Ralph Stahl opened the session by welcoming participants to the Assessment Subgroup meeting. (A list of meeting attendees is included as Attachment A.) Stahl said the agenda for the meeting was to (1) review the Subgroup’s draft white papers and (2) discuss the Subgroup’s plans for the November 2000 Society of Environmental Toxicology and Chemistry (SETAC) meeting.

 REVIEW OF DRAFT WHITE PAPERS

The Subgroup is preparing 11 white papers, each of which addresses a different sediment remediation issue. Nine of these papers were submitted for review during this Subgroup meeting. The white papers’ schedule for completion is ambitious: the group would like to collect the papers under one cover (with the RTDF logo) for the SETAC meeting in November. The U.S. Environmental Protection Agency (EPA) has to review the papers before the RTDF logo can be applied to the collection. In this session, the group was asked to comment about the papers’ content—particularly missing information or skewed concepts. Stahl, who led the session, asked the group also to think about how the diverse topics and formats could be blended under one cover as an RTDF pamphlet. The Subgroup members concurred that the white papers should serve as primers for people making decisions about sediment remediation, and should refer to one another where possible. Each white paper discusses a type of assessment or remediation technology and the concerns that must be considered when assessing or remediating sites. The white papers that describe technologies discuss advantages and disadvantages, as well as technical requirements to consider when using them. The papers strike a balance between being technical documents for internal use and being simple enough for wide distribution. The Subgroup members agreed that they will try to pull the papers together for distribution at the November 2000 SETAC meeting. An introductory section will need to be prepared, Stahl said, to introduce the entire set of white papers.

Stahl said that this white paper discusses issues that pertain to reference area condition. Investigators compare chemical, biological, and physical data that are collected from reference sites against those that are collected at contaminated sites (also referred to as "study" areas.) The reference area is used to determine if remediation is needed, evaluate changes in the study area after remediation, and determine if remediation has been successful. Stahl stressed that reference areas should be similar to study areas, but that they should not be contaminated with the constituents that are present in the study area.

Stahl said that it is very important to select an appropriate reference area. Failure to do so can lead investigators and risk managers to draw inappropriate conclusions and make incorrect risk management decisions. This white paper presents several criteria to consider during the selection process.

Stahl explained that his paper stresses that the criteria selected for a reference site serve as a benchmark for comparing that site to a contaminated site. Simeon Hahn commented that, throughout the paper, reference area conditions should be referred to as "a benchmark" for comparison, not "the benchmark." Other participants wanted Stahl to make it clear that the identification of reference sites depends on critical "physical" parameters. For example, a pristine river should not be compared with a channelized stream system. The group emphasized the importance of setting, adding that northeastern U.S. sites may not always be comparatively favorable because waterways there have been constrained by physical development.

Sabine Apitz stressed that there is no reference sediment that addresses all the characteristics that need to be investigated. She asked Stahl to address how the identification of a reference site depends on critical (physical and chemical) parameters. This can be a contentious issue—the perfect reference site for Apitz, a geochemist, could be perceived as an appalling choice by a benthic ecologist. Joe Iovenitti pointed out that one may never find a perfect reference site, but that it is important to find a relevant reference site.

David Moore spoke of beneficial reuse and of defining reference sites based on the idea that they reflect a remediation effort’s end goals. Two reference sites could be looked at: one that reflects the site without chemical contamination and one that reflects the end state that remediation workers are trying to achieve.

One participant stressed that the goals in choosing a site are compatibility, as well as beneficial and sustainable ecology. Apitz added that identification of a reference site may depend on remedial goals, options, and environmental characteristics, as well as the critical physical, chemical, and biological parameters being evaluated.

Stahl said that the second portion of the paper deals with why this subject is important. The paper’s underlying theme is how one selects a reference site. This depends upon one’s goals, the site’s past characteristics, and the steps one plans to take to remediate the contaminated site. Having criteria is important, because investigators often find sites that are "close" but not perfect. Stahl reminded attendees that choosing an inappropriate reference site can lead to inaccurate conclusions. It is important to anticipate what is desired from the chosen reference site.

One of the audience members wanted it clarified, early in the paper, that naturally occurring contamination (e.g., background levels of arsenic in sediments) can exceed cleanup goals. Iovenitti stated that the term "reference area" needs to be qualified as "the selected reference area."

