DECIDING WHEN TO INTERVENE

There is a consensus among diverse sectors in the Great Lakes Basin (e.g., government, industry, non-governmental organizations, RAP groups) that contaminated sediment is an important element leading to many of the impairments to beneficial uses of the Great Lakes. All 42 Great Lakes Areas of Concern have contaminated sediment based on application of chemical guidelines. This universal obstacle to environmental recovery in Areas of Concern can potentially pose a challenge to restoring 11 of the 14 beneficial use impairments identified in the Great Lakes Water Quality Agreement (SedPAC 1997).

These findings were revealed by SedPAC, which was established in 1996 by the WQB of the IJC. SedPACs' mandate is to examine the magnitude of the contaminated sediment problem in Great Lakes Areas of Concern and provide advice on how to overcome obstacles to sediment management. The challenges to progress in sediment remediation include, but are not limited to: the inability to define the extent of the problem, developing a strategy to address the problem, and defining the cleanup standard (SedPAC 1997).

By way of illustration, in many Areas of Concern, technical and community team members are struggling to reach decisions on whether or not environmental or ecological harm resulting from the presence of contaminated sediment is such that intervention is needed. For RAPs, sediment management decisions need to be made bearing in mind the relationship between contaminated sediment and restoration of beneficial uses. This goes far beyond setting a numerical chemical cleanup criteria, as these are not generally based on the need to fully restore beneficial uses.

In this light, guidance is needed on the breadth of information that should be collected and how the information or data are interpreted. No comprehensive and ecologically-based methods are commonly available that illustrate how to evaluate and integrate chemical, eco-toxicological, and ecological results in an objective, pre-defined manner to arrive at a decision surrounding the severity of sediment contamination.

To address this need, one of several initiatives of SedPAC is to explore and exchange methods to interpret sediment assessment data and formulate decisions on whether to take action beyond source control. Apart from source control, the required levels and rates for cleanup to restore uses are far from obvious, and in some cases, appear unknown. While decisions to clean up contaminated sediment depend on a large number of variables (e.g., economics, regulations, technology), sound science must be one important element. However, scientific frameworks for evaluating the ecological significance of contaminants in sediment are either lacking or not widely used or communicated. Local decision-making has been assisted by the proliferation and adoption of numerous bioassessment techniques. Such decision-making, however, is hampered by lack of guidance on defining quantitatively acceptable or unacceptable results or conditions. To add a further layer of difficulty, there are few widely-accepted methods to integrate the large number of environmental measurements that result from a comprehensive sediment assessment.

What is needed is a pragmatic decision-making framework that leads to the selection of ecosystem- and cost-effective options for management of contaminated sediment. As SedPAC (1997) has noted:

"It is imperative that any active intervention for sediment management beyond source control be aimed at use restoration, based on the weight of evidence of the biological data that demonstrates action other than natural recovery is necessary."

Recently, the Parties and the IJC have been cooperating to develop joint decision-making tools that will allow for consistent, comprehensive, ecologically-based approaches to sediment management. This is consistent with the needs stated in Annex 14 of the Great Lakes Water Quality Agreement.

In December 1998, sediment management experts from throughout the Great Lakes Basin and beyond met in Windsor, Ontario to exchange and examine the tools that are used as a means for arriving at a decision regarding whether or not to take action beyond source control. This report synthesizes the scientific methodologies and management experiences brought together by the participants. The intent is to provide RAP decision-makers with advice on methods for resolving those considerations, in order to finalize site-specific sediment management strategies.