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There are many sites where soil and/or groundwater are contaminated with metals and metalloids (collectively referred to as “metals” henceforth) that require some type of response. The most commonly occurring metals at Superfund sites are lead, chromium, arsenic, zinc, cadmium, copper, and mercury. Many remediation technologies that are used at sites with organic contaminants can be also be used at sites with metals contamination with one major exception: metals are not destroyed by chemical or biological degradation. At smaller sites, metal contaminants in soils are commonly treated by excavation. In groundwater, metals plumes are treated by pump-and-treat systems, monitored natural attenuation of metals, or remediated by changing the groundwater geochemistry to immobilize the metal contaminants to prevent migration to receptors.
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The heterogeneous distribution of munitions constituents, released as particles from munitions firing and detonations on military training ranges, presents challenges for representative soil sample collection and for defensible decision making. Military range characterization studies and the development of the incremental sampling methodology (ISM) have enabled the development of recommended methods for soil sampling that produce representative and reproducible concentration data for munitions constituents. This article provides a broad overview of recommended soil sampling and processing practices for analysis of munitions constituents on military ranges.  
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<div style="float:right;margin:0 0 2em 2em;">__TOC__</div>
  
<div style="float:right;margin:0 0 2em 2em;">__TOC__</div>
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'''Related Article(s)''':  
  
'''Related Article(s)''':
 
*[[Metal and Metalloid Contaminants]]
 
*[[Mobility of Metals and Metalloid Contaminants in Groundwater]]
 
*[[Monitored Natural Attenuation (MNA) of Metal and Metalloid Contaminants]]
 
  
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'''CONTRIBUTOR(S):'''  [[Dr. Samuel Beal]]
  
'''CONTRIBUTOR(S):''' [[Dr. Miles Denham]] and [[Dr. Charles Newell, P.E.]]
 
  
 
'''Key Resource(s)''':  
 
'''Key Resource(s)''':  
*[http://www.environmentalrestoration.wiki/images/1/16/Evanko-1997-Remed_of_Metals.pdf Remediation of Metals Contaminated Soils and Groundwater]<ref name="Evanko1997">Evanko, C.R. and Dzombak, D.A., 1997. Remediation of metals-contaminated soils and groundwater. TE-97-01. Ground-water remediation technologies analysis center. [http://www.environmentalrestoration.wiki/images/1/16/Evanko-1997-Remed_of_Metals.pdf Report pdf]</ref>
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*[[media:Taylor-2011 ERDC-CRREL TR-11-15.pdf| Guidance for Soil Sampling of Energetics and Metals]]<ref name= "Taylor2011">Taylor, S., Jenkins, T.F., Bigl, S., Hewitt, A.D., Walsh, M.E. and Walsh, M.R., 2011. Guidance for Soil Sampling for Energetics and Metals (No. ERDC/CRREL-TR-11-15). [[media:Taylor-2011 ERDC-CRREL TR-11-15.pdf| Report.pdf]]</ref>
 
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*[[Media:Hewitt-2009 ERDC-CRREL TR-09-6.pdf| Report.pdf | Validation of Sampling Protocol and the Promulgation of Method Modifications for the Characterization of Energetic Residues on Military Testing and Training Ranges]]<ref name= "Hewitt2009">Hewitt, A.D., Jenkins, T.F., Walsh, M.E., Bigl, S.R. and Brochu, S., 2009. Validation of sampling protocol and the promulgation of method modifications for the characterization of energetic residues on military testing and training ranges (No. ERDC/CRREL-TR-09-6). Engineer Research and Development Center / Cold Regions Research and Engineering Lab (ERDC/CRREL) TR-09-6, Hanover, NH, USA. [[Media:Hewitt-2009 ERDC-CRREL TR-09-6.pdf | Report.pdf]]</ref>  
*Groundwater and Soil Cleanup: Improving Management of Persistent Contaminants<ref name= "NAS1999">National Research Council, 1999. Groundwater and soil cleanup: Improving management of persistent contaminants. National Academies Press.</ref>
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*[[media:Epa-2006-method-8330b.pdf| U.S. EPA SW-846 Method 8330B: Nitroaromatics, Nitramines, and Nitrate Esters by High Performance Liquid Chromatography (HPLC)]]<ref name= "USEPA2006M">U.S. Environmental Protection Agency (USEPA), 2006. Method 8330B (SW-846): Nitroaromatics, Nitramines, and Nitrate Esters by High Performance Liquid Chromatography (HPLC), Rev. 2. Washington, D.C. [[media:Epa-2006-method-8330b.pdf | Report.pdf]]</ref>
 
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*[[media:Epa-2007-method-8095.pdf | U.S. EPA SW-846 Method 8095: Explosives by Gas Chromatography.]]<ref name= "USEPA2007M">U.S. Environmental Protection Agency (US EPA), 2007. Method 8095 (SW-846): Explosives by Gas Chromatography. Washington, D.C. [[media:Epa-2007-method-8095.pdf| Report.pdf]]</ref>
*[http://www.environmentalrestoration.wiki/images/e/e3/TRUEX-2011-Scenarios_Approach_to_Attenuation-Based_Remedies.pdf The Scenarios Approach to Attenuation-Based Remedies for Inorganic and Radionuclide Contaminants]<ref name="Truex2011">Truex, M., Brady, P., Newell, C.J., Rysz, M., Denham, M., Vangelas, K. 2011. The scenarios approach to attenuation-based remedies for inorganic and radionuclide contaminants. Savannah-River National Laboratory U.S. Department of Energy. [http://www.environmentalrestoration.wiki/images/e/e3/TRUEX-2011-Scenarios_Approach_to_Attenuation-Based_Remedies.pdf Report pdf]</ref>  
 
  
 
==Introduction==
 
==Introduction==
Engineered remediation of metal and metalloid contaminants in groundwater can be accomplished by (a) removal of the contaminants from the subsurface or (b) treating them in situ to reduce their mobility or concentration to levels considered safe to human health or the environment. In situ treatment means the contaminant metals are left in the subsurface. Therefore, it must be demonstrated that the rate of release of the contaminants from the treatment zone will be low and stable enough that the contaminants will pose minimal risk over a long period of time. Excellent reviews of technologies for remediation of metal and metalloid contaminated groundwater are available such as:
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[[File:Beal1w2 Fig1.png|thumb|200 px|left|Figure 1: Downrange distance of visible propellant plume on snow from the firing of different munitions. Note deposition behind firing line for the 84-mm rocket. Data from: Walsh et al.<ref>Walsh, M.R., Walsh, M.E., Ampleman, G., Thiboutot, S., Brochu, S. and Jenkins, T.F., 2012. Munitions propellants residue deposition rates on military training ranges. Propellants, Explosives, Pyrotechnics, 37(4), pp.393-406. [http://dx.doi.org/10.1002/prep.201100105 doi: 10.1002/prep.201100105]</ref><ref>Walsh, M.R., Walsh, M.E., Hewitt, A.D., Collins, C.M., Bigl, S.R., Gagnon, K., Ampleman, G., Thiboutot, S., Poulin, I. and Brochu, S., 2010. Characterization and Fate of Gun and Rocket Propellant Residues on Testing and Training Ranges: Interim Report 2. (ERDC/CRREL TR-10-13.  Also: ESTCP Project ER-1481)  [[media:Walsh-2010 ERDC-CRREL TR-11-15 ESTCP ER-1481.pdf| Report]]</ref>]]
*''Remediation of Metals Contaminated Soils and Groundwater (1997)''<ref name="Evanko1997"/>: Describes the sources, fate, transport, and influence of soil properties on mobility and then discusses general remediation approaches followed by several commercial processes.
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[[File:Beal1w2 Fig2.png|thumb|left|200 px|Figure 2: A low-order detonation mortar round (top) with surrounding discrete soil samples produced concentrations spanning six orders of magnitude within a 10m by 10m area (bottom). (Photo and data: A.D. Hewitt)]]
  