Craig Phelps said the paper should discuss the possible goals of a remediation effort: it should tell readers to determine whether they intend to remediate a site so that its level of contamination is similar to a "historical" level or whether their goals are different. Sometimes, one has goals in addition to reducing or eliminating exposure pathways at a site. Hahn said that there is a conflict between risk assessment and risk management; this conflict is ultimately resolved in the remedial decision-making process. It is especially hard to make decisions about reference areas, he said, particularly when there are several sources of contamination.

Apitz concluded that Stahl has to address the differences between risk assessment and risk management. According to Hahn, some regions use reference sites more as management tools than as risk assessment tools.

Attendees noted the importance of acknowledging that some areas have high contaminant concentrations naturally. In some cases, a site that has high natural background levels may be considered an acceptable reference site for a study area. If this is the case, remediation efforts will probably not be expected to reduce contaminant concentration below naturally occurring levels.

Next, Stahl talked about another criterion: the physical nature of the sediments. Differences in grain sizes translate to differences in the benthic community. Chemical composition (i.e., organic carbon or acid volatile sulfide) can also be used as a parameter.

The Subgroup felt that Stahl’s paper should address speciation of chemical contaminants.

Stahl then made two comments on his own paper. First, he is writing this paper for an audience of decision-makers; therefore, his intent is to lay out most of the paper’s concepts in a simple fashion. Second, the composition and abundance of a site’s biotic community is an important criterion to consider when choosing a reference site.

Nancy Grosso suggested that upland characteristics are another important criterion.

One attendee pointed out that many sites are disturbed physically, which makes it challenging to find an appropriate reference area. Stahl agreed to note this in his paper.

The Subgroup agreed that sites vary substantially—no contaminated site has a reference site that is similar in all regards. Shaded habitats, for example, have different biological conditions than sunny habitats.

Kelly Madalinski suggested including more references in all of the Subgroup white papers. This particular paper could be made stronger, Madalinski noted, if references were added for other documents that discuss how to identify and select reference sites. Moore said that Stahl’s paper should also reference the other Subgroup white papers where applicable.

Stahl asked Subgroup members to send him their additional comments in writing.

Moore said that this white paper provides an overview of tools that can be used to assess sites, evaluate remedial alternatives, and perform post-remediation monitoring. The paper describes what the tools are, explains why they are important, and describes what they are used for in the context of remediation. The paper does not address potential for exposure or uptake of contaminants. It does not mention biomarkers or bioaccumulation tests. Above all, the paper focuses on the tools’ strengths and weaknesses in potential application.

A member of the Subgroup commented that the paragraphs in the paper are too long and could be broken down. Moore said he would be happy to incorporate any paragraph breaks suggested by the group.

Hahn asked if Moore discussed the mode of action of particular contaminants, noting that this often affects which tests are chosen. Moore said he had brought this concept into the discussion in various places.

Throughout the paper, Moore tried to put the tools in context of their strengths and weaknesses. He also referred to other Subgroup white papers and cited standard protocols; he plans to update the latter with information from the American Society for Testing and Materials’ (ASTM’s) 2000 meeting. EPA has some updates coming up for sediment toxicity test methods for freshwater species—Moore plans to incorporate these into the paper as well.

Moore noted that he did not specify how to use a reference area. He needs to explain how to use reference areas in conjunction with each of the tools he describes, as well as how to interpret and evaluate the related test results.

Hahn asked if the paper discusses when to consider using a toxicity test and what criteria to use if references or benchmarks are exceeded or if contamination is detected. Moore said that he tried to keep the paper general—to describe, in broad terms, the tools, strengths, and weaknesses involved in the approach. The scale of his paper is too large to address all the different scenarios one might encounter, depending upon the goal of one’s project. Where possible, Moore said, he indicated that some types of tests are useful for some applications, but probably not for others. For example, the discussion of sediment water interface tests mentions that these tests might be particularly useful if there is a concern about flux of contaminants into the overlying water column.

The paper does not go so far as to say, "If measured levels at a site are above ambient water quality criteria, then sediment water interface tests should be performed." Rather, the paper gives people who have decided to use toxicity tests some things to consider. From Moore’s point of view, particular approaches to toxicity testing have some pitfalls and some strengths, based on the kind of application involved.

