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 11-5-2-280.4-4.4 - Tank Closure in Place or Change in Service
Section 11-5-2-280.4-4.4.4 - Field Screening of Soils
In order to properly evaluate the appropriate depths to collect soil samples, conduct field screening in two foot intervals of the soil column in each boring. Field screening involves placing the soil in a container (normally a zipper-type plastic bag) and evaluating the headspace with a suitable hydrocarbon meter.
Because soils must be relatively undisturbed to obtain accurate field screening results, any boring that is conducted during sample collection/screening must be accomplished in a manner that will produce a "core" of the soil column. Cuttings produced from rotary drilling equipment are not acceptable for either field screening or sample collection.
In order for the field screening to be evaluated by UST staff, a boring log must be submitted along with the analytical results of sampling. The boring log must show the type of soil encountered throughout the length of the boring. The boring log must also show hydrocarbon vapor levels in parts per million as determined by the field screening process for every two feet of the boring. Please refer to Appendix G for an example of an acceptable boring log.
Soil samples must be conducted at the depth at which the highest levels of hydrocarbon vapors were detected during the field screening process. If no significant variations are found during field screening, samples must be collected from a depth of at least one foot below the bottom of the tanks into the native soil. If the field screening process reveals that all samples should be collected at less than maximum depths, at least one additional sample must be collected from the borehole that had the highest level of vapors found during the field screening process. This additional sample must be collected from a depth of one foot below the bottom of the tanks and into the native soil.
