^ryJK United states Environmental Protection M % Agency EPA 600/S-16/291 | September 2016 Innovative Research for a Sustainable Future Research Summary Sustainable and Healthy Communities (SHC) Project 3.61-Contaminated Sites Progress and Fu D. Pope, M. Brooks, L. Burkhard, B. Schumacher, D. Timberlake, and D. Jewett 1.0 Introduction Air, water, food, shelter, clothing, energy, and everything else that allows us to live on the Earth are all part of our environment. The United States Environmental Protection Agency (EPA) protects these resources to ensure that future generations will have an environment that can continue to provide clean air, clean water, food, and energy. This idea of continuing provision of the environmental resources necessary for a good life is called sustainability. Sustainability is the central theme of EPA's mission and EPA's Office of Research and Development's (ORD) research to protect, preserve, and sustain human and environmental health. EPA's Fiscal Year (FY) 2014-2018 Strategic Plan (U.S. EPA 2016) outlines EPA's overall course and strategic goals to protect human health and the environment. To fulfill the ORD's part of the EPA Strategic Plan, ORD's Sustainable and Healthy Communities (SHC) research program developed a Strategic Research Action Plan, 2016-2019 (StRAP) to present and guide ORD's approaches and strategies to achieve the particular goals delineated in EPA's Strategic Plan. ORD Research Action Plan (RAP) projects present research focused on achieving particular parts of the SHC program goals. Sustainable and Healthy Communities (SHC) Program Research What is Sustainability? Sustainability is based on a simple principle: Everything that we need for our survival and well-being depends, either directly or indirectly, on our natural environment. To pursue sustainability is to create and maintain the conditions under which humans and nature can exist in productive harmony to support present and future generations. SHC develops user-friendly knowledge, data, and tools to help all communities and stakeholders to make optimal economic, societal, and environmental decisions. The StRAP highlights how the SHC research program coordinates and integrates with other ORD research programs, other EPA Program Offices, EPA Regional Offices, and external stakeholders such as the general public, academia, Native American Tribes, and business. The goal of the StRAP is to set forth a vision and mechanism to connect, unify, and streamline an efficient and effective SHC research portfolio focused on sustainability. The SHC program supports research to provide the knowledge, data, and tools that communities must have to meet current needs in sustainable ways, so that current and future generations will be able to meet their needs in economically viable, socially just, and healthful ways. ------- SHC Program goals include: Developing easily accessible data, user-friendly models, and tools to allow communities to make sustainable social, economic, and environmental decisions, providing for a robust economy and human health/well-being, with environmental integrity (Figure 1) Determining cause and effect relationships between environmental conditions and human health, and how to measure and evaluate those relationships Providing research and technical support for cleaning up communities, groundwater, and oil spills; restoring habitats and revitalizing communities; and advancing sustainable waste and materials management Figure 1 Nested relationships ofa resilient economy existing within a healthy society dependent on an intact, functional environment. (USEPA 2016a] Developing a Sustainability Assessment and Management Toolbox to incorporate sustainability goals and approaches into day to day activities 1.1 Tasks 2, 3, and 4 ORD constructs RAPs to design research for each of the SHC program goals. SI Project 3.61-Contaminated Sites, one of the RAP projects, is scheduled to produce five outputs (publications, etc.) over the years 2016-2019. Each project consists of interrelated tasks; each task is composed of a set of research efforts. SHC Project 3.61 Output #3 (this current document, the Sustainable and Healthy Communities (SHC) Project 3.61-Contaminated Sites Research Summary: Progress and Future Directions) provides a concise discussion, with examples, of SHC research and other efforts such as technical support carried out under: Task 2: Contaminated Groundwater Research Task 3: Contaminated Sediments Research Task 4: Vapor Intrusion Research This Research Summary also includes a discussion and synopsis of proposed future research work for these three tasks. SHC Project 3.61 Contaminated Sites David Jewett, NRMRL, Project Lead Dennis Timberlake, NRMRL, Deputy Project Lead 2 ------- 2.0 Task Summaries 2.1 Task 2: SHC Contaminated Groundwater Research Contaminated groundwater is a nationwide problem, as illustrated by the fact that 80% of Superfund sites have contaminated groundwater. Contaminated groundwater impacts: Public and private water supplies for drinking water and other usages Surface water, due to groundwater-surface water interactions Subsurface soil gas, causing exposure to contaminant vapors ORD research on contaminated groundwater addresses known or anticipated knowledge gaps related to the characterization and restoration of contaminated groundwater resources. Research in this Task concentrates on the following focus areas: Why Is Groundwater Important? Over a third if the United States population relies on groundwater to drink (U.S. EPA 2015a) Public water supplies used 42.0 billion gallons per day in 2010; total freshwater groundwater usage was 306 billion gallons per day in 2010 (Maupin et al. 2014) High Resolution Characterization - Improve application and interpretation of high resolution groundwater characterization technologies such as modeling and geophysical tools Inorganic Groundwater Contaminants - Research on inorganic groundwater contaminants and associated inorganic contaminant remediation technologies. Geophysics for Groundwater Characterization - Advance the educated and effective adoption of geophysical technology to manage contaminated groundwater. Flux Based Site Management - Characterize contaminant flux and mass discharge, as well as groundwater flux (i.e., groundwater velocity) across a specific chosen area in the subsurface. Back Diffusion - Understand the role diffusion of contaminants from low permeability zones back into the groundwater (back diffusion) plays in plume persistence, essential for effective and protective