Hahn asked if Moore recommends using a porewater test as a screening-type evaluation. To clarify his points on that subject, Moore will add a sentence about how such a test helps delineate where samples should be taken for subsequent, longer-term, more expensive tests.

Henry Tabak said that Microtox® is not always reliable. Thus, he recommended using Microtox® in conjunction with another type of test. If the results consistently show that the tests yield comparable numbers, then it might be suitable to use Microtox® on its own. Phelps said Photobacterium phosphoreum is an outdated term for the bacterium in the Microtox® kit. The bacterium is now referred to as Vibrio fischeri.

Dick Jensen raised the issue of the paper’s title. He suggested having all of the paper titles converge on the subject of assessment. Jensen cautioned that using the word "remediation" in the paper’s title raises confusing issues involving management. Upon Apitz’s suggestion, Moore agreed to shorten the title, taking out the words "In Site Remediation Activities."

Apitz suggested adding a decision matrix at the front of the paper, noting that results from chemical testing often conflict with results obtained from toxicity tests. She said that none of the testing provides a nice clear-cut answer.

Jensen pointed out that digging too deep and taking samples incorrectly can result in false positives on toxicity when the benthic community is healthy. Moore said that the paper devotes considerable discussion on confounding factors that must be considered when interpreting and selecting tests.

Hahn spoke about some of the negative views that people have on toxicity testing. He said that there is a general reluctance to perform toxicity tests because they are perceived as being too costly or too academic. He feels that toxicity testing is presently out of favor, even though it often provides site-specific information and more weight of evidence than chemistry alone. Nonetheless, people seem to be more than willing to perform chemistry testing, but are reluctant to do toxicity testing. Moore concluded that this is a subject for another white paper.

Depending on what kind of treatment approach is used, Tabak said, it may be necessary to compare the results of toxicity testing before and after treatment. The paper, he said, needs to emphasize this.

One attendee said that the paper needs some form of guidance on the likelihood of false positives and false negatives. It should also provide guidance on how to manage the reliability of data. Managing positive test results can be very difficult. Risk communication is another issue the group needs to address. Moore acknowledged the importance of communicating risk and identifying the things that can affect the interpretation of tools before collecting data and making decisions.

Joseph Jersak provided a brief overview of his white paper: it explains how to characterize the spatial extent of sediment contamination in a logical, defensible, and cost-effective manner. The paper outlines a seven-step approach to characterization.

Iovenitti asked for clarification on the overall goal of characterization, noting that what is done for characterization purposes may not be adequate for remediation purposes. It is important, said Iovenitti, to point out that one must do a certain level of characterization to understand a problem, a certain level to decide what to do about it, and then another level to decide how to remediate it and, later on, validate it.

Moore asked if the wording "sediment contamination X" could be replaced with "contaminants of potential concern for the site." Usually, he said, more than one contaminant is evaluated during site characterization.

Attendees noted two other characterization strategies that might be interesting to address in the white paper. Jensen described an approach that Al Robond, a professor at Tufts University, refers to as "dynamic site assessment." Jensen said the process involves performing a rough screening for metals before designing subsequent sampling events. Using this approach, Jensen said, assessment plans can be changed based on the most recently received results. Moore added that a compositing strategy exists that looks across three dimensions. In this strategy, a larger set of samples is taken, but fewer are analyzed; investigators can use this strategy to get information on the location of hot spots within a site without having to analyze all of the samples collected.

One attendee noted that the Subgroup might be able to learn some lessons about characterization from the gold-mining and metal-mining industries, both of which have performed work on depositional environments for years. The attendee noted that there is no need to "reinvent the wheel" when work has already been done on a subject. As a follow up to this comment, Tabak suggested including information about models that are used to study mining deposition.

Hahn said that direct characterization seems to emphasize collection followed by analysis in a laboratory, even though there are techniques for chemical screening in the field that can provide rapid results and large spatial coverage.

Iovenitti said that the conceptual model was buried in the paper, but said that the problem could be fixed by profiling the conceptual model at the beginning of the document.