*''Groundwater and Soil Cleanup: Improving Management of Persistent Contaminants (1999)''<ref name= "NAS1999"/>: Focuses on both mobilization technologies (in order to move metals to a location where it can be treated) and immobilization technologies (in order to stabilize metals in place and prevent further spreading).
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Munitions constituents are released on military testing and training ranges through several common mechanisms. Some are locally dispersed as solid particles from incomplete combustion during firing and detonation. Also, small residual particles containing propellant compounds (e.g., [[Wikipedia: Nitroglycerin | nitroglycerin [NG]]] and [[Wikipedia: 2,4-Dinitrotoluene | 2,4-dinitrotoluene [2,4-DNT]]]) are distributed in front of and surrounding target practice firing lines (Figure 1). At impact areas and demolition areas, high order detonations typically yield very small amounts (<1 to 10 mg/round) of residual high explosive compounds (e.g., [[Wikipedia: TNT | TNT ]], [[Wikipedia: RDX | RDX ]] and [[Wikipedia: HMX | HMX ]]) that are distributed up to and sometimes greater than) 24 m from the site of detonation<ref name= "Walsh2017">Walsh, M.R., Temple, T., Bigl, M.F., Tshabalala, S.F., Mai, N. and Ladyman, M., 2017. Investigation of Energetic Particle Distribution from High‐Order Detonations of Munitions. Propellants, Explosives, Pyrotechnics, 42(8), pp.932-941. [https://doi.org/10.1002/prep.201700089 doi: 10.1002/prep.201700089] [[media: Walsh-2017-High-Order-Detonation-Residues-Particle-Distribution-PEP.pdf| Report.pdf]]</ref>.
  
*''Remediation Technologies for Metal-Contaminated Soils and Groundwater; an Evaluation (2001)''<ref name="Mulligan2001">Mulligan, C.N., Yong, R.N. and Gibbs, B.F., 2001. Remediation technologies for metal-contaminated soils and groundwater: an evaluation. Engineering Geology, 60(1), pp.193-207. [http://dx.doi.org/10.1016/s0013-7952(00)00101-0 doi: 10.1016/S0013-7952(00)00101-0]</ref>: Explains how remediation approach depends on site characteristics, concentration, pollutants types, and the final use of the soil or groundwater. Key approaches include isolation, immobilization, toxicity reduction, physical separation, and extraction.  
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Low-order detonations and duds are thought to be the primary source of munitions constituents on ranges<ref>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(6), pp.888-894. [https://doi.org/10.1016/j.chemosphere.2005.04.058 doi: 10.1016/j.chemosphere.2005.04.058]</ref><ref>Walsh, M.R., Walsh, M.E., Poulin, I., Taylor, S. and Douglas, T.A., 2011. Energetic residues from the detonation of common US ordnance. International Journal of Energetic Materials and Chemical Propulsion, 10(2). [https://doi.org/10.1615/intjenergeticmaterialschemprop.2012004956 doi: 10.1615/IntJEnergeticMaterialsChemProp.2012004956] [[media:Walsh-2011-Energetic-Residues-Common-US-Ordnance.pdf| Report.pdf]]</ref>. Duds are initially intact but may become perforated or fragmented into micrometer to centimeter;o0i0k-sized particles by nearby detonations<ref>Walsh, M.R., Thiboutot, S., Walsh, M.E., Ampleman, G., Martel, R., Poulin, I. and Taylor, S., 2011. Characterization and fate of gun and rocket propellant residues on testing and training ranges (No. ERDC/CRREL-TR-11-13). Engineer Research and Development Center / Cold Regions Research and Engineering Lab (ERDC/CRREL) TR-11-13, Hanover, NH, USA. [[media:Epa-2006-method-8330b.pdf| Report.pdf]]</ref>. Low-order detonations can scatter micrometer to centimeter-sized particles up to 20 m from the site of detonation<ref name= "Taylor2004">Taylor, S., Hewitt, A., Lever, J., Hayes, C., Perovich, L., Thorne, P. and Daghlian, C., 2004. TNT particle size distributions from detonated 155-mm howitzer rounds. Chemosphere, 55(3), pp.357-367.[[media:Taylor-2004 TNT PSDs.pdf| Report.pdf]]</ref>
  
*''Remediation technologies for heavy metal contaminated groundwater (2011)''<ref name="Hashim2011">Hashim, M.A., Mukhopadhyay, S., Sahu, J.N. and Sengupta, B., 2011. Remediation technologies for heavy metal contaminated groundwater. Journal of Environmental Management, 92(10), pp.2355-2388. [http://dx.doi.org/10.1016/j.jenvman.2011.06.009 doi: 10.1016/j.jenvman.2011.06.009]</ref>: Describes “Thirty-five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes.
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The particulate nature of munitions constituents in the environment presents a distinct challenge to representative soil sampling. Figure 2 shows an array of discrete soil samples collected around the site of a low-order detonation – resultant soil concentrations vary by orders of magnitude within centimeters of each other. The inadequacy of discrete sampling is apparent in characterization studies from actual ranges which show wide-ranging concentrations and poor precision (Table 1).
  
==Subsurface Removal of Contaminants==
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In comparison to discrete sampling, incremental sampling tends to yield reproducible concentrations (low relative standard deviation [RSD]) that statistically better represent an area of interest<ref name= "Hewitt2009"/>.
The advantage of remediation technologies that remove metal and metalloid contaminants from the subsurface is that, when remediation is complete, the risk is eliminated. Excavation and pump-and-treat are also widely available and accepted by regulators and stakeholders. However, the primary disadvantage of technologies that remove contaminants from the subsurface is that they create contaminated solid waste that must be disposed. Additional issues are worker exposure, prolonged disturbance of the surface environment, and long-term maintenance costs for treatments relying on treating groundwater at the surface. Overall, there is a large range of contaminant removal technologies each with advantages and disadvantages (Table 1).
 
