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

Site 1: Saskatoon, Saskatchewan

Site 2: Raymore, Saskatchewan

DU1: Estimated impacted area

DU2

DU4

DU3

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

Drilling and collecting cores

Storage at -20 ͦͦ C

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

ISM Protocol: Preparing the core

ISM Protocol: Sampling

Wedge sampling Plug sampling

ISM Protocol: Homogenizing

ISM Protocol: Volatile extractions

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

How much soil is contaminated?

Plume example: Saskatoon, SK

ISM Plug Protocol Phase II Protocol

Courtesy of Steve Mamet

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

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.