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 11-5-2-280.4-5 - SAMPLING LOCATIONS FOR DISPENSER ISLANDS & PIPING
Section 11-5-2-280.4-5.2 - Dispenser Islands
Section 11-5-2-280.4-5.2.3 - Dispenser Island Closure in Place
Since potentially contaminated soils cannot be seen during closure in place activities as when excavating, the sampling requirements for closure in place are more conservative. You must follow the exact guidelines given in this document unless special circumstances do not allow such. Any alternative sampling plan must be submitted to the UST Branch for approval at the same time the "Notice of Intent to Permanently Close UST System(s)" form is submitted.
Soil borings must be conducted at each end of the dispenser island and along the length of the island such that no more than 25 feet exists between any two borings as shown in Figure 9. The borings must extend to a depth of at least one foot below the bottom of the piping trench and into the native soil. Samples must be collected from each boring following the field screening practices as described in Section 4.4.4. If "true" groundwater (refer to Section 3.2) is encountered during soil boring activities, groundwater samples must be collected from each boring that contains groundwater and each sample must be analyzed separately. Soil sampling must be conducted from those borings that do not have groundwater. In addition, regardless of whatever soil and/or groundwater sampling that is conducted, one soil sample must be collected from the boring that exhibited the highest level of petroleum contamination during the field screening process.
