Difference between revisions of "User:Jhurley/sandbox"

Latest revision as of 21:57, 22 July 2024

Munitions Constituents – Sample Extraction and Analytical Techniques

Munitions Constituents, including insensitive munitions IM), are a broad category of compounds and, in areas where manufactured or used, can be found in a variety of environmental matrices (waters, soil, and tissues). This presents an analytical challenge when a variety of these munitions are to be quantified. This article discusses sample extraction methods for each typical sample matrix (high level water, low level water, soil and tissue) as well as the accompanying HPLC-UV analytical method for 27 compounds of interest (legacy munitions, insensitive munitions, and surrogates).

Introduction

The primary intention of the analytical methods presented here is to support the monitoring of legacy and insensitive munitions contamination on test and training ranges, however legacy and insensitive munitions often accompany each other at demilitarization facilities, manufacturing facilities, and other environmental sites. Energetic materials typically appear on ranges as small, solid particulates and due to their varying functional groups and polarities, can partition in various environmental compartments^[3]. To ensure that contaminants are monitored and controlled at these sites and to sustainably manage them a variety of sample matrices (surface or groundwater, process waters, soil, and tissues) must be considered. (Process water refers to water used during industrial manufacturing or processing of legacy and insensitive munitions.) Furthermore, additional analytes must be added to existing methodologies as the usage of IM compounds changes and as new degradation compounds are identified. Of note, relatively new IM formulations containing NTO, DNAN, and NQ are seeing use in IMX-101, IMX-104, Pax-21 and Pax-41 (Table 1)^[4]^[5].

Sampling procedures for legacy and insensitive munitions are identical and utilize multi-increment sampling procedures found in USEPA Method 8330B Appendix A^[1]. Sample hold times, subsampling and quality control requirements are also unchanged. The key differences lie in the extraction methods and instrumental methods. Briefly, legacy munitions analysis of low concentration waters uses a single cartridge reverse phase SPE procedure, and acetonitrile (ACN) is used for both extraction and elution for aqueous and solid samples^[1]^[6]. An isocratic separation via reversed-phase C-18 column with 50:50 methanol:water mobile phase or a C-8 column with 15:85 isopropanol:water mobile phase is used to separate legacy munitions^[1]. While these procedures are sufficient for analysis of legacy munitions, alternative solvents, additional SPE cartridges, and a gradient elution are all required for the combined analysis of legacy and insensitive munitions.

Previously, analysis of legacy and insensitive munitions required multiple analytical techniques, however the methods presented here combine the two munitions categories resulting in an HPLC-UV method and accompanying extraction methods for a variety of common sample matrices. A secondary HPLC-UV method and a HPLC-MS method were also developed as confirmatory methods. The methods discussed in this article were validated extensively by single-blind round robin testing and subsequent statistical treatment as part of ESTCP ER19-5078. Wherever possible, the quality control criteria in the Department of Defense Quality Systems Manual for Environmental Laboratories were adhered to^[7]. Analytes included in these methods are found in Table 1.

The chromatograms produced by the primary and secondary HPLC-UV methods are shown in Figure 1 and Figure 2, respectively. Chromatograms for each detector wavelength used are shown (315, 254, and 210 nm).

Extraction Methods

High Concentration Waters (> 1 ppm)

Aqueous samples suspected to contain the compounds of interest at concentrations detectable without any extraction or pre-concentration are suitable for analysis by direct injection. The method deviates from USEPA Method 8330B by adding a pH adjustment and use of MeOH rather than ACN for dilution^[1]. The pH adjustment is needed to ensure method accuracy for ionic compounds (like NTO or PA) in basic samples. A solution of 1% HCl/MeOH is added to both acidify and dilute the samples to a final acid concentration of 0.5% (vol/vol) and a final solvent ratio of 1:1 MeOH/H2O. The direct injection samples are then ready for analysis.

Low Concentration Waters (< 1 ppm)

Aqueous samples suspected to contain the compounds of interest at low concentrations require extraction and pre-concentration using solid phase extraction (SPE). The SPE setup described here uses a triple cartridge setup shown in Figure 3. Briefly, the extraction procedure loads analytes of interest onto the cartridges in this order: Strata^TM X, Strata^TM X-A, and Envi-Carb^TM. Then the cartridge order is reversed, and analytes are eluted via a two-step elution, resulting in 2 extracts (which are combined prior to analysis). Five milliliters of MeOH is used for the first elution, while 5 mL of acidified MeOH (2% HCl) is used for the second elution. The particular SPE cartridges used are noncritical so long as cartridge chemistries are comparable to those above.

Soils

Soil collection, storage, drying and grinding procedures are identical to the USEPA Method 8330B procedures^[1]; however, the solvent extraction procedure differs in the number of sonication steps, sample mass and solvent used. A flow chart of the soil extraction procedure is shown in Figure 4. Soil masses of approximately 2 g and a sample to solvent ratio of 1:5 (g/mL) are used for soil extraction. The extraction is carried out in a sonication bath chilled below 20 ⁰C and is a two-part extraction, first extracting in MeOH (6 hours) followed by a second sonication in 1:1 MeOH:H₂O solution (14 hours). The extracts are centrifuged, and the supernatant is filtered through a 0.45 μm PTFE disk filter.

The solvent volume should generally be 10 mL but if different soil masses are required, solvent volume should be 5 mL/g. The extraction results in 2 separate extracts (MeOH and MeOH:H2O) that are combined prior to analysis.

Tissues

Tissue matrices are extracted by 18-hour sonication using a ratio of 1 gram of wet tissue per 5 mL of MeOH. This extraction is performed in a sonication bath chilled below 20 ⁰C and the supernatant (MeOH) is filtered through a 0.45 μm PTFE disk filter.

Due to the complexity of tissue matrices, an additional tissue cleanup step, adapted from prior research, can be used to reduce interferences^[8]^[2]. The cleanup procedure uses small scale chromatography columns prepared by loading 5 ¾” borosilicate pipettes with 0.2 g activated silica gel (100–200 mesh). The columns are wetted with 1 mL MeOH, which is allowed to fully elute and then discarded prior to loading with 1 mL of extract and collecting in a new amber vial. After the extract is loaded, a 1 mL aliquot of MeOH followed by a 1 mL aliquot of 2% HCL/MeOH is added. This results in a 3 mL silica treated tissue extract. This extract is vortexed and diluted to a final solvent ratio of 1:1 MeOH/H₂O before analysis.

Most federal, state, and local regulatory guidance for assessing and mitigating the vapor intrusion pathway reflects USEPA’s Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air^[9]. The paradigm outlined by that guidance includes: 1) a preliminary and mostly qualitative analysis that looks for site conditions that suggest vapor intrusion might occur (e.g., the presence of vapor-forming chemicals in close proximity to buildings); 2) a multi-step and more detailed quantitative screening analysis that involves site-specific data collection and their comparison to screening levels to identify buildings of potential VI concern; and 3) selection and design of mitigation systems or continued monitoring, as needed. With respect to (2), regulatory guidance typically recommends consideration of “multiple lines of evidence” in decision-making^[9]^[10], with typical lines-of-evidence being groundwater, soil gas, sub-slab soil gas, and/or indoor air concentrations. Of those, soil gas measurements and/or measured short-term indoor air concentrations can be weighted heavily, and therefore decision making might not be completed without them. Effective evaluation of VI risk from sub-slab and/or soil gas measurements would require an unknown building-specific attenuation factor, but there is also uncertainty as to whether or not indoor air data is representative of maximum and/or long-term average indoor concentrations. Indoor air data can be confounded by indoor contaminant sources because the number of samples is typically small, indoor concentrations can vary with time, and because a number of household products can emit the chemicals being measured. When conducting VI pathway assessments in neighborhoods where it is impractical to assess all buildings, the EPA recommends following a “worst first” investigational approach.

The limitations of this approach, as practiced, are the following:

Decisions are rarely made without indoor air data and generally, seasonal sampling is required, delaying decision making.
The collection of a robust indoor air data set that adequately characterizes long term indoor air concentrations could take years given the typical frequency of data collection and the most common methods of sample collection (e.g., 24-hour samples). Therefore, indoor air sampling might continue indefinitely at some sites.
The “worst first” buildings might not be identified correctly by the logic outlined in USEPA’s 2015 guidance and the most impacted buildings might not even be located over a groundwater plume. Recent studies have shown VI impacts in homes as a result of sewer and other subsurface piping connections, which are not explicitly considered nor easily characterized through conventional VI pathway assessment^[11]^[12]^[13]^[14]^[15].
The presumptive remedy for VI mitigation (sub-slab depressurization) may not be effective for all VI scenarios (e.g., those involving vapor migration to indoor spaces via sewer connections).

The VI Diagnosis Toolkit components were developed considering these limitations as well as more recent knowledge gained through research, development, and validation projects funded by SERDP and ESTCP.

The VI Diagnosis Toolkit Components

Figure 1. Vapor intrusion pathway conceptualization considering “alternate VI pathways”, including “pipe flow VI” and “sewer VI” pathways^[16].

The primary components of the VI Diagnosis Toolkit and their uses include:

External VI source strength screening to identify buildings most likely to be impacted by VI at levels warranting building-specific testing.
Indoor air source screening to locate and remove indoor air sources that might confound building specific VI pathway assessment.
Controlled pressurization method (CPM) testing to quickly (in a few days or less) measure the worst-case indoor air impact likely to be caused by VI under natural conditions in specific buildings. CPM tests can also be used to identify the presence of indoor air sources and diagnose active VI pathways.
Passive indoor sampling for determining long-term average indoor air concentrations under natural VI conditions and/or for verifying mitigation system effectiveness in buildings that warrant VI mitigation.
Comprehensive VI conceptual model development and refinement to ensure that appropriate monitoring, investigation, and mitigation strategies are being selected (Figure 1).

Expanded discussions for each of these are given below.

External VI source strength screening identifies those buildings that warrant more intrusive building-specific assessments, using data collected exterior to the buildings. The use of groundwater and/or soil gas concentration data for building screening has been part of VI pathway assessments for some time and their use is discussed in many regulatory guidance documents. Typically, the measured concentrations are compared to relevant screening levels derived via modeling or empirical analyses from indoor air concentrations of concern.

More recently it has been discovered that VI impacts can occur via sewer and other subsurface piping connections in areas where vapor migration through the soil would not be expected to be significant, and this could also occur in buildings that do not sit over contaminated groundwater^[15]^[12]^[13]^[14].

Therefore, in addition to groundwater and soil gas sampling, external data collection that includes and extends beyond the area of concern should include manhole vapor sampling (e.g., sanitary sewer, storm sewer, land-drain). Video surveys from sanitary sewers, storm sewers, and/or land-drains can also be used to identify areas of groundwater leakage into utility corridors and lateral connections to buildings that are conduits for vapor transport. During these investigations, it is important to recognize that utility corridors can transmit both impacted water and vapors beyond groundwater plume boundaries, so extending investigations into areas adjacent to groundwater plume boundaries is necessary.

