By Charles (Pony) Ellingson
ECAC has decided to cease operations. Edmonds Citizen Awareness Committee recently decided to cease operations because most of the cleanup work at the former UNOCAL site is done, risks to citizens and the environment are much reduced, and prior to the public meeting of August 2015, citizens had not expressed concerns to ECAC for a long time. Ironically, ECAC responded to one inquiry following the public meeting. ECAC did not renew the State grant that has funded ECAC’s participation. Therefore this is likely the last blog entry, although I understand that this website will be maintained for up to a year as a source of information and comment.
Summary of activities since last blog update. Since my last blog update in May 2014, the following work has been performed by Chevron and Ecology on this project:
- Continued quarterly monitoring of groundwater
- Submitted an Addendum to the draft Feasibility Study report which introduced “Alternative 6” (excavation to remove contaminants near DB-2, and Dual Phase Extraction (DPE) to clean up soil and groundwater in-situ near the DOT stormwater line)
- Following Ecology’s acceptance of Alternative 6 as an “Interim Action”, Chevron submitted a Public Review Draft of an Interim Action Work Plan (July 2015)
- Completed a field pilot study of DPE in February and March 2015
- Submitted applications to agencies for permits related to interim action construction
- Held a public meeting to introduce the Interim Action and solicit comments
- Continued to manage and sample onsite stormwater
The following paragraphs describe some of the work on the topics above, and ECAC’s participation in the project. Much additional information is available on Ecology’s project website at https://fortress.wa.gov/ecy/gsp/Sitepage.aspx?csid=5180.
Groundwater Monitoring Results. Data from five additional rounds of quarterly sampling are now available. Sampling occurred in June, October, and December of 2014; and March and June of 2015. The December and June rounds included both point of compliance (POC) and interior wells whereas the other rounds included only the POC wells. As with nearly all cleanup sites, the responsible parties collect their own samples, typically contracting with technical specialists for this work. ECAC has occasionally observed sampling but did not observe Chevron’s field work to collect samples in this period. The following descriptions are based on quarterly data reports.
During the latest round in June 2015, oil was present in one well and three piezometers; and hydrocarbons (TPH) were detected by chemical analysis in nine wells which is lower than the 11 wells with detectable TPH in June 2013, and the 14 wells with detectable TPH in December 2014. The locations of the detections are consistent with contamination that is known to remain in soils and which is the subject of the additional remedial actions discussed below. Interior wells MW-525 and MW-526, near the WSDOT storm drain line where contamination was not removed, appear to have the highest remaining TPH concentrations at 2,693 and 923 ug/L in June. High concentrations are also likely in the three piezometers where oil was detected; however, the piezometers are not sampled for chemical analysis. Note that TPH can be detected below the “cleanup level”. Detections above the cleanup level are discussed in the following paragraph.
Of the 23 POC wells, only well MW-510 has had a TPH concentration above its respective cleanup level since June 2014 – and that well has been below its cleanup level since December 2014. In the interior of the site, groundwater from wells MW-525 and MW-526 has consistently exceeded cleanup levels.
Alternative 6 – Excavation and DPE. Chevron and Ecology agreed to move forward with plans to excavate contamination near DB-2 and to treat contamination in-situ near the DOT stormwater line using dual phase extraction (DPE). The Addendum to the Feasibility Study, Interim Action Work Plan, pilot test work, solicitation of public comment, and applications for permits are all tasks leading the implementation of this alternative. Ecology, WSDOT, and ECAC reviewed and responded to the written deliverables. ECAC also did a site visit during pilot test field work. ECAC generally supports implementation of this alternative but does not accept Chevron’s predictions of hydraulic effects based on the model, nor the predicted time frame to achieve cleanup. I do believe that pilot testing and monitoring of the system during early phases of operation will allow Chevron to eventually optimize the design. And importantly – monitoring of soil and groundwater over time will indicate the effectiveness of the action. The monitoring plan is described in the Interim Action Work Plan currently out for public review. If DPE is not sufficiently effective – Ecology can require addition actions.
The field pilot test was conducted by Chevron’s contractor in February and March of 2015 – yet the results of that work have not been published, nor is it apparent that the results have been used to refine the proposed DPE design, as described in the July 2015 Interim Action Work Plan. ECAC has criticized Ecology’s apparent approval of this communication sequence. The DPE design may have been modified based on the pilot work, but this is not apparent in material provided for public review.
Groundwater Model. The groundwater model was not improved based on our comments (see May 2014 blog entry). Ecology cited ECAC’s concerns on the model in its response to Chevron on the draft Feasibility Study, but did not require Chevron to improve the model. Nor did Chevron choose to improve it or provide a response to ECAC’s comments. One of Ecology’s reasons for requiring that Alternative 6 be implemented as an interim, rather than final action, was the level of uncertainty in the model and thus DPE’s effectiveness. That said, the intended process of pilot testing and responding to data collected during startup of the DPE system is a better means of improving the design than a model can be.
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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.