cleanup of contaminated sites. Figure 2 Depiction of the distribution of contaminants] within the pore space of the unsaturated and saturated zones of an unconsolidated aquifer (Ford et al. 2014] In Situ Chemical Oxidation - Develop and evaluate updated approaches for use of ISCO for ground water treatment technologies and strategies. Emulsified Zerovalent Iron - Summarize a source zone treatment study of dense non-aqueous phase liquid contaminants at a contaminated site using emulsified zerovalent iron. Organic Constituent Leaching Methodologies - Understand the ability of organic contaminants to leach from waste material and to transport into groundwater. Dissolved NAPL Soil Grain NAPL SATURATED Soil Grain Sorbed to immobile-" grain Sorbed to mobile _ colloid, micelle, etc. Dissolved UNSATURATED Unsaturated Zone Saturated Zone Sorbed to detachable colloid Volatilized contaminant 3 ------- 2.2 Task 3: SHC Contaminated Sediments Research Contaminated sediments are significant hazards in numerous iakes, rivers, and bays, harbors, and marine waterbodies of the United States, causing restrictions on the use of the waterbodies. For example, many of the over 3200 fish consumption advisories issued nationwide are because of contaminated sediments. SHC has designated six focus areas for Task 3 Contaminated Sediments Research. WARNING: Contaminated Sediments Boating arm swimming should I L be avoided in tnซ aroa There is a fish consumption advisory for these watere Cwpuwobe mwe wkwe I vmmq t.rfn; m) wamr, I Sue !ปt* rt a kttunc* am re urtta ซk- | imnte, nip w tarn 4ซMC9 t ซ0Dซ1 Passive sampling: Improve the analytical technology, and develop guidance on how to use the resulting data within the Superfund decision-making process Bioaccumulation: Understand the linkages between contaminant concentrations in sediment and fish tissue concentrations Remedy effectiveness: Evaluate the effectiveness of sediment remediation alternatives and associated impacts for meeting Remedial Action Objectives at Superfund sites Source identification: Develop methods, metrics, and approaches to identify, track, and apportion contaminant sources Restoration effectiveness: Develop long-term assessment methods, metrics, and guidance to characterize, monitor, and maintain habitat restoration following remediation and restoration actions Measuring toxicity: Revise EPA's Methods for Measuring the Toxicity and Bioaccumulation of Sediment- associated Contaminants with Freshwater Invertebrates Figure 3 Contaminated sediments warning sign. Sediments are the loose sand, clay, silt and other soil particles that settle at the bottom of a body of water such as lakes and streams (USFWS 2016]. Number o er Miles Under Advisory for rious Pollutants, 1993 - 2011 Figure 4 River miles] under advisoiy for various pollutants U.S. EPA No Date).! i Zjoao i,ooo Riv*# Mike* Urate Advfcory OJOti ฆ 201ฉ n .' i ~ 200* ฆ *99ซ 600,000 80-0,000 1,000,000 River Mllv-s Undor Advisory National Fish and Wildlife Contamination Program Source: 7011 National listing of Fish Advisories 4 ------- 2.3 Task 4: Vapor Intrusion Research Vapor intrusion (VI) into occupied buildings is a serious and often difficult to evaluate problem, particularly at many Superfund sites where significant amounts of contaminants may remain in the subsurface for many years. Potential problems due to VI range from non-life-threatening odors to acute health impacts, explosions, or long-term chronic health effects. ft Stack Effects Wind Effects io^=> M \ Vadose Zone Contaminant Advection & Diffusion Through Floor- Wall Cracks Enclo r sed Space i 1 Tnrr sll Cracks a a ฑ4 vaaosf w Contaminant Diffusion Through the VadoseZone Dissolved Contamination in Groundwater What is Vapor Intrusion? VI is the transport of contaminant vapors such as volatile/semivolatile organic compounds, or inorganics such as radon from soil and groundwater into buildings Focus areas for Task 4 Vapor Intrusion include: Vapor pathways: Understand distribution and movement of VOCs from groundwater through soil to soil surface/subslab, and into a residence/building VI Characterization: Evaluate short-duration screening to induce maximum vapor intrusion Mitigation systems: evaluate effectiveness of mitigation systems to reduce or eliminate vapor intrusion Sampling materials: Determine influence of tubing type used to collect soil gas samples Sampling probe/well installation: Determine time required to reach dynamic concentrational gas equilibrium after installation has been completed Timing of sampling events: evaluate use of simple, inexpensive, and rapid measurement devices to predict when peak vapor concentrations will occur Figure 5 Movement of vapors from groundwater to a building (U.S. EPA 2016b] 5 ------- 3.0 Task Products Examples (2014-2016) 3.1 Task 2: Contaminated Groundwater Research 3.1.1 Task 2: Example Contaminated Groundwater Research and Applications Example 1: Screening-level estimates of mass discharge uncertainty from point measurement methods Contaminant concentrations have long been the driver for regulatory and remedial decisions; e.g., the maximum allowable groundwater concentration of a contaminant to protect human and environmental health. However, evaluating the mass of contaminant moving per unit area and per unit time (mass flux) or the total mass of contaminant per unit time (mass discharge) moving at a particular location (i.e., a plane perpendicular to the plume at that location) can be very useful because these measures incorporate two important features of contaminant risk: concentration and mobility. It can be difficult to determine mass flux and mass discharge. Often estimates are made using contaminant concentration data taken at several discrete points, such as from monitoring wells screened at specific points within the plume (i.e., point measurements). However, the question arises as to how uncertain these estimates are; is the estimated mass discharge likely correct within 10% - or within an order of magnitude? Such potential variability can make a big difference in the usefulness of the estimates. High uncertainty about the actual value of mass discharge might mean that much more sampling and monitoring needs to be done in order to proceed with exposure estimates and remedial decisions. In the journal article Screening-level estimates of mass discharge uncertainty from point measurement methods, researchers Michael C. Brooks, Ki Young Cha, A. Lynn Wood, and Michael D. Annable presented a screening method to predict the uncertainty of mass discharge measurements based