Using projected indoor air concentrations from modeling and empirical data analyses, and distance screening approaches, external source screening can identify areas and buildings that can be ruled out, or conversely, those that warrant building-specific testing.

Demonstration of neighborhood-scale external VI source screening using groundwater, depth, sewer, land drain, and video data is documented in the ER-201501 final report^[16].

Indoor air source screening seeks to locate and remove indoor air sources^[17] that might confound building specific VI pathway assessment. Visual inspections and written surveys might or might not identify significant indoor air sources, so these should be complemented with use of portable analytical instruments^[18]^[19].

The advantage of portable analytical tools is that they allow practitioners to expeditiously test indoor air concentrations under natural conditions in each room of the building. Concentrations in any room in excess of relevant screening levels trigger more sampling in that room to identify if an indoor source is present in that room. Removal of a suspected source and subsequent room testing can identify if that object or product was the source of the previously measured concentrations.

Building-specific controlled pressurization method (CPM) testing directly measures the worst case indoor air impact, but it can also be used to determine contributing VI pathways and to identify indoor air sources^[20]^[19]^[12]^[21]^[16]^[22]. In CPM testing, blowers/fans installed in a doorway(s) or window(s) are set-up to exhaust indoor air to outdoor, which causes the building to be under pressurized relative to the atmosphere. This induces air movement from the subsurface into the test building via openings in the foundation and/or subsurface piping networks with or without direct connections to indoor air. This is similar to what happens intermittently under natural conditions when wind, indoor-outdoor temperature differences, and/or use of appliances that exhaust air from the structure (e.g. dryer exhaust) create an under-pressurized building condition.

The blowers/fans can also be used to blow outdoor air into the building, thereby creating a building over-pressurization condition. A positive pressure difference CPM test suppresses VI pathways; therefore, chemicals detected in indoor air above outdoor air concentrations during this condition are attributed to indoor contaminant sources which facilitates the identification of any such indoor air sources.

Data collected during CPM testing, when combined with screening level VI modeling, can be used to identify which VI chemical migration pathways are significant contributors to indoor air impacts^[12]. CPM testing guidelines were developed and validated under ESTCP Project ER-201501^[22]^[23].

Passive samplers can be used to measure long term average indoor air concentrations under natural conditions and during VI mitigation system operation. They will provide more confident assessment of long term average concentrations than an infrequent sequence of short term grab samples. Long term average concentrations can also be determined by long term active sampling (e.g., by slowly pulling air through a thermal desorption (TD) tube). However, passive sampling has the advantage that additional equipment and expertise is not required for sampler deployment and recovery.

Use of passive samplers in indoor air under time-varying concentration conditions was demonstrated and validated by comparing against intensive active sampling in ESTCP Project ER-201501^[16]^[24].

The purpose of maintaining an evergreen comprehensive VI conceptual model is to ensure that the most complete and up-to-date understanding of the site is informing decisions related to future sampling, data interpretation, and the need for and design of mitigation systems. The VI conceptual model can also serve as an effective communication tool in stakeholder discussions.

Use of these tools for residential neighborhoods and in non-residential buildings overlying chlorinated solvent groundwater plumes is documented comprehensively in a series of peer reviewed articles^[16]^[23]^[25]^[12]^[22]^[26]^[24]^[21].

Summary

In summary, the VI Diagnosis Toolkit provides a set of tools that can lead to quicker, more confident, and more cost effective neighborhood-scale VI pathway and impact assessments. Toolkit components and their use can complement conventional methods for assessing and mitigating the vapor intrusion pathway.

References

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 United States Environmental Protection Agency (USEPA), 2006. EPA Method 8330B (SW-846) Nitroaromatics, Nitramines, and Nitrate Esters by High Performance Liquid Chromatography (HPLC), Revision 2. USEPA Website Method 8330B.pdf
^ ^2.0 ^2.1 Crouch, R.A., Smith, J.C., Stromer, B.S., Hubley, C.T., Beal, S., Lotufo, G.R., Butler, A.D., Wynter, M.T., Russell, A.L., Coleman, J.G., Wayne, K.M., Clausen, J.L., Bednar, A.J., 2020. Methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil/sediment, and tissue matrices. Talanta, 217, Article 121008. doi: 10.1016/j.talanta.2020.121008 Open Access Manuscript.pdf
^ 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
^ Mainiero, C. 2015. Picatinny Employees Recognized for Insensitive Munitions. U.S. Army, Picatinny Arsenal Public Affairs. Open Access Press Release
^ Frem, D., 2022. A Review on IMX-101 and IMX-104 Melt-Cast Explosives: Insensitive Formulations for the Next-Generation Munition Systems. Propellants, Explosives, Pyrotechnics, 48(1), e202100312. doi: 10.1002/prep.202100312
^ United States Environmental Protection Agency (USEPA), 2007. EPA Method 3535A (SW-846) Solid-Phase Extraction (SPE), Revision 1. USEPA Website Method 3535A.pdf
^ US Department of Defense and US Department of Energy, 2021. Consolidated Quality Systems Manual (QSM) for Environmental Laboratories, Version 5.4. 387 pages. Free Download QSM Version 5.4.pdf
^ Russell, A.L., Seiter, J.M., Coleman, J.G., Winstead, B., Bednar, A.J., 2014. Analysis of munitions constituents in IMX formulations by HPLC and HPLC-MS. Talanta, 128, pp. 524–530. doi: 10.1016/j.talanta.2014.02.013
^ ^9.0 ^9.1 USEPA, 2015. OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air. U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, OSWER Publication No. 9200.2-154, 267 pages. USEPA Website Report.pdf
^ NJDEP, 2021. Vapor Intrusion Technical Guidance, Version 5.0. New Jersey Department of Environmental Protection, Trenton, NJ. Website Guidance Document.pdf
^ Beckley, L, McHugh, T., 2020. A Conceptual Model for Vapor Intrusion from Groundwater Through Sewer Lines. Science of the Total Environment, 698, Article 134283. doi: 10.1016/j.scitotenv.2019.134283 Open Access Article
^ ^12.0 ^12.1 ^12.2 ^12.3 ^12.4 Guo, Y., Holton, C., Luo, H., Dahlen, P., Gorder, K., Dettenmaier, E., Johnson, P.C., 2015. Identification of Alternative Vapor Intrusion Pathways Using Controlled Pressure Testing, Soil Gas Monitoring, and Screening Model Calculations. Environmental Science and Technology, 49(22), pp. 13472–13482. doi: 10.1021/acs.est.5b03564
^ ^13.0 ^13.1 McHugh, T., Beckley, L., Sullivan, T., Lutes, C., Truesdale, R., Uppencamp, R., Cosky, B., Zimmerman, J., Schumacher, B., 2017. Evidence of a Sewer Vapor Transport Pathway at the USEPA Vapor Intrusion Research Duplex. Science of the Total Environment, pp. 598, 772-779. doi: 10.1016/j.scitotenv.2017.04.135 Open Access Manuscipt
^ ^14.0 ^14.1 McHugh, T., Beckley, L., 2018. Sewers and Utility Tunnels as Preferential Pathways for Volatile Organic Compound Migration into Buildings: Risk Factors and Investigation Protocol. ESTCP ER-201505, Final Report. Project Website Final Report.pdf
^ ^15.0 ^15.1 Riis, C., Hansen, M.H., Nielsen, H.H., Christensen, A.G., Terkelsen, M., 2010. Vapor Intrusion through Sewer Systems: Migration Pathways of Chlorinated Solvents from Groundwater to Indoor Air. Seventh International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May, Monterey, CA. Battelle Memorial Institute. ISBN 978-0-9819730-2-9. Website Report.pdf
^ ^16.0 ^16.1 ^16.2 ^16.3 ^16.4 Cite error: Invalid <ref> tag; no text was provided for refs named JohnsonEtAl2020
^ Doucette, W.J., Hall, A.J., Gorder, K.A., 2010. Emissions of 1,2-Dichloroethane from Holiday Decorations as a Source of Indoor Air Contamination. Ground Water Monitoring and Remediation, 30(1), pp. 67-73. doi: 10.1111/j.1745-6592.2009.01267.x
^ McHugh, T., Kuder, T., Fiorenza, S., Gorder, K., Dettenmaier, E., Philp, P., 2011. Application of CSIA to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs. Environmental Science and Technology, 45(14), pp. 5952-5958. doi: 10.1021/es200988d
^ ^19.0 ^19.1 Beckley, L., Gorder, K., Dettenmaier, E., Rivera-Duarte, I., McHugh, T., 2014. On-Site Gas Chromatography/Mass Spectrometry (GC/MS) Analysis to Streamline Vapor Intrusion Investigations. Environmental Forensics, 15(3), pp. 234–243. doi: 10.1080/15275922.2014.930941
^ McHugh, T.E., Beckley, L., Bailey, D., Gorder, K., Dettenmaier, E., Rivera-Duarte, I., Brock, S., MacGregor, I.C., 2012. Evaluation of Vapor Intrusion Using Controlled Building Pressure. Environmental Science and Technology, 46(9), pp. 4792–4799. doi: 10.1021/es204483g
^ ^21.0 ^21.1 Holton, C., Guo, Y., Luo, H., Dahlen, P., Gorder, K., Dettenmaier, E., Johnson, P.C., 2015. Long-Term Evaluation of the Controlled Pressure Method for Assessment of the Vapor Intrusion Pathway. Environmental Science and Technology, 49(4), pp. 2091–2098. doi: 10.1021/es5052342
^ ^22.0 ^22.1 ^22.2 Guo, Y., Dahlen, P., Johnson, P.C., 2020a. Development and Validation of a Controlled Pressure Method Test Protocol for Vapor Intrusion Pathway Assessment. Environmental Science and Technology, 54(12), pp. 7117-7125. doi: 10.1021/acs.est.0c00811
^ ^23.0 ^23.1 Cite error: Invalid <ref> tag; no text was provided for refs named JohnsonEtAl2021
^ ^24.0 ^24.1 Guo, Y., O’Neill, H., Dahlen, P., and Johnson, P.C. 2021. Evaluation of Passive Diffusive-Adsorptive Samplers for Use in Assessing Time-Varying Indoor Air Impacts Resulting from Vapor Intrusion. Groundwater Monitoring and Remediation, 42(1), pp. 38-49. doi: 10.1111/12481
^ Cite error: Invalid <ref> tag; no text was provided for refs named JohnsonEtAl2022
^ Guo, Y., Dahlen, P., Johnson, P.C. 2020b. Temporal variability of chlorinated volatile organic compound vapor concentrations in a residential sewer and land drain system overlying a dilute groundwater plume. Science of the Total Environment, 702, Article 134756. doi: 10.1016/j.scitotenv.2019.134756 Open Access Manuscript

