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Protocols for Use of Five Passive Samplers

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1 Protocols for Use of Five Passive Samplers
Welcome – Thanks for joining us. ITRC’s Internet-based Training Program Protocols for Use of Five Passive Samplers All groundwater samplers or sampling methodologies attempt to collect a well-water sample which is representative of the groundwater adjacent to the well. The ITRC Passive Sampler Team has defined a passive groundwater sampler as one that is able to acquire a sample from a discrete position in a well without active media transport induced by pumping or purge techniques. Passive sampling is synonymous with no-purge sampling and can be used as a substitute or replacement for any current groundwater sampling technology. Passive samplers have been used in every state in the U.S. and in many other countries. Passive samplers are easy to use; eliminate purge-water production (therefore, there is little or no disposal cost); reduce field sampling variability resulting in highly reproducible data; decrease field labor and project management costs for long-term monitoring; allow rapid field sample collection; sample discrete intervals in a well; are practical for use where access is difficult or discretion is desirable; can be deployed in series to provide a vertical contaminant profile; and have virtually no depth limit. This training supports the understanding and use of the ITRC Protocols for Use of Five Passive Samplers to Sample for a Variety of Contaminants in Groundwater (DSP-5, 2007). The five technologies included in this document include diffusion samplers (Regenerated Cellulose Dialysis Membrane Sampler and Rigid Porous Polyethylene Sampler), equilibrated grab samplers (Snap Sampler™ and HydraSleeve™ Sampler); and an accumulation sampler (GORE™ Module). The training starts with information common to all five samples then focuses on each sampler as instructors describe the sampler and explain how it works; discuss deployment and retrieval of the sampler; highlight advantages and limitations; and present results of data comparison studies. ITRC (Interstate Technology and Regulatory Council) Training Co-Sponsored by: US EPA Technology Innovation and Field Services Division (TIFSD) ( ITRC Training Program: Phone: ITRC Protocols for Use of Five Passive Samplers to Sample for a Variety of Contaminants in Groundwater (DSP-5, 2007) Sponsored by: Interstate Technology and Regulatory Council ( Hosted by: US EPA Clean Up Information Network (

2 Housekeeping Course time is 2¼ hours Phone line participants
Do NOT put this call on hold *6 to mute; #6 to unmute Question & Answer breaks Phone - unmute #6 to ask question out loud Simulcast - ? icon at top to type in a question Turn off any pop-up blockers Move through slides Arrow icons at top of screen List of slides on left Feedback form available from last slide – please complete before leaving This event is being recorded Archives accessed for free Although I’m sure that some of you are familiar with these rules from previous CLU-IN events, let’s run through them quickly for our new participants. We have started the seminar with all phone lines muted to prevent background noise. Please keep your phone lines muted during the seminar to minimize disruption and background noise. During the question and answer break, press #6 to unmute your lines to ask a question (note: *6 to mute again). Also, please do NOT put this call on hold as this may bring unwanted background music over the lines and interrupt the seminar. You should note that throughout the seminar, we will ask for your feedback. You do not need to wait for Q&A breaks to ask questions or provide comments using the ? icon. To submit comments/questions and report technical problems, please use the ? icon at the top of your screen. You can move forward/backward in the slides by using the single arrow buttons (left moves back 1 slide, right moves advances 1 slide). The double arrowed buttons will take you to 1st and last slides respectively. You may also advance to any slide using the numbered links that appear on the left side of your screen. The button with a house icon will take you back to main seminar page which displays our agenda, instructor bios, links to the slides and additional resources. Lastly, the button with a computer disc can be used to download and save today’s presentation slides. Download slides as PPT or PDF Go to slide 1 Submit comment or question Report technical problems Move back 1 slide Go to seminar homepage Go to last slide Move forward 1 slide 2

3 ITRC Disclaimer and Copyright
Although the information in this ITRC training is believed to be reliable and accurate, the training and all material set forth within are provided without warranties of any kind, either express or implied, including but not limited to warranties of the accuracy, currency, or completeness of information contained in the training or the suitability of the information contained in the training for any particular purpose. ITRC recommends consulting applicable standards, laws, regulations, suppliers of materials, and material safety data sheets for information concerning safety and health risks and precautions and compliance with then-applicable laws and regulations. ECOS, ERIS, and ITRC shall not be liable for any direct, indirect, incidental, special, consequential, or punitive damages arising out of the use of any information, apparatus, method, or process discussed in ITRC training, including claims for damages arising out of any conflict between this the training and any laws, regulations, and/or ordinances. ECOS, ERIS, and ITRC do not endorse or recommend the use of, nor do they attempt to determine the merits of, any specific technology or technology provider through ITRC training or publication of guidance documents or any other ITRC document. Here’s the lawyer’s fine print. I’ll let you read it yourself, but what it says briefly is: We try to be as accurate and reliable as possible, but we do not warrantee this material. How you use it is your responsibility, not ours. We recommend you check with the local and state laws and experts. Although we discuss various technologies, processes, and vendor’s products, we are not endorsing any of them. Finally, if you want to use ITRC information, you should ask our permission. Copyright 2010 Interstate Technology & Regulatory Council, 444 North Capitol Street, NW, Suite 445, Washington, DC 20001 3

4 ITRC ( – Shaping the Future of Regulatory Acceptance
Host organization Network State regulators All 50 states, PR, DC Federal partners ITRC Industry Affiliates Program Academia Community stakeholders Wide variety of topics Technologies Approaches Contaminants Sites Products Technical and regulatory guidance documents Internet-based and classroom training DOE DOD EPA The Interstate Technology and Regulatory Council (ITRC) is a state-led coalition of regulators, industry experts, citizen stakeholders, academia and federal partners that work to achieve regulatory acceptance of environmental technologies and innovative approaches. ITRC consists of all 50 states (and Puerto Rico and the District of Columbia) that work to break down barriers and reduce compliance costs, making it easier to use new technologies and helping states maximize resources. ITRC brings together a diverse mix of environmental experts and stakeholders from both the public and private sectors to broaden and deepen technical knowledge and advance the regulatory acceptance of environmental technologies. Together, we’re building the environmental community’s ability to expedite quality decision making while protecting human health and the environment. With our network of organizations and individuals throughout the environmental community, ITRC is a unique catalyst for dialogue between regulators and the regulated community. For a state to be a member of ITRC their environmental agency must designate a State Point of Contact. To find out who your State POC is check out the “contacts” section at Also, click on “membership” to learn how you can become a member of an ITRC Technical Team. 4

5 ITRC 2-day Classroom Training: Vapor Intrusion Pathway
ITRC Course Topics Planned for 2010 – More information at Popular courses from 2009 New in 2010 Decontamination and Decommissioning of Radiologically-Contaminated Facilities Enhanced Attenuation of Chlorinated Organics In Situ Bioremediation of Chlorinated Ethene - DNAPL Source Zones LNAPL Part 1: An Improved Understanding of LNAPL Behavior in the Subsurface LNAPL Part 2: LNAPL Characterization and Recoverability Perchlorate Remediation Technologies Performance-based Environmental Management Phytotechnologies Protocol for Use of Five Passive Samplers Quality Consideration for Munitions Response Determination/Application of Risk-Based Values Use of Risk Assessment in Management of Contaminated Sites Decision Framework for Applying Attenuation Processes to Metals and Radionuclides LNAPL Part 3: Evaluating LNAPL Remedial Technologies for Achieving Project Goals Mining Waste Remediation Risk Management: An Approach to Effective Remedial Decisions and More Protective Cleanups More details and schedules are available from under “Internet-based Training” and “Classroom Training.” ITRC 2-day Classroom Training: Vapor Intrusion Pathway 5 5

