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The term “vapor intrusion” or “VI” refers to the migration of volatile organic compounds (VOCs) from a subsurface source into an overlying building.  Preferential pathways for VI are specific migration routes that support higher contaminant flux, or discharge, into a building compared to transport through bulk soil.  Sewers and other utility conduits or tunnels are an important type of preferential pathway that can result in VI when VOC vapors migrate through the interior of the conduits into buildings.
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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):'''
 
*[[Vapor Intrusion (VI)]]
 
  
'''CONTRIBUTOR(S):''' [[Matthew Zenker]], [[Dr. Shaily Mahendra]], and [[Dr. Michael Hyman]]
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'''CONTRIBUTOR(S):''' [[Dr. Samuel Beal]]
  
  
'''Key Resource(s)''':
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'''Key Resource(s)''':  
*[[media:2018b-McHugh-ER-201505_Conceptual_Model.pdf| Conceptual Model for Sewer/Utility Tunnel VI]]<ref>McHugh, T.; Beckley, L, 2018(b). Conceptual Model: Sewers and Utility Tunnels as Preferential Pathways for Volatile Organic Compound Migration into Buildings:  Risk Factors and Investigation Protocol, ESTCP Project ER-201505. [[media:2018b-McHugh-ER-201505_Conceptual_Model.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>
*[[media:2018a-McHugh-ER-201505_Investigation_Protocol.pdf| Investigation protocol for sewer/utility tunnel VI]]<ref name= "McHugh2018a">McHugh, T. and Beckley, L., 2018. Sewers and Utility Tunnels as Preferential Pathways for Volatile Organic Compound Migration into Buildings: Risk Factors and Investigation Protocol. ESTCP Project ER-201505 [[media:2018a-McHugh-ER-201505_Investigation_Protocol.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>
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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>
  
 
==Introduction==
 
==Introduction==
A utility tunnel or utility corridor is a passage built underground or aboveground to carry utility lines such as electricity, water, and sewer pipes. Communication utilities like fiber optics, cable television, and telephone cables are also sometimes carried. They may also be referred to as a services tunnel, services trench, services vault, or cable vault. Utility tunnels are often installed in large military facilities as well as industrial plants and large institutions such as universities, hospitals, research labs, and other facilities managed in common. They are not generally installed in residential areas. A directly buried utility, such as an electrical or gas line, is not a utility tunnel.
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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>]]
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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)]]
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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>.
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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>
  
Although not historically evaluated in a systematic manner, sanitary sewers and utility tunnels have been identified as important preferential transport pathways for VI at a growing number of sites<ref>McHugh, T., Beckley, L., Sullivan, T., Lutes, C., Truesdale, R., Uppencamp, R., Cosky, B., Zimmerman, J. and Schumacher, B., 2017a. Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex. Science of the Total Environment, 598, pp.772-779. [https://doi.org/10.1016/j.scitotenv.2017.04.135 doi: 10.1016/j.scitotenv.2017.04.135]</ref><ref name= "McHugh2017b">McHugh, T., Loll, P. and Eklund, B., 2017. Recent advances in vapor intrusion site investigations. Journal of Environmental Management, 204, pp.783-792. doi: 10.1016/j.jenvman.2017.02.015 [[media:2017b-McHugh-Recent_advances_in_vapor_intrusion.pdf| Report.pdf]</ref>.  They should, therefore, be considered during planning and implementation of VI assessment programs.  Recognizing sewer/utility tunnel VI early in the site characterization process should help avoid wasted investigation efforts and delays in response actions where those are needed.  
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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).
  