@@ Line 1: / Line 1: @@
-==Contaminated Sediment Risk Assessment==
+==Munitions Constituents – Sample Extraction and Analytical Techniques==
-[[Contaminated Sediments - Introduction | Contaminated sediments]] in rivers and streams, lakes, coastal harbors, and estuaries have the potential to pose ecological and human health risks. The goals of risk assessment applied to contaminated sediments are to characterize the nature and magnitude of the current and potential threats to human health, wildlife and ecosystem functioning posed by contamination; identify the key factors contributing to the potential health and ecological risks; evaluate how implementation of one or more remedy actions will mitigate the risks in the short and long term; and evaluate the risks and impacts from sediment management, both during and after any dredging or other remedy construction activities.
+Munitions Constituents, including [[Wikipedia: Insensitive munition | insensitive munitions]] IM), are a broad category of compounds and, in areas where manufactured or used, can be found in a variety of environmental matrices (waters, soil, and tissues). This presents an analytical challenge when a variety of these munitions are to be quantified. This article discusses sample extraction methods for each typical sample matrix (high level water, low level water, soil and tissue) as well as the accompanying [[Wikipedia: High-performance liquid chromatography | HPLC]]-UV analytical method for 27 compounds of interest (legacy munitions, insensitive munitions, and surrogates).
 <div style="float:right;margin:0 0 2em 2em;">__TOC__</div>
 '''Related Article(s):'''
-*[[Contaminated Sediments - Introduction]]
-*[[In Situ Treatment of Contaminated Sediments with Activated Carbon]]
+*[[Munitions Constituents]]
-*[[Sediment Capping]]
-*[[Passive Sampling of Sediments]]
 '''Contributor(s):'''
-*Richard J. Wenning
-*Sabine E. Apitz
+*Dr. Austin Scircle
 '''Key Resource(s):'''
-* Contaminated Sediment Remediation Guidance for Hazardous Waste Sites<ref name="USEPA2005">United States Environmental Protection Agency (USEPA), 2005. Contaminated Sediment Remediation Guidance for Hazardous Waste Sites. Office of Solid Waste and Emergency Response, Washington, D.C. EPA-540-R-05-012. OSWER 9355.0-85.  Free download from: [https://semspub.epa.gov/work/HQ/174471.pdf USEPA]&nbsp;&nbsp; [[Media: EPA-540-R-05-012.pdf | Report.pdf]]</ref>
-* Principles for Environmental Risk Assessment of the Sediment Compartment<ref name="Tarazona2014">Tarazona, J.V., Versonnen, B., Janssen, C., De Laender, F., Vangheluwe, M. and Knight, D., 2014. Principles for Environmental Risk Assessment of the Sediment Compartment: Proceedings of the Topical Scientific Workshop. 7-8 May 2013. European Chemicals Agency, Helsinki. Document ECHA-14-R-13-EN. Free download from: [https://echa.europa.eu/documents/10162/22816050/environmental_risk_assessment_final_en.pdf/3515b685-6601-40ce-bd48-3f8d5332c0f8 European Chemicals Agency]&nbsp;&nbsp; [[Media: ECHA-14-R-13-EN.pdf | Report.pdf]]</ref>
+*[https://www.epa.gov/sites/default/files/2015-07/documents/epa-8330b.pdf USEPA Method 8330B]<ref name= "8330B">United States Environmental Protection Agency (USEPA), 2006. EPA Method 8330B (SW-846) Nitroaromatics, Nitramines, and Nitrate Esters by High Performance Liquid Chromatography (HPLC), Revision 2. [https://www.epa.gov/esam/epa-method-8330b-sw-846-nitroaromatics-nitramines-and-nitrate-esters-high-performance-liquid USEPA Website]&nbsp; &nbsp;[[Media: epa-8330b.pdf | Method 8330B.pdf]]</ref>
-* Assessing and managing contaminated sediments:
+*Methods for simultaneous quantification of legacy and insensitive munition (IM) constituents in aqueous, soil/sediment, and tissue matrices<ref name="CrouchEtAl2020">Crouch, R.A., Smith, J.C., Stromer, B.S., Hubley, C.T., Beal, S., Lotufo, G.R., Butler, A.D., Wynter, M.T., Russell, A.L., Coleman, J.G., Wayne, K.M., Clausen, J.L., Bednar, A.J., 2020. Methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil/sediment, and tissue matrices. Talanta, 217, Article 121008. [https://doi.org/10.1016/j.talanta.2020.121008 doi: 10.1016/j.talanta.2020.121008]&nbsp; &nbsp;[[Media: CrouchEtAl2020.pdf | Open Access Manuscript.pdf]]</ref>
-:: Part I, Developing an Effective Investigation and Risk Evaluation Strategy<ref name="Apitz2005a">Apitz, S.E., Davis, J.W., Finkelstein, K., Hohreiter, D.W., Hoke, R., Jensen, R.H., Jersak, J., Kirtay, V.J., Mack, E.E., Magar, V.S. and Moore, D., 2005. Assessing and Managing Contaminated Sediments: Part I, Developing an Effective Investigation and Risk Evaluation Strategy. Integrated Environmental Assessment and Management, 1(1), pp. 2-8. [https://doi.org/10.1897/IEAM_2004a-002.1 DOI: 10.1897/IEAM_2004a-002.1] Free access article from: [https://setac.onlinelibrary.wiley.com/doi/epdf/10.1897/IEAM_2004a-002.1 Society of Environmental Toxicology and Chemistry]&nbsp;&nbsp; [[Media: Apitz2005a.pdf | Report.pdf]]</ref>
-:: Part II, Evaluating Risk and Monitoring Sediment Remedy Effectiveness<ref name="Apitz2005b">Apitz, S.E., Davis, J.W., Finkelstein, K., Hohreiter, D.W., Hoke, R., Jensen, R.H., Jersak, J., Kirtay, V.J., Mack, E.E., Magar, V.S. and Moore, D., 2005b. Assessing and Managing Contaminated Sediments: Part II, Evaluating Risk and Monitoring Sediment Remedy Effectiveness. Integrated Environmental Assessment and Management, 1(1), pp.e1-e14. [https://doi.org/10.1897/IEAM_2004a-002e.1 DOI: 10.1897/IEAM_2004a-002e.1]</ref>
 ==Introduction==
-Improving the management of [[Contaminated Sediments - Introduction | contaminated sediments]] is of growing concern globally. Sediment processes in both marine and freshwater environments are important to the function of aquatic ecosystems<ref name="Apitz2012">Apitz, S.E., 2012. Conceptualizing the role of sediment in sustaining ecosystem services: Sediment-Ecosystem Regional Assessment (SEcoRA), Science of the Total Environment, 415, pp. 9-30. [https://doi.org/10.1016/j.scitotenv.2011.05.060 DOI:10.1016/j.scitotenv.2011.05.060] Free download from: [https://d1wqtxts1xzle7.cloudfront.net/7588577/Apitz_SEcoRA%202012.pdf?1326618388=&response-content-disposition=inline%3B+filename%3DConceptualizing_the_role_of_sediment_in.pdf&Expires=1637094311&Signature=c2wczG59XxkitPjmBhc9PaODHJ8Vufg3gyzdG8tqGD6~mIVhLoz30E7eQNIghfMlH~jbch3KTVxMqD2AQFMQCSeXghIwqH~lXjGrEP07MJXCEgntzSW-V8Gws~33it5pEm9Ied64fSOvMLJR-PUXVr2OVTsVHQJHurHdGrtEmhUd90bKrC0NNlD28YLGQpkVUOlqa75e0K4sjPngwPUwUxhq18NAH6-1Uc3fQU5g5AjXwGph-VNe7EwzT-0do5OD056AsG-Eg8xIZi0ABJqMsg1wb92tIPpmmNy6ntdklHeN6tq~3IJFB7Tg8XYntQ-CGT8pYV9S7Kz14GhXVm9OQA__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA Academia.edu]</ref>, and many organisms rely on certain sediment quality and quantity characteristics for their life cycle<ref name="Hauer2018">Hauer, C., Leitner, P., Unfer, G., Pulg, U., Habersack, H. and Graf, W., 2018. The Role of Sediment and Sediment Dynamics in the Aquatic Environment. In: Schmutz S., Sendzimir J. (ed.s) Riverine Ecosystem Management. Aquatic Ecology Series, vol. 8, pp. 151-169. Springer. [https://doi.org/10.1007/978-3-319-73250-3_8 DOI: 10.1007/978-3-319-73250-3_8]  Open access book from: [https://library.oapen.org/bitstream/handle/20.500.12657/27726/1002280.pdf?seque#page=153 SpringerOpen]</ref>. Human health can also be affected by sediment conditions, either via direct contact, as a result of sediment impacts on water quality, or because of the strong influence sediments can have on the quality of fish and shellfish consumed by people<ref name="Greenfield2015">Greenfield, B.K., Melwani, A.R. and Bay, S.M., 2015. A Tiered Assessment Framework to Evaluate Human Health Risk of Contaminated Sediment. Integrated Environmental Assessment and Management, 11(3), pp. 459-473.  [https://doi.org/10.1002/ieam.1610 DOI: 10.1002/ieam.1610]</ref>. A common approach to achieving the explicit management goals inherent in different sediment assessment frameworks in North America and elsewhere is the use of the ecological risk assessment (ERA)<ref name="USEPA1997a">US Environmental Protection Agency (USEPA), 1997. The Incidence and Severity of Sediment Contamination in Surface Waters of the United States: Volume 1, National Sediment Quality Survey. EPA-823R-97-006. Washington, DC.  [[Media: EPA-823-R-97-006.pdf | Report.pdf]]</ref>. An ERA “evaluates the likelihood and magnitude of adverse effects from exposure to a chemical for organisms, such as animals, plants, or microbes, in the environment”<ref name="SETAC2018">Society of Environmental Toxicology and Chemistry (SETAC), 2018. Technical Issue Paper: Environmental Risk Assessment of Chemicals. SETAC, Pensacola, FL. 5 pp. Free download from: [https://cdn.ymaws.com/www.setac.org/resource/resmgr/publications_and_resources/setac_tip_era.pdf SETAC]&nbsp;&nbsp; [[Media: setac_tip_era2018.pdf | Report.pdf]]</ref>. An ERA provides information relevant to the management decision-making process<ref name="Stahl2001">Stahl, R.G., Bachman, R., Barton, A., Clark, J., deFur, P., Ells, S., Pittinger, C., Slimak, M., Wentsel, R., 2001. Risk Management: Ecological Risk-Based Decision Making. SETAC Press, Pensacola, FL, 222 pp.  ISBN: 978-1-880611-26-5</ref>. It should be performed in a scientifically based, defensible manner that is cost-effective and protective of human health and the environment<ref name="CNO1999">Chief of Naval Operations (CNO), 1999. Navy Policy for Conducting Ecological Risk Assessments, Letter 5090, Ser N453E/9U595355, dated 05 April 99. Department of the Navy, Washington, DC. Free download from: [https://www.navfac.navy.mil/content/dam/navfac/Specialty%20Centers/Engineering%20and%20Expeditionary%20Warfare%20Center/Environmental/Restoration/er_pdfs/gpr/cno-ev-pol-era-19990405.pdf the US Navy]&nbsp;&nbsp; [[Media: CNO1999.pdf | Report.pdf]]</ref>. Therefore, science-based methods for assessing sediment quality and use of risk-based decision-making in sediment management are important for identifying conditions suspected to adversely affect ecological and human services provided by sediments, and predicting the likely consequences of different sediment management actions<ref name="Bridges2006">Bridges, T.S., Apitz, S.E., Evison, L., Keckler, K., Logan, M., Nadeau, S. and Wenning, R.J., 2006. Risk‐Based Decision Making to Manage Contaminated Sediments. Integrated Environmental Assessment and Management, 2(1), pp. 51-58.  [https://doi.org/10.1002/ieam.5630020110 DOI: 10.1002/ieam.5630020110]  Free access article from: [https://setac.onlinelibrary.wiley.com/doi/epdf/10.1002/ieam.5630020110 SETAC]</ref><ref name="Apitz2011">Apitz, S.E., 2011. Integrated Risk Assessments for the Management of Contaminated Sediments in Estuaries and Coastal Systems. In: Wolanski, E. and McLusky, D.S. (eds.) Treatise on Estuarine and Coastal Science, Vol 4, pp. 311–338. Waltham: Academic Press. ISBN: 9780123747112</ref>.