6 Meet the ITRC Instructors
Kimberly McEvoy New Jersey Department of Environmental Protection Trenton, New Jersey Hugh Rieck US Army Corps of Engineers Omaha, Nebraska Kimberly McEvoy is a Senior Geologist with the New Jersey Department of Environmental Protection (NJDEP) in the Site Remediation Program in Trenton, New Jersey. Before joining the NJDEP, Kimberly worked for five years as a geologist with private environmental consulting companies located in Philadelphia, New Jersey, and Maryland, where she became familiar with various environmental regulations and guidelines associated with groundwater sampling. In 2000, she was hired as a regulator within the NJDEP Bureau of Groundwater Pollution Assessment, advising consultants and private citizens on how to collect a representative groundwater sample. At this time, she was introduced to the work of the ITRC Passive Sampler Team by a coworker who was deploying polyethylene diffusion bags (PDBs) and the regenerated cellulose dialysis (RCD) samplers to collect pore water from stream sediments. Kimberly 's interest led her to become a co-leader of the ITRC Diffusion/Passive Sampler Team in She currently investigates unknown sources of groundwater contamination for the NJDEP Bureau of Environmental Measures and Site Assessment (BEMSA) and has taken over as Team Leader. She has helped the team develop two ITRC-supported technical documents and speaks, on behalf of the team, on the value and usefulness of passive sampling technologies at various conferences across the country. Her goal for the team is to help identify the validity of passive sampling approaches to the regulatory and consulting communities to the point that these technologies are not considered "innovative" sampling techniques but are accepted approaches to collect groundwater samples. Kimberly earned a bachelor's degree in geological science from Pennsylvania State University in State College, Pennsylvania in 1998. Hugh Rieck is a geologist with the US Army Corps of Engineers - Hazardous, Toxic, and Radioactive Waste Center of Expertise (HTRW-CX) in Omaha, Nebraska. Before joining the HTRW-CX in 2006, Hugh worked six years as a hydrologist with the Arizona Department of Environmental Quality Superfund Programs Section, where he became interested in problems of groundwater sampling for environmental investigations. He began his involvement with the ITRC Diffusion/Passive Sampling team shortly after its inception in 2001 and was an alternate instructor for the ITRC Internet-based training course for the use of polyethylene-based passive diffusion bag (PDB) samplers in Prior to his state regulatory experience, Hugh worked 13 years as a research geologist with the U.S. Geological Survey, where he specialized in the application of paleomagnetic stratigraphy to investigations of geologic records of climate change. He earned a bachelor's degree in 1974 and master's degree in 1983 in geology and earth science from Northern Arizona University in Flagstaff, Arizona. Louise Parker has been a Research Physical Scientist at the U.S. Army Engineer Research and Development Center's Cold Regions Research and Engineering Laboratory (ERDC-CRREL) in Hanover, NH for over 25 years. She has a broad background in environmental chemistry and microbiology. Since the early 1990s, her primary research focus has been groundwater monitoring and sampling, and analyte/material interactions, with over 60 publications, presentations, and workshops. Recent research studies have examined the suitability of direct-push (DP) monitoring wells for long-term monitoring and passive groundwater sampling methods. Older studies examined sorption of organic contaminants and leaching of constituents by sampling and well casing materials, decontamination of sampling devices, and the affects of harsh environments on sampling and well casing materials. Since 2002, she has been a member of the ITRC Sampling, Characterization, and Monitoring Team, where she has worked on a technical regulatory document on the use DP wells. Since 2003, she has also a member of the ITRC Diffusion/Passive Sampler team, where she has worked on an overview document on passive groundwater sampling techniques and a technical regulatory document on five passive groundwater sampling methods. Louise earned a bachelor's degree in microbiology from the University of New Hampshire in Durham, NH in 1972 and a master's degree in food science from the University of Massachusetts in Amherst, MA in 1979. Louise Parker U.S. Army Engineer Research and Development Center Hanover, New Hampshire

7 What you will learn… What is passive sampling?
What passive samplers offer Quantitative data Cost savings (40-70%) How passive samplers reflect aquifer conditions Technical and regulatory guidance Acceptance of passive sampling Classes and types of passive samplers The Team defines passive sampler as a device that collects a sample of water, or selectively targeted constituents of water, from a specific depth interval in well (or other location), under ambient conditions (i.e. without the use of a pump). Use of the sampler does not affect the conditions in the well or the sampled medium. Passive samplers can collect information about aquifer conditions and contaminant migration by different mechanisms than conventional active (i.e. pumped) sampling techniques. They can provide information that would be cost-prohibitive by any other means. In environmental investigations, passive samplers can often replace conventional sampling methods to collect groundwater samples that will meet Data Quality Objectives at significantly lower cost. The principal exception being drinking water quality compliance; therefore they are not recommended for drinking water sampling. All passive (no-purge) samplers collect quantitative data. The principal distinguishing aspect of passive samplers is that they collect information about conditions at a specific depth within a well. In contrast, pumped samples (low-flow or high volume purge) actively draws in water from above, below and/or adjacent to the screened interval; therefore, collect a flow-weighted average groundwater sample. Passive Samplers: Do not rely on purge sampling Save money and time since no purge water disposal costs. Are depth-specific; therefore; can profile contaminant concentrations within the screened interval of a well which can aid in refining your Site Conceptual Model, targeting monitoring, and Remedial Process Optimization. ITRC and other references give Technical and Regulatory Guidance on the applicability, usability and value of passive sampling, and provide a basis for consultants and regulators to evaluate passive samplers for their appropriate application. The team has identified three classes of passive groundwater sampling devices, based on their underlying operating mechanisms. The five most mature examples of passive samplers samplers covered in this document and training represent all three classes.

8 Passive Sampler Team Diffusion Sampler Team formed in 2000
Initial goal Develop guidance on polyethylene diffusion bags (PDBs) for collection of volatile organic compounds (VOCs) in groundwater 1st passive sampling device - diffusion type sampler (DSP-3) Limited in analyte capabilities Increased interest and development of passive devices Transition to “Passive Sampler Team” What technologies are being developed and what they can do? Disseminate guidance on passive sampling technologies Be premier resource on the use of passive sampling technologies Promote adoption of regulatory guidance (i.e., acceptance) The ITRC Diffusion Sampler Team was formed in 2000 and currently is known as the ITRC Passive Sampler Team. This name change occurred in the beginning of 2006 when the team recognized that passive sampler technologies were being validated in lab and field studies and starting to replace the traditional sampling methods. Passive methods will not entirely replace conventional pumped sampling in all situations – for example, initial “broad-brush” site reconnaissance scale sampling, or drinking water compliance, but will rather complement and refine data from pumped methods, usually at substantially lower per-sample cost. The ITRC Passive Sampler Team Technical and Regulatory Guidance has been used to provide a basis for acceptance of passive sampling techniques. There is growing confidence and acceptance of passive sampling techniques, particularly in the last five years, among regulatory agencies, consultants, and their clients as awareness increases and understanding of how they work, how to use them correctly (including better definition of the sampling objectives, sampling plan strategies, and field techniques), how to interpret the data (what the data represent). Passive samplers, including the well-known polyethylene diffusion bag (PDB), have been deployed at sites in every state across the country. More rapid acceptance has been hindered by a lack of understanding of the reasons for, or discomfort with differences between results by different methods, particularly between passive samples and historical pumped data. The field of groundwater sampling has broadened by the development of passive sampling techniques. There is a changing paradigm in groundwater sampling for environmental investigations. The emergence and development of a variety of passive groundwater sampling techniques during the last decade or so is providing data of focus, reproducibility, and ability to target objectives that we’ve not typically had available to us before (at least not without extraordinary effort and expense). Data generated by passive sampling techniques can be more informative, more consistent, and quite often acquired at a much lower “per-sample” cost than conventional or low-flow pumped samples. However, passive sampling techniques represent groundwater conditions somewhat differently than pumped samples, and are driving a need to re-examine our understanding and interpretation of all groundwater sampling data, including seldom considered biases inherent in historical pump and purge sampling, whether low-flow or high flow 3-casing volume purge.

9 What Does a Purge Sample Represent?
Active transport of water induced either by pumping or hand-purging Often draws water from above and below as well as adjacent to the screened interval/open borehole Flow-weighted average Based on indicator parameter stabilization or evacuation of the sampling system (i.e., volume purge) Gas exchange and mixing May elevate turbidity Mobilization of colloids and sediment Mobilization of normally immobile NAPL microglobules Compliance with drinking water standards The ITRC Diffusion/Passive Sampler Team recognized that passive sampler technologies were being validated in lab and field studies and starting to replace the traditional sampling methods. Passive methods will not entirely replace conventional pumped sampling in all situations – for example, initial “broad-brush” site reconnaissance scale sampling, or drinking water compliance, but will rather complement and refine data from pumped methods, usually at substantially lower per-sample cost. Purge sampling defined as: * 3-volume purging: volume based purge with pump equipment or hand-bailing * low-flow purge: parameter stabilization based purge , no volume restrictions, only flow restrictions and parameter identifiers that determine when to collect a sample Field experiments, laboratory simulations and numerical modeling support the position that samples are derived from the entire screen zone under low-flow pumping conditions. Varljen, et. al. 2006 Describe the physical aspect of collecting a sample by purging vs passive for various compliance levels

10 What Does a Passive Sample Represent?
No active transport of water induced by pumping or purging Samples are collected from a specific depth Rely on sampling device and well water being in ambient equilibrium with the formation water during deployment period Reduce disturbance to the well and aquifer typically caused by bailing or over-pumping Reduce turbidity Represent “natural conditions” To retain consistency throughout the training module and published documents, the team has used the above general definitions that are used throughout the documents and training modules. The Team uses the term “passive” synonymously with “no-purge”. Unfiltered samples can be used to get a better estimation of the true mobile contaminant load. The emergence and development of a variety of passive groundwater sampling techniques during the last decade or so is providing data of focus, reproducibility, and ability to target objectives that we’ve not typically had available to us before (at least not without extraordinary effort and expense). Data generated by passive sampling techniques can be more informative, more consistent, and quite often acquired at a much lower “per-sample” cost than conventional or low-flow pumped samples. However, passive sampling techniques represent groundwater conditions very differently than pumped samples, and are driving a need to re-examine our understanding and interpretation of all groundwater sampling data, including seldom considered biases inherent in historical pump and purge sampling, whether low-flow or high flow 3-casing volume purge.

11 Advantages of Passive Samplers
Highly reproducible data Provides low turbidity samples Disposable/dedicated - no decontamination between wells Decrease costs Field labor  Rapid field deployment and collection Leave in quarterly Little or no disposal cost (no purge-water) Samples discrete intervals Vertical contaminant profiling Monitor zone of highest contaminant influx Easy to use – minimal equipment needs No depth limit “Green” sampling method Advantages apply to all 5 technologies discussed in this ITRC Protocol Document (DSP-5) and training module. None of these passive sampling devices use moving parts, they are easy to handle, carry, and deploy since they have minimal equipment needs. Due to their ease of use, passive devices can be valuable tools when you need to sample areas where there is difficult access or when you desire discretion. To-date, no depth limit has been identified by the Team. Passive sampling devices have been deployed in wells up to 700-feet below ground surface. Passive technologies have replaced low-flow sampling techniques due to depth limitations with pumps sampling at depth under low-flow pump rates. For example, a groundwater sampling projects was using low-flow to sample wells 100-feet or less deep; however, there where problems with the pumps sampling at a low-flow rate at depths greater than 100-feet so passive sampling device was used to sample wells greater than 100-feet deep to supplement low-flow sampling techniques.

