Edmonds UNOCAL / Chevron Cleanup

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, May 2013

 

By Greg Glass 

 

Public Participation Grant.  ECAC’s current two-year Public Participation Grant from Ecology (2011-2013) ends as of June 30^th.  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 1^st.  The revised CUL/REL Report is due by June 30^th.  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 8^th.  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, 1^st 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.

 

Feel free to contact:  gglassenviro@comcast.net

 

“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.”

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, May 2013

 

By Greg Glass 

 

Public Participation Grant.  ECAC’s current two-year Public Participation Grant from Ecology (2011-2013) ends as of June 30^th.  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 1^st.  The revised CUL/REL Report is due by June 30^th.  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 8^th.  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, 1^st 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.

 

Feel free to contact:  gglassenviro@comcast.net

 

“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.”

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, May 2013

 

By Greg Glass 

 

Public Participation Grant.  ECAC’s current two-year Public Participation Grant from Ecology (2011-2013) ends as of June 30^th.  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 1^st.  The revised CUL/REL Report is due by June 30^th.  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 8^th.  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, 1^st 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.

 

Feel free to contact:  gglassenviro@comcast.net

 

“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.”

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, February 2013

 

By Greg Glass 

 

Feasibility Study.  Since the stakeholders meeting on November 16, 2012, Chevron and its consultant ARCADIS have been responding to comments and revising the Draft Conceptual Site Model (CSM) Report.  The Final CSM Report is due to be submitted soon.  The next steps for the FS are a determination of cleanup levels and remediation levels, especially for allowable residual soil TPH concentrations; development of cleanup alternatives; and development of a ground water capture model.  The current schedule calls for submittal of a Draft FS Report by the end of 2013.  Work on the ground water model may begin by May 2013, but a draft report is not due until August 2013.  Until more interim deliverables are submitted, there is very little for ECAC to review during FS preparation.

 

Ecology Grant Application for 2013-2015.  ECAC submitted a grant application to Ecology for the 2013-2015 two-year grant period, to continue technical review and education activities on behalf of citizens.  The current grant ends on June 30, 2013.  We expect to hear from Ecology later this Spring about continued funding, after Ecology reviews and ranks all of the submitted applications.

 

Ground Water Monitoring Results, 4^th Quarter 2012.  The entire system of ground water monitoring wells, including both perimeter and interior wells, was sampled in December 2012.  The results were reported by Chevron with the February 15, 2012 monthly progress report.  With substantially increased precipitation (heavier than normal) in November and December, ground water elevations had rebounded from lower levels in September and are expected to continue to rise through Spring 2013.

 

Small amounts of LNAPLs product were found in the area of the former slops pond:  well MW-510 and two nearby piezometers, P-12 and P-13.  The only perimeter Point of Compliance well that had total TPH above cleanup levels was MW-510, with 1,759 ug/L.  Previous measurements at that well, before LNAPLs started being detected, were up to a maximum of 25,090 ug/L.  Many of the perimeter wells had no detected TPH.

 

The only interior wells with notable TPH concentrations were two recently installed wells near the WSDOT storm drain line, in the south central Lower Yard:  MW-526, at 1,045 ug/L and MW-525 at 23,416 ug/L.  No LNAPLs were reported at MW-525 despite the substantial TPH concentration.  This is similar to the early results from MW-510, where TPH values of 22,930 and 25,090 ug/L were reported in April and June 2009 with no LNAPLs detected.  LNAPLs were subsequently observed at MW-510.  Future sampling rounds will determine if a similar time trend occurs at MW-525.

 

Seasonal effects, with higher TPH concentrations reported when ground water elevations are higher, have been noted at some wells.  At times there has been a delay in when the higher TPH levels occur.  For instance, at well LM-2 in December 2011 no TPH were detected, but in the following sampling round in March 2012 TPH were 5,925 ug/L.  Similar time trends in total TPH for the same two sampling rounds occurred at MW-129R and MW-136.  One possible explanation for a delay like this is that the TPH source affecting the monitoring well ground water TPH concentration (e.g., residual soil TPH contamination in the vadose zone) is located upgradient, and the delay reflects lateral transport time for the ground water to reach the monitoring well.  It will be interesting to see what the TPH results are for wells like LM-2 and MW-129R in the next sampling round, scheduled for March 2013 (with results likely available by mid-May).

 

The 4^th Quarter 2012 ground water monitoring results are encouraging.  The emerging picture for Lower Yard TPH contamination is two localized areas with TPH well above cleanup levels and/or LNAPLs present – near the former slops pond and near the WSDOT storm drain line – and possibly some intermittent, seasonally-elevated TPH in a few additional perimeter wells.

