1.6 Frequently Asked Questions
Table 11 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. lowlevel VOC analysis, possibly metal speciation, etc.) It is anticipated that technology advances will allow these limitations to be addressed.
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 11, 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 lowlevel 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 costeffective?  Section 8.5.3 
Can ISM data/results be compared to regulatory criteria (e.g., “not to exceed”)?  Sections 8.5.4.5 