{|  
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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"/>.
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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.)
 
|-
 
|-
| colspan="2" |''' Key Terms and Concepts:'''
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! Military Range Type !! Analyte !! Range<br/>(mg/kg) !! Median<br/>(mg/kg) !! RSD<br/>(%)
 
|-
 
|-
| style="height:5px;" |
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| colspan="5" style="text-align: left;" | '''Discrete Samples'''
 
|-
 
|-
| style="vertical-align:top; width:20%;" | Vapor intrusion || Migration of VOCs from any subsurface source into an overlying building.
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| Artillery FP || 2,4-DNT || <0.04 – 6.4 || 0.65 || 110
 
|-
 
|-
| style="height:5px;" |
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| Antitank Rocket || HMX || 5.8 – 1,200 || 200 || 99
 
|-
 
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| style="vertical-align:top;" | Conventional, or standard, vapor intrusion
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| Bombing || TNT || 0.15 – 780 || 6.4 || 274
| style="vertical-align:top;" | Migration of VOCs from a subsurface source into an overlying building by advection and/or diffusion through soil (i.e., not through a preferential pathway).  These mechanisms for vapor entry into buildings can also be viewed as “soil gas intrusion.”  Conventional VI refers to the conceptual model that has historically and most commonly been utilized to describe VOC flux from the subsurface into buildings.
 
 
|-
 
|-
| style="height:5px;" |
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| Mortar || RDX || <0.04 – 2,400 || 1.7 || 441
 
|-
 
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| style="vertical-align:top;" | Preferential pathway
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| Artillery || RDX || <0.04 – 170 || <0.04 || 454
| style="vertical-align:top;" | A migration pathway from a subsurface source that supports higher VOC flux/discharge into a building compared to transport through bulk soil. This general term typically includes features such as elevator shafts and dry wells that can enhance vertical transport from a VOC source below the building into the building, and features such as sewers and utility tunnels that can enhance both lateral and vertical transport of VOCs.  The term “sewer/utility tunnel vapor intrusion” or “sewer/utility tunnel VI” refers to VOC flux from the subsurface into buildings though this specific preferential pathway.
 
 
|-
 
|-
| style="height:5px;" |
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| colspan="5" style="text-align: left;" | '''Incremental Samples*'''
 
|-
 
|-
| style="vertical-align:top;" | Sewer/utility tunnel vapor intrusion (sewer/utility tunnel VI)
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| Artillery FP || 2,4-DNT || 0.60 – 1.4 || 0.92 || 26
| style="vertical-align:top;" | A sewer or utility tunnel that supports higher VOC flux/discharge into a building compared to transport through bulk soil.  The VOC flux is through the interior of the sewer line or tunnel.  Sewer/utility tunnel vapor intrusion has also been referred to as “pipe VI”<ref name= "Guo2015">Guo, Y., Holton, C., Luo, H., Dahlen, P., Gorder, K., Dettenmaier, E. and Johnson, P.C., 2015. Identification of alternative vapor intrusion pathways using controlled pressure testing, soil gas monitoring, and screening model calculations. Environmental Science & Technology, 49(22), pp.13472-13482. [https://doi.org/10.1021/acs.est.5b03564 doi: 10.1021/acs.est.5b03564]</ref>.  Sewers or utility tunnels can enhance VOC transport into a building from a VOC source that is laterally separated from the building (i.e., not located directly below the building).
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|-
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| Bombing || TNT || 13 – 17 || 14 || 17
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|-
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| Artillery/Bombing || RDX || 3.9 – 9.4 || 4.8 || 38
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|-
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| Thermal Treatment || HMX || 3.96 – 4.26 || 4.16 || 4
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|-
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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.
 
|}
 
|}
  
==Conceptual Model==
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==Incremental Sampling Approach==
The standard VI and sewer/utility tunnel VI conceptual models are illustrated in Figure 1.  One important difference is that, for sewer/utility tunnel VI, the building may be located outside the footprint of the subsurface contaminant source.  In general, for standard VI, potentially affected buildings are situated over the source. 
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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.
{| class="wikitable" style="float:left; margin-right: 20px;"
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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]]
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| style="padding: 25px;" | [[File:Beckley1w2 Fig1a.png|thumb|300 px|Figure 1a. Conventional (Standard) Vapor Intrusion (from McHugh et al., 2017b<ref name= "McHugh2017b"/>)]]
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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.
| style="padding: 25px;" | [[File:Beckley1w2 Fig1b.png|thumb|300 px|Figure 1b. Sewer/Utility Tunnel Vapor Intrusion (from McHugh et al., 2017b<ref name= "McHugh2017b"/>)]]
 