12 Limitations of Passive Samplers
May have volume/analyte limitations Contaminant stratification requires consideration before deploying Well must restabilize before sample collection Limitations apply to all 5 technologies discussed in this ITRC Protocol Document (DSP-5) and training module. As in all groundwater sampling events, these samplers may require special consideration in wells having a layer of free product [re: sample integrity] Other consideration to be addressed by any sampler that are not considered limitations but deployment considerations that may affect the quality of the sample collected by the sampler: - must be submerged in the screened interval during deployment - require the aquifer be in hydraulic communication with the screened portion of the well

13 Passive Sampler Team Publications
User’s Guide for Polyethylene-Based Passive Diffusion Bag Samplers to Obtain VOC Concentrations in Wells (March 2001, DSP-1) Jointly developed with USGS Basic principles for deployment Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor VOCs in Groundwater (February 2004, DSP-3) Easy to use for groundwater and surface water Quantify savings (40-70%) Technology Overview of Passive Sampler Technologies (March 2006, DSP-4) Main application was groundwater sampling Summarized 12 passive sampling technologies ITRC Protocols for Use of Five Passive Samplers to Sample for a Variety of Contaminants in Groundwater (February 2007, DSP-5 ) Details on “mature” passive sampling technologies from Overview Document (DSP-4) The Team initially had coordinated an effort with USGS to assess the applicability of one type of passive sampler - the Polyethylene Diffusion Bag (PDB). Basically, DSP-1 was the first document the Team had worked on together. The Team used the research and the USGS organization to collect and analyze information regarding the use and value of the PDB to assist in groundwater sampling projects for limited volatile organic compounds (VOCs). Basically, replace purge sampling techniques for VOCs only. The issuance of this USGS research led to the Teams first Tech Reg document and Internet Training. In addition, led to the development of the Diffusion Sampler website as a forum to discuss the PDB. The Guidance on Polyethylene Diffusion Bags (DSP-3) provides basic principles of passive sampling and general considerations that should be made when performing any groundwater sampling event. An archive of the associated ITRC Internet-based training, titled “Passive Diffusion Bag Samplers for Volatile Organic Compounds in Groundwater” is available at The Overview Document (DSP-4) was generated to provide a summary of developing and mature passive sampler technologies that were being used to sample groundwater. This document provides general information on technologies such as development status, cost, applicability, case studies, vender information, etc. Cost information is available in Table Technology availability and cost. These documents provide background and studies which are a good reference if you are not familiar with passive sampling. ITRC’s Passive Sampler Team documents can be downloaded for free at the ITRC website ( under “Guidance Documents” and “Diffusion Samplers.”

14 Classes of Passive Samplers
Diffusion Samplers: analytes reach and maintain equilibrium via diffusion through membrane Regenerated-Cellulose Dialysis Membrane (Dialysis) Sampler Rigid Porous Polyethylene (RPP) Sampler Equilibrated Grab Samplers: collect a whole-water sample instantaneously Snap Sampler™ HydraSleeve™ Sampler Accumulation Sampler: rely on diffusion and sorption to accumulate analytes in sampler GORE™ Module Identified more mature technologies from Overview Document (DSP-4) “Maturity” defined as validation of sampler by lab and field testing Team found that consultants and regulators had questions on how to use technologies so the team decided to provide guidance on using the “mature” technologies from ITRC Overview Document (DSP-4). This training module is based on the ITRC Protocol Document (DSP-5) and basic principles found in the polyethylene diffusion bag Tech/Reg. Document. (Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor Volatile Organic Compounds in Groundwater (February 2004, DSP-3), available at under “Guidance Documents” and “Diffusion Samplers”) We try to stress that passive sampling relies on basic groundwater principles that should be considered when performing any sampling event. There is no “special” criteria or studies that need to be performed when implementing general sampling.

15 Ambient Flow Through a Well
Relies on flow through in the well screen Screened zone is in active exchange with formation water Water above screen may be “stagnant” References ASTM, 2002 Powell R.M., and R.W. Puls, 1993 Robin, M.J.L. and R.W. Gillham, 1987 Typical ambient flow in a formation is horizontal. You may not see only horizontal flow within the well. There can be both horizontal and vertical flow components within a screened or open interval. Formation water migrating through the well screen or open interval, reaching equilibrium within the well, may flow vertically, either upward or downward, through the well screen to zones of lower hydraulic head (more specifically, toward zones of a lower pressure head component of total hydraulic head). Contrast ambient with induced flow. Groundwater sampling is performed to collect a sample of formation quality water from the screened or open portion of a well. Induced flow involves the active transport of water, while ambient flow allows water to naturally flow through the formation across a screened interval; therefore, a passive device would represent the water that comes in contact with the device under ambient equilibrium conditions. General formula used for water in the well to be representative of the aquifer: the rate of solute contribution from the aquifer to the well must equal the rate of in-well contaminant loss, including outflow and volatilization. Powell, R.M., and R.W. Puls Passive Sampling of Groundwater Monitoring Wells Without Purging: Multilevel Well Chemistry and Tracer Disappearance. Journal of Contaminant Hydrology 12: American Society of Testing Materials (ASTM) Standard Practice for Low-Flow Purging and Sampling for Wells and Devices Used for Ground-Water Quality Investigations. ASTM Subcommittee D18.21: Designation D Robin, M.J.L. and R.W. Gillham Field Evaluation of Well Purging Procedures. Ground Water Monitoring Review 7, no. 4:

16 General Deployment Device suitable for analytes of interest
Sample volume i.e., QA/QC and duplicates Appendix A: Minimum Volumes Deployment period Device and site specific Well restabilization Sampler equilibration Deployment depth Should not be arbitrary Depends on well or site specific data quality objectives (DQOs) Sampler represents a depth interval These are general considerations before the selection or deployment of a passive sampling technology. Retrieval considerations should point out a prompt transfer of sample to sampler container once extracted from the well. Deployment period = the period of time that accounts for both restabilization of the well and the equilibration of the well water and sampler materials Restabilization = the period of time well water requires to reach its ambient state following physical agitation Equilibration = the period of time required for well water and or sampler material to reach chemical equilibrium with the formation water Team’s general consensus is that the deployment period is a minimum of 2 weeks which is a conservative estimate to cover most restabilization and equilibration time considering most groundwater conditions; however, specific samplers and specific conditions might accommodate less deployment times. e.g. Longer deployment times should be considered for low-yield wells to account for a longer restabilization period once a sampler is introduced into the well. Passive samplers may be a practical approach since they... do not pump, drawing in contamination from other zones or dry out well displace water but can collect sample within interval Team has prepared a “Limited Volumes for Analysis” table with minimum volume requirements, if volume is a concern. Available in Appendix A of “ITRC Protocols for Use of Five Passive Samplers to Sample for a Variety of Contaminants in Groundwater” (DSP-5, 2007). ITRC’s Passive Sampler team documents are available at the ITRC website ( under “Guidance Documents” and “Diffusion Samplers.”

17 Contaminant Stratification
Stratification is well-specific Majority of wells are not stratified Contaminant stratification in an aquifer vs. in the well You can have: Stratified or unstratified contaminant distributions in aquifers Contaminant concentrations in the well may not reflect the same stratification in the aquifer due to vertical flow. Unstratified aquifers will yield unstratified wells. This drawing shows stratified contaminants flowing to a well. For stratified contaminant distributions in aquifers, some wells show contaminants that tend to maintain their position in the well (e.g. BTEX toward the water table—point to upper contaminant zone or dense contaminant could sink to bottom—point to lower contaminant); Stratified contaminants can also disperse and diffuse while in the open well bore, which tends to flow-weight and average the contaminant concentrations (a flow-weighted average of the influx of clean and contaminated water--point to clean and contaminated water entering the well) Stratified contaminants can also redistribute by vertical pressure differentials (in this picture, an upward gradient might be reflected by a clean zone below the level of the contaminant plume)

18 Contaminant Stratification (continued)
No stratification Total BTEX Concentration (mg/L) 160 400 800 1200 140 150 170 Water Table 180 PDB Samples Purge Sample Stratification in a well Depth (feet) 15 20 Low-flow sample 25 PDB samples 30 Depth (feet below top of casing) 35 PDB = Polyethylene Diffusion Bag Diagram A: Lack of stratification in the well may be due to the presence of vertical flow or reflect uniform contaminant distribution in the aquifer. Diagram B: Stratification was identified in the well screen. Longer screened or open intervals increase the likelihood of stratification. Pumped samples would not be able to identify stratification since it collects a flow-weighted average concentration from zones above and below the intake point. 40 45 50 20 40 60 Toluene (µg/L)

19 Contaminant Distribution
Multiple samplers deployed through screened or open interval Can represent contaminant concentrations over water column Vertical flow profiling, depending data quality objectives (DQOs), determines primary input/exit of groundwater flow Borehole flowmeter Interval packer/pump tests Profiling techniques can aid in Refining site conceptual model Remedial process optimization (RPO) Profiling techniques Target a specific depth interval Can monitor interval with highest concentration Conservative approach for long-term monitoring Groundwater sampling is performed to collect a sample of formation quality water from the screened or open portion of a well. To lower the cost of multiple vertical profile samples, samples can be analyzed with field analytical screening tools or by a certified laboratory for appropriate indicator parameters.