 

Feel free to contact:  gglassenviro@comcast.net

 

“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.”

 

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, November 2012

 

By Greg Glass

 

New ECAC Consultant.  Charles “Pony” Ellingson has joined ECAC’s technical consultant team for the UNOCAL Edmonds site.  Pony is a hydrogeologist and principal at Pacific Groundwater Group in Seattle, with lots of experience in studies at contaminated sites.  The Feasibility Study now in progress will address alternatives to achieve compliance with ground water cleanup levels at the Point of Compliance wells along the outer boundary of the Lower Yard.  Pony’s expertise in ground water contamination investigations will significantly advance ECAC’s review of the Feasibility Study and cleanup options.  His first task is review and comment on the revised Conceptual Site Model for the site (see below); he attended the November 16^th stakeholder meeting with Ecology to discuss preliminary review issues.

 

 

Feasibility Study:  Conceptual Site Model Report.  On November 2, 2012 Chevron submitted a Draft Conceptual Site Model (CSM) report to Ecology.  That report was prepared by Chevron’s consultant, ARCADIS.  This is the first of several Interim Deliverables within the overall Feasibility Study schedule, with a completed Draft FS report due to be submitted in December 2013.

 

Ecology held a stakeholders meeting on the Draft CSM report at the Northwest Regional Office in Bellevue on November 16^th.  In addition to Ecology, Chevron, and ARCADIS representatives, WSDOT and its consultant, Landau Associates and ECAC participated.  Duane Uusitalo, Greg Glass, and Pony Ellingson attended for ECAC.  Ecology has requested review comments by November 30^th, after which Chevron/ARCADIS will prepare a Final CSM report and then start work on the next elements of the FS:  a review of cleanup levels and remediation levels for soil and ground water, screening of potentially applicable cleanup technologies, and development of a set of alternatives to be evaluated.

 

At the stakeholders meeting on November 16^th participants shared preliminary comments on the Draft CSM Report and posed clarifying questions.  Pony Ellingson focused on hydrogeology issues, which will be central to the identification and evaluation of alternatives to achieve compliance with ground water cleanup standards.  Scott Zorn, ARCADIS summarized site data and portrayed remaining site contamination of interest as limited to two areas, near the former slops pond/DB-2 and near the WSDOT storm drain line.  Ground water monitoring will continue during preparation of the FS and those forthcoming results may confirm or expand this view of remaining site issues.  WSDOT and Chevron will continue to coordinate on alternatives for addressing the documented TPH contamination near the WSDOT storm drain line.  Those alternatives could include having WSDOT take on physical cleanup activities and responsibility for any damage and repairs to the storm drain line that occur during soil excavations.

 

 

Ground Water Monitoring Results, 3^rd Quarter 2012.  In September the perimeter Point of Compliance monitoring wells were sampled; the interior wells were not sampled.  This 3^rd Quarter 2012 sampling round occurred during the latter stages of one of the longest dry periods on record, and ground water elevations were consequently pretty low.  Well MW-510 near the former slops pond had measurable product (LNAPLs) and was not sampled.  All of the other 22 POC wells had total TPH concentrations below cleanup criteria, continuing recent trends.  It will be interesting to see if further sampling rounds with higher ground water elevations continue to show no exceedances of cleanup levels, given the possible seasonal trends previously observed.  The next two sampling rounds in December 2012 and March 2013 will occur during much wetter periods, when ground water elevations will be higher.  Rainfall amounts have been above normal for October and November.  Nonetheless, the recent trends for TPH in POC wells are encouraging.

 

Several piezometers near MW-510 continue to have observed LNAPLs.  Considering both ground water and soils data in this area, it is likely that the former leg of the DB-1 pond area, a portion of which was bermed off to create the slops pond some years after the asphalt plant was put into operation, defines the spatial extent of remaining contamination near and beneath DB-2 (see more at the August 2012 update).

 

The monitoring wells near the WSDOT storm drain line, where elevated soil TPH has been documented, were not sampled in September 2012.  The first result for recently installed well MW-525 was over 13,000 ug/L total TPH.  Further characterization of ground water TPH in this area will occur in the next scheduled sampling round in December 2012.

 

Feel free to contact:  gglassenviro@comcast.net

 

"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."