|}
 
  
Not all sites are equally at risk for sewer/utility tunnel VI. In general, higher risk sites are those where contaminated groundwater or soil gas has infiltrated into the underground utility line.  This occurs most commonly at sites with sewers or utility tunnels that intersect shallow impacted water tables, sites with discharge of contaminated groundwater into sanitary sewer lines, or sites with sewer lines or utility tunnels that intersect strong contaminant sources (e.g., nonaqueous phase liquid (NAPL)) in the unsaturated zone (Figure 2).
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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)]]
  
Elevated VOC concentrations in sewer vapor can be found at both higher and lower risk sites. At higher risk sites, these elevated VOC concentrations can be present over a larger area, extending beyond the footprint of the subsurface contamination. Standard VI investigations typically focus on areas above this footprint. To factor in sewer/utility tunnel VI, it is important to identify higher risk sites early in the VI investigation process so that potential impacts outside the footprint are not overlooked.
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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.
  
==Investigation Approaches==
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[[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>]]
  
Basic screening for sewer/utility tunnel VI can be done at any site by determining if the site has higher or lower risk for this pathway. If the site has higher risk, initial testing can be done by sampling vapor from manholes (Figure 3; Also add link to video) above the core of the groundwater plume to get an understanding of the level of VOCs that may be present.
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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.
  
Follow-up testing may be needed depending on the initial results. Vapor intrusion guidance documents generally do not provide screening values for sewer vapor samples. However, results from ESTCP Project ER-201505 show that sewer to indoor air attenuation is similar in magnitude to sub-slab to indoor air attenuationThis suggests that sub-slab screening values can also be used to evaluate sewer vapor results<ref name= "McHugh2018a"/>.  VOC vapors can migrate from sewers into buildings through a variety of different entry mechanisms that are difficult to predict (Figure 4).  As a result, if sewer vapor concentrations exceed screening levels, then indoor air testing may be needed to determine the presence or absence of VI.  
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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>.
  
{| class="wikitable" style="float:left; margin-right: 20px; text-align:right;"
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==Sample Processing==
|+ Higher and Lower Risk Scenarios for Sewer/Utility Tunnel Vapor Intrusion
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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.
|-
 
! Higher Risk Scenarios
 
! Lower Risk Scenario
 
|-
 
| style="padding: 25px;" | [[File:Beckley1w2_Fig2a.png | thumbnail | Figure 2a. Sewer Intersects Contaminated Groundwater]]
 
| style="padding: 25px;" | [[File:Beckley1w2_Fig2d.png | thumbnail | Figure 2d. Sewer in Vadose Zone above Plume]]
 
|-
 
| style="padding: 25px;" | [[File:Beckley1w2_Fig2b.png | thumbnail | Figure 2b. Discharge of Groundwater to Sewer Line]] ||
 
|-
 
| style="padding: 25px;" | [[File:Beckley1w2_Fig2c.png | thumbnail | Figure 2c. Sewer Intersects NAPL/Vadose Zone Source]]
 
| style="padding: 25px;" | [[File:Beckley1w2_Fig2_legend.png | 200px]]
 
|}
 
  
[[File:Beckley1w2 Fig3.png|thumb|right|Figure 3. Vapor Sample Collection from Sewer]]
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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:Beckley1w2 Fig4.png|thumb|right|Figure 4.  Potential Entry Points into Buildings. VOCs can move from sewers and utility tunnels into buildings through a variety of features, for example:  A. Dry p-traps; B. Faulty seal on plumbing fixture<ref>Pennell, K.G., Scammell, M.K., McClean, M.D., Ames, J., Weldon, B., Friguglietti, L., Suuberg, E.M., Shen, R., Indeglia, P.A. and Heiger‐Bernays, W.J., 2013. Sewer gas: an indoor air source of PCE to consider during vapor intrusion investigations. Groundwater Monitoring & Remediation, 33(3), pp.119-126. [https://doi.org/10.1111/gwmr.12021 doi: 10.1111/gwmr.12021]</ref>; and C. French drain tied to sewer line<ref name= "Guo2015"/>. Utility tunnels can vent directly into buildings.]]
 