20 Data Quality Objectives (DQOs)
Prior to implementation, all parties should agree on DQOs For instance Vertical contaminant distribution may be a DQO so multiple samplers deployed in a well may be advised (vertical profiling) Long-term monitoring projects, a single sampler may be appropriate for the DQO Is your sampling method meeting the DQOs? Do all parties agree? Site-specific DQOs guide the design of sampling programs including the selection of sampling devices. Because of these potential differences, it is essential that all parties involved in the implementation of passive samplers at regulated sites identify and agree on DQOs, data evaluation techniques, and data end use beforehand. If acceptance criteria are met, then a passive sampler may be approved for use in that well. Low-temporal concentration variability: historical sampling results comparison High-temporal concentration variability: side-by-side comparison may be more useful

21 Data Quality Objectives (DQOs) (continued)
Pumping moves water toward intake from the induced flow field in proportion to hydraulic conductivity DQOs define Sampling goal Target analytes Hydrologic concerns Pumping methods Draw groundwater into the well screen from an undefined area Example: 3-volume purge and low flow Passive methods Sample depth-specific intervals in well Groundwater moves through the well screen under ambient flow conditions Every groundwater sampling technique characterizes contamination differently! A representative DQO process, as it is used by the Department of Energy (DOE), can be found at OLD SPEAKING POINT: When replacing one type of sampling method with another the Team finds that a comparison study may be required for approval of the new method. The Team has found that side by side tests or historical sampling results are the most common ways of comparing techniques. The Team has found that 80 to 90 percent of these comparison studies show similar (I.e. compare well) or the same results. ADDED: One comparison study conducted at the former McClellan Air Force Base will be referred to as the McClellan Study in upcoming slides of some of the passive sampling technologies. To date, this is the only large-scale federally funded study comparing passive samplers, volume purge sampling, and low-flow purge and sampling. If interested in this report, we encourage you to also look at the sampling protocols to understand the reported results. Pump Intake

22 Regulatory Perspective
Does your state have any Statutes, Regulations, or Guidance that prohibit or impede the use of passive sampling technologies for the collection of groundwater samples? (16 state responses: Appendix B) No regulatory or statutory prohibitions to using passives samplers “De facto” acceptance of passive samplers in 50 states and worldwide New Jersey Department of Environmental Protection guidance on polyethylene diffusion bags (PDBs) (2005) Regulatory agencies use ITRC Polyethylene Diffusion Bag (PDB) guidance for state guidance Passive samplers have been used 16 States responded (April 14, 2006) The principles of polyethylene diffusion bags (PDBs) are applicable to all passive samples. While a lack of specific regulatory barriers or prohibitions, and the acknowledgment the de facto use and acceptance of PDBs (and other passive devices) by some regulatory agencies, leaves open the opportunity to use passive samplers, most regulatory agencies remaining silent on the question, and having no official policy or guidance, can itself be a hindrance to their use. This regulatory vacuum needs to be corrected to streamline review and approval of passive sampling proposals and encourage the appropriate use of the best sampling technique to meet data quality objectives by the most efficient means available. Reluctance to use passive samplers may be due in large part to this lack of specific regulatory policy; not everyone wants to be a “pioneer.”

23 In Summary Passive samples collect analytes that come in contact with the sampler under ambient flow Value of passive samplers Inexpensive Broad analyte capabilities Reduced sampler error Assist in site characterization identifying Stratification Target zones for remediation Migration pathways 1:1 correlation may not occur Discrete concentration vs. flow weighted concentration May reflect nature of sampling method i.e., dilution during purging, pumping versus passive Tests have shown that contaminant concentrations from the passive samplers adequately represent local ambient conditions within the screened interval despite whether the contaminant concentrations are higher or lower than the conventional method. This result may be because the pumped samples incorporated water containing higher or lower concentrations either from other water-bearing zones not directly adjacent to the well screen (Vroblesky and Petkewich; 2000), or from mixing of chemically stratified zones (Vroblesky and Peters, 2000) Side-by-side with current sampling method - Deploy pump and passive at same time, retrieving passive sampler first, or - Deploy passive independently, recover immediately prior to placing pump in well These methods are how the team recommends a side-by-side comparison study; however, these methods minimized temporal variability but we can never eliminate spatial variability. Only about 20% of the comparisons are not 1:1

24 Questions and Answers Covered so far
Introduction to passive (no-purge) sampling Advantages/limitations General considerations when using passive samplers Regulatory perspectives Now Questions and answers Next – technical aspects for five passive samplers Diffusion Samplers: analytes reach and maintain equilibrium via diffusion through membrane Regenerated-Cellulose Dialysis Membrane (Dialysis) Sampler Rigid Porous Polyethylene (RPP) Sampler Equilibrated Grab Samplers: collect a whole-water sample instantaneously Snap Sampler™ HydraSleeve™ Sampler Accumulation Sampler: rely on diffusion and sorption to accumulate analytes in sampler GORE™ Module Questions addressed in this class: What is passive (no-pump) sampling, what passive samples represent, and how do passive sample data compare (or not compare) to pumped sample data? How should we interpret passive sampler data? Passive samplers have very broad applicability and could be used at every site in the US that collects groundwater samplers. Expanding our sampling toolbox offers the opportunity to select the most cost effective method. They are not recommended for demonstrating compliance to drinking water standards.

25 Diffusion Samplers Diffusion Samplers: analytes reach and maintain equilibrium via diffusion through membrane Regenerated-Cellulose Dialysis Membrane (Dialysis) Sampler Rigid Porous Polyethylene (RPP) Sampler Equilibrated Grab Samplers: collect a whole-water sample instantaneously Snap Sampler™ HydraSleeve™ Sampler Accumulation Sampler: rely on diffusion and sorption to accumulate analytes in sampler GORE™ Module Diffusion samplers typically are filled initially with deionized (or distilled) water. Analytes from the well water diffuse over time through the sampler membrane and into the sampler, so that concentrations inside the samplers approach equilibrium with those present in the well water. Equilibrium diffusion samplers using a polyethylene membrane, the polyethylene diffusion bag (PDB) sampler, have been previously tested and rapidly increased in use over the last 6 years or so. But, because diffusion samplers using a polyethylene membrane are limited to sampling only VOCs, other diffusion samplers have been developed that can sample for all VOCs, inorganic constituents (cations, anions, trace metals, nutrients), and some semi-volatile organics (explosives and dissolved organic carbon). The two types of diffusion-based samplers discussed in this training are the cellulose membrane diffusion sampler, and the rigid porous polyethylene sampler. Both can sample a wide variety of analyte types. Because diffusion samplers are depth-specific, they can reflect only the analyte concentrations in the well water to which they are exposed under ambient ground water flow conditions. One of the most important considerations in interpreting data from passive sampling is having an in-depth understanding of how a specific well, and the sampling methodology used to sample that well, represent conditions in the aquifer.

26 Diffusion Sampler Basics
The diffusion process is described by Fick’s Law. This simplified general form of Fick’s Law shows that, given the proper amount of time, dissolved chemical concentrations on either side of a semi-permeable membrane will come to equilibrium. As portrayed on the left, the diffusion sampler is initially filled with de-ionized water (low concentration). Analytes outside the sampler in the well water diffuse into the sampler until the concentrations on either side of the membrane are equal. The concentration gradient across the membrane drives the diffusion; the rate of diffusion diminishes as the sampler approaches equilibrium. The rate of diffusion also is strongly affected by temperature; the warmer the water the more quickly equilibrium will be approached. The diffusion coefficient, D, contains the term for temperature, and also is analyte dependent. In this general form, the distance term, L, reflects membrane thickness and other membrane properties affecting the time required for equilibration. It is important to note that this process is reversible. If analyte concentrations in the well water decrease, analytes will diffuse back out of the sampler over time toward a new equilibrium; the sampler will follow, with some time lag, changes in analyte concentrations in the well water. However, this reversibility can be of particular concern when the samplers are retrieved and volatile constituents (VOCs) are analytes of interest. VOCs begin to diffuse out of the sampler as soon as the sampler is exposed to air, or any medium having lower concentration of VOC analytes. Exposure to heat and wind will accelerate VOC loss. The sample must be transferred from the diffusion sampler and sealed in the laboratory container (VOA vial) promptly upon retrieval. Depending on specific conditions, measurable VOC loss can occur within a few minutes. Different membrane materials are used for their different diffusion properties, but the principles remains the same.

27 Diffusion Sampler Advantages
Groundwater sampling time in the field is decreased – no pumping needed Eliminates purge water and disposal costs Excludes turbidity from groundwater samples – no filtering needed Disposable – no cleaning or cross-contamination Regenerated Cellulose Dialysis Membrane (Dialysis) Rigid Porous Polyethylene (RPP) Several of the general advantages of diffusion samplers were mentioned in the introductory slides but bear repeating. - The sampling time needed in the field to recover a diffusion sampler and deploy another for the next sampling event is much shorter than the time it takes to pump and stabilize a well prior to low-flow sample collection. (3x-6x shorter). This significant saving of time for field personnel substantially lowers field sampling costs. - The amount of water removed from the well is minimized. Most, if not all of the water recovered by a diffusion sampler is transferred into the sample containers for shipment to the laboratory. - Diffusion sampler membranes have small pore sizes that eliminate or greatly reduce turbidity. The samplers are themselves essentially big filters, so no field filtering is necessary. - Diffusion samplers are disposable so no cleaning steps are needed and there are no cross-contamination issues between wells.