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, August 2012

 

  By Greg Glass  

 

Feasibility Study.  Chevron submitted a revised Feasibility Study Work Plan to Ecology on July 31, 2012, incorporating responses to Ecology and stakeholder comments on the previous May 2012 version.  Ecology approved certain field investigation activities even while this Work Plan is being finalized.  In June, Chevron’s consultant ARCADIS installed 8 new ground water monitoring wells in the Lower Yard.  Two wells are located in the southeastern Lower Yard, upgradient from MW-135 and MW-136.  Two wells are located close to and downgradient from MW-510 and LM-2, perimeter (Point of Compliance ) wells with higher TPH contamination levels.  Four wells are located in the south central Lower Yard upgradient and downgradient of the 20-mil liner installed near the Washington Department of Transportation (WSDOT) storm drain line, an area of identified remaining soil TPH contamination.  These 8 new wells were installed in time to be included in the 2^nd Quarter 2012 ground water sampling round.  In July, additional sediment sampling was performed (see below).

 

The Feasibility Study Work Plan submitted in July still has a scheduled completion date for a Draft Feasibility Study in December 2013.  ECAC as well as WSDOT’s consultant, Landau Associates, have requested that an interim deliverable identifying the alternatives to be evaluated be added to the schedule, well before the submittal date for the Draft FS.  That milestone will avoid later delays that could occur if the alternatives list is in some respects incomplete.  It will also help identify if additional data could improve the comparative evaluations among alternatives and reduce uncertainties.  ECAC submitted similar review comments to Ecology on both the May and July versions of the Feasibility Study Work Plan.

 

The next milestone for progress on the Feasibility Study is submittal of an updated Conceptual Site Model within a month or two.  Quarterly ground water monitoring will also continue while the FS is being developed.

 

Ground Water Monitoring Results, 2^nd Quarter 2012.  An expanded set of ground water monitoring wells was sampled in June 2012.  This included the 40 wells from the perimeter (Point of Compliance) and interior monitoring networks, four existing wells near the toe of the Upper Yard slope, and eight newly installed wells.  Ground water elevations were also observed in piezometers located in the southeastern Lower Yard and near DB-2.  Chevron submitted the results for the June 2012 sampling round to Ecology with its monthly progress report on August 20^th.  Well MW-510 near DB-2 continued to show a small amount of LNAPL product; product was also observed in two nearby piezometers, and other nearby borings without piezometers or monitoring wells had soil TPH concentrations over 10,000 mg/kg (parts per million).  A review of the 1994 Background History Report provided some of the operating history for this area.  The asphalt plant adjacent to this area to the southwest was constructed in 1953.  An L-shaped leg of the depression (pond, marsh) that later became DB-1 was next to the asphalt plant.  It was not until the late 1960s that a berm was emplaced within this L-shaped extension of the pond area to create what became the “slops pond”.  The asphalt plant therefore operated for approximately 15 years before that berm was emplaced, and any materials (off-spec asphalt product, oil spills, etc.) that made their way into the pond could have been transported beyond the future berm location that defined the “slops pond” – that is, to the locations where product continues to be observed, near DB-2.  The Background History Report notes that DB-2 was constructed after filling of the pond area, with no mention of excavation or removal of contaminated materials.

 

Apart from MW-510, 13 other wells had measurable TPH concentrations.  Five POC wells – 4 along the western site boundary, plus MW-129R near the southeast corner of DB-1 – had low TPH concentrations, below cleanup standards.  Wells LM-2, MW-135, and MW-136, all locations with numerous exceedances in previous sampling rounds, had no detected TPH.  Two new POC wells located near MW-510 and LM-2 also had no detected TPH.  Eight interior wells had detected TPH, with 7 of the 8 at low levels below cleanup standards.  One of the newly installed wells, MW-525 near the WSDOT storm drain line in the south central Lower Yard, had a substantially elevated TPH result in its first sample:  13,363 ug/L.  Further sampling will show whether this is an anomalous “first sample” issue (like what was observed at MW-510) or a more stable result.  Previous soil sampling near MW-525 confirmed that soils with elevated TPH concentrations were still present near the storm drain line.  They were not removed during the Lower Yard Interim Actions because of concern for damaging the storm drain line.  The Feasibility Study will provide further evaluations of alternatives for this area of remaining contamination.  At MW-510, product was not observed for several sampling rounds after installation, but has been frequently observed since then.  So it is also possible that product will show up at MW-525 as monitoring continues.

 

Overall, recent ground water monitoring results show improving conditions with identified residual contamination that appears to be limited in extent.

 

Sediment Sampling Results.  Sediment sampling conducted in Willow Creek around the northern boundary of the UNOCAL Edmonds Site, as part of the Remedial Investigation, identified two areas with failures of at least one bioassay test.  The portion of Willow Creek near the UNOCAL NPDES outfalls along the northwestern site boundary has already been remediated as part of Lower Yard Interim Actions.  Chevron’s consultant, ARCADIS, collected additional sediment samples in July near the other location previously failing a bioassay test, along the northeastern site boundary.  The chemistry results showed little in the way of contamination.  Ecology reviewed those chemical results and determined that no further bioassay tests or sediment cleanup actions are needed in that area of Willow Creek.