The group suggested using the words "biologically relevant" in the white paper. In response, Jersak said that he assumes that benthic organisms are the relevant initial receptors.

Apitz briefly described the contents of this white paper, noting that it addresses how field screening tools and rapid site characterization tools fit into the risk assessment process. Apitz said that she and Victoria Kirtay—the papers authors—present recommendations and describe issues that have not yet been addressed, such as what data can and cannot be used for and the dangers of integrating screening and regulatory, or standard, data. In addition, the paper discusses the goals of site assessment tools and describes how these tools can be used to fill in data gaps during site assessment activities. The paper also provides background on traditional sampling and ecological risk assessment.

Apitz said that the paper’s recommendations are meant to highlight how important it is to use data and report it in an appropriate fashion. She also emphasized the need to balance data in the decision-making process. This, above all, is what she and Victoria Kirtay wanted to convey to their audience.

Iovenitti said that screening tools have no relationship to cleanup levels. Screening simply provides a technical basis for further scientific investigation. Apitz agreed that it is not wise to rely too heavily on screening tools. She said that they are useful at identifying contaminants but they do not necessarily provide information that can be used to make remedial decisions.

A member of the group said that a caveat should be added about detection limits and about the improvements being made in commercial x-ray fluorescent tests. Apitz agreed to add more references on technology and the types of software that are being used to process data.

Moore asked about the differences between QuikLite and QuikSed. Apitz said that QuikLite is for fluids or seawater and QuikSed is an elutriate of sediment. Moore also advised adding a reference to the Subgroup’s white paper that addressed sediment toxicity testing.

Stahl commented on the paper’s recommendations, noting that it might be difficult to obtain EPA’s approval on the paper if actual recommendations are offered. Thus, he suggested couching the recommendations as strengths and weaknesses. Stahl also said that a cost/benefit analysis should be included as an attachment, table, or appendix.

Grosso asked Apitz to elaborate on how field screening techniques can be used to fill in data gaps. She said that she has used field techniques to fill in data gaps and has correlated her results with laboratory data. Sometimes, she added, investigators can obtain a good linear correlation within the range of concentrations they are looking at. Apitz felt the paper did allude to this, but agreed to address it more fully.

Hoke said that this paper, which explains why conceptual site models are necessary, draws on information from an internal DuPont document and an ASTM guide. Hoke said that developing a conceptual site model is a critical part of determining the most cost-effective and efficient ways of dealing with a site. A conceptual site model describes the baseline conditions of a site and serves as a reference for any future actions. It is a three-dimensional description of the site, including physical, chemical, and biological processes that affect transport and fate of contaminants through various environmental media to potential receptors of importance. Hoke said that models are revised as more data are collected. The model serves as the basis for development of an investigation and future remediation activities. It helps explain changes that occur, either through remedial activities or via natural occurrences. Developing a model, Hoke noted, involves conducting a literature review and evaluating all of a site’s geological, hydrological, atmospheric, and biological characteristics.

One attendee felt that the steps listed in the paper are "overkill." He said that site assessment is an iterative process; initially, one would not go through as many steps as the paper suggests to develop a site conceptual model. In response, Bob Hoke said that site assessors who develop their conceptual site models more thoroughly often encounter fewer surprises later in the process.

One participant took issue with gathering data on atmospheric conditions. Hoke defended the need to collect such data, noting that assessors need to know something about atmospheric conditions in all cases that involve mercury contamination. The attendee said that the paper should stress that creating a conceptual model is an iterative process; as one gathers more information, a model can be revised. Apitz said that this last concern could be remedied by moving two paragraphs on page 4 to the front of the paper. This will make it clear that different options can be chosen for a model, depending on the situation’s complexity and the choices made.

Hahn, who reviews a lot of assessments, said that the conceptual site model as it is now used is probably the weakest part of risk assessment. He said that the steps outlined in Hoke’s paper serve as a good framework for developing a strong initial site conceptual model.

