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Happy Halloween: Feasibility Study for the Duwamish Completed, EPA Sends General Notice Letters

Posted in Cleanup & Superfund, Environmental Risk

A one-two punch in terms of the Duwamish Superfund site:

First, late Halloween night, the Lower Duwamish Waterway Group posted the Final Feasibility Study for the Lower Duwamish. The entire document is available on LDWG’s site. This past Tuesday, EPA and Ecology had a public meeting where they outlined the changes between the draft feasibility study (released in 2010) and the final FS in a public meeting. Those changes include the following:

1) Reworking the Remedial Action Objectives in the FS to exclude editorializing about how those objectives should be met. For instance, RAO 1 used to read:

Reduce human health risks associated with the consumption of resident LDW fish and shellfish by reducing sediment and surface water concentrations of COCs to protective levels.

Now that RAO reads:

Reduce human health risks associated with the consumption of contaminated resident LDW fish and shellfish by adults and children with the highest potential exposure to protective levels.

The italicized language is what has changed. EPA’s stated reason for changing these RAOs was to leave out how the risk reduction would occur (“reducing sediment and surface water concentrations of COCs”) and replacing that how with the target of the risk reduction, i.e., “adults and children with the highest potential exposure to protective levels.” RAOs 2, 3, and 4 were edited in a similar fashion.

2) An adjustment of the remedial technologies to be applied under EPA’s preferred remedy (so-called “5C Plus”). This adjustment included an increase in dredge volume, a decrease in the acres of the river that would be capped, a decrease in acres where enhanced natural recovery would be applied, an an increase in acreage (from 0 to 27) where monitored natural recovery would be applied. And, the cost only went up by $13m to $303 million . . .

3) An addition of preliminary remediation goals (“PRGs”) for shellfish and fish. The draft FS had PRGs for sediments, but not fish tissue. The final ROD will likely have fish PRGs based on “background” concentrations of fish and shellfish in Puget Sound–although much of these data still need to be collected.

4) Application of Remedial Action Levels (“RALs”) to subsurface sediments. RALs are point-based concentrations of contaminants that trigger a particular remedial action (i.e., dredging, capping, or monitored recovery). The first draft of the FS applied the RALs to surface sediment concentrations, but was not entirely clear on how to apply RALs in the subsurface. Now, remedial technologies will be applied depending on where a particular area is located and depending on the concentrations of contaminants in the upper 2 feet of the sediment column. The details of how those RALs will be applied can be seen in these figures.

There are some remaining issues with respect to EPA’s selected remedy–likely to be addressed in the still-to-come Proposed Plan. Those issues include whether the remedy is going to be “final” versus interim, the selection of fish tissue levels, and how EPA will integrate environmental justice and source control efforts into the remedy.

At this meeting, EPA stated that it was one day away from sending a second round of general notice letters to a sub-set of the approximately 260 entities that have received Section 104(e) information requests over the past few years. My understanding based on comparing notes with others in town is that those letters have indeed gone out, which I am sure many of the recipients see as a belated Halloween “fright” from EPA given the dollar amounts involved in this cleanup . . .