 

Feel free to contact: gglassenviro@comcast.net

 

“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.”

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, June 2012

 

By Greg Glass

 

Public Participation Grant.  The Edmonds Citizens’ Awareness Committee (ECAC) has received Public Participation Grant funding from Ecology to continue working on the cleanup of the former UNOCAL Edmonds Bulk Fuel Terminal site through June 30, 2013.  ECAC’s work at this site on behalf of citizens began in 1995.  Activities by Chevron and its consultants ARCADIS during this grant period will include continuing ground water monitoring, additional site characterization studies, and work on a Draft Feasibility Study to identify and evaluate alternatives to complete site cleanup.  WSDOT and its consultants Landau Associates, Inc. of Edmonds are also reviewing ongoing site activities.

 

Ground Water Monitoring Results, 4^th Quarter 2011 and 1^st Quarter 2012.  (See the Monitoring Wells Map on the left for the locations of wells mentioned here).  Sampling in the 4^th quarter of 2011 included the 40 monitoring wells from both the Point of Compliance (POC) and interior well systems in the Lower Yard.  Well MW-510 near DB-2 was not sampled because trace amounts of product (LNAPLs) were reported to be present.  Only one other well marginally exceeded the default ground water cleanup level for total petroleum hydrocarbons (TPH); MW-104 along the western site boundary had total TPH of 771 ug/L.  Wells that had shown elevated TPH in earlier sampling rounds, such as POC wells LM-2 and MW-129R and interior well MW-143, had total TPH results that were quite low or not detected.  Overall TPH concentrations in the 4^th quarter 2011 sampling round were markedly lower.

 

For the 1^st quarter 2012 sampling round, only the 20 POC (perimeter) wells were sampled.  Well MW-510 again had evidence of LNAPLs and was not sampled.  The majority of the remaining wells had low TPH concentrations, but 4 wells other than MW-510 had results exceeding default ground water cleanup levels.  Most notable was LM-2 at the northwest corner of DB-1.  The March 2012 total TPH of 5,925 ug/L, with ground water elevation of 6.43 feet, was the highest since post-Interim Action sampling started, and over 50% higher than the next highest TPH value of 3,925 ug/L.  The pattern of higher TPH results when ground water elevations are higher (see the figure in the December 2011 blog posting) was thus continued for LM-2.  Other than TPH at MW-510 where LNAPLs have frequently been detected, the 5,925 ug/L TPH result for LM-2 in March 2012 has been exceeded only once in recent Lower Yard sampling, in an initial 2008 result for well MW-501 in the southeast Lower Yard.  Well LM-2 has recently shown extreme variability; the previous two rounds had not-detected total TPH, after an extended series of elevated results.  Well MW-129R at the southeast corner of DB-1 showed a return to the elevated TPH concentrations of the 12 sampling rounds before the 4^th quarter 2011 event, which had an anomalously low TPH of 104 ug/L; the March 2012 result was 2,055 ug/L (although a duplicate analysis was much lower).  Well MW-104 showed a small increase over the previous round, from 771 to 940 ug/L total TPH, and MW-136 in the southeast Lower Yard had 835 ug/L after lower results over the four previous rounds.

 

As part of recent investigations of the ongoing ground water impacts at MW-510, a set of piezometers was installed near MW-510 and DB-2.  The two piezometers closest to MW-510 (within approximately 15 feet) have also had detected LNAPLs in recent sampling rounds.  Ground water samples are not being collected for analysis at the piezometers; the results for soil samples collected during installation are included in the 2011 Site Investigation Report.

 

The next ground water sampling event will occur in June 2012, with results expected to be reported by mid-September 2012.

 

Final Reports Submitted.  During May 2012 Chevron submitted two final reports to Ecology.  The results of the four quarterly ground water sampling rounds during 2011 were summarized in the Final 2011 Annual Groundwater Monitoring Report.  The same ground water monitoring program, with quarterly sampling of POC (perimeter) wells and semi-annual sampling of interior wells, was proposed for 2012.  However, the Feasibility Study Work Plan proposes the installation and sampling of additional ground water wells during 2012.