  
{| class="wikitable"
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{| class="wikitable" style="float: right; text-align: center; margin-left: auto; margin-right: auto;"
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|+ Table 1. Soil Sample Concentrations and Precision from Military Ranges Using Discrete and Incremental Sampling. (Data from Taylor et al. <ref name= "Taylor2011"/> and references therein.)
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|-
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! Military Range Type !! Analyte !! Range<br/>(mg/kg) !! Median<br/>(mg/kg) !! RSD<br/>(%)
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|-
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| colspan="5" style="text-align: left;" | '''Discrete Samples'''
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|-
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| Artillery FP || 2,4-DNT || <0.04 – 6.4 || 0.65 || 110
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|-
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| Antitank Rocket || HMX || 5.8 – 1,200 || 200 || 99
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|-
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| Bombing || TNT || 0.15 – 780 || 6.4 || 274
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|-
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| Mortar || RDX || <0.04 – 2,400 || 1.7 || 441
 
|-
 
|-
!style="background-color:#CEE0F2;"|Technology (Target Media)!!style="background-color:#CEE0F2;"|Description !!style="background-color:#CEE0F2;"|Advantages!!style="background-color:#CEE0F2;"|Disadvantages !!style="background-color:#CEE0F2;"|Reference(s)
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| Artillery || RDX || <0.04 – 170 || <0.04 || 454
 
|-
 
|-
| Excavation (Contaminated soils)|| Removal of contaminated soils in unsaturated zone to eliminate secondary source of contamination|| Widely available and accepted|| Creates large amount of solid waste; not feasible in some geology; expense increases significantly for excavation below the water table.|| Post, et al., 2013<ref>Post, T.C., Strom, D. and Beulow, L., 2013, July. The 100-C-7 Remediation Project. An Overview of One of DOE's Largest Remediation Projects-13260. WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States). [http://www.environmentalrestoration.wiki/images/c/ce/Post-2013-100-C-7_Remediation_Project.pdf Report pdf]</ref>
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| colspan="5" style="text-align: left;" | '''Incremental Samples*'''
 
|-
 
|-
| Pump-and-Treat (Groundwater plumes)|| Extraction of contaminated groundwater by well network for treatment at surface|| Widely available and accepted|| Surface treatment system can be expensive. Can require long time frames to reach remedial goals because of sorption of metals and metalloids|| Mackay and Cherry, 1989<ref>Mackay, D.M. and Cherry, J.A., 1989. Groundwater contamination: Pump-and-treat remediation. Environmental Science & Technology, 23(6), pp.630-636. [http://dx.doi.org/10.1021/es00064a001 doi: 10.1021/es00064a001]</ref>; Mercer, et al., 1990<ref>Mercer, J.W., Skipp, D.C. and Giffin, D., 1990. Basics of pump-and-treat ground-water remediation technology (pp. 1-66). EPA-600/8-90/003. Robert S. Kerr Environmental Research Laboratory, Office of Research and Development, US Environmental Protection Agency. [http://www.environmentalrestoration.wiki/images/2/28/Mercer-1990-Basics_of_Pump_%26_Treat.pdf Report pdf]</ref>
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| Artillery FP || 2,4-DNT || 0.60 – 1.4 || 0.92 || 26
 
|-
 
|-
| Electrokinetics
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| Bombing || TNT || 13 – 17 || 14 || 17
(Contaminated fine grained material such as clays)
 
|| Deployment of electrodes in subsurface to create an electrical field that drives contaminants to the electrodes|| Effective in clay-rich aquifers; potential for less solid waste than excavation or pump-and-treat|| Rarely used; Increase of pH near cathode causing precipitation of metal salts; efficiency decreases outside of specific aquifer and contamination conditions|| Van Cauwenberghe, 1997<ref>Van Cauwenberghe, L., 1997.  Electrokinetics. TO-97-03. Ground-water remediation technologies analysis center. [http://www.environmentalrestoration.wiki/images/2/20/Van_Cauwenberghe-1997-Electrokinetics.pdf]</ref>; Virkutyte, et al., 2002<ref>Virkutyte, J., Sillanpää, M. and Latostenmaa, P., 2002. Electrokinetic soil remediation—critical overview. Science of the Total Environment, 289(1), pp.97-121. [http://dx.doi.org/10.1016/s0048-9697(01)01027-0 doi: 10.1016/S0048-9697(01)01027-0]</ref>; Vocciante, et al., 2016<ref>Vocciante, M., Caretta, A., Bua, L., Bagatin, R. and Ferro, S., 2016. Enhancements in ElectroKinetic Remediation Technology: Environmental assessment in comparison with other configurations and consolidated solutions. Chemical Engineering Journal, 289, pp.123-134. [http://dx.doi.org/10.1016/j.cej.2015.12.065 doi:10.1016/j.cej.2015.12.065]</ref>
 
 
|-
 
|-
| Phytoextraction
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| Artillery/Bombing || RDX || 3.9 – 9.4 || 4.8 || 38
(Mostly contaminated soils, sometimes groundwater)
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|-  
|| Use of plants to extract contaminants from the subsurface|| Only periodic maintenance (harvesting and processing of plants or plant detritus) once plants are established|| Need long-term access to treat soils. Difficult to treat deep groundwater.  Requires hyperaccumulating plants that may not exist for metals that are not essential nutrients|| Pivetz, 2001<ref>Pivetz, B.E., 2001. Phytoremediation of Contaminated Soil and Ground Water at Hazardous Waste Sites. EPA/540/S-01/500. US Environmental Protection Agency. [http://www.environmentalrestoration.wiki/images/5/5f/Pivetz-2001-Phytoremediation.pdf Report pdf]</ref>; McGrath and Zhao, 2003<ref>McGrath, S.P. and Zhao, F.J., 2003. Phytoextraction of metals and metalloids from contaminated soils. Current Opinion in Biotechnology, 14(3), pp.277-282. [http://dx.doi.org/10.1016/s0958-1669(03)00060-0 doi: 10.1016/S0958-1669(03)00060-0]</ref>; Sheoran and Poonia, 2016<ref>Sheoran, V., Sheoran, A.S. and Poonia, P., 2016. Factors affecting phytoextraction: A review. Pedosphere, 26(2), pp.148-166. [http://dx.doi.org/10.1016/S1002-0160(15)60032-7 doi: 10.1016/S1002-0160(15)60032-7]</ref>
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| Thermal Treatment || HMX || 3.96 – 4.26 || 4.16 || 4
 
|-
 
|-
| colspan="12" style="color:black;text-align:left;"|Table 1:  Summary of technologies that remove contaminants from the subsurface.
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| colspan="5" style="text-align: left; background-color: white;" | * For incremental samples, 30-100 increments and 3-10 replicate samples were collected.
 
|}
 
|}
Improving the efficiency and reducing the cost of excavation, pump-and-treat, electrokinetics, and phytoextraction remains an important pursuit. Sometimes, the technologies in Table 1 can be combined to reduce costs. For excavation, the primary focus has been on reducing the volume of contaminated soil needing special disposal. This can involve soil washing<ref>ITRC, 1997. Technical and Regulatory Guidelines for Soil Washing. Interstate Technology and Regulatory Council. [http://www.environmentalrestoration.wiki/images/3/3c/ITRC-1997-Tech_%26_Reg_Guidelines_for_Soil_Washing.pdf Report pdf]</ref><ref>Dermont, G., Bergeron, M., Mercier, G. and Richer-Laflèche, M., 2008. Soil washing for metal removal: a review of physical/chemical technologies and field applications. Journal of Hazardous Materials, 152(1), pp.1-31. [http://dx.doi.org/10.1016/j.jhazmat.2007.10.043 doi: 10.1016/j.jhazmat.2007.10.043]</ref> where water-based solutions of chemicals are used to removal metals from excavated soils, though electrokinetics and phytoextraction can also be used to clean contaminated soil piles. Soil flushing involves injecting reagents into the subsurface that mobilize the metal contaminants to make them more available for removal by pump-and-treat, electrokinetics, and phytoextraction<ref>Roote, D.S., 1997. In Situ Flushing. TO-97-02. Ground-water remediation technologies analysis center.[http://www.environmentalrestoration.wiki/images/c/ca/Roote-2008-In_Situ_Flushing.pdf Report pdf]</ref><ref>Leštan, D., Luo, C.L. and Li, X.D., 2008. The use of chelating agents in the remediation of metal-contaminated soils: a review.  Environmental Pollution,153(1), pp.3-13. [http://dx.doi.org/10.1016/j.envpol.2007.11.015 doi: 10.1016/j.envpol.2007.11.015]</ref>.
 
