DECIDING WHEN TO INTERVENE

Brief summary of breakout group B

Breakout Group B was facilitated by Marcia Damato (U.S. EPA) and David Cowgill (U.S. EPA).

Breakout Group B discussed the circumstances under which one would utilize the "Weight of Evidence" approach to sediment assessment vs. a "Tiered Approach". Whichever framework is selected should be consistent at a scientific level in its approach and information. It should also accommodate any size and scope of a project. The group acknowledged that there is considerable frustration associated with dealing with contaminated sediment because of the slow progress of remediation.

Weight of evidence approach vs. tiered approach

The group discussed the "Tiered Approach" and determined that it is useful for smaller, less complex sites such as Collingwood Harbour, but is not as applicable in an area such as the Detroit River Area of Concern. A "Weight of Evidence" approach should often be used on larger, more complex projects. The group noted that chemistry can't be disconnected from the biology for Superfund Sites. For example, in the Great Lakes, nearly all Superfund Projects use the "Weight of Evidence" approach. Sometimes the "Weight of Evidence" approach and the "Tiered Approach" result in the same decisions being made. The group noted that when working with industry in a partnering/cooperative forum where their involvement is voluntary, a reasonable approach is to use a limited amount of data that has been accepted by all parties. The group agreed that the cost of cleanup is a factor in both approaches.

Weight of Evidence	Tiered
Larger Scale	Smaller Scale
Complex	More simple
Non-voluntary	Voluntary parties
Multiple Sources	Single Source

After the science is accepted in defining a problem, then the next steps must be determined. There must be consistency in data interpretation. The group acknowledged the influence of social-political pressures on contaminated sediment problems. The group agreed that the approach should be science-based and the social-political influence should be limited. Science should be used to achieve a comfort level for the decision being made and social-political considerations should be considered later in the process.

Data elements and assessment

The group then discussed some of the important information that should be incorporated into a consistent framework. The following data elements were identified which will help determine the extent of risk from sediment contamination. Is there a risk to:

• Aquatic Life?
  (i.e., toxicity, bioaccumulation, chemistry, and impaired benthic community)
• Wildlife?
  (i.e., bioaccumulation, biomagnification) Human Health?
  (i.e., exposure, biomagnification, fate, and transport)

The logic of what entails a complete assessment was discussed next. The group discussed the importance of making a determination of: whether sources of contamination have been controlled; the extent of risk to aquatic, wildlife, and human receptors; whether sediment deposits will move over time; and being able to predict when the system will recover (using models to predict when fish consumption advisories will no longer be needed under various remedial options such as dredging, capping, and natural recovery) so that all 14 beneficial uses have been restored. The following logical steps were identified:

1. Risk Assessment (aquatic, wildlife, and human risk)

2. Benefits Forecasting:

   Purpose-	Demonstrate benefits and restoration of beneficial uses; public, private, governments
   Method-	Sources, transport, fate, effects (i.e. mass balance models)
   Procedure-	Perform the following checks:
   	What are the sources? Are they controlled? Is it feasible to remediate? Where to remediate? How much? What will happen if:
   		No further action is taken (natural recovery)? A catastrophic event occurs? Other selected scenarios occur? We achieve the maximum remediation bound (i.e. if we take out everything, how much good will it do)?
   Endpoints-	sediment contaminant concentration, fish concentrations (over time), toxicity benthic community
   Engineering issues-	disposal, removal methods, risk to wildlife, risk to habitat

Summary and conclusions

Finally, the group attempted to summarize what had been discussed, recognizing that a number of important factors had been identified. One concept that was posed was that if one were asked to perform a peer review of someone else's sediment management decision, what criteria would you use to evaluate the quality of the decision? This appears to be a concept that could be of use in ensuring that all of the important factors identified above, and aggregated during the plenary session, are given thorough consideration for all Great Lakes sediment projects, regardless of the organization that is responsible for the project and the particular program making the decision.

The group discussed the importance of a Great Lakes protocol that would address sampling, QA/QC, assessment, and data interpretation. The group recommended that there may be a need for "bench marking" (baseline from which we make decisions) among the two provinces, eight states, and two federal governments for three categories of data elements and source control, natural recovery, etc. It was noted that the Great Lakes Water Quality Initiative in the United States took eight years of coordination, consensus building, and administrative rule-making to develop consistent water quality standards for the Great Lakes. Any such protocol would likely be very resource intensive and time-consuming. Therefore, a first step could be to "bench mark", or document, the existing decision-making frameworks now being used. It was noted that the United States Environmental Protection Agency published a document in 1990 entitled "Managing Contaminated Sediment: EPA Decision-Making Processes."