on point measurement methods. This screening method can be used to help select sample spacing for initial sampling for mass discharge measurements, or to evaluate the usefulness of point measurement approaches to other methods of assessing mass discharge. Mass Flux/Mass Discharge Mass flux is the rate of mass movement per unit area (e.g., grams per day per meter squared). Mass discharge is the rate of mass movement through a defined area, such as a control plane at some location (e.g., grams per day). How Many Samples Are Needed? How many sampling locations are needed for the initial assessment of contaminant mass discharge from a given plume? This screening tool helps to decide the minimum number of locations. The screening method can be used to evaluate uncertainty in two ways: As related to the length of the plane across the plume where samples were taken and the number of wells, or As related to the sample spacing The researchers were able to show that the required sampling density to achieve a particular level of certainty depends not only on the magnitude of the mass discharge, but also on the distribution of the mass across the plane where samples were taken. 6 ------- Example 2: Semianalvtical solutions for transport in aquifer and fractured clay matrix system The presence of nonaqueous phase liquid (NAPL) contaminants, such as dense NAPL (DNAPL), in the subsurface greatly complicates characterization, monitoring, and remediation of the subsurface. For instance, DNAPL may move downward through relatively permeable zones such as sands and silts in the subsurface, and pool on a relatively impermeable clay layer. Not only will this pool of DNAPL be a source of contaminants to slowly dissolve into the groundwater passing around the pool of DNAPL, but also the DNAPL (and groundwater-dissolved contaminants from the DNAPL) can slowly move into the clay layer. Such a clay layer can serve as a storage zone for contaminants. Long after the pool of DNAPL directly over the clay layer is gone, the contaminants within the clay layer can continue to slowly diffuse back into the groundwater, providing a long-term source of contaminants to the groundwater in the more permeable zones of the subsurface in cc clay layer. Many mathematical models that simulate this diffusion of contaminants into and out of clay layers assume that the clay layer is competent - that is, that the clay layer is fairly uniform, continuous, and does not have any cracks in it. But clay layers often have fissures in them, and in fact DNAPL itself can cause clay layers to develop cracks. Huang and Goltz (2014) reported a model to simulate the effect of fractures in a low-permeability zone on movement of contaminants into and out of a clay layer containing fractures. They found that even a small amount of fractures can greatly increase the rate of contaminant movement into a clay layer, and (eventually) back out of the clay layer into the groundwater in the more permeable zones. This back diffusion of contaminants from the clay can cause the dissolved contaminant plume in the more permeable zones to persist for much longer, as the contaminants "stored" in the clay slowly move back into the more permeable zones. This model solution developed by Huang and Goltz can be used to evaluate the effect of fractured clay zones on contaminant attenuation processes. What is a NAPL? A NAPL is a liquid that is immiscible in or will not dissolve in water. A DNAPL is denser than water and tends to sink in water. with the less permeable Impact of Fractures in a Clay Layer "In essence, the fractures serve as a shortcut which allows more mass to access the matrix- even though the volume of fractures is much smaller than the volume of matrix in the low- permeability zone, the impact of the fractures is large..." 7 ------- 3.1.2 Task 2: Bibliography of Contaminated Groundwater Publications Flux-Based Site Management: Brooks, M.C., Cha, K.Y., Wood, A.L., and Annabelle, M.D. 2015. Screening-level estimates of mass discharge uncertainty from point measurement methods. J. Contam. Hydro/., 177-178: 167-182. (EPA Point of Contact: Michael Brooks, brooks.michael@epa.gov) Chen, X., Brooks, M.C., and Wood, A.L. 2014. The uncertainty of mass discharge measurements using pumping methods under simplified conditions. J. Contam. Hydro/., 156: 16-26. (EPA Point of Contact: Michael Brooks, brooks.michael@epa.gov) Modeling: Huang, J., and Goltz, M.N., 2014. Spatial Moment Equations for a Groundwater Plume with Degradation and Rate-Limited Sorption. J. Hydro/. Eng., 19:1053-1058. (EPA Point of Contact: Junqi Huang, huang.junqi@epa.gov) Huang, J., and Goltz, M.N., 2015. Semianalytical solutions for transport in aquifer and fractured clay matrix system. Wat. Resour. Res. Vol 51, Issue 9, 7218-7237. September 2015. (EPA Point of Contact: Junqi Huang, huang.junqi@epa.gov) Huang, J., Christ, J.A., Goltz, M.N., and Demond, A.H. 2015. Modeling NAPL dissolution from pendular rings in idealized porous media. Wat. Resour. Res. Vol 51, Issue 10, 8182-8197. October 2015. (EPA Point of Contact: Junqi Huang, huang.junqi@epa.gov) Remediation/Remedial Technologies: Atekwana, E.A., Mewafy,F.M., Abdel Aal, G., Slater, L.D., Werkema Jr, D.D., Revil, A. 2014. High-Resolution Magnetic Susceptibility Measurements for Investigating Magnetic Mineral Formation during Microbial Mediated Iron Reduction. Journal of Geophysical Research - Biogeosciences, doi: 10.1002/2013JG002414, 2014. (EPA Point of Contact: Dale Werkema, werkema.dale@epa.gov) Bell, J.M., Christ, J.A., and Huang, J. 2015. Remediation complications: subsurface cracking at hazardous waste sites. The Military Eng. Vol 107. No. 693:59-60. (EPA Point of Contact: Junqi Huang, huang.junqi@epa.gov) He, T., Wilson. J.T., Su, C., and Wilkin, R.T. 2014. Review of Abiotic Degradation of Chlorinated Solvents by Reactive Iron Minerals in Aquifers. Groundwater Monitoring & Remediation, 35: 3: 55-75. (EPA Point of Contact: Rick Wilkin, wilkin.rick@epa.gov) Heenan, J., Slater, L.D., Ntarlagiannis, D., Atekwana, E.A., Fathepure, B.Z., Dalvai, S., Ross, C., Werkema, D.D., and Atekwana, E.A.. 2015. Electrical resistivity imaging for long term autonomous monitoring of hydrocarbon degradation: lessons from the Deepwater Horizon Oil Spill. Geophysics, 2015, doi: 10.1190/geo2013-0468.1 (EPA Point of Contact: Dale Werkema, werkema.dale@epa.gov) 8 ------- Kim, J.R., Huling, S.G. Kan, E. 2015. Adsorption and oxidative degradation of Bisphenol A on surface modified iron-amended activated carbon: effects of temperature on adsorption and Fenton oxidation. Chemical Engineering Journal, 262, 1260-1267. (EPA Point of Contact: Scott Huling, huling.scott@epa.gov) Karaoulis, M., Revil, A., Minsley, B., Todesco, M., Zhang, J., Werkema, D.D.. 2014. Time-lapse gravity inversion with an active time constraint. Geophysical Journal International, 196, 748-759, doi: 10.1093/gji/ggt408, 2014. (EPA Point of Contact: Dale Werkema, werkema.dale@epa.gov) Karaoulis,M., Revil, A., Werkema Jr., D.D. 2015. 