  
At lower risk sites, a specific, early focus on sewers or utility tunnels is generally not needed. A standard VI investigation that includes indoor air testing can be conducted with evaluation of sewers/utility tunnels only if indicated by the building-specific investigation results (e.g., if elevated indoor air concentrations in one section of the building suggest a specific vapor entry point).
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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).
  
Many indoor air testing techniques utilized to assess conventional vapor intrusion are also applicable to buildings potentially impacted by sewer/utility tunnel VI. Techniques that focus on VOC source identification (e.g., indoor VOC sources vs. vapor entry points) include on-site analysis, compound-specific isotope analysis, and building pressure cycling.
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<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>
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<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>
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<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>
  
==Mitigation==
+
==Analysis==
If sewer/utility tunnel VI is identified, mitigation approaches include preventing contaminants from entering the sewer or utility (e.g., by rerouting or lining the sewer), ventilating the line, or correcting plumbing defects. Examples are provided in Table 1.
+
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"
+
{| class="wikitable" style="float: center; text-align: center; margin-left: auto; margin-right: auto;"
|+ Table 1. Examples of Sewer Mitigation Methods Used to Control Vapor Intrusion
+
|+ 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>)
 
|-
 
|-
! Mitigation Method
+
! rowspan="2" | Compound
! Reference
+
! colspan="2" | Soil Reporting Limit (mg/kg)
 
|-
 
|-
| Depressurization of sewer line || Nielsen et al., 2014<ref>Nielsen, K.B., Hivdberg, B. and Hyldegaard, W., 2014. Vinyl chloride in the indoor air solved by depressurization of the sewer. In Battelle Ninth International Conference on Remediation of Chlorinated and Recalcitrant Compounds Monterey, CA.</ref>
+
! HPLC (8330)
 +
! GC (8095)
 
|-
 
|-
| Replacement of collapsed portion of sanitary sewer line and installation of an interior liner to prevent infiltration of LNAPL || Macklin et al., 2014<ref>Macklin, Y., Welfare, W., Kowalczyk, G., Mitchem, L., Modi, A., Craswell, A., Brown, M. and Lighton, L., 2014. Sewers, culverts and other underground pipes–an under recognised pathway for chemical exposures in acute incidents: case series. Chemical Hazards and Poisons Report, p.15. [[media:2014-Chemical_Hazards_and_Poisons_Rpt.pdf| Report.pdf]]</ref>
+
| HMX || 0.04 || 0.01
 
|-
 
|-
| Sewer line relocation to avoid intersecting contaminated groundwater plume || ERM, 2017<ref name= "ERM2017">ERM, 2017. Vapor Intrusion Evaluation Activities Summary Report - February to December 2016, Indianapolis, Indiana. [[media:2017-ERM-Vapor_Intrusion_Eval_Activities_Summary.pdf| Report.pdf]]</ref>
+
| RDX || 0.04 || 0.006
 
|-
 
|-
| Various options including:
+
| [[Wikipedia: 1,3,5-Trinitrobenzene | TNB]] || 0.04 || 0.003
* Repairing or lining sewer line to prevent infiltration of liquids or vapors
 
