1.6 Frequently Asked Questions

Although ISM has advantages over traditional soil sampling practices, it may not be appropriate for all sampling applications.

Table 1-1 conveys many challenging points taken on by the ISM Team in preparing this document, including key points and frequently asked questions that are addressed within the referenced sections. Although ISM has advantages over traditional soil sampling practices, it may not be appropriate given the current state of technology for all sampling applications (e.g. low-level VOC analysis, possibly metal speciation, etc.) It is anticipated that technology advances will allow these limitations to be addressed.

Table 1-1. Crosswalk for frequently asked questions on ISM

Key Point/Question Reference
How can a regulator (or anyone) better assess ISM?
Section 1. Introduction
What is ISM and what are the advantages/ disadvantages of using it? Sections 1.3, 2.6.3, 3.5, and 8.5
Is ISM compositing? Sections 1.4, 2.6.2, and 2.6.3
Is ISM data more representative than discrete data? Sections 1.3, 2.3.2, and 2.6
When should ISM not be employed? Figure 1-1, Sections 3.1, 8.3, and 8.5
Section 2. Nature of Soil Sampling and Increment Sampling Principles
Is ISM really based on Gy's Theory? Section 2.5
Why do we care about the mean value in a DU? Section 2.1
Section 3. Systematic Planning and Decision Unit Designation
What is a DU, and how is it established? Sections 3.2 and 3.3
At what types of sites can ISM be used? Section 3.3
Can ISM be used at any point of an investigation? Sections 3.1, 3.2, and 3.3
How many increment and replicate samples should be collected? Sections 3.1, 2.5.6, 4, 5.3, 6.2.2.7, and Appendix A
How can ISM be used in risk assessments? Sections 3.1 and 3.3
Can ISM be used for ecological investigations? Sections 3.1, 3.2, 3.3, 4.4.4, 7.1, and 7.2.7
Can ISM be used to delineate "contamination"? Section 3
Can I use ISM when needed to determine whether contamination is a leaching concern? Sections 3.1, 3.2, 3.3, 8.3, and 8.5
How do you compare ISM background samples to background generated from discrete samples? Sections 3.1, 3.2, 3.3, 4.4.3.3, 7.2.4, and 8.5.4.7
Does ISM "mask" areas of high concentration or hot spots? Sections 3.5, 8.2, and 8.5
What soil sampling depth should be used with ISM? Sections 3.1, 3.3, 5.3.1, and 5.3.2
Section 4. Statistical Sampling Designs for ISM
How do you calculate a 95% upper confidence limit with ISM data? Section 4.2
Can ISM data/results be compared to discrete data/results? Sections 4.4.3.2 and 8.5.4.4
Section 5. Field Implementation, Sample Collection, and Processing
How do you sample for volatile organic compounds (VOCs) with ISM? Section 5.4.2
How do you ship VOC ISM samples? Section 5.4.2
Section 6. Laboratory Sample Processing and Analysis
What contaminants are most suitable for ISM? Section 6.1
Do ISM samples require more laboratory sample preparation? Section 6.2 and 8.5.5.2
What effects does sample processing (grinding, etc.) have on contaminant concentration? Section 6.2
How are DQOs addressed in the laboratory? Section 6.1
How do you address low-level reporting requirements of VOCs with ISM? Sections 6.3.2
Section 7. Making Decisions Using ISM Data
How do you use ISM data? Section 7
Section 8. Regulatory Concerns with ISM
What are the regulatory challenges and what are possible solutions? Section 8
Are there cost savings when using ISM instead of discrete only sampling? Section 8.5.3
Is subsurface ISM sampling cost-effective? Section 8.5.3
Can ISM data/results be compared to regulatory criteria (e.g., “not to exceed”)? Sections 8.5.4.5