SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
SEDIMENTS REMEDIATION ACTION TEAM
GROUND WATER-SURFACE WATER INTERACTIONS WORKGROUP
CONFERENCE CALL
1:00 p.m.-2:00 p.m.
September 5, 2003
On September 5, 2003, the following members of the Remediation Technologies Development Forum's (RTDF's) Sediments Remediation Action Team, Ground Water-Surface Water Interactions Workgroup, met in a conference call:
Nancy Grosso, DuPont Corporate Remediation (Action Team Co-chair)
Peter Adriaens, University of Michigan
Bruce Duncan, U.S. Environmental Protection Agency (EPA), Region 10
Bob Maxey, U.S. EPA, Office of Solid Waste
Farukh Mohsen, Gannett Fleming
Bernie Zavala, U.S. EPA, Region 10
Christine Hartnett of ERG was also present.
BACKGROUND INFORMATION
The Ground Water-Surface Water Interactions Workgroup is writing a short summary of issues that were identified during an October 2002 Sediments Remediation Action Team workshop. The Workgroup met (via conference call) in June 2003 and August 2003 to discuss the document's content. On August 15, 2003, Nancy Grosso distributed a draft document, entitled Ground Water/Surface Water Workshop--Summary of Discussion Issues. Grosso has already received some comments via e-mail. This call was held so that she could obtain additional feedback.
DISCUSSION
What is the purpose of the document, who are the authors, and does consensus have to be reached before releasing the document?
Grosso said that she hopes to finalize the document and post it on the RTDF Web site before the end of the year. Those who have contributed to the document will be listed on the front page; the author list will include representatives from EPA, industry, and academia. Bob Maxey expressed concern that the diverse authorship will lead people to believe that government and industry reached consensus on the approaches outlined in the document. Such an interpretation would be problematic, he said: the "weight of evidence" screening approach that appears in the document's appendices has received opposition from some EPA personnel. Also, that approach--which outlines a method for evaluating potential ground-water discharge impacts--differs from the approach that Bruce Duncan and his associates at EPA use. Given these realties, Maxey asked, how does the Workgroup plan to reach consensus about the document's content? Grosso and Duncan said that consensus does not have to be reached, since the document is not intended to offer policy guidance in any way. It is simply intended to summarize discussion and identify different approaches that can be used to address ground water-surface water issues. Duncan said that multiple approaches can be described in the document and that it is not necessary to say which is preferable.
Duncan advised making the following points clear: (1) the document captures the main points that emerged during the October 2002 RTDF workshop, (2) some additional information on existing approaches and tools has been included in an effort to further the discussions, and (3) many areas still require further exploration. Duncan noted that four concrete goals were identified for the workshop. He advised developing a report card that lists the goals and indicates whether they were fully achieved during the workshop. Where deficiencies are identified, he said, suggestions for additional studies and activities should be recommended. In addition, issues of contention should be listed and identified as topics that require further exploration. Duncan agreed to take a stab at developing the report card, listing research needs, and identifying topics that require additional exploration.
What tools and approaches can be used to address the following question: How does one go about finding and assessing ground-water discharge area in large tidal and estuarine settings where sediment issues may occur on a watershed scale?
Peter Adriaens knows of an article that might present useful information on this topic. He agreed to obtain the article, summarize its main points, and forward text to Grosso for inclusion in the Workgroup's document. Duncan and Maxey chimed in on this topic as well. If the goal is simply to determine whether there is a potential for impacts, Duncan said, tools like infrared technology can be used to reveal areas of discharge. If however, the goal is to identify areas with high contaminant concentrations, other tools must be employed. Maxey said that he thinks information of the latter sort is what the Workgroup should hone in on. He said that investigators will want estimates of contaminant mass loading. This comment prompted Duncan to say that ecologists are more interested in exposure point concentrations than they are in contaminant mass loading. While the latter is important for fate and transport modeling, he said, the former provides more detailed information about how receptors could be impacted.
Is Appendix A ("Highlights of the Conceptual Site Model Development Discussion") adequate?
Grosso asked for feedback on the section that she wrote about conceptual models. Duncan said that this section captures many important points. Maxey said that he also thinks the section is well done, but said that he has not yet had a chance to crosscheck the information that Grosso provided against that which is being gathered for an EPA document. Grosso said that she plans to make slight modifications to Appendix A. For example, she plans to add some references and to indicate that it is important to seek input from an interdisciplinary team when developing a conceptual site model.
ACTION ITEMS