2-D Time-lapse seismic tomography using an active time constrain (ATC) approach. The Leading Edge: Near Surface Special Issue, Feb 2015. (EPA Point of Contact: Dale Werkema, werkema.dale@epa.gov) Koch, F. W., Voytek, E. B., Day-Lewis, F. D., Healy, R., Briggs, M. A., Lane, J. W. and Werkema, D. 2016. lDTempPro V2: New Features for Inferring Groundwater/Surface-Water Exchange. Groundwater, 54: 434-439. doi:10.1111/gwat. 12369. (EPA Point of Contact: Dale Werkema, werkema.dale@epa.gov) Liao, X. Zhao, D., Yan, X., Huling, S.G. 2014. Identification of persulfate oxidation products of polycyclic aromatic hydrocarbon during remediation of contaminated soil. J. Haz. Mater. 276, 26-34. (EPA Point of Contact: Scott Huling, huling.scott@epa.gov) Su, C.; Puis, R.W.; Krug, T.A.; Watling, M.T.; O'Hara, S.K.; Quinn, J.W.; Ruiz, N.E. 2016. Long-term Performance Evaluation of Groundwater Chlorinated Solvents Remediation Using Nanoscale Emulsified Zerovalent Iron at a Superfund Site. In Sung Hee Joo (ed.) "Applying Nanotechnology for Environmental Sustainability", IGI Global (in press). (EPA Point of Contact: Chunming Su, su.chunming@epa.gov) Wilkin, R.T., Acree, S.D., Ross, R.R., Puis, R.W., Lee, T.R., and Woods, L.L. 2014. Fifteen-year assessment of a permeable reactive barrier for treatment of chromate and trichloroethylene in groundwater. Science of the Total Environment, 468-469: 186-194. (EPA Point of Contact: Rick Wilkin, wilkin.rick@epa.gov) Zhao, A., Al, T., Chapman, S.W., Parker, B., Mishkin, K.R., Cutt. D., and Wilkin, R.T. 2015. Determination of hexavalent chromium concentrations in matrix porewater from a contaminated aquifer in fractured sedimentary bedrock. Chem. Geo!., 419: 142-148. (EPA Point of Contact: Rick Wilkin, wilkin.rick@epa.gov) Risk Assessment: Ford, R. G., Brooks, M.C., Enfield, C.G., and Kravitz, M. 2014. Evaluating potential exposures to ecological receptors due to transport of hydrophobic organic contaminants in subsurface systems. U.S. EPA, Office of Research and Development, EPA/600/R-10/015. (EPA Points of Contact: Robert Ford, ford.robert@epa.gov, or Michael Brooks, brooks.michael@epa.gov) 9 ------- 3.2.1 Task 3: Example Contaminated Sediment Research and Applications Example 1: The Gellvfish: an in-situ equilibrium-based sampler for determining multiple free metal ion concentrations in marine ecosystems. Metals in natural waters can exist in many forms, but usually the most chemically reactive and bioavailable form is the free metal ion. This means that the concentration of the free metal ions, rather than the total dissolved metals, tends to be the determinant of metal bioaccumulation and toxicity. Therefore ambient water quality criteria for metals are now focusing more on free metal ions rather than the total dissolved concentrations. However, free metal ions are often in very low concentrations, especially as compared to total dissolved metals, and so are difficult to properly sample and analyze. Numerous useful methods have been designed, but there was still a need for a method meeting these qualifications: Sensitive to below-nanomolar concentrations Low equilibration time Simple, convenient, and inexpensive Specific to free metal ions Capable of sampling/analyzing multiple metals simultaneously Can be used to cost-effectively acquire large datasets of multi-metal free ions under environmental conditions "... the Gellyfish is an easy-to- use and inexpensive tool for routine monitoring of multi- metal free ion concentrations in marine systems... its capacity to generate multi-metal free ion datasets may for the first time provide opportunities for complex statistical analysis of metal speciation over space and time." Dong et al. (2015) developed a new version of the Gellyfish passive sampler to meet these needs, and demonstrated in laboratory and field studies (Boton Harbor) that the new Gellyfish met the qualifications above. This new approach opens the door for a deeper understanding of how metal ions fluctuate and interact over time. Figure 6 Gellyfish mounted in snap-together slide holders are placed in a plastic basket for field deployment (Dong, Lewis, Burgess, and Shine. 2015] Example 2: Evaluating cost when selecting performance reference compounds for the environmental deployment of polyethylene passive samplers. Equilibrium passive sampling approaches for monitoring contaminants in aquatic systems have been shown to offer numerous advantages, including the ability to accurately estimate dissolved concentrations without some of the problems associated with traditional sampling methods (e.g., analyte losses during removal of colloids, etc.) However, equilibrium samplers depend on the target contaminants reaching equilibrium between the sampler and the sampled environmental phases, and it is problematic to determine when such equilibrium has been achieved. Several approaches to determine equilibrium are used, but all have difficulties, and the most robust methods are expensive and time-consuming. The performance reference compounds (PRC) method uses compounds loaded into the samplers, which equilibrate with the environment when deployed. After the sampler is removed for analysis, the remaining PRCs in the sampler provide a basis for evaluating equilibrium by comparing pre- and post- deployment concentrations of the PRCs. Many commonly-used PRCs are isotope-labeled, but these can be expensive. However, deuterated PRCs can be much less costly than other isotope labels (e.g., 13C). "...passive sampling using inexpensive and smaller quantities of PRCs can yield cost savings of approximately 75%. This approach appears most promising in the marine water column and when focusing on dissolved concentrations of low and medium molecular weight congeners or total PCBs." 10 ------- Wildlife Dissolved and Bioavailable Concentration passive " Samplers"' |)i Mussels (Not to Seals) PAHS Perron et al. (2015) compared the performance of deuterated polynuclear aromatic hydrocarbons (PAHs) and 13C-labeled polychlorinated biphenyls (PCBs) to estimate dissolved PCB concentrations in freshwater and marine deployments, and also