Hahn asked if conceptual site models are related to exposure and migration only, or also effects. Hoke said that a model is ultimately about receptors, and the selection of the receptors reflects the contaminants of concern and the modes of action of those contaminants. Hahn said that one can use a conceptual site model to choose more appropriate tests if one considers the mode of ecotoxicity and human health impacts. He elaborated by asking what happens to a contaminant once it reaches a receptor: Does it accumulate? Should a tissue measurement be taken? Does the contaminant cause toxicity? Should toxicity be measured? Is the contaminant metabolized? Answering all of these questions makes it possible to design the study appropriately. Hahn said this needs to be spelled out, because some conceptual models are too simplistic. Hoke acknowledged the importance of identifying potential environmental receptors and relative endpoints of those receptors. Moore pointed out that the function of conceptual site models is to consider everything, then go back through the process discounting pathways (e.g., eliminating benthic receptors because they either rapidly metabolize a contaminant of concern or don’t possess the appropriate receptors). After hearing these comments, Hoke agreed that it would be useful to add a sentence about environmental receptors and relevant endpoints for those receptors.

Grosso said the paper should caution readers against relying too heavily on the working hypotheses they generate while they develop conceptual site models. Assuming a certain type of groundwater flow, she said, can marry a model to preconceived ideas about a particular site.

Iovenitti recommended that Hoke repeat, at the beginning of the paper, the sentence that starts on line 132 that describes what a conceptual site model is.

Jensen said that this paper defines the concept of monitored natural recovery (MNR) and explains how it differs from monitored natural attenuation of groundwater. The paper discusses the physical, chemical, and biological processes that are involved with natural recovery; lists tools and techniques that are used to assess MNR; discusses the role of modeling; and provides a summary and bibliography of related references. The paper argues that MNR requires complex assessment and is not a "no-action remedy." The paper also notes that natural recovery always plays an important role, regardless of any other remedies applied—either to repair collateral damage from other remedies or to treat marginal areas that are not significantly contaminated. Jensen said that MNR, a risk-based approach, should never be assessed by itself, but should always be compared to other viable remedies.

One attendee questioned always needing the monitoring component of natural recovery. He said that in some cases a site may not require monitoring in perpetuity. Thus, he felt that, sometimes, it is reasonable to assume that natural recovery is occurring without having to prove it through monitoring activities. In response, Apitz suggested adding text saying that monitoring is not always necessary.

Jersak said the term "monitored natural recovery" is now officially recognized. The word "monitored" was inserted to separate natural recovery from the "do-nothing approach." Tabak added that some contaminants undergo natural recovery more slowly than others, so "monitored" was added to give the idea more credibility. Another Subgroup member concurred that from the regulatory standpoint, the word "monitored" must be included: the public is already skeptical about natural recovery because it is not viewed as an "active" approach. Speaking from a political perspective, Jensen said, monitoring usually needs to be performed when risk management remedies, like natural recovery, are used, but perhaps not for the entire area expected to undergo natural recovery.

Moore concluded that the term "monitored natural recovery" clarifies the concept; it shows that something is implemented, achieving the end state to meet the remedial goals. One attendee said that if a contaminated site does not exceed risk-based criteria, no action would be taken. In such a case, natural recovery can be allowed to occur, bringing the contaminant to lower levels; monitoring may not be required. Even when a site is contaminated in excess of risk-based criteria (and treatment is therefore under way), adjacent areas may meet the criteria. Natural recovery should be monitored in cases where cleanup criteria are exceeded. Jensen said he would add a paragraph that explains when there is not a need for monitoring.

Tabak asked if any discussion could be added on microbial transport toward areas of contamination. He pointed out that microbes migrate to trichloroethylene when they are added to aquifer sediments. Jensen said he would consider adding a paragraph on the subject.

Grosso asked why the title reads "Remedial Strategy" instead of "Remediation Alternative." Jensen said that he is changing the title.

Stahl said that a request was submitted for a room at the Nashville Convention Center. The dates for the Subgroup’s open house have not been finalized. It will either take place on the afternoon of Monday, November 13, or on Tuesday, November 14. The Subgroup made the following proposals for the open house:

• Display posters about the RTDF, posters about the Sediments Remediation Action Team, and abstracts of the white papers.
  
  
• Have EPA display a historical RTDF poster.
  
  
• Display flyers throughout the convention center and on the hotel marquee.
  
  
• Have posters copied for display in the main area, as well as in the meeting room.

Moore, Apitz, Hoke, Jensen, Hahn, Ken Finkelstein, Jersak, and Tabak volunteered to be in the room for the open house.