+The primary intention of the analytical methods presented here is to support the monitoring of legacy and insensitive munitions contamination on test and training ranges, however legacy and insensitive munitions often accompany each other at demilitarization facilities, manufacturing facilities, and other environmental sites. Energetic materials typically appear on ranges as small, solid particulates and due to their varying functional groups and polarities, can partition in various environmental compartments<ref>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]</ref>. To ensure that contaminants are monitored and controlled at these sites and to sustainably manage them a variety of sample matrices (surface or groundwater, process waters, soil, and tissues) must be considered. (Process water refers to water used during industrial manufacturing or processing of legacy and insensitive munitions.) Furthermore, additional analytes must be added to existing methodologies as the usage of IM compounds changes and as new degradation compounds are identified.  Of note, relatively new IM formulations containing NTO, DNAN, and NQ are seeing use in [[Wikipedia: IMX-101 | IMX-101]], IMX-104, Pax-21 and Pax-41 (Table 1)<ref>Mainiero, C. 2015. Picatinny Employees Recognized for Insensitive Munitions. U.S. Army, Picatinny Arsenal Public Affairs.  [https://www.army.mil/article/148873/picatinny_employees_recognized_for_insensitive_munitions Open Access Press Release]</ref><ref>Frem, D., 2022. A Review on IMX-101 and IMX-104 Melt-Cast Explosives: Insensitive Formulations for the Next-Generation Munition Systems. Propellants, Explosives, Pyrotechnics, 48(1), e202100312. [https://doi.org/10.1002/prep.202100312 doi: 10.1002/prep.202100312]</ref>.
+Sampling procedures for legacy and insensitive munitions are identical and utilize multi-increment sampling procedures found in USEPA Method 8330B Appendix A<ref name= "8330B"/>. Sample hold times, subsampling and quality control requirements are also unchanged. The key differences lie in the extraction methods and instrumental methods. Briefly, legacy munitions analysis of low concentration waters uses a single cartridge reverse phase [[Wikipedia: Solid-phase extraction | SPE]] procedure, and [[Wikipedia: Acetonitrile | acetonitrile]] (ACN) is used for both extraction and [[Wikipedia: Elution | elution]] for aqueous and solid samples<ref name= "8330B"/><ref>United States Environmental Protection Agency (USEPA), 2007. EPA Method 3535A (SW-846) Solid-Phase Extraction (SPE), Revision 1. [https://www.epa.gov/esam/epa-method-3535a-sw-846-solid-phase-extraction-spe USEPA Website]&nbsp; &nbsp;[[Media: epa-3535a.pdf | Method 3535A.pdf]]</ref>. An [[Wikipedia: High-performance_liquid_chromatography#Isocratic_and_gradient_elution | isocratic]] separation via reversed-phase C-18 column with 50:50 methanol:water mobile phase or a C-8 column with 15:85 isopropanol:water mobile phase is used to separate legacy munitions<ref name= "8330B"/>. While these procedures are sufficient for analysis of legacy munitions, alternative solvents, additional SPE cartridges, and a gradient elution are all required for the combined analysis of legacy and insensitive munitions.
+Previously, analysis of legacy and insensitive munitions required multiple analytical techniques, however the methods presented here combine the two munitions categories resulting in an HPLC-UV method and accompanying extraction methods for a variety of common sample matrices. A secondary HPLC-UV method and a HPLC-MS method were also developed as confirmatory methods. The methods discussed in this article were validated extensively by single-blind round robin testing and subsequent statistical treatment as part of ESTCP [https://serdp-estcp.mil/projects/details/d05c1982-bbfa-42f8-811d-51b540d7ebda ER19-5078]. Wherever possible, the quality control criteria in the Department of Defense Quality Systems Manual for Environmental Laboratories were adhered to<ref>US Department of Defense and US Department of Energy, 2021. Consolidated Quality Systems Manual (QSM) for Environmental Laboratories, Version 5.4. 387 pages. [https://www.denix.osd.mil/edqw/denix-files/sites/43/2021/10/QSM-Version-5.4-FINAL.pdf Free Download]&nbsp; &nbsp;[[Media: QSM-Version-5.4.pdf | QSM Version 5.4.pdf]]</ref>. Analytes included in these methods are found in Table 1.
+The chromatograms produced by the primary and secondary HPLC-UV methods are shown in Figure 1 and Figure 2, respectively. Chromatograms for each detector wavelength used are shown (315, 254, and 210 nm).
+==Extraction Methods==
+===High Concentration Waters (> 1 ppm)===
+Aqueous samples suspected to contain the compounds of interest at concentrations detectable without any extraction or pre-concentration are suitable for analysis by direct injection. The method deviates from USEPA Method 8330B by adding a pH adjustment and use of MeOH rather than ACN for dilution<ref name= "8330B"/>. The pH adjustment is needed to ensure method accuracy for ionic compounds (like NTO or PA) in basic samples. A solution of 1% HCl/MeOH is added to both acidify and dilute the samples to a final acid concentration of 0.5% (vol/vol) and a final solvent ratio of 1:1 MeOH/H2O. The direct injection samples are then ready for analysis.
+===Low Concentration Waters (< 1 ppm)===
+Aqueous samples suspected to contain the compounds of interest at low concentrations require extraction and pre-concentration using solid phase extraction (SPE). The SPE setup described here uses a triple cartridge setup shown in '''Figure 3'''. Briefly, the extraction procedure loads analytes of interest onto the cartridges in this order: Strata<sup><small>TM</small></sup> X, Strata<sup><small>TM</small></sup> X-A, and Envi-Carb<sup><small>TM</small></sup>. Then the cartridge order is reversed, and analytes are eluted via a two-step elution, resulting in 2 extracts (which are combined prior to analysis). Five milliliters of MeOH is used for the first elution, while 5 mL of acidified MeOH (2% HCl) is used for the second elution. The particular SPE cartridges used are noncritical so long as cartridge chemistries are comparable to those above.
+===Soils===
+Soil collection, storage, drying and grinding procedures are identical to the USEPA Method 8330B procedures<ref name= "8330B"/>; however, the solvent extraction procedure differs in the number of sonication steps, sample mass and solvent used. A flow chart of the soil extraction procedure is shown in '''Figure 4'''. Soil masses of approximately 2 g and a sample to solvent ratio of 1:5 (g/mL) are used for soil extraction. The extraction is carried out in a sonication bath chilled below 20 ⁰C and is a two-part extraction, first extracting in MeOH (6 hours) followed by a second sonication in 1:1 MeOH:H<sub>2</sub>O solution (14 hours). The extracts are centrifuged, and the supernatant is filtered through a 0.45 μm PTFE disk filter.
+The solvent volume should generally be 10 mL but if different soil masses are required, solvent volume should be 5 mL/g. The extraction results in 2 separate extracts (MeOH and MeOH:H2O) that are combined prior to analysis.
+===Tissues===
+Tissue matrices are extracted by 18-hour sonication using a ratio of 1 gram of wet tissue per 5 mL of MeOH. This extraction is performed in a sonication bath chilled below 20 ⁰C and the supernatant (MeOH) is filtered through a 0.45 μm PTFE disk filter.
+Due to the complexity of tissue matrices, an additional tissue cleanup step, adapted from prior research, can be used to reduce interferences<ref name="RussellEtAl2014">Russell, A.L., Seiter, J.M., Coleman, J.G., Winstead, B., Bednar, A.J., 2014. Analysis of munitions constituents in IMX formulations by HPLC and HPLC-MS. Talanta, 128, pp. 524–530. [https://doi.org/10.1016/j.talanta.2014.02.013 doi: 10.1016/j.talanta.2014.02.013]</ref><ref name="CrouchEtAl2020"/>. The cleanup procedure uses small scale chromatography columns prepared by loading 5 ¾” borosilicate pipettes with 0.2 g activated silica gel (100–200 mesh). The columns are wetted with 1 mL MeOH, which is allowed to fully elute and then discarded prior to loading with 1 mL of extract and collecting in a new amber vial. After the extract is loaded, a 1 mL aliquot of MeOH followed by a 1 mL aliquot of 2% HCL/MeOH is added. This results in a 3 mL silica treated tissue extract. This extract is vortexed and diluted to a final solvent ratio of 1:1 MeOH/H<sub>2</sub>O before analysis.
-Sediment risk assessment is increasingly used by governmental agencies to support sediment management in freshwater, estuarine, and marine environments. Strategies for sediment management encompass a wide variety of actions, from removal, capping or treatment of contaminated sediment to the monitoring of natural processes, including sedimentation, binding, and bio- and photo-degradation that serve to reduce the potential threat to aquatic life over time. It is not uncommon to revisit a sediment risk assessment periodically to check how changed environmental conditions reflected in sediment and biotic sampling work has either reduced or exacerbated the threats identified in the initial assessment.
