Global Approaches to Environmental Management on Military Training Ranges. Tracey Temple

reversible. Then, the delayed contaminants can return to their soluble state after a prolonged period of time, producing a long trail of contamination. The process of retardation in the transport of a contaminant is caused mainly by the adsorption processes.

      Adsorption refers to the attachment of a chemical to the surface of a soil particle. In soil, this process is exhibited when a molecule of gas, free liquid, or contaminants dissolved in water is attached to the surface of an individual soil particle (often in the form of organic carbon). This surface attachment can be physical (very weak, caused by van der Waals forces), chemical (much stronger, which often requires significant effort to separate) and exchange, i.e. characterised by electrical attraction between the sorbate and the surface (exemplified by ion-exchange processes). Since sorption is primarily a surface phenomenon, its activity is a direct function of the surface area of the solid as well as the electrical forces active on that surface. When a pollutant is adsorbed onto soil, it can be released only when the equilibrium between it and the passing fluid (water or air) is disrupted [109, 115].

      The process is complex, for which a delay factor is defined that slows down the transport velocity of the contaminant according to the following expression (1.9):

Vc=VwRd(1.9)

      where Vc = contaminant velocity, [L/T]; Vw = water velocity, [L/T]; Rd = retardation factor.

      The retardation factor describes the apparent discrepancy between the actual migration rate of aquifer water and that of a dissolved organic chemical (somewhat slower). The difference in travel rates is the result of sorption of the chemical onto the aquifer matrix and release into water by the concentration gradient and time of contact. A general equation used for gross estimation of the retardation factor R_d is (1.10):

Rd=1+ρnKd(1.10)

      where Rd = retardation factor, ρ = bulk density of soil, [M/L3]; Kd = partitioning coefficient, [L3/M]; n = effective porosity.

      The partitioning coefficient Kd can be calculated by (1.11):

Kd=Kocfoc(1.11)

      where Koc [L3/M] is the organic carbon equilibrium coefficient and foc is the fraction of organic carbon.

1.5 Conclusion

      Explosive contamination is frequently found in soil and groundwater at military training ranges. In order to prevent contamination, minimise remediation costs and ensure continued operation it is essential to understand the potential SPR linkages at a given site. This chapter has shown how the use of conceptual models based on the training range environment can be augmented by laboratory experiments and computational models to understand and predict explosive fate and transport to support identification of pollutant linkages.

References

[1] Oglanis A 2017 Study of environmental management systems on defence Glob. J. Environ. Sci. Manag. 3 103–20

[2] Walsh M E, Walsh M R, Collins C M and Racine C H 2014 White phosphorus contamination of an active army training range, water Air, Soil Pollut. 225 2001

[3] Clausen J, Robb J, Curry D and Korte N 2004 A case study of contaminants on military ranges: Camp Edwards, Massachusetts, USA Environ. Pollut. 129 13–21

[4] Fetter C W, Boving T and Kreamer D 2018 Derivation of the advection-dispersion equation for solute transport Contaminant Hydrogeology 3rd edn (Long Grove: Waveland Press) p 647

[5] Akhavan J 2011 The Chemistry of Explosives 3rd edn (Cambridge: The Royal Society of Chemistry)

[6] Dorbratz B M 1972 Technical Report: Properties of chemical explosives and explosive simulants, (UCRL-51319), Lawrence Livermore Laboratory, USA

[7] Singh S, Jelinek L, Samuels P, Di Stasio A and Zunino L IMX-104 Characterization for DoD qualification 2010 Insensitive Munitions Energ. Mater. Technol. Symp. (Munich, Germany) October 2010

[8] Walsh M R, Walsh M E, Taylor S, Ramsey C A, Ringelberg D B, Zufelt J E, Thiboutot S, Ampleman G and Diaz E 2013 Characterization of PAX-21 insensitive munition detonation residues Propell. Explosives, Pyrotech. 38 399–409

[9] Jenkins T F, Hewitt A D, Grant C L, Thiboutot S, Ampleman G, Walsh M E, Ranney T A, Ramsey C A, Palazzo A J and Pennington J C 2006 Identity and distribution of residues of energetic compounds at army live-fire training ranges Chemosphere 63 1280–90

[10] Hewitt A D, Jenkins T F, Ranney T A, Stark J A and Walsh M E 2003 Technical Report: Estimates for explosives residue from the detonation of army munitions ERDC/CRREL TR-03, 16 Hanover, USA

[11] Hewitt A D, Jenkins T F, Walsh M E, Walsh M R and Taylor S 2005 RDX and TNT residues from live-fire and blow-in-place detonations Chemosphere 61 888–94

[12] Taylor S, Campbell E, Perovich L, Lever J and Pennington J 2006 Characteristics of composition B particles from blow-in-place detonations Chemosphere 65 1405–13

      [13] Walsh M R, Walsh M E, Ramsey C A, Rachow R J, Zufelt J E, Collins C M, Gelvin A B, Perron N M and Saari S P 2006 Technical Report: Energetic residues deposition from 60-mm and 81-mm mortars ERDC/CRREL TR-06-10, Hanover, USA

[14] Walsh M R 2007 Technical Report: Explosives Residues Resulting from the Detonation of Common Military Munitions: 2002-2006 ERDC/CRREL TR-07-02, Hanover, USA

[15] Jenkins T F, Walsh M E, Miyares P H, Hewitt A D, Collins N H and Ranney T A 2002 Use of snow-covered ranges to estimate explosives residues from high-order detonations of army munitions Thermochim. Acta 384 173–85

[16] Walsh M R, Walsh M E and Ramsey C A 2012 Measuring energetic contaminant deposition rates on snow Water Air Soil Pollut. 223 3689–99

[17] Pennington J C, Silverblatt B, Poe K, Hayes C A and Yost S 2008 Explosive residues from low-order detonations of heavy artillery and mortar rounds Soil Sediment Contam. 17 533–46

[18] Taylor S, Lever J, Walsh M, Walsh M E, Bostick B and Packer B 2004 Technical Report: Underground UXO: Are They a Significant Source of Explosives in Soil Compared to Low-and High-Order Detonations? TR-04-23, Hanover, USA

[19] Taylor S, Bigl S and Packer B 2015 Condition of in situ unexploded ordnance Sci. Total Environ. 505 762–69

[20] United States Environmental Protection Agency 2014 Technical Fact Sheet—Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

[21] Lynch J C, Brannon