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
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
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
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
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
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
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
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
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
Cap
illary C
on
tamin
ated
Deep
All samples analyzed by
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 - -
Sample Jar 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.
Phase II False Negatives – What did Phase II miss that ISM captured? 2D Graph 8
Benzene F1-BTEX
Rate
of fa
lse n
egatives (%
)
0
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
CCME F1 Hydrocarbon Concentration 2D Graph 1
Plug Wedge Discrete Phase II
Concentr
ation (
ug/g
)
0
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
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
• 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
Top Related