   
 
The most common approaches for managing soils contamination at smaller metals sites are excavation and phytoextraction. Pump-and-treat systems are widely used for metal and metalloid contaminated groundwater. Electrokinetic projects for remediating metals sites are now relatively rare with few applications after the mid 2000s.
 
  
==In Situ Remediation==
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==Incremental Sampling Approach==
Issues with the access, cost, and efficiency of metals and metalloids removal from the subsurface have driven efforts to develop methods that rely solely on in situ reactions to minimize the movement of these contaminants towards points of exposure. These efforts can range from monitored natural attenuation of metals<ref name="EPA2015">U.S. Environmental Protection Agency (USEPA), 2015. Use of Monitored Natural Attenuation for Inorganic contaminants in Groundwater at Superfund Sites. Directive 9283.1-36, Office of Solid Waste and Emergency Response, United States Environmental Protection Agency. [http://www.environmentalrestoration.wiki/images/d/dc/MNA-Guidance-2015.pdf Report.pdf]</ref> that relies solely on natural processes to engineered treatments deployed in the subsurface. Examples of engineered treatments include:
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ISM is a requisite for representative and reproducible sampling of training ranges, but it is an involved process that is detailed thoroughly elsewhere<ref name= "Hewitt2009"/><ref name= "Taylor2011"/><ref name= "USEPA2006M"/>. In short, ISM involves the collection of many (30 to >100) increments in a systematic pattern within a decision unit (DU). The DU may cover an area where releases are thought to have occurred or may represent an area relevant to ecological receptors (e.g., sensitive species). Figure 3 shows the ISM sampling pattern in a simplified (5x5 square) DU. Increments are collected at a random starting point with systematic distances between increments. Replicate samples can be collected by starting at a different random starting point, often at a different corner of the DU. Practically, this grid pattern can often be followed with flagging or lathe marking DU boundaries and/or sampling lanes and with individual pacing keeping systematic distances between increments. As an example, an artillery firing point might include a 100x100 m DU with 81 increments.
*Adding an electron donor, such as lactate, to biologically turn the groundwater anaerobic, thereby precipitating or increasing the sorption metals such as chromium, uranium, cadmium, copper, lead, and zinc in groundwater. Sometimes, sulfate is also added with the electron donor so this reaction will generate hydrogen sulfide, which can also precipitate these metals<ref name = "NABIR2003">NABIR, 2003. Bioremediation of metals and radionuclides – what it is and how It works. LBNL-42595, Lawrence Berkeley National Laboratory for the Natural and Accelerated Bioremediation Research Program, Office of Science, U.S. Department of Energy [http://www.environmentalrestoration.wiki/images/9/97/NABIR-2003-Bioremediation_of_Metals_and_Radionuclides.pdf Report pdf]</ref>
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[[File:Beal1w2 Fig3.png|thumb|200 px|left|Figure 3. Example ISM sampling pattern on a square decision unit. Replicates are collected in a systematic pattern from a random starting point at a corner of the DU. Typically more than the 25 increments shown are collected]]
*Adding oxygen to turn groundwater more aerobic, thereby reducing the mobility of arsenic<ref name="Hashim2011"/>
 
  
In situ remediation requires strong evidence that remaining, treated contaminants will not be a threat for long time periods. For example, when mobile Chrome(VI) (oxidation state of six) is converted to immobile Chrome(III) by adding electron donor, it does not reoxidize back to Chrome(VI) except under unique conditions (e.g., high manganese concentrations)<ref name="Truex2011"/>. The strength of the evidence for effective treatment usually depends on the toxicity of the contaminant and the length of time it will take the contaminant to reach receptors at hazardous concentrations. In situ treatments are not designed to eliminate the flux of contaminants toward receptors, but rather to keep the flux below levels that are a threat.
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DUs can vary in shape (Figure 4), size, number of increments, and number of replicates according to a project’s data quality objectives.
  
In situ remediation can be divided into two broad categories:
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[[File:Beal1w2 Fig4.png|thumb|right|250 px|Figure 4: Incremental sampling of a circular DU on snow shows sampling lanes with a two-person team in process of collecting the second replicate in a perpendicular path to the first replicate. (Photo: Matthew Bigl)]]
#Physical barriers to contaminant migration, and
 
#Chemical barriers to contaminant migration.  
 
  
Physical barriers include subsurface walls that block or redirect groundwater flow and methods of trapping contaminants in engineered low permeability zones. An example is a slurry wall where a low-permeability benonite material is emplaced in a trench around groundwater source zone to reduce the flow through this source zone<ref name= "Pearlman1999">Pearlman, L., 1999. Subsurface containment and monitoring systems: Barriers and beyond. National Network of Environmental Management Studies Fellow for US Environmental Protection Agency, pp.1-61. [http://www.environmentalrestoration.wiki/images/b/b6/Pearlman-1999-Barriers_and_Beyond.pdf Report pdf]</ref>. Chemical barriers involve placement of reagents in the subsurface that react with contaminants to minimize their mobility in groundwater. The reagents either react directly with the contaminants or change the geochemistry of the subsurface in a way that reduces contaminant mobility. An example of this approach is construction of a permeable reactive barrier filled with zero valent iron that reduces soluble uranium(VI) entering the barrier to uranium(IV) that is removed from groundwater by precipitation<ref name= "Naftz2002">Naftz, D., Morrison, S.J., Fuller, C.C. and Davis, J.A. eds., 2002. Handbook of groundwater remediation using permeable reactive barriers: applications to radionuclides, trace metals, and nutrients. Academic Press. [http://store.elsevier.com/Handbook-of-Groundwater-Remediation-using-Permeable-Reactive-Barriers/isbn-9780080533056/ eISBN:9780080533056]</ref><ref name = "ITRC2011PRB">ITRC, 2011. Permeable Reactive Barrier: Technology Update. Interstate Technology and Regulatory Council. [http://www.environmentalrestoration.wiki/images/0/0e/ITRC-2011-PRB_Tech_Update.pdf Report pdf]</ref>. Treatment by chemical barriers is often referred to as enhanced attenuation because the purpose is to increase the attenuation capacity of the aquifer. Combinations of physical and chemical barriers can also be used. For example, “funnel-and-gate” systems use subsurface physical barriers to direct contaminated groundwater through “gates” where reagents are deployed to react with the contaminants.
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==Sampling Tools==
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In many cases, energetic compounds are expected to reside within the soil surface. Figure 5 shows soil depth profiles on some studied impact areas and firing points. Overall, the energetic compound concentrations below 5-cm soil depth are negligible relative to overlying soil concentrations. For conventional munitions, this is to be expected as the energetic particles are relatively insoluble, and any dissolved compounds readily adsorb to most soils<ref>Pennington, J.C., Jenkins, T.F., Ampleman, G., Thiboutot, S., Brannon, J.M., Hewitt, A.D., Lewis, J., Brochu, S., 2006. Distribution and fate of energetics on DoD test and training ranges: Final Report. ERDC TR-06-13, Vicksburg, MS, USA. Also: SERDP/ESTCP Project ER-1155. [[media:Pennington-2006_ERDC-TR-06-13_ESTCP-ER-1155-FR.pdf| Report.pdf]]</ref>. Physical disturbance, as on hand grenade ranges, may require deeper sampling either with a soil profile or a corer/auger.
  