-At present, several countries lack common recommendations specific to conducting risk assessment of contaminated sediments<ref name="Bruce2020">Bruce, P., Sobek, A., Ohlsson, Y. and Bradshaw, C., 2020. Risk assessments of contaminated sediments from the perspective of weight of evidence strategies – a Swedish case study. Human and Ecological Risk Assessment, 27(5), pp. 1366-1387.  [https://doi.org/10.1080/10807039.2020.1848414 DOI: 10.1080/10807039.2020.1848414]&nbsp;&nbsp; [https://www.tandfonline.com/doi/full/10.1080/10807039.2020.1848414 Website]</ref>. In the European Union, sediment has played a secondary role in the Water Framework Directive (WFD), with most quality standards being focused on water with the option for the development of national standards for sediment and biota for bioaccumulative compounds. The Common Implementation Strategy (CIS) in 2010 provided guidance on the monitoring of contaminants in sediments and biota, but not on risk-based decision-making<ref name="EC2010">European Commission, 2010. Common Implementation Strategy For The Water Framework Directive (2000/60/EC), Technical Report - 2010 – 041; Guidance document No. 25 On Chemical Monitoring Of Sediment And Biota Under The Water Framework Directive. 82pp. ISBN 978-92-79-16224-4.  [https://op.europa.eu/en/publication-detail/-/publication/5ff7a8ec-995b-4d90-a140-0cc9b4bf980d  Free download]</ref>. There are efforts underway to incorporate guidance for management of contaminated sediment in the Common Implementation Strategy in 2021<ref name="Brils2020">Brils, J., 2020. Including sediment in European River Basin Management Plans: Twenty years of work by SedNet. Journal of Soils and Sediments, 20(12), pp.4229-4237.  [https://doi.org/10.1007/s11368-020-02782-1 DOI: 10.1007/s11368-020-02782-1]&nbsp;&nbsp; [https://link.springer.com/content/pdf/10.1007/s11368-020-02782-1.pdf Open Access Article]</ref>. Sediment risk assessment guidance from Norway, Canada, the Netherlands, and the US are most often referenced when assessing the risks from contaminated sediments<ref name="Bruce2020"/><ref name="Birch2018">Birch, G.F., 2018. A review of chemical-based sediment quality assessment methodologies for the marine environment. Marine Pollution Bulletin, 133, pp.218-232.  [https://doi.org/10.1016/j.marpolbul.2018.05.039 DOI: 10.1016/j.marpolbul.2018.05.039]</ref><ref name="Kwok2014">Kwok, K.W., Batley, G.E., Wenning, R.J., Zhu, L., Vangheluwe, M. and Lee, S., 2014. Sediment quality guidelines: challenges and opportunities for improving sediment management. Environmental Science and Pollution Research, 21(1), pp. 17-27.  [https://doi.org/10.1007/s11356-013-1778-7 DOI: 10.1007/s11356-013-1778-7] Free download from: [https://www.researchgate.net/profile/Graeme-Batley/publication/236836992_Sediment_quality_guidelines_Challenges_and_opportunities_for_improving_sediment_management/links/0c96052b8a8f5ad0c6000000/Sediment-quality-guidelines-Challenges-and-opportunities-for-improving-sediment-management.pdf ResearchGate]</ref>. Some European countries, such as Norway, have focused their risk assessment guidance on the assessment of sediment conditions relative to general chemical thresholds, while in North America, risk assessment guidance focuses on site- or region-specific conditions<ref name="Apitz2008">Apitz, S.E., 2008. Is risk-based, sustainable sediment management consistent with European policy?. Journal of Soils and Sediments, 8(6), p.461-466.  [https://doi.org/10.1007/s11368-008-0039-8 DOI: 10.1007/s11368-008-0039-8]&nbsp;&nbsp; Free download from: [https://d1wqtxts1xzle7.cloudfront.net/7081664/apitz%20jss%20risk-based%20europe-with-cover-page-v2.pdf?Expires=1637274548&Signature=KqIoYyQ6VPAFN7lKHJMVC3bbn00RRMCR68bsQNBGrFJ9kbX5BnI-aucFCqRgVUNUb1lu0Q4tzUkCjPXJRGBsTA3OnbH8Ol9sNoXZ001aOwG7tKuV8qEblGiqtQUHh9GdiNAPQsm50f~E1iozL9a6imApWjqK8oFCfdUbcUd1oaW7PCDu28KWN-k5ddefWNZBAzGIdaWt3mBJ1EYeKRrp4F6Codlny3pWCT5MpA~c4c0IKq8L7Uj~-VxH5LXjFDd7cm07JeOY8S5rlxgF1zMoTIggMo5v2M3AS3CO2SAqy7yR3HC-IjUx3RsMqKa5eS2jT1ADiXcqeVygCdCCXza05g__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA Academia.edu]</ref>.
+Most federal, state, and local regulatory guidance for assessing and mitigating the [[Vapor Intrusion (VI) | vapor intrusion]] pathway reflects USEPA’s ''Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air''<ref name="USEPA2015">USEPA, 2015. OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air. U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, OSWER Publication No. 9200.2-154, 267 pages. [https://www.epa.gov/vaporintrusion/technical-guide-assessing-and-mitigating-vapor-intrusion-pathway-subsurface-vapor USEPA Website]&nbsp;&nbsp; [//www.enviro.wiki/images/0/06/USEPA2015.pdf  Report.pdf]</ref>. The paradigm outlined by that guidance includes: 1) a preliminary and mostly qualitative analysis that looks for site conditions that suggest vapor intrusion might occur (e.g., the presence of vapor-forming chemicals in close proximity to buildings); 2) a multi-step and more detailed quantitative screening analysis that involves site-specific data collection and their comparison to screening levels to identify buildings of potential VI concern; and 3) selection and design of mitigation systems or continued monitoring, as needed. With respect to (2), regulatory guidance typically recommends consideration of “multiple lines of evidence” in decision-making<ref name="USEPA2015" /><ref>NJDEP, 2021. Vapor Intrusion Technical Guidance, Version 5.0. New Jersey Department of Environmental Protection, Trenton, NJ. [https://dep.nj.gov/srp/guidance/vapor-intrusion/vig/ Website]&nbsp;&nbsp; [//www.enviro.wiki/images/e/ee/NJDEP2021.pdf  Guidance Document.pdf]</ref>, with typical lines-of-evidence being groundwater, soil gas, sub-slab soil gas, and/or indoor air concentrations.  Of those, soil gas measurements and/or measured short-term indoor air concentrations can be weighted heavily, and therefore decision making might not be completed without them. Effective evaluation of VI risk from sub-slab and/or soil gas measurements would require an unknown building-specific attenuation factor, but there is also uncertainty as to whether or not indoor air data is representative of maximum and/or long-term average indoor concentrations. Indoor air data can be confounded by indoor contaminant sources because the number of samples is typically small, indoor concentrations can vary with time, and because a number of household products can emit the chemicals being measured. When conducting VI pathway assessments in neighborhoods where it is impractical to assess all buildings, the EPA recommends following a “worst first” investigational approach.
-There is general consensus from a regulatory perspective, globally, on the importance of sediment risk assessment. Technical guidance documents prepared by Canada<ref name="Fletcher2008">Fletcher, R., Welsh, P. and Fletcher, T., 2008. Guidelines for Identifying, Assessing, and Managing Contaminated Sediments in Ontario. Ontario Ministry of the Environment. PIBS6658e. [http://www.ene.gov.on.ca/publications/6658e Website]</ref><ref name="HealthCanada2017">Health Canada, 2017. Supplemental Guidance on Human Health Risk Assessment of Contaminated Sediments: Direct Contact Pathway,  Federal Contaminated Site Risk Assessment in Canada. ISBN: 978-0-660-07989-9. Cat.: H144-41/2017E-PDF. Pub. 160382. Free download from: [https://publications.gc.ca/collections/collection_2018/sc-hc/H144-41-2017-eng.pdf Health Canada]&nbsp;&nbsp; [[Media: HealthCanada2117.pdf | Report.pdf]]</ref> , the European Union<ref name="Tarazona2014"/>, and the United States Environmental Protection Agency (USEPA)<ref name="USEPA2005"/> advise a flexible, tiered approach for sediment risk assessment. Sediment quality guidelines in many countries reflect the scientific importance of including certain sediment-specific measurement and biotic assessment endpoints, as well as certain physical sediment processes and chemical transformation processes potentially affecting biotic responses to contaminant exposure in the sediment<ref name="Wenning2005">Wenning, R.J. Batley, G.E., Ingersoll, C.G., and Moore, D.W., (eds), 2005. Use Of Sediment Quality Guidelines And Related Tools For The Assessment Of Contaminated Sediments. SETAC, Pensacola, FL. 815 pp.  ISBN 1-880611-71-6.</ref>. New risk assessment methods continue to emerge in the scientific literature<ref name="Benson2018">Benson, N.U., Adedapo, A.E., Fred-Ahmadu, O.H., Williams, A.B., Udosen, E.D., Ayejuyo, O.O. and Olajire, A.A., 2018. A new method for assessment of sediment-associated contamination risks using multivariate statistical approach. MethodsX, 5, pp. 268-276.  [https://doi.org/10.1016/j.mex.2018.03.005 DOI: 10.1016/j.mex.2018.03.005]&nbsp;&nbsp; [https://www.sciencedirect.com/science/article/pii/S2215016118300438/pdfft?md5=85b8a3a1062310e4c7c4a06e670e66c4&pid=1-s2.0-S2215016118300438-main.pdf  Free Access Article]&nbsp;&nbsp; [[Media: Benson2018.pdf | Report.pdf]]</ref><ref name="Saeedi2015">Saeedi, M. and Jamshidi-Zanjani, A., 2015. Development of a new aggregative index to assess potential effect of metals pollution in aquatic sediments. Ecological Indicators, 58, pp. 235-243.  [https://doi.org/10.1016/j.ecolind.2015.05.047 DOI: 10.1016/j.ecolind.2015.05.047]  Free download from: [https://www.academia.edu/download/49801572/mRAC_published.pdf Academis.edu]</ref><ref name="Vaananen2018">Väänänen, K., Leppänen, M.T., Chen, X. and Akkanen, J., 2018. Metal bioavailability in ecological risk assessment of freshwater ecosystems: from science to environmental management. Ecotoxicology and Environmental Safety, 147, pp. 430-446.  [https://doi.org/10.1016/j.ecoenv.2017.08.064 DOI: 10.1016/j.ecoenv.2017.08.064]</ref>. These new methods, however, are likely to be considered supplemental to the more generalized framework shared globally.
+The limitations of this approach, as practiced, are the following:
-==Cap Design and Materials for Chemical Containment==
+*Decisions are rarely made without indoor air data and generally, seasonal sampling is required, delaying decision making.
-An inert material such as sand can be effective as a capping material where contaminants are strongly associated with solids and where the operative site specific transport mechanisms do not lead to rapid contaminant migration through such a material. Additional contaminant containment can often be achieved through the placement of clean sediment, e.g. dredged material from a nearby location.   Other materials as cap layers or amendments may be useful to address particularly mobile contaminants or when particular degradative mechanisms can be exploited. The Anacostia River was the site of a demonstration that first tested “active” or “amended” capping in the field<ref name="Reible2003">Reible, D., Constant, D.W., Roberts, K. and Zhu, Y., 2003. Active capping demonstration project in anacostia DC. In Second International Conference on the Remediation of Contaminated Sediments: October.  Free download available from: [https://www.researchgate.net/profile/Danny-Reible/publication/237747790_ACTIVE_CAPPING_DEMONSTRATION_PROJECT_IN_ANACOSTIA_DC/links/0c96053861030b7699000000/ACTIVE-CAPPING-DEMONSTRATION-PROJECT-IN-ANACOSTIA-DC.pdf ResearchGate]</ref><ref name="Reible2006">Reible, D., Lampert, D., Constant, D., Mutch Jr, R.D. and Zhu, Y., 2006. Active Capping Demonstration in the Anacostia River, Washington, DC. Remediation Journal: The Journal of Environmental Cleanup Costs, Technologies and Techniques, 17(1), pp. 39-53.  [https://doi.org/10.1002/rem.20111 DOI: 10.1002/rem.20111]  Free download available from: [https://www.academia.edu/download/44146457/Remediation_Journal_Paper_2006.pdf Academia.edu]</ref>. Amended caps are often the best option when groundwater upwelling or other advective processes promote significant mobility of contaminants and the addition of sorbents can slow that contaminant migration<ref name="Ghosh2011">Ghosh, U., Luthy, R.G., Cornelissen, G., Werner, D. and Menzie, C.A., 2011. In-situ Sorbent Amendments: A New Direction in Contaminated Sediment Management. Environmental Science and Technology, 45(4), pp. 1163-1168. [https://doi.org/10.1021/es102694h DOI: 10.1021/es102694h]  Open access article from: [https://pubs.acs.org/doi/pdf/10.1021/es102694h American Chemical Society]&nbsp;&nbsp; [[Media: Ghosh2011.pdf | Report.pdf]]</ref>.  Although a variety of materials have been proposed for sediment caps, a far smaller number of options have been successfully employed in the field.