Hahn said that he is working with a group called the Anacostia Watershed Toxics Alliance (AWTA). The Anacostia River is located in the Washington, D.C., area and is considered one of the 10 most polluted rivers in the country. Many environmental justice issues have arisen within the watershed, because the Anacostia flows through low-income communities. The river falls within the jurisdiction of the Chesapeake Bay Program and flows into the Potomac. To date, a conceptual site model has been assembled; all the relevant information was put on a CD-ROM and the Internet. In a second phase of work, the scope of the project was outlined to fill in any data gaps. The third phase involved considering possible actions and options for remediation and restoration. The AWTA would benefit from a partner with knowledge of remedial technology. There are many human health issues to be dealt with. Recently, tests revealed that the tumor rate in bullhead catfish was high. The contaminants that affect the river include polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and metals. The study area is roughly 15 square miles in size and encompasses the intertidal reaches of the Anacostia watershed.

The AWTA meets every six weeks. Thus far, the visibility of and support for efforts within the watershed have helped to involve 25 organizations from government, industry, academia, and the community. Stahl would like to convene a conference call with members of the RTDF about using the Anacostia River as a demonstration site. Hahn also suggested that a few members of the RTDF attend the next AWTA meeting, which will be in October.

 POTENTIAL INTERACTION WITH THE WESTERN DREDGING ASSOCIATION

Jersak asked the Subgroup to consider the potential for RTDF interaction with the Western Dredging Association (WDA). Jersak said that WDA has mentioned the RTDF organization in past meetings. WDA investigates dredging both from a navigational and remedial perspective. The association focuses on dredging as a primary management alternative, but it welcomes the discussion of other management techniques as well. A WDA representative could talk to the RTDF to set up a dialogue on philosophy and ideas. Jersak asked whether the Subgroup would be interested in working with WDA. Attendees expressed a definite interest. Stahl said that the RTDF could collaborate with WDA to perform studies. Jensen expressed considerable interest as well, noting that capping projects and reactive CDFs might be of interest to WDA. Moore thought that a partnership between RTDF and WDA made sense, noting that both groups have incentive to evaluate nondredging alternatives. Jersak said he would send Madalinski, Stahl, and Jensen the names of his contacts within WDA. Jersak added that Greg Hartman from Seattle may be the point person to talk to about the WDA. Moore agreed to present information about the RTDF at WDA’s next Pacific Chapter meeting. Moore asked to be sent some handouts to take to the WDA meeting.

 ACTION ITEMS

• A Subgroup member will assemble a cover page for all of the white papers.
  
  
• A Subgroup member will check the papers to make sure they have proper reference lists.
  
  
• White paper authors will make sure to refer readers to other white papers for more information.
  
  
• A Subgroup member will review the papers’ titles to ensure that they converge on site assessment.
  
  
• Stahl will recruit a Subgroup member to write a white paper on the use of various tools in site assessment.
  
  
• A Subgroup member will decide whether to include a white paper dealing with statistical design.
  
  
• Revised versions of white papers, as well as 300-word abstracts, are due on September 22, 2000.
  
  
• White papers will be submitted to EPA on September 25, 2000.
  
  
• Final editing will take place between October 16 and October 20.
  
  
• An RTDF pamphlet will be published between October 30-November 8, 2000.
  
  
• Copies of the RTDF pamphlet, for distribution at the SETAC meeting, will be provided on November 9, 2000.
  
  
• The next conference call is scheduled for October 6, 2000, at 11:30 a.m. Eastern Standard Time.
  
  
• During the next conference call, the Subgroup will finalize details about the next RTDF meeting. The meeting will take place on Wednesday,
  January 24, and Thursday, January 25, 2001, at the NOAA Sandpoint Laboratory facility in Seattle, Washington.
  
  
• Stahl will convene a conference call between the RTDF and the AWTA.
• Hahn will arrange to have RTDF members attend an AWTA meeting to discuss a potential study site.
  
  
• Moore will provide information on the RTDF to WDA at the latter group’s Pacific Chapter meeting. He will also arrange for a conference call with WDA officials.
  
  
• Jersak will provide WDA contact names to Jensen and Timberlake.