evaluated the use of smaller quantities of PRC relative to amounts commonly used for estimating dissolved PAH and PCB concentrations. They found, for particular applications, that using deuterated PRCs, in lower quantities, could reduce costs as much as 75%. Figure 7 Using passive samplers to monitor organic contaminants (U.S. EPA. 2012] 11 ------- 3.2.2 Task 3: Bibliography of Contaminated Sediment Publications Remedy Effectiveness: Meier, J. R., Lazorchak, J. M., Mills, M., Wernsing, P., & Baumann, P. C. 2015. Monitoring exposure of brown bullheads and benthic macroinvertebrates to sediment contaminants in the Ashtabula River before, during, and after remediation. Environmental Toxicology and Chemistry, 34(6), 1267-1276. (EPA Point of Contact: Marc Mills, mills.marc@epa.gov) Lazorchak, J. M., Griffith, M. B., Mills, M., Schubauer-Berigan, J., McCormick, F., Brenner, R., & Zeller, C. 2015. Proof of concept for the use of macroinvertebrates as indicators of polychlorinated biphenyls (PCB) contamination in Lake Hartwell. Environmental Toxicology and Chemistry, 34(6), 1277-1282. (EPA Point of Contact: Marc Mills, mills.marc@epa.gov) Improved Laboratory Toxicity Testing: Burkhard, L. P., Hubin-Barrows, D., Billa, N., Highland, T. L., Hockett, J. R., Mount, D. R., Norberg-King, T. J., Hawthorne, S., Miller, D. J., & Grabanski, C. B. 2015. Sediment Bioaccumulation Test with Lumbriculus variegatus: Effects of Feeding. Archives of Environmental Contamination and Toxicology, 68(4), 696-706. (EPA Point of Contact: Lawrence Burkhard, burkhard.lawrence@epa.gov) Burkhard, L. P., Hubin-Barrows, D., Billa, N., Highland, T. L., Hockett, J. R., Mount, D. R., Norberg-King, T. J., 2016. Sediment Bioaccumulation Test with Lumbriculus variegatus: Effects of Organisms Loading. Archives of Environmental Contamination and Toxicology, in press (EPA Point of Contact: Lawrence Burkhard, burkhard.lawrence@epa.gov) Ingersoll, C.G., Kunz, J.L., Hughes, J.P., Wang, N., Ireland, D.S., Mount, D.R., Hockett, J.R. and Valenti, T.W. 2015. Relative sensitivity of an amphipod Hyalella azteca, a midge Chironomus dilutus, and a unionid mussel Lampsilis siliquoidea to a toxic sediment. Environmental Toxicology and Chemistry, 34(5), pp.1134-1144. (EPA Point of Contact: David Mount, mount.dave@epa.gov) Soucek, D. J., Mount, D. R., Dickinson, A., Hockett, J. R., & McEwen, A. R. 2015. Contrasting effects of chloride on growth, reproduction, and toxicant sensitivity in two genetically distinct strains of Hyalella azteca. Environmental Toxicology and Chemistry. 34(10), 2354-2362. (EPA Point of Contact: David Mount, mount.dave@epa.gov) Ivey, C. D., Ingersoll, C. G., Brumbaugh, W. G., Hammer, E. J., Mount, D. R., Hockett, J. R., Norberg-King, T. J., Soucek, D. and Taylor, L. 2016. Using an interlaboratory study to revise methods for conducting 10-D to 42-D water or sediment toxicity tests with Hyalella azteca. Environ Toxicol Chem. doi:10.1002/etc.3417 (EPA Point of Contact: David Mount, mount.dave@epa.gov) Interstitial Water Measurements Using Passive Sampling: Burgess, R. M., Lohmann, R., Schubauer-Berigan, J. P., Reitsma, P., Perron, M. M., Lefkovitz, L., & Cantwell, M. G. 2015. Application of passive sampling for measuring dissolved concentrations of organic contaminants in the water column at three marine superfund sites. Environmental Toxicology and Chemistry, 34(8), 1720-1733. (EPA Point of Contact: Rob Burgess, burgess.robert@epa.gov) Joyce, A. S., Portis, L. M., Parks, A. N., Burgess, R. M.. 201x. Evaluating the relationship between equilibrium passive sampler uptake and aquatic organism bioaccumulation. Environmental Science and Technology (submitted) 12 ------- (EPA Point of Contact: Rob Burgess, burgess.robert@epa.gov) Perron, M. M., Burgess, R. M., Cantwell, M. G., & Fernandez, L. A. 2015. Evaluating cost when selecting performance reference compounds for the environmental deployment of polyethylene passive samplers. Integrated Environmental Assessment and Management, 11(2), 256-265. (EPA Point of Contact: Rob Burgess, burgess.robert@epa.gov) U.S. EPA. 2016. Deriving Sediment Interstitial Water Remediation Goals (IWRGs) at Superfund Sites for the Protection of Benthic Organisms from Direct Toxicity. U.S. EPA, Office of Research and Development, EPA/600/R-XX/XXX (in external review) (EPA Point of Contact: Lawrence Burkhard, burkhard.lawrence@epa.gov) Dong Z, CG Lewis, RM Burgess, JP Shine. 2015. The Gellyfish: an in-situ equilibrium-based sampler for determining multiple free metal ion concentrations in marine ecosystems. Environmental Toxicology and Chemistry 34:983-992. (EPA Point of Contact: Rob Burgess, burgess.robert@epa.gov) Booij K, CD Robinson, RM Burgess, P Mayer, CA Roberts, L Ahrens, IJ Allan, J Brant, L Jones, UR Kraus, MM Larsen, P Lepom, J Petersen, D Proefrock, P Roose, S Schafer, F Smedes, CTixier, K Vorkamp, P Whitehouse. 2016. Passive sampling in regulatory chemical monitoring of nonpolar organic compounds in the aquatic environment. Environmental Science and Technology. 50:3-17. (EPA Point of Contact: Rob Burgess, burgess.robert@epa.gov) Dong Z, C Lewis, RM Burgess, B Coull, J Shine. 2016. Statistical evaluation of biogeochemical variables affecting spatiotemporal distributions of multiple free metal ion concentrations in an urban estuary. Chemosphere 150:202-210. (EPA Point of Contact: Rob Burgess, burgess.robert@epa.gov) 13 ------- 3.3.1 Task 4: Example Vapor Intrusion Research and Applications Example 1: The effect of equilibration time and tubing material on soil gas measurements The collection of soil vapor samples representative of in-situ conditions presents challenges associated with the unavoidable disturbance of the subsurface and potential losses to the atmosphere. Sampling for soil gas involves disturbing the soil to get to the proper depth to collect the gas sample; i.e., the pushing a hoilow probe rod into the soil with direct-push equipment, or drilling a hole with a hollow-stem auger, hand auger, or sonic drill. Inserting sampling tubing after hole drilling can involve more disturbance, and exposure of the borehole to the atmosphere. When the soil (and surrounding soil gas) is thus disturbed or sampling procedures require the sampler to pull back the probe to create a void for soil gas collection, time is required for the soii gas around the probe to come into equilibrium so as to be representative of the soil gas conditions in the surrounding soii. Numerous regulatory agencies and industry groups provide recommendations for equilibration times for the various techniques, but empirical