Mississippi Administrative Code
Title 11 - Mississippi Department of Environmental Quality
Part 5 - Underground Storage Tank Regulations
Chapter 2 - Mississippi Commission on Environmental Quality Underground Storage Tanks Regulations Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST) (Adopted March 22, 1989; Amended August 25, 2011, Last Amended August 23, 2018)
Appendix 11-5-2-280.4 - GUIDELINES FOR THE PERMANENT CLOSURE OF PETROLEUM UNDERGROUND STORAGE TANK SYSTEMS
Section 11-5-2-280.4-4 - SAMPLING LOCATIONS FOR TANKS
Section 11-5-2-280.4-4.3 - Removal of Two or More Tanks Within a Common Excavation
Section 11-5-2-280.4-4.3.2 - Removal of Two of More Tanks - Sidewall Contamination Apparent
If any of the sidewalls appear to be contaminated, all of the sidewalls must be sampled. As shown in Figure 5 below, a minimum of five samples are required to assess the excavation when the sidewalls are contaminated. One sample must be collected from each of the four sidewalls and one from the floor of the excavation. The sidewall samples must be collected from the area of each sidewall that appears to be the most contaminated. If a wall appears to be clean, the sample for that uncontaminated wall must be collected from the same depth where the highest level of contamination appears in the most contaminated wall of the excavation.
The fifth sample must come from the floor of the excavation. The floor sample must be collected from the area of the floor that appears to be the most contaminated. If no area of the floor appears contaminated or if it appears uniformly contaminated, the sample must be collected from the center of the excavation.
Soil sampling must also be conducted in such a manner that no more than 50 feet exists between any two sampling locations along each wall of the excavation.