 

The Final 2011 Site Investigation Completion Report was also submitted to Ecology.  During 2011 several additional field studies were performed to provide needed information for the Feasibility Study work.  The extensive excavations and backfilling in the Lower Yard through completion of the Interim Actions changed the physical and hydraulic properties of the Lower Yard materials.  To support further evaluations of ground water conditions, a tidal study and hydraulic studies were performed.  Soil borings, soil sampling, and piezometer installation and observations were also performed near DB-2 and MW-510 to further explore the nature and extent of TPH and cPAH contamination in that portion of the Lower Yard.  The Final Report describes these investigations and summarizes the results.  Soil TPH concentrations as high as 220,400 ppm were found just beyond the margin of previous excavations near DB-2, by far the highest remaining soil TPH levels identified so far.  The occurrence of such high TPH concentrations in borings that were not completed as piezometers indicates a somewhat greater extent of LNAPLs around DB-2

 

Revised Draft Feasibility Study Work Plan Submitted.  Chevron submitted a revised Draft Feasibility Study Work Plan to Ecology in May 2012.  The proposed schedule included with that Work Plan calls for a draft Feasibility Study Report to be submitted in December 2013.  A Cleanup Action Plan with a selected remedy would be prepared by Ecology following review, comment, and revision to that draft report.  Allowing for engineering/design reports and other necessary activities to implement the selected remedy, final cleanup actions would probably not occur until 2015.  ECAC is currently reviewing the revised FS Work Plan and will submit comments to Ecology shortly.  Chevron is proposing additional site characterization studies within the Feasibility Study to support the evaluation of alternatives, including supplemental sediment sampling and additional ground water monitoring well installation and sampling.  Interim deliverables before the Draft Feasibility Study Report is submitted are identified for new site data and an update to the Site Conceptual Model, as well as ground water capture modeling.  One key issue to be evaluated is the allowable soil TPH concentrations within the Lower Yard that are protective of ground water; soil remediation levels will be re-examined and presented in another interim deliverable.

 

Feel free to visit:  gglassenviro@comcast.net

 

“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.”

 

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, December 2011

 

 

By Greg Glass

 

 

Public Participation Grant.  The Edmonds Citizens’ Awareness Committee (ECAC) was notified by Ecology earlier this year that it was awarded a two-year Public Participation Grant for 2011-2013.  However, as a result of the ongoing state budget woes continued funding for this next two-year period has been withdrawn by Ecology.  ECAC is considering other options for funding its role in supporting good cleanup decisions and community education for the UNOCAL Edmonds site.  ECAC has been working on this site since 1995; it now appears that final cleanup will not occur until 2014 or 2015.  Suggestions for funding sources are welcome!

 

 

Ground Water Monitoring Results, 3rd Quarter 2011.  An additional round of ground water samples was collected in September.  Chevron reported the results of that sampling round in its November monthly progress report to Ecology.  As outlined in the proposal for continued ground water monitoring, the September 2011 sampling round included only the 21 perimeter (point-of-compliance) wells.  The next sampling round will occur in December and will include both perimeter and interior wells.

 

 

LNAPLs were reported at MW-510 (near the former slops pond), and also at two newly installed piezometers near MW-510 to the southwest and southeast.  No ground water sample was collected for analysis at MW-510 because LNAPLs were present.  Of the remaining 20 wells that were sampled, only one – MW-129R near the SE corner of DB-1 – had a high total TPH concentration.  The September 2011 TPH level at MW-129R was 2,955 ug/L.  This was the second highest concentration over the last 3 years of ground water monitoring.  The lack of any downward trend in TPH continues to suggest that there is an ongoing TPH source near MW-129R.

 

 

Overall the TPH concentrations in the other 19 perimeter wells were very low in September; MW-129R is notable as an exception to this overall pattern.  The second highest reported TPH level was only 330 ug/L at MW-518 on the western property boundary.  None of these other 19 wells exceeded the ground water TPH cleanup levels for the site.  In some cases the decline in TPH concentrations from the previous rounds was dramatic.  At well LM-2, for example, TPH declined from a range of 2,345 to 3,925 ug/L over the last 3 rounds (October 2010 to June 2011) to not detected in September 2011.  As has been noted before, some wells have shown a distinct “up-and-down” pattern over time in TPH concentrations.  With 14 rounds of sampling over three years, it is possible to start to look at how TPH concentrations vary with ground water elevations, which in the Northwest reflect a typical seasonal variation, with lowest water levels in early Fall (e.g., during the last sampling round in September) after typically dry summers.  A scatterplot of ground water elevations (X-axis) versus well LM-2 total TPH concentrations (Y-axis) is provided below to illustrate this relationship.  It is apparent that for this well TPH levels are high when ground water elevations are high, and low when ground water elevations are low.  (A similar relationship is shown at well MW-104, but not at all wells).  The not-detected result for the last sampling round at LM-2 in September 2011 occurred in combination with one of the lowest water levels seen in that well.  It will be interesting to see whether TPH concentrations rebound to higher levels in continued sampling rounds, as water levels rise.  Any (annual) seasonality trends would be combined with any long-term (multi-year) trends in the record of TPH concentrations over time.  Therefore, a seasonality trend could be “stable” over periods of years or could be repeated at lower and lower levels if there is an overall declining trend in TPH.  This difference could reflect either “steady-state” conditions (ongoing source) or “recovery” conditions (diminishing or absent source).  The take-home message:  a single round of low, even extremely low, TPH concentrations is not definitive, especially where seasonal trends have been evident over previous rounds.