+*The collection of a robust indoor air data set that adequately characterizes long term indoor air concentrations could take years given the typical frequency of data collection and the most common methods of sample collection (e.g., 24-hour samples).  Therefore, indoor air sampling might continue indefinitely at some sites.
+*The “worst first” buildings might not be identified correctly by the logic outlined in USEPA’s 2015 guidance and the most impacted buildings might not even be located over a groundwater plume.  Recent studies have shown [[Vapor Intrusion – Sewers and Utility Tunnels as Preferential Pathways |VI impacts in homes as a result of sewer and other subsurface piping connections]], which are not explicitly considered nor easily characterized through conventional VI pathway assessment<ref> Beckley, L, McHugh, T., 2020. A Conceptual Model for Vapor Intrusion from Groundwater Through Sewer Lines. Science of the Total Environment, 698, Article 134283. [https://doi.org/10.1016/j.scitotenv.2019.134283 doi: 10.1016/j.scitotenv.2019.134283]&nbsp;&nbsp; [//www.enviro.wiki/images/4/4e/BeckleyMcHugh2020.pdf  Open Access Article]</ref><ref name="GuoEtAl2015">Guo, Y., Holton, C., Luo, H., Dahlen, P., Gorder, K., Dettenmaier, E., Johnson, P.C., 2015. Identification of Alternative Vapor Intrusion Pathways Using Controlled Pressure Testing, Soil Gas Monitoring, and Screening Model Calculations. Environmental Science and Technology, 49(22), pp. 13472–13482. [https://doi.org/10.1021/acs.est.5b03564 doi: 10.1021/acs.est.5b03564]</ref><ref name="McHughEtAl2017">McHugh, T., Beckley, L., Sullivan, T., Lutes, C., Truesdale, R., Uppencamp, R., Cosky, B., Zimmerman, J., Schumacher, B., 2017.  Evidence of a Sewer Vapor Transport Pathway at the USEPA Vapor Intrusion Research Duplex.  Science of the Total Environment, pp. 598, 772-779. [https://doi.org/10.1016/j.scitotenv.2017.04.135 doi: 10.1016/j.scitotenv.2017.04.135]&nbsp;&nbsp; [//www.enviro.wiki/images/6/63/McHughEtAl2017.pdf  Open Access Manuscipt]</ref><ref name="McHughBeckley2018">McHugh, T., Beckley, L., 2018. Sewers and Utility Tunnels as Preferential Pathways for Volatile Organic Compound Migration into Buildings: Risk Factors and Investigation Protocol. ESTCP ER-201505, Final Report. [https://serdp-estcp.mil/projects/details/f12abf80-5273-4220-b09a-e239d0188421 Project Website]&nbsp;&nbsp; [//www.enviro.wiki/images/5/55/2018b-McHugh-ER-201505_Conceptual_Model.pdf  Final Report.pdf]</ref><ref name="RiisEtAl2010">Riis, C., Hansen, M.H., Nielsen, H.H., Christensen, A.G., Terkelsen, M., 2010. Vapor Intrusion through Sewer Systems: Migration Pathways of Chlorinated Solvents from Groundwater to Indoor Air. Seventh International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May, Monterey, CA. Battelle Memorial Institute. ISBN 978-0-9819730-2-9. [https://www.battelle.org/conferences/battelle-conference-proceedings Website]&nbsp;&nbsp; [//www.enviro.wiki/images/9/95/2010-Riis-Migratioin_pathways_of_Chlorinated_Solvents.pdf  Report.pdf]</ref>.
+*The presumptive remedy for VI mitigation (sub-slab depressurization) may not be effective for all VI scenarios (e.g., those involving vapor migration to indoor spaces via sewer connections).
-Metals migration is very site dependent due to the potential for many metals to complex with other species in the interstitial water and the specific metal speciation present at a site.  Often, the strongly reducing environment beneath a cap renders many common metals unavailable through the formation of metal sulfides.  In such cases, a simple sand cap can be very effective.  Amended caps to manage metal contaminated sediments may be advantageous when site specific conditions lead to elevated metals mobility, but should be supported with site specific testing<ref name="Viana2008">Viana, P.Z., Yin, K. and Rockne, K.J., 2008. Modeling Active Capping Efficacy. 1. Metal and Organometal Contaminated Sediment Remediation. Environmental Science and Technology, 42(23), pp. 8922-8929. [https://doi.org/10.1021/es800942t DOI: 10.1021/es800942t]</ref>.
+The '''VI Diagnosis Toolkit''' components were developed considering these limitations as well as more recent knowledge gained through research, development, and validation projects funded by SERDP and ESTCP.
-For hydrophobic organic contaminants, cap amendments that directly control groundwater upwelling and also sorbents that can remove migrating contaminants from that groundwater have been successfully employed.   Examples include clay materials such as AquaBlok<sup>&reg;</sup> for permeability control, sorbents such as [[Wikipedia: Activated carbon | activated carbon]] for truly dissolved contaminants, and [[Wikipedia: Organoclay | organophilic clays]] for separate phase contaminants.
+==The VI Diagnosis Toolkit Components==
+[[File:DahlenFig1.png|thumb|450px|Figure 1. Vapor intrusion pathway conceptualization considering “alternate VI pathways”, including “pipe flow
+VI” and “sewer VI” pathways<ref name="JohnsonEtAl2020" />.]]
+The primary components of the VI Diagnosis Toolkit and their uses include:
-The placement of clean sediment as an ''in situ'' cap can be difficult when the material is fine grained or has a low density.  Capping with a layer of coarse grained material such as clean sand mitigates this issue although clean sands have minimal sorption capacity.  Because of this limitation, sand caps may not be sufficient for achieving remedial goals in sites where contamination levels are high or transport rates are fast due to pore water upwelling or tidal pumping effects. Conditions such as these may require the use of “active” amendments to reduce transport rates.
+*'''External VI source strength screening''' to identify buildings most likely to be impacted by VI at levels warranting building-specific testing.
+*'''Indoor air source screening''' to locate and remove indoor air sources that might confound building specific VI pathway assessment.
-Capping with clean sand provides a physical barrier between the underlying contaminated material and the overlying water, stabilizes the underlying sediment to prevent re-suspension of contaminated particles, and can reduce chemical exposure under certain conditions.  Sand primarily provides a passive barrier to the downward penetration of bioturbating organisms and the upward movement of sediment or contaminants.  Although conventional sandy caps can often be an effective means of managing contaminated sediments, there are conditions when sand caps may not be capable of achieving design objectives.  Some factors that reduce the effectiveness of sand caps include:
+*'''Controlled pressurization method (CPM)''' testing to quickly (in a few days or less) measure the worst-case indoor air impact likely to be caused by VI under natural conditions in specific buildings. CPM tests can also be used to identify the presence of indoor air sources and diagnose active VI pathways.
+*'''Passive indoor sampling''' for determining long-term average indoor air concentrations under natural VI conditions and/or for verifying mitigation system effectiveness in buildings that warrant VI mitigation.
+*'''Comprehensive VI conceptual model development and refinement''' to ensure that appropriate monitoring, investigation, and mitigation strategies are being selected (Figure 1).
-*erosion and loss of cap integrity
+Expanded discussions for each of these are given below.
-*high groundwater upwelling rates
-*mobile (low sorption) contaminants of concern (COCs)
-*high COC concentrations
-*unusually toxic COCs
-*the presence of tidal influences
-*the presence of non-aqueous phase liquids (NAPLs)
-*high rates of gas ebullition
-Of these, the first three are common limitations to capping and often control the ability to effectively design and implement a cap as a sediment remedial strategy. In these cases, it may be possible to offset these issues by increasing the thickness of the cap.  However, the required thickness can reach infeasible levels in shallow streams or navigable water bodies.  In addition, increased construction costs associated with thick caps may become prohibitive.  As a result of these issues, caps that use alternative materials (also known as active caps) to reduce the thickness or increase the protectiveness of a cap may be necessary.  The materials in active caps are designed to interact with the COCs to enhance the containment properties of the cap.
+'''External VI source strength screening''' identifies those buildings that warrant more intrusive building-specific assessments, using data collected exterior to the buildings. The use of groundwater and/or soil gas concentration data for building screening has been part of VI pathway assessments for some time and their use is discussed in many regulatory guidance documents. Typically, the measured concentrations are compared to relevant screening levels derived via modeling or empirical analyses from indoor air concentrations of concern.
