of Science & Tech.
 Vanderbilt University
30 May - 1 June 2012
U.S. Commercial Laboratories

ECN (The Netherlands)

DHI (Denmark)
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Study Materials
Coal Combustion Fly Ash
• Collected for EPA study
• Selected for validation of …


• Copper smelter site
• Selected for validation of…




Method 1313
Method 1316
Solidified Waste Analog
• Created at Vanderbilt University
• Blast Furnace Slag, Class C Fly
Ash, Type I/II Cement, Metal Salts
• Selected for validation of …



Contaminated Field Soil
Method 1313
Method 1316
Method 1315
Method 1314
Brass Foundry Sand
• Selected for validation of …


Method 1315
Method 1314
Method 1313
Method 1316
Method 1315
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11
Data Processing
Log10-Transform of Test Output
• Method 1313 – Eluate Concentration
• Method 1314 – Eluate Concentration,
•
Cumulative Mass Release
Method 1315 – Interval Mass Flux,
Cumulative Mass Release
Selenium (mg/L)
10
1
0.1
ML
MDL
• Method 1316 – Eluate Concentration
0.01
0
2
4
6
8
10
12
14
pH
Implications for Compliance Standards
Selenium (mg/L)
Linear Interpolation and Extrapolation
• Collected Data Shows Variability
• Brings Data to Specified pH, L/S or Time
• Consistency in Comparisons
10
1
0.1
ML
MDL
0.01
0
2
4
6
8
10
12
14
target pH
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12
Statistical Analysis
Data Consistency and Spread
• Method Blank Analysis – to identify potential sources of contamination
• 95% Prediction and Robust Confidence Limits
Method Precision
• Repeatability Relative Standard Deviation (RSDr)

“Within-Lab” Variance
• Reproducibility Relative Standard Deviation (RSDR)