 

 

 

2011 Site Investigation Completion Report.  In Summer 2011 Chevron’s consultant, ARCADIS, completed several additional site investigations to provide information needed for the Feasibility Study leading to selection of final cleanup actions.  ARCADIS submitted a report on these additional site investigations to Ecology on December 9, 2011.  That report presents the results of the following types of studies:  1) a study of tidal influences on Lower Yard ground water, including the influence of the widespread soil excavation and backfill activities during Interim Actions; 2) hydraulic conductivity studies of site ground water; 3) an LNAPL baildown test to investigate LNAPL mobility at MW-510; and 4) field observations and soil testing results from a program of borings near well MW-510 and DB-2.

 

 

The ground water investigation results will inform the development and evaluation of cleanup alternatives in the Feasibility Study for addressing continued ground water contamination in excess of site cleanup levels.

 

 

The borings near well MW-510 and DB-2 revealed areas of elevated soil TPH, with 8 borings having at least one soil sample above 10,000 ppm (mg/kg) total TPH and a maximum of over 220,000 ppm TPH.  LNAPLs were also observed during field activities at some locations and confirmed by subsequent monitoring of installed piezometers near MW-510.

 

 

Draft Feasibility Study Work Plan.  Chevron submitted a Draft FS Work Plan to Ecology on September 21, 2011.  That report proposed a number of additional site investigations to support the Feasibility Study evaluations of cleanup alternatives, but did not actually address the FS process or schedule.  ECAC met with Ecology and Washington State Department of Transportation representatives at Ecology’s Northwest Regional Office on October 28th to discuss this FS Work Plan and site status.  David South, Ecology’s site manager, asked for comments on remaining site issues and then proposed that agency and stakeholder comments on the Draft FS Work Plan await review of the forthcoming Site Investigation report (see above).  Ecology has scheduled a meeting for January 20, 2012 to continue development of a final FS Work Plan by Chevron.  After the October 28th Ecology meeting with stakeholders, Chevron submitted a preliminary proposed schedule for completion of the FS process, which will formally become part of the Final FS Work Plan.

 

 

Feel free to visit:  gglassenviro@comcast.net

 

 

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, September 2011

By Greg Glass

 

 

Feasibility Study.  The first milestone for completion of the Feasibility Study (FS) is submittal of a Draft Work Plan for Ecology review.  Chevron expects to submit that Draft Work Plan by the end of September 2011.  Ecology schedules indicate that the agency’s review will not be completed until near the end of 2011, with a final revised and approved Work Plan expected early in 2012.  Stakeholders, including ECAC and the Washington State Department of Transportation (WSDOT), will receive the Draft Work Plan for review concurrently with Ecology in September.  The Work Plan will include a schedule for completion of the Feasibility Study, which is expected to take a year or more.  Depending on the time required for selecting and designing final cleanup actions, completion of Lower Yard cleanup could extend to 2014.

 

Identifying and evaluating alternatives for Lower Yard cleanup in the Feasibility Study will require a sufficient understanding of the nature and extent, and any ongoing sources for, remaining Lower Yard contamination.  Part of the Feasibility Study process will therefore be the identification and resolution of any remaining data gaps.  Even before submittal of the Draft FS Work Plan, Chevron sought and received Ecology approval for an additional investigation of remaining contamination, including LNAPLs (oil product), in the vicinity of monitoring well MW-510 and the former slops pond (called the Detention Basin No. 2 Investigation by Chevron).  Soil samples were collected from 17 borings in this area in August and are now being analyzed at the lab for TPH and benzene, and for cPAHs if TPH levels are sufficiently high.  Piezometers were installed at a number of the soil borings and will be observed for water levels and LNAPL occurrence.  An LNAPL bail down test was also performed at MW-510 where product has frequently been observed over the past two years of ground water monitoring.  The results of this additional investigation are scheduled to be submitted to Ecology by November 2011.  Chevron, Ecology, WSDOT, and ECAC representatives visited the site and observed portions of this recent field investigation program by Chevron’s consultant, ARCADIS.

