Jay Clausen

Fate and Transport of High Explosives in a Sandy Soil: Adsorption and Desorption

Several areas of the Massachusetts Military Reservation (MMR) have soils with significant levels of high explosives (HE) contamination because of a long history of training and range activities (such as open burning, open detonation, disposal, and artillery and mortar firing). Site-specific transport and attenuation mechanisms were assessed in sandy soils for three contaminants of concern: the nitramine hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and the nitroaromatics 2,4-dinitrotolune (2,4-DNT) and 2,4,6-trinitrotoluene (TNT). For all three contaminants, linear distribution coefficients (Kd) were dependent on the fraction of organic carbon in soil. The nitroaromatics sorbed much more strongly than RDX in both soils. Over 120 hours, the desorption rate of RDX from field contaminated surface soil was much slower than its sorption rate, with the desorption Kd (1.5 L/kg) much higher than Kd for sorption (0.37 L/kg). Desorption of 2,4-DNT was negligible over 120 hours. Thus, applying sorption-derived Kd values for transport modeling may significantly overestimate the flux of explosives from MMR soils. Based on multiple component column transport tests, RDX will be the most mobile of these contaminants in MMR soils. In saturated columns packed with uncontaminated soil, RDX broke through rapidly, whereas the nitroaromatics were significantly attenuated by irreversible sorption or abiotic transformations.

Acetone Production as a Result of Sodium Bisulfate Preservation of Soil Samples

The use of sodium bisulfate for field preservation of soil samples collected for the analysis of volatile organics (VOCs) can result in the formation of acetone. The work was performed at Camp Edwards, Massachusetts, as part of a multi-year investigation of the effects of training activities on the local environment. Preservation with sodium bisulfate was initiated in 1999 under regulatory mandate. The frequency of acetone detection and the quantities reported increased immediately thereafter. Correlation of duplicate sample results and a side-by-side comparison of six sample handling methods involving two analytical laboratories suggest the interaction of sodium bisulfate with naturally occurring organic matter in samples from Camp Edwards cause the formation of acetone. The data also indicate that a higher content of natural organic matter results in a greater production of acetone, and more acetone is formed the longer the sodium bisulfate is in contact with the soil.