===Design Considerations===
+
[[File:Beal1w2 Fig5.png|thumb|left|200 px|Figure 5. Depth profiles of high explosive compounds at impact areas (bottom) and of propellant compounds at firing points (top). Data from: Hewitt et al. <ref>Hewitt, A.D., Jenkins, T.F., Ramsey, C.A., Bjella, K.L., Ranney, T.A. and Perron, N.M., 2005. Estimating energetic residue loading on military artillery ranges: Large decision units (No. ERDC/CRREL-TR-05-7). [[media:Hewitt-2005 ERDC-CRREL TR-05-7.pdf| Report.pdf]]</ref> and Jenkins et al. <ref>Jenkins, T.F., Ampleman, G., Thiboutot, S., Bigl, S.R., Taylor, S., Walsh, M.R., Faucher, D., Mantel, R., Poulin, I., Dontsova, K.M. and Walsh, M.E., 2008. Characterization and fate of gun and rocket propellant residues on testing and training ranges (No. ERDC-TR-08-1). [[media:Jenkins-2008 ERDC TR-08-1.pdf| Report.pdf]]</ref>]]
Engineered treatment of contaminants in situ requires careful consideration of groundwater flow to ensure that treatments are placed in the optimal locations and orientations. In addition, the effects of the treatment on groundwater flow must be considered. Physical barriers redirect groundwater flow by design. In the case of subsurface barriers designed to block groundwater flow, the groundwater will “pile” up at the barrier, flow around the barrier, and/or flow beneath the barrier and designs must incorporate these consequences. Likewise, chemical barriers can sometimes reduce permeability forcing contaminated groundwater around the treated zone.
 
  
The design and limitations of physical barriers depend primarily on the characteristics of the site rather than the contaminants present. For example, if there is hard crystalline rock between the surface and the contamination, it may be difficult to install a physical barrier. In contrast, site characteristics influence design of chemical barriers or enhanced attenuation, but the primary consideration is the contaminants present.  
+
Soil sampling with the Cold Regions Research and Engineering Laboratory (CRREL) Multi-Increment Sampling Tool (CMIST) or similar device is an easy way to collect ISM samples rapidly and reproducibly. This tool has an adjustable diameter size corer and adjustable depth to collect surface soil plugs (Figure 6). The CMIST can be used at almost a walking pace (Figure 7) using a two-person sampling team, with one person operating the CMIST and the other carrying the sample container and recording the number of increments collected. The CMIST with a small diameter tip works best in soils with low cohesion, otherwise conventional scoops may be used. Maintaining consistent soil increment dimensions is critical.
  
===Enhanced Attenuation Remedies===
+
The sampling tool should be cleaned between replicates and between DUs to minimize potential for cross-contamination<ref>Walsh, M.R., 2009. User’s manual for the CRREL Multi-Increment Sampling Tool. Engineer Research and Development Center / Cold Regions Research and Engineering Lab (ERDC/CRREL) SR-09-1, Hanover, NH, USA.  [[media:Walsh-2009 ERDC-CRREL SR-09-1.pdf | Report.pdf]]</ref>.
Paraphrasing and rearranging the four tiers of evidence required by the U.S. Environmental Protection Agency<ref name="EPA2015"/> to demonstrate monitored natural attenuation (MNA) for inorganic compounds provides a general guide to designing an enhanced attenuation remediation:
 
  
#Decide on a mechanism/reagent and determine the rate of attenuation necessary.
+
==Sample Processing==
#Determine the capacity needed for long-term attenuation of the contaminant plume.
+
While only 10 g of soil is typically used for chemical analysis, incremental sampling generates a sample weighing on the order of 1 kg. Splitting of a sample, either in the field or laboratory, seems like an easy way to reduce sample mass; however this approach has been found to produce high uncertainty for explosives and propellants, with a median RSD of 43.1%<ref name= "Hewitt2009"/>. Even greater error is associated with removing a discrete sub-sample from an unground sample. Appendix A in [https://www.epa.gov/sites/production/files/2015-07/documents/epa-8330b.pdf U.S. EPA Method 8330B]<ref name= "USEPA2006M"/> provides details on recommended ISM sample processing procedures.
#Demonstrate long-term stability of the attenuated contaminants in bench and field-scale tests.
 
#Design a performance monitoring program and identify mitigation strategies for undesirable collateral effects.
 
  
The U.S. Department of Energy has produced an aid to design enhanced attenuation remedies that categorizes sites and contaminants into groups with similar characteristics<ref name="Truex2011"/> (see Monitored Natural Attenuation of Metals and Metalloids). Sites and contaminants within each group can be treated with generally similar approaches and mechanisms. Demonstrating long-term stability of attenuated contaminants is the most difficult challenge to deploying enhanced attenuation remedies. Contaminant plumes are dynamic systems and conditions today may be very different from conditions in the future. In general, the geochemical conditions of a waste site evolve from the contaminated conditions back toward natural conditions. Demonstration of long-term effectiveness for a remedy with a primary attenuation mechanism that is consistent with this evolution is more convincing than for a remedy with a primary attenuation mechanism that is likely to be reversed by the natural evolution of the site. Figure 1 shows an “Attenuation Conceptual Model” that can help guide if, when, and where metals MNA, enhanced attenuation, or more aggressive remediation is required<ref name="Truex2011"/>. Sometimes reactive transport modeling can help understand the geochemistry of groundwater at complicated metals sites.  
+
Incremental soil samples are typically air dried over the course of a few days. Oven drying thermally degrades some energetic compounds and should be avoided<ref>Cragin, J.H., Leggett, D.C., Foley, B.T., and Schumacher, P.W., 1985. TNT, RDX and HMX explosives in soils and sediments: Analysis techniques and drying losses. (CRREL Report 85-15) Hanover, NH, USA. [[media:Cragin-1985 CRREL 85-15.pdf| Report.pdf]]</ref>. Once dry, the samples are sieved with a 2-mm screen, with only the less than 2-mm fraction processed further. This size fraction represents the USDA definition of soil. Aggregate soil particles should be broken up and vegetation shredded to pass through the sieve. Samples from impact or demolition areas may contain explosive particles from low order detonations that are greater than 2 mm and should be identified, given appropriate caution, and potentially weighed.
[[File:Denham-Article 4-Figure 1.PNG|800px|thumbnail|center|Figure 1. Example of an Attenuation Conceptual Model for metals contamination (from Truex et al., 2011)<ref name="Truex2011"/>. This type of model is used to evaluate the attenuation potential for various metal contaminants, the permanence of the attenuation, and whether MNA, enhanced MNA or more active metals remediation technology is required. Key subsurface parameters driving the remediation decision are things such as pH, redox potential (Eh), the flux of contaminants from the source, and the amount of natural organics in the soil.]]
 