 

 

Ground Water Monitoring Results, 2^nd Quarter 2011.  An additional round of ground water samples – the 13^th since the end of Lower Yard Interim Actions in 2008 – was collected in June.  Chevron reported the results of that sampling round in its August monthly progress report to Ecology.  As outlined in the proposal for continued ground water monitoring, the June 2011 sampling round included both perimeter (point-of-compliance) and interior wells (40 total).  The next sampling round will occur in September and will include only the perimeter wells.

 

For the first time since August 2009 no LNAPLs were reported at MW-510.  The total TPH concentration of 15,300 ug/L at that well still indicated significant ground water contamination; this was by far the highest reported TPH result.

 

Overall the results were similar to the previous sampling round in March 2011.  In the southeast corner of the Lower Yard, wells MW-135 and MW-136 repeated their comparatively lower results (still marginally above default cleanup levels) showing a substantial reduction from earlier sampling rounds.  MW-136 has had a pretty consistent declining trend since its maximum value in June 2009.  MW-135 has had a more up-and-down pattern and rebounded once before from a concentration similar to the June 2011 result to a level almost three times higher.  June 2011 results for MW-135 and MW-136 were 785 ug/L and 645 ug/L, respectively.

 

Three perimeter wells, in addition to MW-510, at locations previously noted for higher TPH concentrations continued to show similar results in June 2011.  MW-129R near the southeast corner of DB-1 was slightly lower than previous rounds, at 1,935 ug/L.  LM-2 at the far northern corner of DB-1, with 2,345 ug/L total TPH, was the highest in June of all wells other than MW-510.  LM-2 TPH levels have declined somewhat over the last 3 rounds but remain well above cleanup levels.  On the western site boundary, well MW-104 had its second highest result since the end of Lower Yard Interim Actions; at 2,274 ug/L it was almost twice the previous concentration in March 2011.  MW-104 has had one of the most extreme up-and-down patterns for TPH.

 

One other notable result was for interior well MW-143, which was not sampled in March 2011.  In the last sampling round at MW-143, in October 2010, total TPH was very low at 169 ug/L  The June 2011 result was more than 10 times higher, at 1,745 ug/L – very close to the round just before October 2010, when 1,585 ug/L was reported in July 2010.  MW-143 has also had a very notable up-and-down pattern for total TPH.

 

The June 2011 results continue the post-Interim Action pattern with several areas along the site perimeter continuing to show the highest residual ground water TPH contamination.  MW-143 in the southwest Lower Yard is the interior well with the highest remaining TPH contamination.  The focus in these notes on remaining areas of contamination is consistent with the decision by Ecology that the completed Interim Actions are not Final Actions and that a Feasibility Study to evaluate additional cleanup actions is required.  But this focus on residual contamination should not obscure the fact that most of the monitoring wells, and nearly all of those in the interior of the site, already show acceptable TPH levels.

 

(For well orientation check the well map in the categories at the left.)

 

Feel free to visit:  gglassenviro@comcast.net  

 

UNOCAL EDMONDS BULK FUEL TERMINAL SITE

 

                                     Public Participation Grant No. G1000328 (2009-2011)

                                                                                to

                                             Edmonds Citizens’ Awareness Committee,

                                                       Brackett’s Landing Foundation

 

                                                PPG PROJECT EVALUATION REPORT

 

UNOCAL EDMONDS SITE

 

UNOCAL operated a Bulk Fuel Terminal in Edmonds, Washington from 1923 to 1991.  In addition to the large volumes of various fuels handled at this site for almost 70 years, an asphalt plant was also in operation at the site for about 20 years.  The site is located near Puget Sound, adjacent to Willow Creek and the Edmonds Marsh.  A fish hatchery is also located at the southeast corner of the property.

 

The UNOCAL Edmonds site includes an Upper Yard where storage tanks and distribution piping were located and a Lower Yard with offices, rail and truck loading facilities, the asphalt plant and associated warehouse, and storm water handling facilities (Detention Basins 1 and 2).  After extensive excavation of contaminated soils, the Upper Yard was sold and is now a residential condominium development.  The Lower Yard has been identified for use as a multimodal transportation hub, including relocation of the Edmonds ferry.  A purchase and sale agreement for the Lower Yard has been completed between UNOCAL (since purchased by Chevron) and the Washington State Department of Transportation (WSDOT).  Due to budget constraints, the schedule for development of the multi-modal transportation hub, known as Edmonds Crossing, has been delayed.