“Overall” Variance
Reproducibility Limit Interval (RL)
• Based on reproducibility limit (R)
• Interval within which reproducibility data
is considered to be the same with 95% confidence
30 May - 1 June 2012
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sr
RSDr   100%
y
s
RSD R  R  100%
y
R  2.8  sR
RL  log( y )  log( R)
13
Method 1313 Validation Examples
Coal Combustion Fly Ash
1000
M1313 EaFA Mean
Overall SD
Between Lab SD
Within Lab SD
10
1
0.1
ML
MDL
0.01
0
2
4
6
8
10
12
14
As Reproducibility (%)
Arsenic (mg/L)
100
Reproducibility
CFS RSD-R
EaFA RSD-R
SWA RSD-R
100
10
ICP-OES RSD
1
0
2
Target pH
4
6
8
10
12
14
Target pH
Study Materials
• CFS Contaminated Field Soil
• EaFA Coal Combustion Fly Ash
• SWA Solidified Waste Analog
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Evaluation Basis
Percolation Column
Mass Transfer
100
1000
Flux in 4th Interval
(7-day cumulative time)
10
Concentration in 2nd Fraction (L/S0.5)
ICP-OES RSD
M1314 CFS RSD-R
M1314 JaFS RSD-R
Barium Flux RSDR (%)
Aluminum RSDR (%)
Concentration in 9th Fraction (L/S10)
Mean Flux 2nd - 4th Intervals
(excludes washoff)
100
10
ICP-OES RSD
M1315 CFS RSD-R
M1315 SWA RSD-R
1
0.1
1
1
0.01
10
0.1
L/S (L/kg)
Aluminum Release RSDR (%)
Boron Release RSDR (%)
M1314 CFS RSD-R
M1314 JaFS RSD-R
Release at End of Test
(L/S = 10 mL/g-dry )
10
2nd
Release through
Fraction
(L/S = 0.5 mL/g-dry )
1
0.1
1
10
100
10
100
Release after 4th Interval
(7-day cumulative time)
10
Release at End of Test
(63-day cumulative time)
ICP-OES RSD
M1315 CFS RSD-R
M1315 SWA RSD-R
1
0.01
L/S (L/kg)
30 May - 1 June 2012
1
Time (days)
100
ICP-OES RSD
Mean Flux 2nd - 9th Intervals
(excludes washoff)
0.1
1
10
100
Time (days)
WASCON, Gothenburg, Sweden
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LEAF Method Precision
Method
Test Output
RSDr
(%)
RSDR
(%)
Method 1313
Eluate Concentration (average over pH range)
10
26
Method 1314
Eluate Concentration (9th fraction at L/S=10)
Mass Release (cumulative to L/S=0.5)
Mass Release (cumulative to L/S=10)
13
7
5
28
18
14
Method 1315
Interval Flux (average excluding wash-off)
Mass Release (cumulative to 7-days)
Mass Release (cumulative to 63-days)
11
9
6
28
19
23
Method 1316
Eluate Concentration (average over L/S range)
7
17
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Precision Comparison
(pH-dependence Tests)
Repeatability
Max SWA
Sb @ pH 2
RSDr = 130%
100
Max CFS
Ba @ pH 13
RSDr = 114%
80
80
60
60
RSDR (%)
RSDr (%)
100
Reproducibility
40
20
Max SWA
Sb @ pH 2
RSDR = 500%
Max CFS
Ba @ pH 13
RSDR = 300%
Max
RSDR = 124%
Max
RSDR = 118%
40
20
0
EaFA
SWA
CFS
EN12457-2
0
EaFA
SWA
CFS
EN12457-2
TCLP
Method Precision
• Method 1314 Eluate Concentration (2  pH  13)
• EN12457
Eluate Concentration (natural pH)
• TCLP
Eluate Concentration (acetic acid buffer)
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Precision Comparison
(Percolation Tests)
Reproducibility
100
100
80
80
60
60
RSDR (%)
RSDr (%)
Repeatability
40
20
0
0
JaFS
DIN19528
Max
RSDR = 118%
40
20
CFS
Max
RSDR = 139%
CFS
JaFS
DIN19528
TCLP
Method Precision
• Method 1314 Cumulative Release at L/S = 10 L/kg
• DIN 19528
Cumulative Release at L/S = 4.0 L/kg
• TCLP
Eluate Concentration (L/S = 20 L/kg)
30 May - 1 June 2012
WASCON, Gothenburg, Sweden
18
Precision Comparison
(Mass Transfer Tests)
Reproducibility
100
100
80
80
60
60
RSDR (%)
RSDr (%)
Repeatability
40
Max
RSDR = 118%
40
20
20
0
0
SWA
CFS
NEN 7345
SWA
CFS
NEN 7345
TCLP
Method Precision
• Method 1315 Cumulative Release after 63 days
• NEN 7345
Cumulative Release after 16 days
• TCLP
Eluate Concentration
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Precision Comparison
(L/S-dependence Tests)
Reproducibility
Repeatability
100
80
80
60
60
RSDR (%)
RSDr (%)
100
40
20
Max SWA
Ba @ L/S 0.2
RSDR = 175%
Max
RSDR = 124%
Max
RSDR = 118%
40
20
0
EaFA
SWA
CFS
EN12457-2
0
EaFA
SWA
CFS
EN12457-2
TCLP
Method Precision
• Method 1316 Eluate Concentration (0.5  L/S  10 L/kg)
• EN12457-2
Eluate Concentration (L/S = 10 L/kg)
• TCLP
Eluate Concentration (L/S = 20 L/kg)
30 May - 1 June 2012
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20
Comparison of LEAF and EU Test Results
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WASCON, Gothenburg, Sweden
21
pH-dependence Tests
100
100
Solidified Waste Analog
Coal Combustion Fly Ash
1
0.1
0.01
ML
MDL
0.001
1
0.1
0.01
ML
MDL
0.001
0.0001
0.0001
2
4
6
8
10
12
14
0
2
4
6
pH
10
1
0.1
Coal Combustion Fly Ash
ML
MDL
0.001
0
2
4
6
8
pH
30 May - 1 June 2012
10
12
14
Molybdenum (mg/L)
10
0.01
8
10
12
14
pH
10
Solidified Waste Analog
Contaminated Field Soil
1
0.1
0.01
ML
MDL
0.001
0
2
4
6
8
10
12
pH
WASCON, Gothenburg, Sweden
14
Molybdenum (mg/L)
0
Molybdenum (mg/L)
L11-CEN/TS14429-A
L11-CEN/TS14429-B
L11-CEN/TS14429-C
L11-CEN/TS14997-A
L12-CEN/TS14997-A
L12-CEN/TS14997-B
L12-CEN/TS14997-C
M1313 Mean
M1313 95% RL
10
Chromium (mg/L)
Chromium (mg/L)
10
1
0.1
0.01
ML
MDL
0.001
0
2
4
6
8
10
12
14
pH
22
Percolation (Column) Tests
1000
Calcium Release (mg/kg)
100
10
1
0.1
ML
MDL
0.01
0.001
0.0001
Contaminated Field Soil
100
10
1
0.1
ML
MDL
0.01
0.001
0.0001
0.1
1
10
100
0.1
1
L/S (L/kg)
Molybdenum Release (mg/kg)
10
1
ML
0.1
MDL
0.01
0.001
0.0001
0.1
1
10
L/S (L/kg)
30 May - 1 June 2012
10
100
L/S (L/kg)
100
Copper Release (mg/kg)
L11-CEN/TS14405-A
L11-CEN/TS14405-B
L11-CEN/TS14405-C
M1313 Mean
M1313 95% RL
100
100
1
Zinc Release (mg/kg)
Boron Release (mg/kg)
1000
0.1
ML
MDL
0.01
0.001
0.0001
10
1
0.1
ML
0.01
MDL
0.001
0.0001
0.1
1
10
L/S (L/kg)
WASCON, Gothenburg, Sweden
100
0.1
1
10
100
L/S (L/kg)
23
Mass Transfer Tests
100000
Calcium Release (mg/m2)
Barium Release (mg/m2)
1000
100
10
1
ML
0.1
MDL
0.01
0.01
0.1
1
10
Solidified Waste Analog
10000
100
10
1
0.1
0.01
100
ML
MDL
0.1
10
100
1000
Iron Release (mg/m2)
10
1
ML
MDL
Antimony Release (mg/m2)
10
100
Boron Release (mg/m2)
1
Time (days)
Time (days)
0.1
1
ML
MDL
0.01
0.01
L11-CEN/TS15863-A
L11-CEN/TS15863-B
L11-CEN/TS15863-C
L11-NEN 7375-A
L11-NEN 7375-B
L11-NEN 7375-C
M1313 Mean
M1313 95% RL
1000
0.1
1
Time (days)
30 May - 1 June 2012
10
100
0.1
0.01
0.1
1
10
Time (days)
WASCON, Gothenburg, Sweden
100
100
10
1
ML
MDL
0.1
0.01
0.1
1
10
100
Time (days)
24
Conclusions
LEAF Method Validation
• Interlaboratory testing of triplicate tests from multiple laboratories
• LEAF methods can be performed with high degree of precision