  
Table 2 summarizes the in situ treatment technologies for metals and metalloid contaminants. For enhanced attenuation, there is a wide spectrum of reagents that may be used that is too extensive to cover here. Hence, we only mention the general mechanisms.  
+
The <2-mm soil fraction is typically still ≥1 kg and impractical to extract in full for analysis. However, subsampling at this stage is not possible due to compositional heterogeneity, with the energetic compounds generally present as <0.5 mm particles<ref name= "Walsh2017"/><ref name= "Taylor2004"/>. Particle size reduction is required to achieve a representative and precise measure of the sample concentration. Grinding in a puck mill to a soil particle size <75 µm has been found to be required for representative/reproducible sub-sampling (Figure 8). For samples thought to contain propellant particles, a prolonged milling time is required to break down these polymerized particles and achieve acceptable precision (Figure 9). Due to the multi-use nature of some ranges, a 5-minute puck milling period can be used for all soils. Cooling periods between 1-minute milling intervals are recommended to avoid thermal degradation. Similar to field sampling, sub-sampling is done incrementally by spreading the sample out to a thin layer and collecting systematic random increments of consistent volume to a total mass for extraction of 10 g (Figure 10).
  
 +
<li style="display: inline-block;">[[File:Beal1w2 Fig6.png|thumb|200 px|Figure 6: CMIST soil sampling tool (top) and with ejected increment core using a large diameter tip (bottom).]]</li>
 +
<li style="display: inline-block;">[[File:Beal1w2 Fig7.png|thumb|200 px|Figure 7: Two person sampling team using CMIST, bag-lined bucket, and increment counter. (Photos: Matthew Bigl)]]</li>
 +
<li style="display: inline-block;">[[File:Beal1w2 Fig8.png|thumb|200 px|Figure 8: Effect of machine grinding on RDX and TNT concentration and precision in soil from a hand grenade range. Data from Walsh et al.<ref>Walsh, M.E., Ramsey, C.A. and Jenkins, T.F., 2002. The effect of particle size reduction by grinding on subsampling variance for explosives residues in soil. Chemosphere, 49(10), pp.1267-1273. [https://doi.org/10.1016/S0045-6535(02)00528-3 doi: 10.1016/S0045-6535(02)00528-3]</ref> ]]</li>
 +
<li style="display: inline-block;">[[File:Beal1w2 Fig9.png|thumb|200 px|Figure 9: Effect of puck milling time on 2,4-DNT concentration and precision in soil from a firing point. Data from Walsh et al.<ref>Walsh, M.E., Ramsey, C.A., Collins, C.M., Hewitt, A.D., Walsh, M.R., Bjella, K.L., Lambert, D.J. and Perron, N.M., 2005. Collection methods and laboratory processing of samples from Donnelly Training Area Firing Points, Alaska, 2003 (No. ERDC/CRREL-TR-05-6). [[media:Walsh-2005 ERDC-CRREL TR-05-6.pdf| Report.pdf]]</ref>.]]</li>
 +
<li style="display: inline-block;">[[File:Beal1w2 Fig10.png|thumb|200 px|center|Figure 10: Incremental sub-sampling of a milled soil sample spread out on aluminum foil.]]</li>
 +
 +
==Analysis==
 +
Soil sub-samples are extracted and analyzed following [[Media: epa-2006-method-8330b.pdf | EPA Method 8330B]]<ref name= "USEPA2006M"/> and [[Media:epa-2007-method-8095.pdf | Method 8095]]<ref name= "USEPA2007M"/> using [[Wikipedia: High-performance liquid chromatography | High Performance Liquid Chromatography (HPLC)]] and [[Wikipedia: Gas chromatography | Gas Chromatography (GC)]], respectively. Common estimated reporting limits for these analysis methods are listed in Table 2.
 +
 +
{| class="wikitable" style="float: center; text-align: center; margin-left: auto; margin-right: auto;"
 +
|+ Table 2. Typical Method Reporting Limits for Energetic Compounds in Soil. (Data from Hewitt et al.<ref>Hewitt, A., Bigl, S., Walsh, M., Brochu, S., Bjella, K. and Lambert, D., 2007. Processing of training range soils for the analysis of energetic compounds (No. ERDC/CRREL-TR-07-15). Hanover, NH, USA. [[media:Hewitt-2007 ERDC-CRREL TR-07-15.pdf| Report.pdf]]</ref>)
 +
|-
 +
! rowspan="2" | Compound
 +
! colspan="2" | Soil Reporting Limit (mg/kg)
 +
|-
 +
! HPLC (8330)
 +
! GC (8095)
 +
|-
 +
| HMX || 0.04 || 0.01
 +
|-
 +
| RDX || 0.04 || 0.006
 +
|-
 +
| [[Wikipedia: 1,3,5-Trinitrobenzene | TNB]] || 0.04 || 0.003
 +
|-
 +
| TNT || 0.04 || 0.002
 +
|-
 +
| [[Wikipedia: 2,6-Dinitrotoluene | 2,6-DNT]] || 0.08 || 0.002
 +
|-
 +
| 2,4-DNT || 0.04 || 0.002
 +
|-
 +
| 2-ADNT || 0.08 || 0.002
 +
|-
 +
| 4-ADNT || 0.08 || 0.002
 +
|-
 +
| NG || 0.1 || 0.01
 +
|-
 +
| [[Wikipedia: Dinitrobenzene | DNB ]] || 0.04 || 0.002
 +
|-
 +
| [[Wikipedia: Tetryl | Tetryl ]]  || 0.04 || 0.01
 +
|-
 +
| [[Wikipedia: Pentaerythritol tetranitrate | PETN ]] || 0.2 || 0.016
 +
|}
  
 
==References==
 
==References==
 
 
<references/>
 
<references/>
  
 
==See Also==
 
==See Also==
 +
*[https://itrcweb.org/ Interstate Technology and Regulatory Council]
 +
*[http://www.hawaiidoh.org/tgm.aspx Hawaii Department of Health]
 +
*[http://envirostat.org/ Envirostat]

Latest revision as of 18:58, 29 April 2020

The heterogeneous distribution of munitions constituents, released as particles from munitions firing and detonations on military training ranges, presents challenges for representative soil sample collection and for defensible decision making. Military range characterization studies and the development of the incremental sampling methodology (ISM) have enabled the development of recommended methods for soil sampling that produce representative and reproducible concentration data for munitions constituents. This article provides a broad overview of recommended soil sampling and processing practices for analysis of munitions constituents on military ranges.

Related Article(s):


CONTRIBUTOR(S): Dr. Samuel Beal


Key Resource(s):

Introduction

Figure 1: Downrange distance of visible propellant plume on snow from the firing of different munitions. Note deposition behind firing line for the 84-mm rocket. Data from: Walsh et al.[5][6]
Figure 2: A low-order detonation mortar round (top) with surrounding discrete soil samples produced concentrations spanning six orders of magnitude within a 10m by 10m area (bottom). (Photo and data: A.D. Hewitt)

Munitions constituents are released on military testing and training ranges through several common mechanisms. Some are locally dispersed as solid particles from incomplete combustion during firing and detonation. Also, small residual particles containing propellant compounds (e.g., nitroglycerin [NG] and 2,4-dinitrotoluene [2,4-DNT]) are distributed in front of and surrounding target practice firing lines (Figure 1). At impact areas and demolition areas, high order detonations typically yield very small amounts (<1 to 10 mg/round) of residual high explosive compounds (e.g., TNT , RDX and HMX ) that are distributed up to and sometimes greater than) 24 m from the site of detonation[7].