28 Regenerated-Cellulose Dialysis Membrane Sampler Basics
Fully assembled Dialysis sampler ready for deployment Referred to as the “Dialysis Sampler” Regenerated-cellulose dialysis membrane Filled with deionized water Hydrophilic membrane Currently must be constructed Membrane sizes 2.5-inch diameter for 4-inch wells 1.25-inch diameter for 2-inch wells Sample volumes 2.5-inch x 2 ft long contains 2 liters 1.25-inch x 2 ft long contains 500 mls Pore size is 18 Angstroms Developed by U.S. Geological Survey (USGS) The regenerated-cellulose dialysis membrane diffusion sampler is commonly referred to as simply the “dialysis sampler.” It was first developed about 6 years ago by researchers at the US Geological Survey. It uses a tubular membrane made of regenerated cellulose dialysis material, filled with deionized water, and suspended in the water column in the open interval of a well. After a sufficient equilibration period, the sampler is removed and the water transferred to appropriate containers for transport to the laboratory. Because the dialysis membrane is hydrophilic, water molecules, ions, and dissolved compounds pass through the membrane. [As opposed to the polyethylene membranes which are hydrophobic so water and ions can not pass through them.] The cellulose membrane material has an average pore size of about 18 Angstroms ( microns), and thus is a very effective particulate filter excluding even colloidal size clay particles. Thus, turbidity is minimal and the sample will contain only truly dissolved concentrations, and not analytes adsorbed onto suspended material. Currently, dialysis samplers are not commercially available so they must be constructed by the user prior to deployment. The cellulose membrane material comes as roles of lay-flat in tubing, available in different sizes – 1.25-inch diameter which fits inside a 2-inch diameter well, and 2.5-inch diameter which fits inside a 4-inch diameter. A 1.25-inch diameter by 2 ft long sampler contains ~500 ml of sample, and a 2-foot long 2.5-inch diameter sampler contains ~2 liters. The material has a sulfide-based preservative which must be washed off. Once wet, the samplers should be kept wet (submerged) until deployment to avoid drying and cracking of the membrane. Construction of a sampler typically takes about 20 minutes, but can differ based on specific configuration (fittings, accessories, etc.). Samplers can be slipped into nylon mesh sleeves (as pictured) to protect the membrane from abrasion or tearing during placement into and retrieval from the well. The mesh also allows convenient and secure attachment to the deployment line using plastic “zip” ties.

29 Dialysis Equilibration Times
Determined in laboratory in bench-scale tests 95% or greater equilibrium reached in dialysis samplers within 1-7 days for most cations and trace metals 1-3 days for all VOCs on 8260B list (including MTBE) 1-3 days for anions, silica, DOC, CH4, sulfide 7-14 days for explosives compounds 28 days or more for Hg, Ag, Sn As with all diffusion samplers, once deployed in a well, dialysis samplers must remain completely submerged for the entire deployment period, and be allowed to equilibrate for the appropriate amount of time for the chemicals of interest. The equilibration times shown here for general categories of analytes were determined by USGS and US Army researchers in periodically stirred batch tests in the lab. A more detailed list of analytes tested in the laboratory is given in Table 5-2 of the ITRC Protocol Document (DSP-5). Most of the common analytes that have been tested come to equilibrium in the dialysis samplers within 1 to 14 days. Only mercury, silver, and tin were found to take longer than 14 days. Under field conditions where groundwater is flowing through the open interval of the well, chemical equilibration may occur at somewhat different rates due to temperature differences and other considerations, but a 14-day rule-of-thumb for deployment should be enough for most situations.

30 Dialysis Sampler Advantages
Collects inorganic and organic chemical constituents Quick equilibration and deployment times – generally 1-2 weeks Relatively inexpensive to construct Excludes turbidity from groundwater samples – no filtering needed Sample volume can be up to 2 L An important characteristic of dialysis samplers is that, unlike PDBs, they can collect both organic and inorganic constituents. Dialysis samplers are slightly more expensive to construct than PDBs but are still inexpensive compared to renting or buying pumps and related equipment. Because of their small pore size, dialysis samplers exclude particulates from the collected groundwater sample so no field filtering is needed. The volume collected can easily be adjusted by varying the length and/or diameter of the sampler when it is constructed. A typical practical limitation might be about 2 liters. Keep in mind that longer samplers will integrate concentrations over a longer depth interval in the well, and require a longer water column in the screened interval so that the entire sampler remains completely submerged during the entire deployment period.

31 Dialysis Sampler Limitations
Must construct sampler from raw materials Samplers must be kept wet between construction and deployment Membrane can biodegrade within 4-6 weeks Not a problem for shorter deployments Can maintain integrity for longer periods in very cold water Samplers lose water volume slowly (<3% per week) Not a problem for short deployments Internal support for high ionic strength waters is available Field-ready dialysis samplers are not commercially available and must be constructed. As previously mentioned, the cellulose material should be thoroughly rinsed in DI water to remove preservative, and must be kept hydrated between the time they are constructed and the time they are deployed in a well to prevent drying and cracking. Regenerated cellulose is a biodegradable material, that is, it is food for some bacteria. The rate of biodegradation is well-specific, depending on the level of biological activity, which is in turn largely dependent on temperature. These membranes have been shown to biodegrade in wells in temperate climates within 4 to 6 weeks, however some recent results have shown that their integrity is maintained for six months and longer in very cold water. Nonetheless, most analytes tested thus far equilibrate quickly enough through the dialysis membrane so this limitation should not adversely affect their usefulness for sampling in most wells. Because diffusion is a two-way process and the cellulose membrane is permeable to water, not only are dissolved analytes in the well water diffusing into the sampler, but water molecules are also diffusing outward in an attempt to dilute the well water. Fortunately, the gradient for ions diffusing inward is higher that the gradient for water molecules diffusing outward. In general, tests have shown that less than 3% per week of the samplers original volume is lost through this process. This loss may be a more significant problem in high ionic strength waters. An internal support can be inserted inside the dialysis membrane to ensure that a minimum volume of water will still be retained inside the sampler.

32 Dialysis Field Comparison Results
1000 1000 Ethylbenzene (µg/L) Chloride (mg/L) 10 10 LRL LRL 0.1 1/2 MDL 1/2 MDL Low-Flow Purging 0.1 0.1 10 1000 0.1 10 1000 1000 1000 These graphs show examples of field comparison results from a study by Imbrigiotta et al. (ESTCP final report, 2007) for one aromatic VOC (ethylbenzene), one chlorinated VOC (vinyl chloride), one anion (chloride), and one cation (manganese). Each graph shows the concentrations recovered by the dialysis sampler on the x-axis vs. the concentrations recovered by low-flow purging on the y-axis. Each red diamond represents one comparison from one well. If both sampling techniques recover equal concentrations, all red diamonds should be on the 1:1 correspondence line. The white area of each graph is where concentrations are above the laboratory reporting limit (LRL) for the parameter being shown. The yellow area of the graph is where concentrations are between the reporting limit and one-half the minimum detection limit (1/2 MDL). The pink area of the graph is where concentrations are less than one-half the detection limit. As you can see for all of the parameters plotted, all graphs show reasonably close agreement between the concentrations recovered by dialysis samplers and low-flow purging. Deviations, such as those seen at low concentrations for ethylbenzene, are most likely due to water of different chemistry being drawn into the well during purging than was in the open interval during the dialysis sampler equilibration period. In fact, PDB and dialysis sampler VOC results agreed very well in these same wells. Vinyl Chloride (µg/L) 10 Manganese (µg/L) LRL 10 LRL 0.1 From: Imbrigiotta et al. (2007) 1/2 MDL 1/2 MDL 0.001 0.1 0.001 0.1 10 1000 0.1 10 1000 Dialysis Sampler

33 See Table 5-3 in ITRC Protocols Document (DSP-5)
Dialysis Field Comparison Results (Dialysis Samplers vs Purging Methods) Parameters with favorable results VOCs Cations and anions Most trace metals Explosive compounds Others (silica, ethene, CO2, CH4, TDS, SC, DOC) Parameters with questionable results p-Isopropyltoluene n-Butylbenzene s-Butylbenzene Nickel Sulfide Field comparisons between dialysis samplers and low-flow purging have found equal recoveries of: Most chlorinated VOCs (PCE, TCE, cisDCE, DCE, transDCE, VC, 111-TCA, 11-DCA, CM, Chloroform, MC, DCDFM, 12DBE) Most aromatic VOCs (BTEX, Styrene, 124-TMB, 135-TMB, iso-propylbenzene, t-butylbenzene, n-propylbenzene, naphthalene) Ethers (MTBE, 1,4-Dioxane) Cations and anions (Ca, Mg, Na, K, alkalinity, Cl, SO4, NO3, Br, F) Most trace metals (Fe, Mn, Al, As, Ba, Cd, Cr, Cu, Mo, Pb, Sb, Se, V, Zn) Explosive compounds (e.g. RDX, HMX) Dissolved gases, ethene, CO2, CH4, and TDS, silica, DOC The only parameters with questionable field comparison to low-flow results include a few aromatic VOCs (for which dialysis sampler results did compare favorably to PDBs in side by side tests), nickel, which was present only below reporting limit concentration, and sulfide which was recovered in equal or higher concentrations in the dialysis sampler than in the low-flow purged samples. More investigation is needed into these last few parameters to determine if these differences are found at other sites. A more detailed list of results for various analytes is given in Table 5-3 of the ITRC Protocol document (DSP-5) available the ITRC website ( under “Guidance Documents” and “Diffusion Samplers.” See Table 5-3 in ITRC Protocols Document (DSP-5)

