SLIDE 1 Integrity Excellence Responsibility
Presenting Members
Comparing Discrete Sampling and Incremental Sampling Methodology with Petroleum Hydrocarbon Contaminated Soils in Canada
Kathlyne Hyde, Lisa Moelhman, Terry Obal, Steven Mamet, Trevor Carlson, Steven D. Siciliano
SLIDE 2 The Interstate Technology & Regulatory Council defines incremental sampling methodology (ISM) as a structured composite sampling and processing protocol.
Finalized guidelines released February 2012.
Advantages
- Estimates of the mean concentration of soil contamination
- Representative samples for a specific decision unit (DU)
- Reduced data variability
Background
SLIDE 3
- 1. Develop a protocol for performing incremental
sampling from push cores to analyze BTEX & F1-F4 hydrocarbons.
- 2. Compare ISM hydrocarbon results to the typical
Phase II results used in site assessments.
- 3. Evaluate ISM protocol for the use of remediation
plans.
Objectives
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1) Choose decision units (DU) 2) Choose sampling points within DU 3) Drill push cores to 6 meters depth 4) Phase II assessment 5) Incremental sampling methodology
Methods
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Site 1: Saskatoon, Saskatchewan
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Site 2: Raymore, Saskatchewan
DU1: Estimated impacted area DU2 DU4 DU3
SLIDE 7
1) Choose decision units (DU) 2) Choose sampling points within DU 3) Drill push cores to 6 meters depth and collect for storage until laboratory sampling can be done 4) Phase II assessment 5) Incremental sampling methodology
Methods
SLIDE 8
Drilling and collecting cores
SLIDE 9
Storage at -20 ͦͦ C
SLIDE 10
1) Choose decision units (DU) 2) Choose sampling points within DU 3) Drill push cores to 6 meters depth and collect for storage until laboratory sampling can be done 4) Phase II assessment 5) Incremental sampling methodology
Methods
SLIDE 11 In field:
- Core drilled
- Length of core scanned with photoionization detector
- Area with highest reading is sampled into methanol and jars for
laboratory analysis of BTEX & F1-F4
- Samples taken at increments of 0.5 m or 0.75 m
- Visual ID of contamination and subsequent sampling
- Details of soil profile are recorded
Phase II assessment
SLIDE 12
1) Choose decision units (DU) 2) Choose sampling points within DU 3) Drill push cores to 6 meters depth and collect for storage until laboratory sampling can be done 4) Phase II assessment 5) Incremental sampling methodology
Methods
SLIDE 13 Vertical DU’s
- Deciding what vertical soil portions to combine
Laboratory sampling
- Plug
- Every 5 cm for 1.5 m DU and every 10 cm for 3.0m DU
- Large for 2-D slabcake
- Small into methanol
- Wedge
- Along entire core
- Every 10 cm, a portion into methanol, 20 cm for 3.0 m DU
- Remainder of soil into 2-D slabcake
- Discrete
- Hotspot
- Terra-core into methanol
- Soil sample unhomogenized into jar
ISM Protocol
0 m 1.5 m 4.5 m 6.0 m Capillary Contaminated Deep All samples analyzed by
SLIDE 14
ISM Protocol: Preparing the core
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ISM Protocol: Sampling
Wedge sampling Plug sampling
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ISM Protocol: Homogenizing
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ISM Protocol: Volatile extractions
SLIDE 18 Soil mass: Phase II vs. ISM
Plug Wedge Discrete Phase II Methanol 54 g 13 g 5 g 5 g Slabcake 220 g 120 g
20 g 20 g Packed Packed
Fundamental error is due to compositional heterogeneity. Fundamental error is unavoidable due to our inability to randomly select soil particles to represent the DU, however, collecting sufficient mass can significantly reduce the error.
SLIDE 19 Phase II False Negatives – What did Phase II miss that ISM captured? Benzene F1-BTEX Rate of false negatives (%)
10 20 30 40 50 60
Plug Wedge Discrete
1) Our discrete sample detected contamination that Phase II did not 2) Wedge sampling protocol needs modification
SLIDE 20 CCME F1 Hydrocarbon Concentration
Plug Wedge Discrete Phase II Concentration (ug/g)
500 1000 1500 2000 2500 3000
Approximately 2000 ppm difference in concentration between plug and discrete sample Approximately 1200 ppm difference in concentration between plug and Phase II sample
SLIDE 21
How much soil is contaminated?
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Plume example: Saskatoon, SK
ISM Plug Protocol Phase II Protocol Courtesy of Steve Mamet
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The ISM plug protocol is much more effective than the wedge protocol. Phase II will provide worst-case scenario data and is suitable for identifying risk and making further site management decisions. ISM is useful for implementing in-situ remediation techniques to efficiently target contamination.
Conclusions
SLIDE 24
- Not useful for ex-situ remediation
When should you use ISM?
- Useful for in-situ remediation
- Replace a second Phase II assessment
- Plug protocol in the field
- Samples sent in for analysis do not increase
- Carefully place biostimulation/bioaugmentation delivery systems
- Fertilize according to soil mass contaminated for optimal C:N:P ratios
SLIDE 25 Integrity Excellence Responsibility
Supervisor: Steven Siciliano Maxxam Director of Scientific Services & Development: Terry Obal Environmental Soil Toxicology Lab Group + the undergrads
Special thanks to Richard Nhan, who without, this might have not been possible.