data to support such recommendations are lacking. In addition to problems with equilibration times, the tubing used for taking the gas sample can interact with the contaminant vapors as the vapors move up into the collection device. Schumacher et ai. (2016) conducted a multidimensional study to investigate the influence of equilibration time and tubing material on the measured concentration of trichloroethene (TCE) in soil gas samples. Three types of probes (macro-purge probes, mini-purge probes, and post-run tubing [PRT] probes), and six types of tubing (stainless steel, copper, polyetheretherketone [PEEK], Tefionฎ, Nylafiowฎ, and polyethylene) were tested. SINGLE DEPTH MACRO-PURGE PROBES ฆ0.04-INCH OD STAINLESS STEEL TUBING -HYDRATED GRANULAR BENTONITE - DRY GRANULAR BENTONITE - #2/12 SAND PACK MINI-PURGE PROBE TIP STEEL DROP-OFF POINT MINI-PURGE PROBES NESTED MACRO-PURGE PROBES NOT TO SCALE Drive Sampling Figure 9 Micro purge vapor probe. (ZimmermanL etal. No dateli-> W Bw 55f*Drive Tip Figure 8 Schematic diagram of macro-purge and mini-purge probes (Schumacher etal. 2016) Results of this study include: Samples from soil vapor probes inserted after drilling reached 90% of their final concentrations within 48 hours after insertion Samples from PRT probes and mini-purge probes reached 80-90% of their final concentrations within 1 to 2 hours and 30 minutes, respectively, after insertion Polyethylene consistently yielded lower soil gas contaminant concentration results than other tubing materials Nylafiowฎ, Teflonฎ, PEEK, and stainless steel tubing yielded similar soil gas contaminant concentration results; and no consistent bias was observed Copper tubing yielded significantly lower soil gas contaminant concentration results for a few days after insertion, but after several months yielded similar results to the other tubing materials The researchers concluded that the results of this study provide a foundation for recommending equilibration times for each of the different types of probes and installation techniques, and the type of tubing to be used 14 ------- Example 2: Assessment of mitigation systems on vapor intrusion: Temporal trends, attenuation factors, and contaminant migration routes under mitigated and non-mitigated conditions Contaminant vapor concentrations within and under a structure (e.g. subslab, and deep soil gas vapor concentrations) with vapor intrusion issues vary widely temporally and spatially. For example, within a given structure vapor concentrations can vary temporally due to use of the building, temperature, wind direction, changes in atmospheric pressure, water table depth, soil moisture, and even snow/ice capping events. Multiple samples taken frequently at numerous locations are necessary in order to capture the temporal and spatial variability of vapor concentrations, driving up the investigation costs. One commonly used mitigation approach for vapor intrusion involves subslab depressurization (SSD), which is used to reduce movement of soil vapors into buildings. However, the design guidelines for SSD are not well-supported by detailed, long-term SSD-specific field testing. Lutes et al. (2015) presents interim results of a long-term continuing study on variation in volatile organic compounds (VOC) and radon concentrations, emitted from a nearby groundwater source and/or vadose zone source, in the indoor air, subslab, and subsurface soil gas of a residential duplex. The interim results presented focus on three areas: Better definition of subsurface conditions that influence movement of VOCs and radon into the residence Design, installation, and monitoring of an SSD mitigation system, to determine effectiveness of the SSD system under the well-defined conditions at the residence Monitoring a winter snow/ice capping event to understand how radon and VOC vapor movement into the residence home were influenced Preliminary analyses on the interim results presented suggest that: The SSD system can be effective for radon, but may not be as effective for VOCs, for reasons that are as yet unclear (but probably due to the large number of variables affecting vapor intrusion at the residence) Helium tracer studies indicated that the SSD did not strongly influence tracer distribution in the subsurface; while soil stratigraphy and the building envelope seemed to have the strongest influence Snow cover or frozen soils may temporarily increase vapor intrusion "A large number of variables have been shown here to most likely have an interactive effect on VOC vapor intrusion, including cold temperatures, snow/ice, barometric pressure, and wind direction. Practitioners should thus expect to not be able to explain in detail temporal patterns drawn from small data sets..." 15 ------- 3.3.2 Task 3: Bibliography of Vapor Intrusion Publications Remediation/Remedial Technologies: Lutes, C. C., Truesdale, R. S., Cosky, B. W., Zimmerman, J. H. and Schumacher, B. A. 2015. Comparing Vapor Intrusion Mitigation System Performance for VOCs and Radon. Remediation, 25: 7-26. doi:10.1002/rem.21438 Brian A. Schumacher, John H. Zimmerman, R. James Elliot, and Greg R. Swanson. 2016. The Effect of Equilibration Time and Tubing Material on Soil Gas Measurements. Soil and Sediment Contamination: An International Journal Vol. 25, Iss. 2, 2016. (EPA Point of Contact: Brian Schumacher, schumacher.brian@epa.gov, or John Zimmerman, zimmerman.john@epa.gov) U.S. EPA. 2015. Assessment of Mitigation Systems on Vapor Intrusion: Temporal Trends, Attenuation Factors, and Contaminant Migration Routes under Mitigated and Non-Mitigated Conditions. U.S. EPA, Office of Research and Development, EPA/600/R-13/241. (EPA Point of Contact: Brian Schumacher, schumacher.brian@epa.gov) Schumacher, B. and John H. Zimmerman. 2015. Simple, Efficient, and Rapid Methods to Determine the Potential for Vapor Intrusion into the Home: Temporal Trends, Vapor Intrusion Forecasting, Sampling Strategies, and Contaminant Migration Routes. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-15/070, 2015. (EPA Point of Contact: Brian Schumacher, schumacher.brian@epa.gov) Zimmerman, J.H., Lutes, C., Cosky, B., Schumacher, B., Salkie, D., Abreu, L., Frizzell, A., Uppencamp R., Truesdale, R., and Hayes, H. 2016. Temporary vs permanent sub-slab ports: a comparative performance study. Soil and Sediment Contamination: An International Journal (submitted). (EPA Point of Contact: John Zimmerman, zimmerman.john@epa.gov, or Brian Schumacher, schumacher.brian@epa.gov) 16 ------- 4.0 Task Future Directions 4.1 Task 3.61.2 Future Directions in Contaminated Groundwater Research Thousands of legacy groundwater pollution sites continue to challenge site managers as difficult problems with non-aqueous phase liquid (NAPL) contaminants, back diffusion of contaminants from low permeability zones, and complex subsurface conditions such as fractured rock, require much greater investment of resources to evaluate and remediate. Emerging contaminants and enactment of lower regulatory contaminant concentration thresholds may require revisiting sites previously deemed to be remediated, all in an era where resources for remediation are increasingly limited. Therefore, a primary driver for groundwater research is the pressing need to do more with less. More efficient and effective site evaluation and remediation strategies are required to allow for accurate and in-depth understanding of the remedial benefits to be gained versus the resource expenditures required to gain those benefits. These resource expenditures to be considered must also include the cost of externalities and sustainability issues such as water scarcity, climate change, etc. Decision-makers need decision support tools to be able to evaluate these factors and strategically allocate limited resources to getting and using data to guide key site decisions. Enhanced decision support tools include: Incremental approaches: Provide a stepped approach to site characterization, remedy implementation, and monitoring with both screening level and complex models Defining sampling: Determine site characterization approaches, such as sample number and location, in an iterative manner using screening and complex models particularly for more complex hydrogeological situations Source materials: Assess impact of source architecture (source distribution and arrangement) and evolution, including contaminant mass in regions of low hydraulic conductivity, and how this mass changes over time or in response to a given remedial or management strategy Uncertainty: Evaluate uncertainty involved with remedial effectiveness and timeframe predictions, and communicate that uncertainty to a range of stakeholders These decision support tools will be developed, tested and refined using historical site data from well-understood sites, and incorporated into a modular, systematic linear/iterative approach suitable for use by a wide variety of decision-makers. Documentation such as manuals and guidance will be used to introduce users to the basic concepts needed for understanding site characterization and remediation approaches, and how to effectively apply the decision tools for their sites. Avenues such as training sessions and demonstrations will be used to provide both development of user skills and feedback from the decision-maker community for improvement of the decision tool framework. Groundwater Issues Focus Nonaqueous phase liquid (NAPL) Back diffusion of contaminants Complex subsurface conditions such as fractured rock Decision Support Tools Inform What kind of site data is needed from which locations? Where are the source materials, and how will they change over time? What is the uncertainly associated with predictions of remedy effectiveness and timeframe? 17 ------- 4.2 Task 3.61.3 Future Directions for Contaminated Sediments Research Future directions for research related to contaminated sediments include sediment toxicity testing, use of passive sampling at sediment sites, remedy effectiveness/restoration measures and metrics, and improving bioaccumulation- forecasting abilities. Toxicity testing of sediments at Superfund sites is often limited in scope, implementation, and interpretation, leading to limited usefulness of the data for both making current site decisions and understanding of long-term effects. Methodology demonstrations conducted at typical Superfund sites are proposed to generate data for case studies illustrating proper techniques and analysis based upon the methods in the forthcoming 3rd Edition of EPA's Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates guidance document. Training courses, coupled with publication of case study results and guidance documents, would then transmit the improved approaches to the user community. Passive sampling methodologies cost-effectively provide data integrated over time, which improves assessment of long-term trends. Efforts toward understanding and promoting the use of passive sampling include: Sampling guidance: Contribute to development of a guidance document for passive sampling of sediments Remediation goals guidance: Contribute to the development of guidance documents for developing sediment Interstitial Water Remediation Goals (IWRGs) for benthic invertebrates and pelagic organisms. Source identification: Develop a guidance document for passive sampling source identification/tracking Bioaccumulation: Continue research to understand and improve the usefulness of data from passive sampling methods for predicting higher trophic level species bioaccumulation A planned guidance document for using weight of evidence approaches for evaluating effectiveness of remedies for contaminated sediments will incorporate tools and measures developed under the Contaminated Sediments Task. Bioaccumulation modeling and forecasting is used to make long-term predictions of contaminant residues in fish and shellfish, but commonly used food chain models may not accurately predict risk reduction after site remediation. A conference session on improving food chain model forecasts is planned to bring together experts for sharing new approaches and generating ideas for improved forecasting. In addition, research on a possible inverse relationship between bioaccumulation and contaminant sediment concentrations is being pursued. Also, perfluoroalkyls are becoming contaminants of concern, but knowledge of their toxicology, bioaccumulation, and fate and transport is limited. Contaminated Sediments Issues Focus Toxicity testing Passive sampling Remedy measures and metrics Bioaccum ulation forecasting Coming in FY17: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates. 3rd Edition 18 ------- 4.3 Task 3.61.4 Future Directions for Vapor Intrusion Vapor intrusion (VI) continues to be a high-profile issue. Knowledge gaps identified by ORD, Office of Land and Emergency Management (OLEM), EPA Regions, and discussions at professional meetings will be addressed focusing on specific aspects of three main focal points: Vapor transport: Characterize vapor travel and distribution in the environment, and inside buildings Vapor sampling: Evaluate sampling