34 Dialysis Sampler Summary
Collects both organic and inorganic chemical constituents Do not require filtration of samples Equilibrate within 1-2 weeks for most constituents Deployment times 1-2 weeks in most wells Dialysis samplers recover comparable concentrations of VOCs vs. PDB samplers VOCs and most inorganics vs. low-flow and purging and sampling Dialysis samplers should not be used when Sampling for mercury, silver, or tin Equilibration will take longer than 4 weeks Total concentrations are needed Dialysis samplers should be used with caution when Sampling for nickel and sulfide Dialysis samplers can collect both organic and inorganic chemical constituents in groundwater. Dialysis samplers do not require field filtration of samples. They collect only the truly dissolved concentrations. Bench-scale testing showed that dialysis samplers chemically equilibrate within 1-2 weeks for most inorganic constituents and VOCs. Deployment times in most wells are generally 1-2 weeks. Field comparisons showed dialysis samplers recover VOCs equal to PDB samplers. Field comparisons have also shown dialysis samplers recover VOCs and most inorganics equal to low-flow purging. Only chemical constituents tested that did not seem to diffuse well through the dialysis membrane were mercury, silver, and tin - possibly due to the formation of metal-organic complexes that either sorb to the membrane or are so large that they don’t diffuse readily through the pore spaces. The potential for biodegradation should be included if dialysis samplers are to be considered for deployment periods or equilibration times that might extend longer than four (4) weeks, although they have been deployed for up to six months in very cold water (ice) without measurable degradation. Dialysis samplers should not be used if total concentrations are required (concentrations that must include analytes adsorbed on to colloidal particles that remain suspended by Brownian motion and are naturally mobile under ambient flow in the aquifer). Sampling for nickel and sulfide needs to be further tested.

35 Rigid Porous Polyethylene (RPP) Samplers
Cap Made of rigid, porous polyethylene Pore sizes 6-15 microns 5 inches long 1.5 inches in diameter Filled with deionized water Standard size holds mL Rigid Porous Polyethylene (RPP) samplers were developed by Don Vroblesky of the USGS, and are commercially available. The RPP sampler is constructed from a rigid cylinder of foam-like porous polyethylene having a wall thickness of about 2 mm. The pore size in the material ranges from about 6 to 15 microns. The outside diameter is approximately 1.5 inch and the individual samplers are limited to about 5 inches in length. If made longer, the higher head pressure in the sampler forces the water inside to “leak” out through the pores when not submerged. The RPP sampler is filled with de-ionized, analyte-free water, capped at one end and a Delrin plug inserted into the other end. The one pictured on the left is equipped with a second smaller plug. Use of the smaller plug will minimize potential loss of VOCs by any vacuum that may be created by the plug’s removal when transferring sampler contents into the laboratory containers. The picture on the right shows an RPP ready for shipment. The RPP is shipped in a mesh liner for protection during deployment and retrieval, and for convenient attachment to the deployment line using cable ties (“zip” ties). RPPs are shipped in a water filled polyethylene bag to ensure that the pores stay water filled. If the pore spaces become blocked by air bubbles, the aqueous diffusion pathway is interrupted and diffusion of analytes into the sampler may be greatly reduced or not occur at all. Water soluble analytes pass through the pores until equilibrium is reached between the water in the sampler and the water to which the sampler is exposed. In bench studies, equilibrium time ranged from hours to days, depending on diffusion properties of the specific analyte. The more water soluble the analyte, the quicker the equilibrium. The general rule of thumb for all diffusion samplers, that they should be deployed not less than 14 days, ensures that most analytes will have equilibrated in an RPP sampler. These samplers can remain deployed in wells for a quarter, but can be expected to maintain integrity for much longer, though there is little information regarding longer deployments. Biofouling has been considered as a potential problem, but has not been reported for any of the long-term (quarterly or longer) for any passive sampling device. Delrin plug In protective mesh ready for deployment and packaged in disposable water-filled sleeve for shipping

36 Select RPP Analytes and Equilibration Times
Equilibration time (days) Dissolved gases 14 Perchlorate, chloride, hexavalent chromium, nitrate, sulfate, soluble iron Methane, ethane, ethene (MEE) Water soluble VOAs (i.e. MTBE, MEK, Acetone, 1,4-Dioxane) Water soluble SVOCs (i.e. NDMA, phenols) Dissolved metals (priority pollutant list) 21 (all except silver and copper) Explosives (i.e. HMX, TNB, RDX and TNT) 21 Please see the tables in Chapter 6 of the Protocol Document (DSP-5) for more detailed equilibration data. New analytes are being added as field studies continue. Additional field studies on low-solubility (hydrophobic) VOCs and SVOCs are needed. In laboratory batch studies in sealed carboys, concentrations of the hydrophobic VOCs and SVOCs were depleted in the test solution, but were not found in the water in the samplers (see Tables 6.5 and 6.7 in the Protocol Document (DSP-5). These results are consistent with a conclusion the hydrophobic analytes were adsorbed onto the sampler itself. It’s thought that with longer equilibration times, and an effectively unlimited volume of contaminated water moving through the wells screen, that the sampler and water within it would eventually reach equilibrium, but field studies are needed to confirm this.

37 RPP Advantages Can be used to collect most inorganic and limited organic analytes Are commercially available and field-ready Can be stacked when additional volume needed Excludes particles larger than the pore space of the sampler RPP Samplers have the same general advantages as other passive samplers: eliminate purge water collection are easily deployed and retrieved reduce field sampling costs significantly may not be a substitute for field filtering using a standard 0.45 micron filter.

38 RPP Limitations Must be stored and shipped fully immersed in deionized water Have not been tested for all analytes Multiple samplers are needed to obtain sufficient volume for multiple Analyte types and/or QA/QC Requires advanced analytical techniques to analyze for SVOCs Equilibrium times for less water soluble VOCs and SVOCs are not currently known To prevent air from entering and blocking the pore spaces of the polyethylene material, field-ready RPPs are shipped sealed in water-filled pouches. Wells must be 2 inches or more in diameter to accommodate the diameter of the RPPs. RPPs provide only mL of sample; if additional sample volume is needed, multiple RPPs must be stacked. As with several of the passive samplers discussed today, it is very important that you discuss the small sample volume with your laboratory to ensure they are prepared to meet your measurement quality objectives (method detection limits (MDL), reporting limits (RL), etc. ) with the limited volume. Ensure that they have equipment that will allow them to use less volume that typically requested. For instance, the standard minimum volume required for SVOCs by EPA Method 8270 is 1000 mL. Theoretically, using solid phase extractors and large volume injectors you would need no more than 10 mL of sample, though most labs would still request mL of sample if available. The evolving trend toward more flexible performance-based approaches to environmental measurement that continue to meet project DQOs, is moving away from prescriptive requirements of the past. A table giving minimum volumes required to meet standard DQOs for many common analytical methods is provided as Appendix A of the Protocol Document (DSP-5). The volumes are those required for a single analysis, without MS/MSD, re-runs, etc.). It’s not yet known how long it would take for VOCs and SVOCs to equilibrate. However, RPPs are frequently co-deployed with a polyethylene diffusion bag (PDB) - the RPPs for water-soluble analytes and the PDB for hydrophobic VOCs. For example, the combination of passive devices can monitor 1,4-dioxane and 1,1,1-TCA concurrently.

39 McClellan AFB Multi-analyte, Multi-sampler Study (Parsons 2005)
Metals: 1,4-Dioxane: Anions: Hex Cr: VOCs: RPPs Sample Concentration (µg/L) For All Data y = 0.941x R2 = This study at the former McClellan AFB, California, compared 4 diffusion-based sampling devices and 2 equilibrated grab samplers against low-flow and conventional 3-volume well purging sampling. This graph depicts results from RPP samplers compared to low-flow pumped sample results. The authors concluded that RPPs “appear to be a technically viable method for monitoring hexavalent chromium, metals and anions. Although concentrations of VOCs and 1,4-dioxane obtained using this method are statistically similar to low-flow concentrations of these analytes, they tended to be biased low relative to concentrations obtained using the three-volume purge method.” 1 It is important to remember that the different purging methods and passive sampling may sample the well somewhat differently, depending on well-specific hydrologic characteristics. As mentioned before, laboratory studies have shown that RPPs should not be used for VOCs unless further equilibration studies are completed. Subsequent field studies have shown that they work well for 1,4-dioxane. The next two slides illustrate side-by-side tests for dioxane. 1. Parsons Results Report for the Demonstration of No-Purge Groundwater Sampling Devices at Former McClellan Air Force Base, California. Prepared for the U.S. Army Corps of Engineers Omaha District, the Air Force Center for Environmental Excellence and the Air Force Real Property Agency. 7-2. Low-Flow Purge Sample Concentration (µg/L)

40 RPP Representative Field Study for 1,4-Dioxane at a North Carolina Site
y = 0.852x n = 9 RPP (mg/L) This correlation plot depicts the low-concentration results from paired samples collected from multiple wells by RPP and low-flow methods. The interest in RPPs for this particular project was because a number of the wells at this site are very deep (some more than 200 feet). The depth of the well screens was below the low-flow pumps operating capability. The RPPs were tested against low-flow pumps in 10 wells at the site from 23 to 110 feet deep to see how they compared to decide whether they were a viable option for the deep wells. The concentrations of 1,4-Dioxane were low in these wells (0.010 to 0.22 mg/L) with the exception of one well, V-23, where the concentration was approximately 3 mg/L. The next page depicts the results from all wells, including V-23. Low Flow (mg/L) Each point on the plot represents a single-constituent data pair of each sampling method.

