Holding-Time Estimates for Soils Containing Explosives Residues: Comparison of Fortification vs. Field Contamination

Abstract

Maximum acceptable preextraction analytical holding times (MHTs) were estimated by spiking aqueous solutions of two nitramines, octahydro-1,3,5,7-tetranitro-l,3,5,7-tetrazocine (HMX) and hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) and three nitroaromatics, 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitrotoluene (TNT), and 2,4-dinitrotoluene (2,4-DNT), into three soils. Nitramines were stable over an 8-week test period at all storage temperatures, but nitroaromatics, which were reasonably stable when frozen, degraded rapidly at room temperature and more slowly under refrigeration. In contrast, both nitroaromatics and nitramines were quite stable under refrigeration for four field-contaminated soils. When three of these field-contaminated soils were subsequently fortified with TNT and TNB, rapid degradation under refrigeration was again observed for the added nitroaromatics. The rates of degradation were quite different in the three soils, further emphasizing the uncertainties in MHT estimates derived from fortified soils. We conclude that fortified soils can produce very different estimates of MHTs, recoveries, treatability, etc., compared to field-contaminated soils even when spiking is done in aqueous media.

Comparison of extraction techniques for the isolation of explosives and their degradation products from soil

“…60%) were achieved by pressurized solvent extraction. Generally, the low extraction recovery of tetryl may be the result of both low [26,38] and strong binding to the soil matrix. The effect of aged samples on the extractability of explosives by methods used in this article will be the subject of individual study focused both on the ageing of contaminated soil samples and relevant degradation processes in different soil matrices.…”

“…Pressurized solvent extraction was used as reference, because this method has been demonstrated more effective than the USE and MSE methods recommended in EPA procedures [22]. The method of spiking soil samples [38] we have used for these purposes. No.…”

Spiking hydrophobic organic compounds into soil and sediment: A review and critique of adopted procedures

“…The assessment of soil and sediment storage effects is often inconclusive when measuring ecotoxicological responses. The results obtained can depend on the type of test employed (whole sediment or pore-water toxicity test), the test species used [8][9][10], and chemical class of the test compound(s) [11,12]. Refrigeration of sediment also affects the chemical composition of interstitial water and aqueous extracts, particularly the concentration and chemical nature of dissolved organic matter [13,14].…”