Low-order detonations and duds are thought to be the primary source of munitions constituents on ranges[8][9]. Duds are initially intact but may become perforated or fragmented into micrometer to centimeter;o0i0k-sized particles by nearby detonations[10]. Low-order detonations can scatter micrometer to centimeter-sized particles up to 20 m from the site of detonation[11]

The particulate nature of munitions constituents in the environment presents a distinct challenge to representative soil sampling. Figure 2 shows an array of discrete soil samples collected around the site of a low-order detonation – resultant soil concentrations vary by orders of magnitude within centimeters of each other. The inadequacy of discrete sampling is apparent in characterization studies from actual ranges which show wide-ranging concentrations and poor precision (Table 1).

In comparison to discrete sampling, incremental sampling tends to yield reproducible concentrations (low relative standard deviation [RSD]) that statistically better represent an area of interest[2].

Table 1. Soil Sample Concentrations and Precision from Military Ranges Using Discrete and Incremental Sampling. (Data from Taylor et al. [1] and references therein.)
Military Range Type Analyte Range
(mg/kg)
Median
(mg/kg)
RSD
(%)
Discrete Samples
Artillery FP 2,4-DNT <0.04 – 6.4 0.65 110
Antitank Rocket HMX 5.8 – 1,200 200 99
Bombing TNT 0.15 – 780 6.4 274
Mortar RDX <0.04 – 2,400 1.7 441
Artillery RDX <0.04 – 170 <0.04 454
Incremental Samples*
Artillery FP 2,4-DNT 0.60 – 1.4 0.92 26
Bombing TNT 13 – 17 14 17
Artillery/Bombing RDX 3.9 – 9.4 4.8 38
Thermal Treatment HMX 3.96 – 4.26 4.16 4
* For incremental samples, 30-100 increments and 3-10 replicate samples were collected.

Incremental Sampling Approach

ISM is a requisite for representative and reproducible sampling of training ranges, but it is an involved process that is detailed thoroughly elsewhere[2][1][3]. In short, ISM involves the collection of many (30 to >100) increments in a systematic pattern within a decision unit (DU). The DU may cover an area where releases are thought to have occurred or may represent an area relevant to ecological receptors (e.g., sensitive species). Figure 3 shows the ISM sampling pattern in a simplified (5x5 square) DU. Increments are collected at a random starting point with systematic distances between increments. Replicate samples can be collected by starting at a different random starting point, often at a different corner of the DU. Practically, this grid pattern can often be followed with flagging or lathe marking DU boundaries and/or sampling lanes and with individual pacing keeping systematic distances between increments. As an example, an artillery firing point might include a 100x100 m DU with 81 increments.

Figure 3. Example ISM sampling pattern on a square decision unit. Replicates are collected in a systematic pattern from a random starting point at a corner of the DU. Typically more than the 25 increments shown are collected

DUs can vary in shape (Figure 4), size, number of increments, and number of replicates according to a project’s data quality objectives.

Figure 4: Incremental sampling of a circular DU on snow shows sampling lanes with a two-person team in process of collecting the second replicate in a perpendicular path to the first replicate. (Photo: Matthew Bigl)

Sampling Tools

In many cases, energetic compounds are expected to reside within the soil surface. Figure 5 shows soil depth profiles on some studied impact areas and firing points. Overall, the energetic compound concentrations below 5-cm soil depth are negligible relative to overlying soil concentrations. For conventional munitions, this is to be expected as the energetic particles are relatively insoluble, and any dissolved compounds readily adsorb to most soils[12]. Physical disturbance, as on hand grenade ranges, may require deeper sampling either with a soil profile or a corer/auger.

Figure 5. Depth profiles of high explosive compounds at impact areas (bottom) and of propellant compounds at firing points (top). Data from: Hewitt et al. [13] and Jenkins et al. [14]

Soil sampling with the Cold Regions Research and Engineering Laboratory (CRREL) Multi-Increment Sampling Tool (CMIST) or similar device is an easy way to collect ISM samples rapidly and reproducibly. This tool has an adjustable diameter size corer and adjustable depth to collect surface soil plugs (Figure 6). The CMIST can be used at almost a walking pace (Figure 7) using a two-person sampling team, with one person operating the CMIST and the other carrying the sample container and recording the number of increments collected. The CMIST with a small diameter tip works best in soils with low cohesion, otherwise conventional scoops may be used. Maintaining consistent soil increment dimensions is critical.

The sampling tool should be cleaned between replicates and between DUs to minimize potential for cross-contamination[15].

Sample Processing

While only 10 g of soil is typically used for chemical analysis, incremental sampling generates a sample weighing on the order of 1 kg. Splitting of a sample, either in the field or laboratory, seems like an easy way to reduce sample mass; however this approach has been found to produce high uncertainty for explosives and propellants, with a median RSD of 43.1%[2]. Even greater error is associated with removing a discrete sub-sample from an unground sample. Appendix A in U.S. EPA Method 8330B[3] provides details on recommended ISM sample processing procedures.

Incremental soil samples are typically air dried over the course of a few days. Oven drying thermally degrades some energetic compounds and should be avoided[16]. Once dry, the samples are sieved with a 2-mm screen, with only the less than 2-mm fraction processed further. This size fraction represents the USDA definition of soil. Aggregate soil particles should be broken up and vegetation shredded to pass through the sieve. Samples from impact or demolition areas may contain explosive particles from low order detonations that are greater than 2 mm and should be identified, given appropriate caution, and potentially weighed.

The <2-mm soil fraction is typically still ≥1 kg and impractical to extract in full for analysis. However, subsampling at this stage is not possible due to compositional heterogeneity, with the energetic compounds generally present as <0.5 mm particles[7][11]. Particle size reduction is required to achieve a representative and precise measure of the sample concentration. Grinding in a puck mill to a soil particle size <75 µm has been found to be required for representative/reproducible sub-sampling (Figure 8). For samples thought to contain propellant particles, a prolonged milling time is required to break down these polymerized particles and achieve acceptable precision (Figure 9). Due to the multi-use nature of some ranges, a 5-minute puck milling period can be used for all soils. Cooling periods between 1-minute milling intervals are recommended to avoid thermal degradation. Similar to field sampling, sub-sampling is done incrementally by spreading the sample out to a thin layer and collecting systematic random increments of consistent volume to a total mass for extraction of 10 g (Figure 10).

  • Figure 6: CMIST soil sampling tool (top) and with ejected increment core using a large diameter tip (bottom).
  • Figure 7: Two person sampling team using CMIST, bag-lined bucket, and increment counter. (Photos: Matthew Bigl)
  • Figure 8: Effect of machine grinding on RDX and TNT concentration and precision in soil from a hand grenade range. Data from Walsh et al.[17]
  • Figure 9: Effect of puck milling time on 2,4-DNT concentration and precision in soil from a firing point. Data from Walsh et al.[18].
  • Figure 10: Incremental sub-sampling of a milled soil sample spread out on aluminum foil.
  • Analysis

    Soil sub-samples are extracted and analyzed following EPA Method 8330B[3] and Method 8095[4] using High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC), respectively. Common estimated reporting limits for these analysis methods are listed in Table 2.