41 RPP Representative Field Study for 1,4-Dioxane at a North Carolina Site
RPP (mg/L) R2 = 0.999 y=1.073x n=10 Including the data from V-23 well gives an R2 of and y=1.073x, but the scale of this plot makes the lower concentrations data points difficult to distinguish. RPPs are now deployed at this site on an on-going basis. This study is described in the Protocol document (DSP-5) Section and Table 6.10. Low Flow (mg/L) Each point on the plot represents a single-constituent data pair of each sampling method.

42 RPP Summary Can be used to sample for
Most inorganics Water soluble VOCs and SVOCs It’s not currently known if they can be used for water-insoluble VOCs and SVOCs Can be used in deep wells Can be used in conjunction with PDBs Disposable sampler No decontamination required RPP Samplers may be used to sample for most inorganics, but further studies are needed to determine suitability for some organics, especially less water soluble VOCs and SVOCs. Depth limitations have not been encountered for any of the passive sampling devices.

43 Diffusion Sampler Summary
Regenerated Cellulose Dialysis Membrane Rigid Porous Polyethylene (RPP) RPP and Dialysis Membrane samplers can be used for VOCs, SVOCs, metals, anions, and cations Minimum deployment time for RPP and Dialysis sampler is ~2 weeks Compare well with conventional methods Collect samples at a discrete interval in well screen RPP sampler can be used for quarterly or longer deployments Major limitation of RPP sampler is sample volume Major limitation of Dialysis sampler is that it undergoes biodegradation *RPP and Dialysis Membrane Samplers are diffusion samplers that provide the important advantages of passive sampling, and can be used for a much broader range of analytes than the Polyethylene Diffusion Bag (PDB) sampler.

44 Equilibrated Grab Samplers
Diffusion Samplers: analytes reach and maintain equilibrium via diffusion through membrane Regenerated-Cellulose Dialysis Membrane (Dialysis) Sampler Rigid Porous Polyethylene (RPP) Sampler Equilibrated Grab Samplers: collect a whole-water sample instantaneously Snap Sampler™ HydraSleeve™ Sampler Accumulation Sampler: rely on diffusion and sorption to accumulate analytes in sampler GORE™ Module We try to stress that passive sampling relies on basic groundwater principles that should be considered when performing any sampling event. There is no “special” criteria or studies that need to be performed when implementing general sampling.

45 Equilibrated Grab Samplers
Collects sample from discrete interval in well screen Collect “whole water” samples that can be tested for any analyte Collects samples in “real time” Equilibration period allows Well to recover from sampler placement Materials to equilibrate with analytes in well water Technologies Snap Sampler™ HydraSleeve™ Sampler Snap Sampler™ Because these samplers do not rely on diffusion or sorption, they can collect a sample that is in real time. Typically, these samplers are placed in the well, and left for an equilibration period. After the equilibration period, the sample is collected. Allowing the well to recover from placing the sampler in the well you allow the flow pattern in the well to reestablish itself & you reduce the possibility of falsely elevating turbidity in your samples through agitation. By allowing the materials to equilibrate with the analytes in the well water, you eliminate possible biases due to sorption that can occur between some types of analytes and the sampler. We want to stress that losses due to sorption can occur with any type of sampler (including bailers and the tubing used in e.g. low-flow sampling) if there is not an adequate equilibration between the analytes and the materials. The two devices in this class included in the ITRC Protocol Document (DSP-5) are the HydraSleeve™ Sampler and the Snap Sampler™. Both of these devices are commercially available. HydraSleeve™ Sampler

46 Snap SamplerTM Components
125 mL Sampler body with trigger mechanism Bottles Have two openings & spring-activated caps 40-mL VOA glass vials Fits in 2-inch wells 125-mL HDPE bottles 350-mL HDPE bottles Fits in 4-inch wells Trigger line Mechanical Electronic Pneumatic Docking station 40 mL Description of the Snap Sampler™ technology can be found in section 4 of the ITRC Protocol Document (DSP-5). Snap Samplers™ are typically dedicated devices. Snap Sampler™ bottles are unique in that they have openings on two ends and caps that are connected by an internal Teflon-coated spring. To deploy the sampler: Place the bottles in the sampler. Place the end caps in an open position using the release pins on the sampler. Attach the trigger line to the sampler and then use the trigger line to lower the device into the well.

47 Snap SamplerTM – Collecting a Sample
Sample bottles deployed & remain in open position Equilibration period Minimum of 1 to 2 weeks Can be used for quarterly, semi-annual, or annual sampling Pull handle on trigger line to close bottle (i.e., collect sample) Samples sealed in situ No sample transfer required at the surface Because the sample bottle is closed in the well, there is no chance of interaction of the sample with the water column as the sample is removed from the well. Samples can be sent to the laboratory in the same bottle the sample was collected in. Or they can be transferred to other sample bottles. E.g., contents of 125-mL sample bottle could be poured into two 50-mL sample bottles, one for anions and one for metals The 40 ml VOA vials are compatible with common autosampler equipment. Acid can be added if preservative is needed without having to open the sample bottle. This procedure is discussed in more detail in the ITRC Protocol Document (DSP-5).

48 Snap SamplerTM Advantages
No analyte restrictions Reduced sampling variability Minimal agitation of well during sampling Collect samples with ambient turbidity Bottles remain sealed under in-situ conditions No sample transfer No exposure to weather, surface contamination, etc. Some studies have shown better recovery of volatiles and gases Because these samples do not agitate the water column, particles from the formation are less likely to be entrained in the samples.

49 Snap SamplerTM Limitations
Sample Volume Multiple bottles are needed to obtain volume for multiple analyte types and/or QA/QC Trigger lines are fixed length and thus cannot be readily moved to other wells Larger volume can be collected by using large sample bottles (i.e., 350-mL) or by deploying multiple samplers either on multiple trigger lines or in series on the same trigger line. The more sample bottles deployed along a trigger line, the longer the interval in well that you are sampling. Up to 6 samplers depending on type of trigger mechanism and sampling depth.

50 Snap SamplerTM – VOC Field Study
10000 1000 100 Snap Sampler VOC (ug/L) 10 1 Comparison from Boeing Santa Susanna Field Laboratory in Chatsworth, California. Zimmerman, Laura, Beth Parker, Amanda Pierce, John Cherry, Sandy Britt, Ramon Arevena, 2009, Use of Snap Sampler and CSIA in Investigations of TCE Natural Attenuation in Fractured Sandstone, Proceedings of the Groundwater Resources Association of California Conference: Groundwater Monitoring:  Design, Analysis Communication & Integration with Decision Making, Orange, California, February 25-26, 2009. Good correlation (as shown by the high correlation coefficient) “Y” values (or slope) slightly >1 Indicates Snap Sampler™ yields slightly higher concentrations than the low-flow sample. This difference may be because of the unique features of this sampler, i.e., there is no sample transfer or exposure to the atmosphere. 0.1 Low Flow VOC (ug/L) Very good correlations Slightly higher concentration values with Snap SamplerTM than low-flow

51 Snap SamplerTM – Multi-analyte Field Study
100000 10000 1000 100 10 1 0.1 0.01 Study at former McClellan Air Force Base (Parsons Inc. 2005) Anions Snap Sampler™ Concentration (µg/L) VOCs 1,4 Dioxane Snap Sampler™ also showed excellent correlations with volume-based purge methods. R2 = 0.99 for all analyte comparisons to low flow Low-Flow Purge Sample Concentration (µg/L)

52 Snap Sampler™ Summary Sample all analyte types
Volume limited for long analyte list Samples are sealed at the point of collection No transfer of sample required Data correlates well with standard sampling methods More information on the Snap Sampler™ technology can be found in section 4 of the ITRC Protocol Document (DSP-5). I have conducted several studies on the Snap Sampler. These tests included both laboratory and field studies. The laboratory studies compared concentrations of analytes taken from a standpipe with control samples taken from the standpipe. Analytes included VOCs, explosives, and a suite of inorganics including metals. Field studies sampled for VOCs, explosives, and inorganic analytes. The results from these studies can be found in two reports available at our website (below) and another that will be published by Fall 2010.

53 HydraSleeve™ Components
Sampler sleeve Reed valve This sampler is simple in design and easy to use. Information on this sampler can be found in Section 3 of the ITRC Protocol Document (DSP-5). Components Polyethylene sleeve Top loading reed style check valve Reusable stainless steal weight and clip Discharge tube HS are designed to fit 2-in wells, (1.5 inches OD) 4-in wells (2.5 inches OD) Also 1-in wells and ¾-in wells. To assemble these samplers, simply Unfold Clip weight to bottom Attach tether (line) to top Discharge tube Reusable sampler weight

54 HydraSleeve™ Sample Collection
Full Sample Interval To deploy the HydraSleeve™, lower the sampler through the water column. The sampler remains empty as the sampler is lowered through the water column and during the equilibration period. To collect a sample, Pull the HydraSleeve™ upward >1 foot per second (~the speed a bailer is recovered). Hydrostatic pressure opens reed valve allowing sleeve to move outward to collect the water In essence you are collecting a “core sample of the water column” The mechanism is much like pulling on a sock. When the sampler is full, the reed valve closes, Reed valve remains closed as the sampler is recovered from the well. This prevents interaction between the water column and the sample inside the sampler. Once the sampler is at the surface, the sample should be transferred immediately to the sample bottles. Done by puncturing sampler with discharge tube. Sampling interval within well is ~1.5 times the length of the sampler Filling Empty

55 HydraSleeve™ Advantages
Fits in most diameter wells Can sample all types of analytes Sample Volume 2-inch HS collects 650 mL to 1 L 4-inch HS collects 1250 mL to 2 L Easy to use with minimal training Can sample Very deep wells Crooked wells Can collect low turbidity samples No associated notes.