* Sealing or repairing leaky/damaged water traps inside building
 
* Passive ventilation of manholes
 
* Depressurization of sewer system
 
| Nielsen and Hivdberg, 2017<ref name= "Nielsen2017">Nielsen, K.B. and Hvidberg, B., 2017. Remediation techniques for mitigating vapor intrusion from sewer systems to indoor air. Remediation Journal, 27(3), pp.67-73. [https://doi.org/10.1002/rem.21520 doi: 10.1002/rem.21520]</ref>
 
 
|-
 
|-
| Installation of check valves (backflow preventers) in sewer lateral lines connecting residences to the sanitary sewer line containing elevated petroleum vapor concentrations. </br>Note: for VI mitigation, the check valve must control both liquid and vapor flow (e.g., Checkmate inline check valve). || Jarvela et al., 2003<ref>Jarvela, S., Boyd, K. and Gadinski, R., 2003, April. Tranguch Gasoline Site Case History. In International Oil Spill Conference (Vol. 2003, No. 1, pp. 637-642). American Petroleum Institute. [https://doi.org/10.7901/2169-3358-2003-1-637 doi: 10.7901/2169-3358-2003-1-637]</ref>
+
| TNT || 0.04 || 0.002
 
|-
 
|-
| Sewer line ventilation || Riis et al., 2010<ref>Riis, C.E., Christensen, A.G., Hansen, M.H., Husum, H. and Terkelsen, M., 2010, May. Vapor intrusion through sewer systems: Migration pathways of chlorinated solvents from groundwater to indoor air. In Seventh Battelle International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey. [[media:2010-Riis-Migratioin_pathways_of_Chlorinated_Solvents.pdf| Report.pdf]]</ref></br>Nielsen and Hivdberg, 2017<ref name= "Nielsen2017"/></br>ERM, 2017<ref name= "ERM2017"/></br>Holton and Simms, 2018<ref>Holton, C.; Simms, J., 2018. A Review of Preferential Pathway Case Studies:  Lessons Learned for Vapor Intrusion Site Assessment. Midwestern States Environmental Consultants Association Spring Seminar, Indianapolis, Indiana. [[media:2018-Holton-A_Review_of_Pref_Path_Case_Studies.pdf| report.pdf]]</ref>
+
| [[Wikipedia: 2,6-Dinitrotoluene | 2,6-DNT]] || 0.08 || 0.002
 
|-
 
|-
| Sewer line repair || Viteri et al., 2018<ref>Viteri, C. R.; Richman, B.; Vitouchkine, A.; Armen, M. A.; Miller, A., 2018. Rapid, Real-time TCE Measurements of Sewer Headspace:  Characterizing Spatial and Temporal Variability. AEHS 28th Annual International Conference on Soil, Water, Energy, and Air, San Diego [[media:2018-Viteri_Rapid_Real-time_TCE_Measurements.pdf| Report.pdf]]</ref>
+
| 2,4-DNT || 0.04 || 0.002
 
|-
 
|-
| Installation of liner (cured in-place pipe (CIPP)) inside sewer line to prevent infiltration of contaminated groundwater || Turco and Huss, 1996 <ref>Turco, M.A. and Huss, E.E., 1996. Rehabilitation of TCE-contaminated Underground Storm Water System using Trenchless Technology. Brown and Root Environment Wayne, PA. [[media:1996-Turco_and_Huss_Rehabilitation_of_TCE.pdf| Report.pdf]]</ref>
+
| 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
 
|}
 
|}
==Summary==
 
Storm and sanitary sewers, electrical and communications conduits, and other tunnels can serve as preferential pathways, in some cases allowing vapor to enter buildings. Sites at higher risk for VI from preferential pathways include sites where contaminated groundwater enters the sewer or where the conduit passes through a concentrated VOC source area. Monitoring results indicate that sewer to indoor air attenuation is similar in magnitude to sub-slab to indoor air attenuation, suggesting that sub-slab screening values can also be used to evaluate sewer vapor results.  Mitigation approaches from sewers and tunnels include preventing contaminants from entering the conduit, ventilating the line, or correcting plumbing defects. 
 
  
 
==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