    Table 2. Typical Method Reporting Limits for Energetic Compounds in Soil. (Data from Hewitt et al.[19])
    Compound Soil Reporting Limit (mg/kg)
    HPLC (8330) GC (8095)
    HMX 0.04 0.01
    RDX 0.04 0.006
    TNB 0.04 0.003
    TNT 0.04 0.002
    2,6-DNT 0.08 0.002
    2,4-DNT 0.04 0.002
    2-ADNT 0.08 0.002
    4-ADNT 0.08 0.002
    NG 0.1 0.01
    DNB 0.04 0.002
    Tetryl 0.04 0.01
    PETN 0.2 0.016

    References

    1. ^ 1.0 1.1 1.2 Taylor, S., Jenkins, T.F., Bigl, S., Hewitt, A.D., Walsh, M.E. and Walsh, M.R., 2011. Guidance for Soil Sampling for Energetics and Metals (No. ERDC/CRREL-TR-11-15). Report.pdf
    2. ^ 2.0 2.1 2.2 2.3 Hewitt, A.D., Jenkins, T.F., Walsh, M.E., Bigl, S.R. and Brochu, S., 2009. Validation of sampling protocol and the promulgation of method modifications for the characterization of energetic residues on military testing and training ranges (No. ERDC/CRREL-TR-09-6). Engineer Research and Development Center / Cold Regions Research and Engineering Lab (ERDC/CRREL) TR-09-6, Hanover, NH, USA. Report.pdf
    3. ^ 3.0 3.1 3.2 3.3 U.S. Environmental Protection Agency (USEPA), 2006. Method 8330B (SW-846): Nitroaromatics, Nitramines, and Nitrate Esters by High Performance Liquid Chromatography (HPLC), Rev. 2. Washington, D.C. Report.pdf
    4. ^ 4.0 4.1 U.S. Environmental Protection Agency (US EPA), 2007. Method 8095 (SW-846): Explosives by Gas Chromatography. Washington, D.C. Report.pdf
    5. ^ Walsh, M.R., Walsh, M.E., Ampleman, G., Thiboutot, S., Brochu, S. and Jenkins, T.F., 2012. Munitions propellants residue deposition rates on military training ranges. Propellants, Explosives, Pyrotechnics, 37(4), pp.393-406. doi: 10.1002/prep.201100105
    6. ^ Walsh, M.R., Walsh, M.E., Hewitt, A.D., Collins, C.M., Bigl, S.R., Gagnon, K., Ampleman, G., Thiboutot, S., Poulin, I. and Brochu, S., 2010. Characterization and Fate of Gun and Rocket Propellant Residues on Testing and Training Ranges: Interim Report 2. (ERDC/CRREL TR-10-13. Also: ESTCP Project ER-1481) Report
    7. ^ 7.0 7.1 Walsh, M.R., Temple, T., Bigl, M.F., Tshabalala, S.F., Mai, N. and Ladyman, M., 2017. Investigation of Energetic Particle Distribution from High‐Order Detonations of Munitions. Propellants, Explosives, Pyrotechnics, 42(8), pp.932-941. doi: 10.1002/prep.201700089 Report.pdf
    8. ^ 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(6), pp.888-894. doi: 10.1016/j.chemosphere.2005.04.058
    9. ^ Walsh, M.R., Walsh, M.E., Poulin, I., Taylor, S. and Douglas, T.A., 2011. Energetic residues from the detonation of common US ordnance. International Journal of Energetic Materials and Chemical Propulsion, 10(2). doi: 10.1615/IntJEnergeticMaterialsChemProp.2012004956 Report.pdf
    10. ^ Walsh, M.R., Thiboutot, S., Walsh, M.E., Ampleman, G., Martel, R., Poulin, I. and Taylor, S., 2011. Characterization and fate of gun and rocket propellant residues on testing and training ranges (No. ERDC/CRREL-TR-11-13). Engineer Research and Development Center / Cold Regions Research and Engineering Lab (ERDC/CRREL) TR-11-13, Hanover, NH, USA. Report.pdf
    11. ^ 11.0 11.1 Taylor, S., Hewitt, A., Lever, J., Hayes, C., Perovich, L., Thorne, P. and Daghlian, C., 2004. TNT particle size distributions from detonated 155-mm howitzer rounds. Chemosphere, 55(3), pp.357-367. Report.pdf
    12. ^ Pennington, J.C., Jenkins, T.F., Ampleman, G., Thiboutot, S., Brannon, J.M., Hewitt, A.D., Lewis, J., Brochu, S., 2006. Distribution and fate of energetics on DoD test and training ranges: Final Report. ERDC TR-06-13, Vicksburg, MS, USA. Also: SERDP/ESTCP Project ER-1155. Report.pdf
    13. ^ Hewitt, A.D., Jenkins, T.F., Ramsey, C.A., Bjella, K.L., Ranney, T.A. and Perron, N.M., 2005. Estimating energetic residue loading on military artillery ranges: Large decision units (No. ERDC/CRREL-TR-05-7). Report.pdf
    14. ^ Jenkins, T.F., Ampleman, G., Thiboutot, S., Bigl, S.R., Taylor, S., Walsh, M.R., Faucher, D., Mantel, R., Poulin, I., Dontsova, K.M. and Walsh, M.E., 2008. Characterization and fate of gun and rocket propellant residues on testing and training ranges (No. ERDC-TR-08-1). Report.pdf
    15. ^ Walsh, M.R., 2009. User’s manual for the CRREL Multi-Increment Sampling Tool. Engineer Research and Development Center / Cold Regions Research and Engineering Lab (ERDC/CRREL) SR-09-1, Hanover, NH, USA. Report.pdf
    16. ^ Cragin, J.H., Leggett, D.C., Foley, B.T., and Schumacher, P.W., 1985. TNT, RDX and HMX explosives in soils and sediments: Analysis techniques and drying losses. (CRREL Report 85-15) Hanover, NH, USA. Report.pdf
    17. ^ Walsh, M.E., Ramsey, C.A. and Jenkins, T.F., 2002. The effect of particle size reduction by grinding on subsampling variance for explosives residues in soil. Chemosphere, 49(10), pp.1267-1273. doi: 10.1016/S0045-6535(02)00528-3
    18. ^ Walsh, M.E., Ramsey, C.A., Collins, C.M., Hewitt, A.D., Walsh, M.R., Bjella, K.L., Lambert, D.J. and Perron, N.M., 2005. Collection methods and laboratory processing of samples from Donnelly Training Area Firing Points, Alaska, 2003 (No. ERDC/CRREL-TR-05-6). Report.pdf
    19. ^ Hewitt, A., Bigl, S., Walsh, M., Brochu, S., Bjella, K. and Lambert, D., 2007. Processing of training range soils for the analysis of energetic compounds (No. ERDC/CRREL-TR-07-15). Hanover, NH, USA. Report.pdf

    See Also