5-13% Repeatability
14-28% Reproducibility
• Precision compares favorably to validated and accepted test methods
LEAF Methods as U.S. EPA SW-846 Standard Methods (Summer 2012)
Comparison to EU Tests
• Analogous EU Test to LEAF methods provide analogous data
• Validation of LEAF methods can serve as a basis for completing the standardization
process for CEN and ISO methods
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25
Acknowledgements
Participating Laboratories
• Oak Ridge National Lab
• Pacific Northwest National Lab
• Savannah River National Lab
• ARCADIS-US, Inc.
• Test America, Inc.
• URS Corporation, Inc.
•
•
•
•
•
•
Ohio State University
University of Wisconsin (Madison)
Missouri Univ. of Science & Tech.
Vanderbilt University
ECN
DHI
Funding and Support
• U.S. EPA, Office of Research and Development
• U.S. EPA, Office of Resource Conservation and Recovery
• U.S. DOE, Office of Environmental Management
• Consortium for Risk Evaluation with Stakeholder Participation (CRESP)
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Supplemental Information
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27
Method 1313 Overview
• Parallel batch as function of pH
Test Specifications
•
•
•
•
•
9 specified target pH values plus natural conditions
Size-reduced material
L/S = 10 mL/g-dry
Dilute HNO3 or NaOH
Contact time based on particle size