-[[Wikipedia: Apatite | Apatites]] are a class of naturally occurring minerals that have been investigated as a sorbent for metals in soils and sediments<ref name="Melton2003">Melton, J.S., Crannell, B.S., Eighmy, T.T., Wilson, C. and Reible, D.D., 2003. Field Trial of the UNH Phosphate-Based Reactive Barrier Capping System for the Anacostia River. EPA Grant R819165-01-0</ref><ref name="Reible2003"/><ref name="Knox2012">Knox, A.S., Paller, M.H. and Roberts, J., 2012. Active Capping Technology—New Approaches for In Situ Remediation of Contaminated Sediments. Remediation Journal, 22(2), pp.93-117.  [https://doi.org/10.1002/rem.21313 DOI: 10.1002/rem.21313]  Free download available from: [https://www.researchgate.net/profile/Anna-Knox-2/publication/233374607_Active_Capping_Technology-New_Approaches_for_In_Situ_Remediation_of_Contaminated_Sediments/links/5a7de4c5aca272a73765c344/Active-Capping-Technology-New-Approaches-for-In-Situ-Remediation-of-Contaminated-Sediments.pdf ResearchGate]</ref>.  Apatites consist of a matrix of calcium phosphate and various other common anions, including fluoride, chloride, hydroxide, and occasionally carbonate. Metals are sequestered either through direct ion exchange with the calcium atom or dissolution of hydroxyapatite followed by precipitation of lead apatite.  [[Wikipedia: Zeolite | Zeolites]], which are microporous aluminosilicate minerals with a high cationic exchange capacity (CEC), have also been proposed to manage metal species<ref name="Zhan2019">Zhan, Y., Yu, Y., Lin, J., Wu, X., Wang, Y. and Zhao, Y., 2019. Simultaneous control of nitrogen and phosphorus release from sediments using iron-modified zeolite as capping and amendment materials. Journal of Environmental Management, 249, p.109369.  [https://doi.org/10.1016/j.jenvman.2019.109369 DOI: 10.1016/j.jenvman.2019.109369]</ref>.
+More recently it has been discovered that VI impacts can occur via sewer and other subsurface piping connections in areas where vapor migration through the soil would not be expected to be significant, and this could also occur in buildings that do not sit over contaminated groundwater<ref name="RiisEtAl2010" /><ref name="GuoEtAl2015" /><ref name="McHughEtAl2017" /><ref name="McHughBeckley2018" />.
-It is possible to create a hydrophobic, sorbing layer for non-polar organics by exchanging a cationic surfactant onto the surface of clays such as zeolites and bentonites,. Organoclay is a modified bentonite containing such substitutions that has been evaluated for control of non-aqueous phase NAPLs and other organic contaminants<ref name="Reible2007">Reible, D.D., Lu, X., Moretti, L., Galjour, J. and Ma, X., 2007. Organoclays for the capping of contaminated sediments. AIChE Annual Meeting.  ISBN: 978-081691022-9</ref>.  An organoclay cap has been implemented for sediment remediation at the McCormick and Baxter site in Portland, OR<ref name="Parrett2005">Parrett, K. and Blishke, H., 2005. 23-Acre Multilayer Sediment Cap in Dynamic Riverine Environment Using Organoclay an Adsorptive Capping Material. Presentation to Society of Environmental Toxicology and Chemistry (SETAC), 26th Annual Meeting.</ref>.  A similar organic sorbing phase can be formed by treating zeolites with surfactants but this approach has not been reported for contaminated sediments.
-Activated carbon is a strong sorbent of hydrophobic organic compounds and has been used as a [[In Situ Treatment of Contaminated Sediments with Activated Carbon | treatment for sediments]] or as an active sorbent within a capping layer<ref name="Zimmerman2004">Zimmerman, J.R., Ghosh, U., Millward, R.N., Bridges, T.S. and Luthy, R.G., 2004. Addition of Carbon Sorbents to Reduce PCB and PAH Bioavailability in Marine Sediments: Physicochemical Tests. Environmental Science and Technology, 38(20), pp. 5458-5464.  [https://doi.org/10.1021/es034992v DOI: 10.1021/es034992v]</ref><ref name="Werner2005">Werner, D., Higgins, C.P. and Luthy, R.G., 2005. The sequestration of PCBs in Lake Hartwell sediment with activated carbon. Water Research, 39(10), pp. 2105-2113.  [https://doi.org/10.1016/j.watres.2005.03.019 DOI: 10.1016/j.watres.2005.03.019]</ref><ref name="Abel2018">Abel, S. and Akkanen, J., 2018. A Combined Field and Laboratory Study on Activated Carbon-Based Thin Layer Capping in a PCB-Contaminated Boreal Lake. Environmental Science and Technology, 52(8), pp. 4702-4710. [https://doi.org/10.1021/acs.est.7b05114 DOI: 10.1021/acs.est.7b05114] Open access article available from: [https://pubs.acs.org/doi/pdf/10.1021/acs.est.7b05114 American Chemical Society]&nbsp;&nbsp; [[Media: Abel2018.pdf | Report.pdf]]</ref><ref name="Payne 2018">Payne, R.B., Ghosh, U., May, H.D., Marshall, C.W. and Sowers, K.R., 2019. A Pilot-Scale Field Study: In Situ Treatment of PCB-Impacted Sediments with Bioamended Activated Carbon. Environmental Science and Technology, 53(5), pp. 2626-2634. [https://doi.org/10.1021/acs.est.8b05019 DOI: 10.1021/acs.est.8b05019]</ref><ref name="Yan2020">Yan, S., Rakowska, M., Shen, X., Himmer, T., Irvine, C., Zajac-Fay, R., Eby, J., Janda, D., Ohannessian, S. and Reible, D.D., 2020. Bioavailability Assessment in Activated Carbon Treated Coastal Sediment with In situ and Ex situ Porewater Measurements. Water Research, 185, p. 116259.  [https://doi.org/10.1016/j.watres.2020.116259 DOI: 10.1016/j.watres.2020.116259]</ref>.  Placement of activated carbon for sediment capping is difficult due to the near neutral buoyancy of the material but it has been applied in this manner in relatively low energy environments such as Onondaga Lake, Syracuse, NY<ref name="Vlassopoulos2017">Vlassopoulos, D., Russell, K., Larosa, P., Brown, R., Mohan, R., Glaza, E., Drachenberg, T., Reible, D., Hague, W., McAuliffe, J. and Miller, S., 2017. Evaluation, Design, and Construction of Amended Reactive Caps to Restore Onondaga Lake, Syracuse, New York, USA. Journal of Marine Environmental Engineering, 10(1), pp. 13-27.  Free download available from: [https://www.researchgate.net/publication/317762995_Evaluation_design_and_construction_of_amended_reactive_caps_to_restore_Onondaga_lake_Syracuse_New_York_USA ResearchGate]</ref>.  Alternatives in higher energy environments include placement of activated carbon in a mat such as the CETCO Reactive Core Mat (RCM)<sup>&reg;</sup> or Huesker Tektoseal<sup>&reg;</sup>, or as a composite material such as SediMite<sup>&reg;</sup> or AquaGate<sup>&reg;</sup>.   In the case of the mats, powdered or granular activated carbon can be placed in a controlled layer while the density of the composite materials is such that they can be broadcast from the surface and allowed to settle to the bottom.  In a sediment treatment application, the composite material would either be worked into the surface or allowed to intermix gradually by bioturbation and other processes.  In a capping application, the mat or composite material would typically be combined or overlain with a sand or other capping layer to keep it in place and to provide a chemical isolation layer away from the sediment surface.
+Therefore, in addition to groundwater and soil gas sampling, external data collection that includes and extends beyond the area of concern should include manhole vapor sampling (e.g., sanitary sewer, storm sewer, land-drain). Video surveys from sanitary sewers, storm sewers, and/or land-drains can also be used to identify areas of groundwater leakage into utility corridors and lateral connections to buildings that are conduits for vapor transport. During these investigations, it is important to recognize that utility corridors can transmit both impacted water and vapors beyond groundwater plume boundaries, so extending investigations into areas adjacent to groundwater plume boundaries is necessary.
-As an alternative to a sorptive capping amendment, low-permeability cap amendments have been proposed to enhance cap design life by decreasing pore water advection.  Low permeability clays are an effective means to divert upwelling groundwater away from a contaminated sediment area but are difficult to place in the aqueous environment.  Bentonite clays can be placed in mats similar to what is done to provide a low permeability liner in landfills. There are also commercial products that can place clays directly such as the composite material AquaBlok<sup>&reg;</sup>, a bentonite clay and polymer based mineral around an aggregate core<ref name="Barth2008">Barth, E.F., Reible, D. and Bullard, A., 2008. Evaluation of the physical stability, groundwater seepage control, and faunal changes associated with an AquaBlok<sup>&reg;</sup> sediment cap. Remediation: The Journal of Environmental Cleanup Costs, Technologies and Techniques, 18(4), pp.63-70.  [https://doi.org/10.1002/rem.20183 DOI: 10.1002/rem.20183]</ref>.
+Using projected indoor air concentrations from modeling and empirical data analyses, and distance screening approaches, external source screening can identify areas and buildings that can be ruled out, or conversely, those that warrant building-specific testing.
-Sediment caps become colonized by microorganisms from the sediments and surface water and potentially become a zone of pollutant biotransformation over time. Aerobic degradation occurs only near the solids-water interface in which benthic organisms are active and thus there might still be significant benthic organism exposure to contaminants. Biotransformation in the anaerobic zone of a cap, which typically extends well beyond the zone of benthic activity, could significantly reduce the risk of pollutant exposure but successful caps encouraging deep degradation processes have not been demonstrated beyond the laboratory.  The addition of materials such as nutrients and oxygen releasing compounds for enhancing the attenuation of contaminants through biodegradation has also been assessed but not applied in the field.  Short term improvements in biodegradation rates can be achieved through tailoring of conditions or addition of nutrients but long term efficacy has not been demonstrated<ref name="Pagnozzi2020">Pagnozzi, G., Carroll, S., Reible, D.D. and Millerick, K., 2020. Biological Natural Attenuation and Contaminant Oxidation in Sediment Caps: Recent Advances and Future Opportunities. Current Pollution Reports, pp.1-14.  [https://doi.org/10.1007/s40726-020-00153-5 DOI: 10.1007/s40726-020-00153-5]</ref>.
-[[File: SedCapFig2.png | thumb |600px|Figure 2. A conceptualization of a cap with accompanying habitat layer]]
-==Cap Design and Materials for Habitat Restoration==
+Demonstration of neighborhood-scale external VI source screening using groundwater, depth, sewer, land drain, and video data is documented in the ER-201501 final report<ref name="JohnsonEtAl2020" />.
