By Greg Glass
Public Participation Grant. ECAC’s current two-year Public Participation Grant from Ecology (2011-2013) ends as of June 30th. The major focus for the current grant has been the evaluation of continuing ground water monitoring results and review of the early tasks for developing a Draft Feasibility Study by Chevron. An end-of-grant report will be prepared to summarize activities during the grant period. No additional remedial actions occurred in this grant period; some additional site investigations were performed, notably near the former slops pond and Detention Basin 2, an area where LNAPLs and elevated ground water TPH concentrations have been found.
Ecology’s funding decisions for awarding grants for the 2013-2015 period await the legislature’s final passage of a state budget. The special legislative session should produce that budget during June 2013. Ecology will then use its grant evaluation rankings to decide which grant proposals will be awarded. A Final Feasibility Study, a Cleanup Action Plan, and engineering design for the selected cleanup alternative for the UNOCAL Edmonds site will occur during the next 2013-2015 grant cycle.
Feasibility Study. Work is continuing on several of the interim deliverables for the Draft Feasibility Study. Chevron is finalizing the Conceptual Site Model report based on comments from WSDOT, ECAC, and Ecology. A Draft Cleanup Levels and Remediation Levels Report (CUL/REL Report) was submitted by Chevron in March 2013. Ecology compiled review comments, including comments submitted by ECAC, and sent them to Chevron for report revisions. One of the most important elements of the CUL/REL Report is the evaluation of appropriate levels for total TPH in soils; several localized areas of the Lower Yard still have soils with more than 10,000 ppm TPH. Chevron has proposed making the Interim Action REL of 2,975 ppm TPH the final soil TPH CUL. ECAC has commented that the support for that determination is insufficient. The Final Conceptual Site Model Report is due to be submitted to Ecology by June 1st. The revised CUL/REL Report is due by June 30th. Another interim deliverable, identifying the alternatives to be evaluated, is also scheduled for submittal by the end of June 2013.
Ecology met with ECAC, WSDOT, Chevron, and Chevron’s consultant ARCADIS on May 8th. Most of the meeting was devoted to a presentation by ARCADIS on initial development of a ground water model that will be used to evaluate alternatives within the Feasibility Study. The nearshore, tidally influenced characteristics of ground water at this site pose several interesting challenges for structuring the ground water model. A Draft Ground Water Model Report is due in August 2013 (beyond the current grant period). The complete Draft Feasibility Study is still due by December 2013.
Ground Water Monitoring Results, 1st Quarter 2013. The perimeter Point of Compliance (POC) wells (but not the interior wells) were sampled in March 2013. Chevron reported the results to Ecology in May. Most of the samples (18 of 23) did not have any detected TPH. Of the five POC wells with quantified TPH concentrations, only one – MW-510 near the former slops pond – exceeded the cleanup level for TPH. No LNAPLs were reported at MW-510 and the total TPH concentration (at 1,730 ug/L TPH), while still above the cleanup level, was markedly lower than in earlier sampling rounds. POC wells that had shown exceedances long after completion of the extensive Lower Yard Interim Actions, including LM-2, MW-129R, MW-135, and MW-136 among others, have now had four or more consecutive quarterly sampling rounds without an exceedance of cleanup levels. The trends in ground water TPH thus continue to be encouraging.
One recently installed interior well, MW-525 near the WSDOT storm drain line, may have the highest remaining TPH concentration. It has been sampled only twice (and not this Q1 2013 round). The most recent sample from December 2012 had 25,090 ug/L total TPH. Well MW-525 and all of the interior wells will be included in the next sampling round scheduled for June 2013.
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“This product was funded through a grant from Washington State Department of Ecology. While these materials were reviewed for grant consistency, this does not necessarily constitute endorsement by the Department.”