56 HydraSleeve™ Limitations
Sample Volume Custom samplers can be fabricated in a wider diameter and/or longer length to maximize sample volume for longer analyte lists Work with lab regarding minimum sample volume Using table in Appendix A of the ITRC Protocol Document, DSP-5 No associated notes.

57 HydraSleeve™ – Field Study (1 of 2)
2-inch diameter well in Northern California (Geomatrix Inc., 2000) Concentration (ppb) Good agreement between the VOC concentrations in the purged samples vs. those taken with the HydraSleeve™ Sampler. This example was the first well that HydraSleeve was ever deployed in. HydraSleeve™ Purge/Sample

58 HydraSleeve™ – Field Study (2 of 2)
Former McClellan Air Force Base (Parsons Inc., 2005) Comprehensive comparison of Low-flow and 3-well volume purged samples Samples collected using 6 no-purge samplers Analytes included VOCs, 1,4 dioxane, anions, metals, and hexavalent chromium Study Findings “The HydraSleeve and Snap SamplerTM produced results most similar to the higher concentrations obtained by low-flow and 3-well volume purging and sampling methods” “Appears to be a technically viable method for monitoring all of the compounds in the demonstration” Available on ITRC Diffusion/Passive Sampler team web site: Technical publications I also conducted several studies on an earlier version of the HydraSleeve (before the reed valve was developed). In those tests, we conducted laboratory studies with known concentrations of VOCs, explosives, pesticides, and metals and a field study that we conducted in one of our wells that was contaminated with TCE. The results from these studies can be found in a report available at our website (below) and in a journal paper published in Ground Water Monitoring and Remediation 24(3):

59 HydraSleeve™ Sampler Summary
Sample all analyte types Sample volumes up to 2 L Can be used in Deep wells Crooked wells Comparable results to conventional pumped methods Can be left in well for quarterly, semi-annual, or annual sampling Disposable sampler No decontamination required Inexpensive to ship (100 samplers will fit in an overnight envelope)

60 Equilibrated Grab Samplers Summary
Snap Sampler™ HydraSleeve™ Sampler Samples can be analyzed for all analyte types Providing there is adequate sample volume Collect whole water samples in real-time Can be used for quarterly, semi-annual, or annual sampling events Use an equilibration period to reduce sampling biases Collect samples at a discrete interval in well screen Compare well with conventional methods No associated notes.

61 Accumulation Samplers
Diffusion Samplers: analytes reach and maintain equilibrium via diffusion through membrane Regenerated-Cellulose Dialysis Membrane (Dialysis) Sampler Rigid Porous Polyethylene (RPP) Sampler Equilibrated Grab Samplers: collect a whole-water sample instantaneously Snap Sampler™ HydraSleeve™ Sampler Accumulation Sampler: rely on diffusion and sorption to accumulate analytes in sampler GORE™ Module We try to stress that passive sampling relies on basic groundwater principles that should be considered when performing any sampling event. There is no “special” criteria or studies that need to be performed when implementing general sampling.

62 Accumulation Samplers
Rely on diffusion and sorption Examples of accumulation samplers Semi-permeable Membrane Devices (SPMD) Polar Organic Chemical Integrative Sampler (POCIS) Passive In-situ Concentration Extraction Sampler (PISCES) GORE™ Module More information on other accumulation samplers is available Overview of Passive Sampler Technologies (March 2006, DSP-4) Rely on diffusion through a membrane and sorption by some type of sorbent material (either granular or liquid) housed within the sampler membrane. This Gore Module is discussed in Section 2 of the ITRC Protocol Document (DSP-5) and is commercially available.

63 GORE™ Module Components
Knot (secure to wellhead) Attachment Line Loop to attach line Tag with unique serial number Adsorbent Weight This sampler is also known as the GORE-SORBER Module (figure on the left). The module comes in its own sample vial Vial and sampler have a unique serial number for identifying sample. Size of the module is ~ the length and diameter of a soda straw. Module consists of: a tube made of GORE-TEX® membrane, which is a vapor-permeable, waterproof membrane. & 2 packets of the sorbent material. To deploy sampler (figures on right): Attach tether line and weights to bottom. After collecting sampler, blot dry with paper towel, place in vial, ship to lab Sampler can be used for sampling VOCs and SVOCs GORE™ Module Section 2 in ITRC Protocol Document (DSP-5) Attachment Line Stainless steel weights

64 GORE™ Module Sample Collection
Dissolved compounds partition to vapor (Henry’s Law) Diffusion through hydrophobic, vapor-permeable membrane Adsorption onto media Duplicate samples GORE-TEX® Membrane Vapors pass through The figure on the left shows the membrane at high magnification. The dark areas represent the pore space in the membrane. The figure on the right shows conceptually how the analytes partition to the vapor phase, diffuse through the membrane, & are sorbed by the sorbent material. While liquid water is prevented from passing through the membrane into the interior of the sampler. Liquid water remains outside Adsorbents

65 GORE™ Module Analysis No adsorbent transfer in field
Thermal desorption/GC/MS VOCs and SVOCs US EPA Method 8260/8270, modified for thermal desorption For analysis the adsorbent is transferred directly to the thermal desorption tube in the lab. There is minimal sample (adsorbent) handling and exposure to ambient air. Thermal desorption is used rather than solvent extraction be cause it allows for lower detection capability.

66 GORE™ Module Advantages
Sample small diameter wells and multi-level systems >0.25 inches Crooked wells No minimum sample volume limitation No need to refrigerate samples Minimal water disruption - ~10 mls displacement Short sampling period - 15 minutes to 4 hours Longer-term deployment – sub ppb concentrations US EPA ETV verified (Einfeld and Koglin, 2000) No associated notes.

67 GORE™ Module Limitations
Sole source supplier and laboratory analysis Organic compounds only Compound detection limited by vapor pressure Data reporting Measured mass (µg) Concentrations are calculated by GORE based on Measured mass, sampling rate, time, water temperature, and water pressure Reference Section of ITRC Protocol Document (DSP-5) W.L GORE The sampling rate refers to the uptake of compounds by the GORE™ Module, mass uptake over time. The sampling rate has been determined experimentally in the lab by Gore. This rate is then corrected for water temperature and water pressure conditions in each well.

68 Low-flow sampling data
GORE™ Module – VOC Field Study Military Base, Mid-Atlantic United States 1,1,2,2-Tetrachloroethane GORE™ Module data Low-flow sampling data The contour map on the left illustrates the total mass recovered with the GORE™ Module (not concentration data). The map on the right illustrates the results of low-flow sampling (in ug/L). This data is provided by the manufacturer. Strong spatial correlation with low-flow sampling Greater sensitivity & better plume delineation

69 GORE™ Module – VOC Field Study Dry Cleaner, Southeastern United States
PCE, TCE, cis-1,2-DCE (ug/L) 30000 20000 10000 y = x R2=0.982 N=12 Concentration - Bailer C1,2-DCE TCE PCE Linear Samples collected with a bailer following low-flow purging GORE™ Module samples were taken first Calculated concentrations are shown This data is provided by the manufacturer. In the summer 2010, I will be conducting the first of two demonstrations of this technology in groundwater monitoring wells. The first site we are testing has chlorinated VOCs and the second site will have hydrocarbon contamination. This work is sponsored by ESTCP and will be available as an ESTCP report on our website under technical publications. Concentration – GORE™ Module Compared to slow purge and disposable bailer Good correlation

70 GORE™ Module Summary Accumulation sampler Easy field deployment
Passive operation Compounds partition to vapor, then diffuse to adsorbent Easy field deployment Small diameter wells Short sampling period Able to detect very low analyte concentrations Collect samples at a discrete interval in well screen Data reported Mass measured or as concentrations (calculated) Data comparable with conventional sampling Can only be used for organic compounds The details of the sampler are described in Section 2 of the ITRC Protocol Document (DSP-5). Because sampler can detect very low concentrations of analytes, it can provide in some cases more accurate delineation of the groundwater plumes. Sampler is only able to recover dissolved organic compounds with sufficient volatility to partition to the vapor phase.

71 Overall Summary for Protocols for Use of Five Passive Samplers
Passive Samplers offer Quantitative data Cost savings Use is dependent upon the DQOs Tech & Reg Guidance Acceptance Diffusion Samplers RPP & Dialysis Equilibrated Grab Samplers Snap Sampler™ & HydraSleeve™ Accumulation Sampler GORE™ Module Collect samples at a discrete interval in well screen

72 Thank You for Participating
2nd question and answer break Links to additional resources Feedback form – please complete Links to additional resources: Your feedback is important – please fill out the form at: The benefits that ITRC offers to state regulators and technology developers, vendors, and consultants include: Helping regulators build their knowledge base and raise their confidence about new environmental technologies Helping regulators save time and money when evaluating environmental technologies Guiding technology developers in the collection of performance data to satisfy the requirements of multiple states Helping technology vendors avoid the time and expense of conducting duplicative and costly demonstrations Providing a reliable network among members of the environmental community to focus on innovative environmental technologies How you can get involved with ITRC: Join an ITRC Team – with just 10% of your time you can have a positive impact on the regulatory process and acceptance of innovative technologies and approaches Sponsor ITRC’s technical team and other activities Use ITRC products and attend training courses Submit proposals for new technical teams and projects Need confirmation of your participation today? Fill out the feedback form and check box for confirmation . 72

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