-In addition to providing chemical isolation and containment, a cap can also be used to provide improvements for organisms by enhancing the habitat characteristics of the bottom substrate<ref name="Yozzo2004">Yozzo, D.J., Wilber, P. and Will, R.J., 2004. Beneficial use of dredged material for habitat creation, enhancement, and restoration in New York–New Jersey Harbor. Journal of Environmental Management, 73(1), pp. 39-52.  [https://doi.org/10.1016/j.jenvman.2004.05.008 DOI: 10.1016/j.jenvman.2004.05.008]</ref><ref name="Zhang2016">Zhang, C., Zhu, M.Y., Zeng, G.M., Yu, Z.G., Cui, F., Yang, Z.Z. and Shen, L.Q., 2016. Active capping technology: a new environmental remediation of contaminated sediment. Environmental Science and Pollution Research, 23(5), pp.4370-4386.  [https://doi.org/10.1007/s11356-016-6076-8 DOI: 10.1007/s11356-016-6076-8]</ref><ref name="Vlassopoulos2017"/>.  Often, contaminated sediment environments are degraded for a variety of reasons in addition to the toxic constituents.  One way to overcome this is to provide both a habitat layer and chemical isolation or contaminant capping layer. Figure 2 illustrates just such a design providing a more appropriate habitat enhancing substrate, in this case by incorporation additional organic material, vegetation and debris, which is often used by fish species for protection, into the surface layer. In a high energy environment, it should be recognized that it may not be possible to keep a suitable habitat layer in place during high flow events.  This would be true of suitable habitat that had developed naturally as well as a constructed habitat layer and it is presumed that if such a habitat is the normal condition of the waterbody that it will recover over time between such high flow events.
+'''Indoor air source screening''' seeks to locate and remove indoor air sources<ref>Doucette, W.J., Hall, A.J., Gorder, K.A., 2010. Emissions of 1,2-Dichloroethane from Holiday Decorations as a Source of Indoor Air Contamination. Ground Water Monitoring and Remediation, 30(1), pp. 67-73. [https://doi.org/10.1111/j.1745-6592.2009.01267.x doi: 10.1111/j.1745-6592.2009.01267.x] </ref> that might confound building specific VI pathway assessment. Visual inspections and written surveys might or might not identify significant indoor air sources, so these should be complemented with use of portable analytical instruments<ref>McHugh, T., Kuder, T., Fiorenza, S., Gorder, K., Dettenmaier, E., Philp, P., 2011. Application of CSIA to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs. Environmental Science and Technology, 45(14), pp. 5952-5958. [https://doi.org/10.1021/es200988d doi: 10.1021/es200988d]</ref><ref name="BeckleyEtAl2014">Beckley, L., Gorder, K., Dettenmaier, E., Rivera-Duarte, I., McHugh, T., 2014. On-Site Gas Chromatography/Mass Spectrometry (GC/MS) Analysis to Streamline Vapor Intrusion Investigations. Environmental Forensics, 15(3), pp. 234–243. [https://doi.org/10.1080/15275922.2014.930941 doi: 10.1080/15275922.2014.930941]</ref>.
+The advantage of portable analytical tools is that they allow practitioners to expeditiously test indoor air concentrations under natural conditions in each room of the building. Concentrations in any room in excess of relevant screening levels trigger more sampling in that room to identify if an indoor source is present in that room. Removal of a suspected source and subsequent room testing can identify if that object or product was the source of the previously measured concentrations.
+'''Building-specific controlled pressurization method (CPM) testing''' directly measures the worst case indoor air impact, but it can also be used to determine contributing VI pathways and to identify indoor air sources<ref>McHugh, T.E., Beckley, L., Bailey, D., Gorder, K., Dettenmaier, E., Rivera-Duarte, I., Brock, S., MacGregor, I.C., 2012. Evaluation of Vapor Intrusion Using Controlled Building Pressure. Environmental Science and Technology, 46(9), pp. 4792–4799. [https://doi.org/10.1021/es204483g doi: 10.1021/es204483g]</ref><ref name="BeckleyEtAl2014" /><ref name="GuoEtAl2015" /><ref name="HoltonEtAl2015">Holton, C., Guo, Y., Luo, H., Dahlen, P., Gorder, K., Dettenmaier, E., Johnson, P.C., 2015. Long-Term Evaluation of the Controlled Pressure Method for Assessment of the Vapor Intrusion Pathway. Environmental Science and Technology, 49(4), pp. 2091–2098.  [https://doi.org/10.1021/es5052342 doi: 10.1021/es5052342]</ref><ref name="JohnsonEtAl2020" /><ref name="GuoEtAl2020a">Guo, Y., Dahlen, P., Johnson, P.C., 2020a. Development and Validation of a Controlled Pressure Method Test Protocol for Vapor Intrusion Pathway Assessment.  Environmental Science and Technology, 54(12), pp. 7117-7125. [https://dx.doi.org/10.1021/acs.est.0c00811 doi: 10.1021/acs.est.0c00811]</ref>. In CPM testing, blowers/fans installed in a doorway(s) or window(s) are set-up to exhaust indoor air to outdoor, which causes the building to be under pressurized relative to the atmosphere. This induces air movement from the subsurface into the test building via openings in the foundation and/or subsurface piping networks with or without direct connections to indoor air. This is similar to what happens intermittently under natural conditions when wind, indoor-outdoor temperature differences, and/or use of appliances that exhaust air from the structure (e.g. dryer exhaust) create an under-pressurized building condition.
+The blowers/fans can also be used to blow outdoor air into the building, thereby creating a building over-pressurization condition. A positive pressure difference CPM test suppresses VI pathways; therefore, chemicals detected in indoor air above outdoor air concentrations during this condition are attributed to indoor contaminant sources which facilitates the identification of any such indoor air sources.
+Data collected during CPM testing, when combined with screening level VI modeling, can be used to identify which VI chemical migration pathways are significant contributors to indoor air impacts<ref name="GuoEtAl2015" />. CPM testing guidelines were developed and validated under ESTCP Project ER-201501<ref name="GuoEtAl2020a" /><ref name="JohnsonEtAl2021" />.
+'''Passive samplers''' can be used to measure long term average indoor air concentrations under natural conditions and during VI mitigation system operation. They will provide more confident assessment of long term average concentrations than an infrequent sequence of short term grab samples. Long term average concentrations can also be determined by long term active sampling (e.g., by slowly pulling air through a thermal desorption (TD) tube). However, passive sampling has the advantage that additional equipment and expertise is not required for sampler deployment and recovery.
+Use of passive samplers in indoor air under time-varying concentration conditions was demonstrated and validated by comparing against intensive active sampling in ESTCP Project ER-201501<ref name="JohnsonEtAl2020" /><ref name="GuoEtAl2021">Guo, Y., O’Neill, H., Dahlen, P., and Johnson, P.C.  2021.  Evaluation of Passive Diffusive-Adsorptive Samplers for Use in Assessing Time-Varying Indoor Air Impacts Resulting from Vapor Intrusion.  Groundwater Monitoring and Remediation, 42(1), pp. 38-49.  [https://doi.org/10.1111/gwmr.12481 doi: 10.1111/12481]</ref>.
+The purpose of maintaining an evergreen '''comprehensive VI conceptual model''' is to ensure that the most complete and up-to-date understanding of the site is informing decisions related to future sampling, data interpretation, and the need for and design of mitigation systems. The VI conceptual model can also serve as an effective communication tool in stakeholder discussions.
+Use of these tools for residential neighborhoods and in non-residential buildings overlying chlorinated solvent groundwater plumes is documented comprehensively in a series of peer reviewed articles<ref name="JohnsonEtAl2020" /><ref name="JohnsonEtAl2021" /><ref name="JohnsonEtAl2022" /><ref name="GuoEtAl2015" /><ref name="GuoEtAl2020a" /><ref name="GuoEtAl2020b">Guo, Y., Dahlen, P., Johnson, P.C. 2020b. Temporal variability of chlorinated volatile organic compound vapor concentrations in a residential sewer and land drain system overlying a dilute groundwater plume. Science of the Total Environment, 702, Article 134756.  [https://doi.org/10.1016/j.scitotenv.2019.134756 doi: 10.1016/j.scitotenv.2019.134756]&nbsp;&nbsp; [//www.enviro.wiki/images/e/e5/GuoEtAl2020b.pdf  Open Access Manuscript]</ref><ref name="GuoEtAl2021" /><ref name="HoltonEtAl2015" />.
 ==Summary==
-Clean substrate can be placed at the sediment-water interface for the purposes of reducing exposure to and risk from contaminants in the sediments.  The cap can consist of simple materials such as sand designed to physically stabilize contaminated sediments and separate the benthic community from those contaminants or may include other materials designed to sequester contaminants even under adverse conditions including strong groundwater upwelling or highly mobile contaminants.  The surface of a cap may be designed of coarse material such as gravel or cobble to be stable under high flow events or designed to be more appropriate habitat for benthic and aquatic organisms.  As a result of its flexibility, simplicity and low cost relative to its effectiveness, capping is one of the most prevalent remedial technologies for sediments.
+In summary, the VI Diagnosis Toolkit provides a set of tools that can lead to quicker, more confident, and more cost effective neighborhood-scale VI pathway and impact assessments. Toolkit components and their use can complement conventional methods for assessing and mitigating the vapor intrusion pathway.
 ==References==
@@ Line 74: / Line 108: @@
 ==See Also==
+*[https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4000681 Evaluation of Radon and Building Pressure Differences as Environmental Indicators for Vapor Intrusion Assessment]
+*[https://pubs.acs.org/doi/10.1021/es4024767 Temporal Variability of Indoor Air Concentrations under Natural Conditions in a House Overlying a Dilute Chlorinated Solvent Groundwater Plume]
+*[https://serdp-estcp.mil/projects/details/e0d00662-c333-4560-8ae7-60f20b0e714b Integrated Field-Scale, Lab-Scale, and Modeling Studies for Improving Our Ability to Assess the Groundwater to Indoor Air Pathway at Chlorinated Solvent Impacted Sites]

Difference between revisions of "User:Jhurley/sandbox"

Latest revision as of 21:57, 22 July 2024

Munitions Constituents – Sample Extraction and Analytical Techniques

Contents

Introduction

Extraction Methods

High Concentration Waters (> 1 ppm)

Low Concentration Waters (< 1 ppm)

Soils

Tissues

The VI Diagnosis Toolkit Components

Summary

References

See Also

Navigation menu

Personal tools

Namespaces

Variants

Views

More

Search

Navigation

Topic Categories

Tools

Admin Tools