strategies, including methods, techniques and timing, to effectively define and monitor vapor intrusion issues VI control: Evaluate vapor intrusion prevention and mitigation approaches Since rapid response efforts are often needed to identify and control existing VI issues, research needs include the development of screening methods to quickly identify VI issues, and examine the efficacy of portable absorption systems to treat and remove chlorinated volatile organic compounds in indoor air. Additional work is needed on high purge-volume approaches to sample subslab soil gas as part of the effort to develop accurate, low-cost, and less intrusive sampling methods for characterizing sub-slab soii gas concentrations, compared to current conventional and alternative sampling approaches. Sampling of indoor air quality for performance and effectiveness of active subslab depressurization systems is intrusive and discontinuous; pressure sampling offers advantages, but testing and comparison of the two monitoring approaches is needed. There are concerns that vented subsurface gases could affect adjacent neighborhoods, especially where multiple venting systems are operating, so improved approaches to monitoring and reducing vented gases are needed. Residential buildings are usually only impacted by relatively low concentration groundwater- derived vapors, and this aspect of VI has been widely studied. However, vapor intrusion in commercial buildings (which not only have different construction, but also may be located directly over contaminant source areas emitting high concentration vapors), is poorly understood. identification and evaluation of the importance of preferential pathways (variations in soil texture, utility trenches, etc.) for vapor travel continues to be a significant issue of investigation. Soil vapor extraction (SVE) to control vapor intrusion is currently being examined; field testing is ongoing to take place at a Superfund site. A research summary and guidance document is planned to provide a summary and assessment of all ORD vapor intrusion research, and provide guidance for application of lessons learned. Vapor Intrusion Issues Focus Vapor travel and distribution Sampling strategies Prevention and mitigation ฆ stack wind effects utility line X \ I n i 1 i i / ป * soil vapor migrat vapor intrusion through cracks in foundation slab vapor intrusion through floor-wall cracks water table 1 groundwater Dlume of VOCs Figure 10 Migration of soil vapors to indoor air (U.S. EPA 2015b) son contaminated witn vous 19 ------- General References Ford, Robert G., Michael C. Brooks, Carl G. Enfield, Michael Kravitz. 2014. Evaluating Potential Exposures To Ecological Receptors Due To Transport Of Hydrophobic Organic Contaminants In Subsurface Systems. June 2014. EPA/600/R- 10/015. ERASC-009 F. U.S. EPA. (no date). 2011 National Listing of Fish Advisories (NLFA). National Fish and Wildlife Contamination Program. https://www.epa.gov/sites/production/files/2015-06/documents/maps-and-graphics-2011.pdf U.S. EPA. 2012. Guidelines for Using Passive Samplers to Monitor Organic Contaminants at Superfund Sediment Sites. OSWER Directive 9200.1-110 FS. December 2012. https://clu- in.org/download/contaminantfocus/sediments/Sediments-Passive-Sampler-SAMS 3.pdf U.S. EPA. 2015a. Basic Information about Your Drinking Water. Webpage last updated on November 30, 2015. Accessed July 27, 2016. https://www.epa.gov/ground-water-and-drinking-water/basic-information-about-vour-drinking-water U.S. EPA. 2015b. What is Vapor Intrusion? Last updated on September 30, 2015. Accessed July 27 2016. https://www.epa.gov/vaporintrusion/what-vapor-intrusion U.S. EPA. 2016a. EPA Strategic Plan: FY 2014-2018 Strategic Plan. Webpage last updated on July 7, 2016. Accessed July 27, 2016. https://www.epa.gov/planandbudget/strategicplan U.S. EPA. 2016b. EPA On-line Tools for Site Assessment Calculation: Evaluating Vapor Intrusion into Buildings from Contaminated Groundwater and Soils. Webpage last updated on February 23, 2016. Accessed July 27, 2016. https://www3.epa.gov/ceampubl/learn2model/part-two/onsite/ine background forward.html U.S. Fish and Wildlife Service (USFWS). 2016. Environmental Contaminants Program in the Midwest: Fish, Wildlife and Environmental Contaminants. Webpage last updated February 10, 2016. Accessed July 27, 2016. https://www.fws.gov/midwest/es/ec/R3ecProgramFS.html Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L., and Linsey, K.S. 2014. Estimated use of water in the United States in 2010: U.S. Geological Survey Circular 1405, 56 p., http://dx.doi.org/10.3133/cirl405. http://pubs.usgs.gov/circ/1405/ Zimmerman, John H.; Greg Swanson, Brian A. Schumacher, James Elliot, and Blayne Hartman. (No date). Effect of Equilibration Time of Soil Vapor Probes on Soil Gas Concentrations. https://cfpub.epa.gov/si/si public file download.cfm?p download id=496110 Keywords Contaminated sites, groundwater, sediments, vapor intrusion 20 ------- Contacts David G. Jewett Project Lead, SHC Contaminated Sites Project (3.61) U.S. EPA, Office of Research and Development, National Risk Management Research Laboratory Ground Water and Ecosystems Restoration Division Address: P.O. Box 1198, Ada, OK 74820; Phone: 580.436.8560; Email: jewett.david@epa.gov Dennis L. Timberlake Deputy Project Lead, SHC Contaminated Sites Project (3.61) U.S. EPA, Office of Research and Development, National Risk Management Research Laboratory Land Remediation and Pollution Control Division Address: 26 West Martin Luther King Drive, Mail Code: 190, Cincinnati, OH 45268; Phone: 513.569.7547; Email: timberlake.dennis@epa.gov Michael C. Brooks SHC Contaminated Sites Project (3.61) - Task 2: Contaminated Groundwater Research U.S. EPA, Office of Research and Development, National Risk Management Research Laboratory Ground Water and Ecosystems Restoration Division Address: P.O. Box 1198, Ada, OK 74820; Phone: 580.436.8982; Email: brooks.michael@epa.gov Lawrence P. Burkhard SHC Contaminated Sites Project (3.61) - Task 3: Contaminated Sediments Research U.S. EPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division Address: 6201 Congdon Boulevard, Duluth, MN 55804; Phone: 218.529.5164; Email: burkhard.lawrence@epa.gov Brian A. Schumacher SHC Contaminated Sites Project (3.61) - Task 4: Vapor Intrusion Research U.S. EPA, Office of Research and Development, National Exposure Research Laboratory, Exposure Methods and Measurements Division Address: 944 East Harmon Avenue, Las Vegas, NV 89119; Phone: 702.798.2242; Email: schumacher.brian@epa.gov 21 ------- |