18-72 hours
• Reported Data



n samples
S1
A
n
chemical
analyses
S2
LA
B
Sn
LB
n
Ln
1000
Copper [mg/L]
Equilibrium Leaching Test
100
10
1
0.1
Equivalents of acid/base added
Eluate pH and conductivity
Eluate constituent concentrations
0.01
2
4
6
8 10 12
Leachate pH
14
Titration Curve and Liquid-solid Partitioning
(LSP) Curve as Function of Eluate pH
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28
Method 1314 Overview
Equilibrium Leaching Test
Luer fitting
air lock
Luer shut-off
valve
• Percolation through loosely-packed material
eluant collection bottle(s)
(sized for fraction volume)
Test Specifications
• 5-cm diameter x 30-cm high glass column
• Size-reduced material
• DI water or 1 mM CaCl2 (clays, organic materials)
• Upward flow to minimize channeling
• Collect leachate at cumulative L/S
Luer fitting
end cap
1-cm sand
layers
subject
material
N2 or Ar
(optional)

end cap
eluant
reservoir
pump
Luer shut-off
valve
0.2, 0.5, 1, 1.5, 2, 4.5, 5, 9.5, 10 mL/g-dry
• Reported Data



Eluate volume collected
Eluate pH and conductivity
Eluate constituent concentrations
Liquid-solid Partitioning (LSP) Curve as Function of
L/S; Estimate of Pore Water Concentration
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WASCON, Gothenburg, Sweden
29
Method 1315 Overview
Mass-Transfer Test
1 Sample
• Semi-dynamic tank leach test
or
Test Specifications
• Material forms


n Leaching Intervals
Δt1
Monolith
Δt2
Compacted
Granular
L2



Refresh time
Eluate pH and conductivity
Eluate constituent concentrations
Flux and Cumulative Release as a Function of
Leaching Time
30 May - 1 June 2012
WASCON, Gothenburg, Sweden
1000
Ln
Granular
Availability
100
Cr Release [mg/m 2]
• Reported Data
An
n
analytical
samples
L1
monolithic (all faces exposed)
compacted granular (1 circular face exposed)
2, 25, 48 hrs, 7, 14, 28, 42, 49, 63 days
Δtn
A2
A1
• DI water so that waste dictates pH
• Liquid-surface area ratio (L/A) of 9±1 mL/cm2
• Refresh leaching solution at cumulative times

Monolithic
10
1
0.1
0.01
ML
MDL
0.001
0.01
0.1
1
10
Leaching Time [days]
100
30
Method 1316 Overview
Equilibrium Leaching Test
• Parallel batch as function of L/S
Test Specifications
• Five specified L/S values (±0.2 mL/g-dry)

10.0, 5.0, 2.0, 1.0, 0.5 mL/g-dry
n samples
S1
S2
A
n
chemical
analyses
B
LA
LB
Sn
n
Ln
• Size-reduced material
• DI water (material dictates pH)
• Contact time based on particle size

18-72 hours
120
• Reported Data
Eluate L/S
Eluate pH and conductivity
Eluate constituent concentrations
Liquid-solid Partitioning (LSP) Curve as a Function
of L/S; Estimate of Pore Water Concentration
30 May - 1 June 2012
WASCON, Gothenburg, Sweden
Molybdenum [µg/L]



100
80
60
40
20
0
0
2
4
6
8
LS Ratio [mL/g-dry]
10
31