 

Site characterization studies of the Lower Yard documented extensive contamination of soils and ground water with TPH and related contaminants.  Floating product (LNAPLs) was also detected at multiple wells over large portions of the Lower Yard.  After early attempts to recover LNAPLs, a series of Interim Actions began in 2001 and included excavation and removal of contaminated soils, removal and treatment of contaminated ground water, and product removal in localized areas of the Lower Yard.  The large Detention Basin 1 was also dewatered and cleaned out.  During 2007-2008 an extensive Interim Action covering most of the Lower Yard was undertaken, intended by Chevron to complete active site remediation.  A post-Interim Action two-year ground water monitoring program started in October 2008.  Ground water chemistry was monitored at 40 wells to track compliance with ground water cleanup levels at the property boundary (the MTCA point of compliance), determine if remaining ground water contamination within the Lower Yard was naturally attenuating, detect any re-occurrence of LNAPLs, and determine if residual soil contamination was adversely affecting ground water quality.

 

The ground water monitoring program was originally intended to include 13 rounds of sampling and analysis of ground water (every two months from October 2008 through October 2010).  The monitoring program was modified midstream to a quarterly schedule, to include only 11 rounds over two years.  Ground water monitoring is continuing on a quarterly basis after completion of the planned two-year post-Interim Action monitoring program.  As of June 30, 2011, data from a total of 12 rounds of sampling are available to track trends in ground water quality following completion of recent Interim Actions.  Based on results to date, Ecology issued a Determination Letter on May 27, 2011 stating that the 2007-2008 Lower Yard Interim Actions do not constitute final cleanup actions for the Lower Yard.  As a result, Chevron will prepare a Feasibility Study to identify and evaluate alternatives for additional cleanup actions.  After the Feasibility Study is completed, Ecology will prepare a Cleanup Action Plan.

 

 

PUBLIC PARTICIPATION GRANT HISTORY

 

Reflecting community interest and concerns regarding cleanup of the UNOCAL Terminal Site, the Brackett's Landing Foundation established the Edmonds Citizens' Awareness Committee (ECAC) to support citizen involvement in the cleanup process.  Brackett's Landing Foundation has applied for and received a series of Public Participation Grants from Ecology, starting in 1995.  Those grants have allowed ECAC to hire its own technical consultants to review site information, provide technical review comments to Ecology, and help educate the community about site contamination issues.  The grants have also supported citizen participation in the extended MTCA cleanup process, so that Ecology can take community interests into account.

 

The formal cleanup process at the UNOCAL Edmonds site started in 1993 when Ecology and UNOCAL signed an Agreed Order for completion of a Remedial Investigation and Feasibility Study.  The time needed to complete site cleanup has far exceeded what was foreseen when ECAC received its first grant in 1995.  Ecology has provided ongoing community support through continuation grants as the cleanup process has been repeatedly extended.  ECAC has applied for a continuation grant for 2011-2013 to continue oversight of the ground water monitoring program, support independent technical reviews of the Feasibility Study (including further site characterization studies to address data gaps) and Cleanup Action Plan, and educate citizens through ECAC’s website.

 

 

CURRENT GRANT ACTIVITIES

 

Monitoring of Site Cleanup.  The planned Lower Yard Interim Actions - which included extensive soil excavations, LNAPL removal, removal and treatment of large volumes of ground water, and backfilling of the Lower Yard – were completed in the second half of 2008.  No additional physical cleanup actions occurred during the 2009-2011 PPG period.  By agreement between Chevron and Ecology, a two-year program for monitoring ground water throughout the Lower Yard and along the property boundary (the MTCA Point of Compliance for ground water cleanup) was instituted after the 2007-2008 Interim Actions.  The status of ground water quality in comparison to established site ground water cleanup levels was to be tracked over this monitoring program (see below).  If ground water conditions had improved and could be shown to be in compliance with the cleanup standards, the Interim Actions could have been considered final cleanup actions.  By the end of the ground water monitoring program it was clear that this was not the case.  The process to complete a Feasibility Study and a Cleanup Action Plan was therefore initiated before the end of the 2009-2011 grant period.  Chevron announced that there would be no further Interim Actions at the site before a final Cleanup Action Plan was developed.  Absent further Lower Yard cleanup actions during this grant period, ECAC’s activities focused on the ongoing ground water monitoring program.  ECAC and its consultant visited the site on two occasions (October 2009 and April 2010) to observe ground water sampling activities.  Ecology’s Blake Nelson, PPG program staff, met with ECAC at the site in October 2009 and was provided with a site briefing.

 

 

Review of Site Reports.  ECAC reviewed and provided technical comments on several reports during the current grant period.  Documents reviewed included the following:

 

• Phase II Lower Yard As-Built Report (May 13, 2009).  Review comments were submitted to Ecology on July 21, 2009.
• 2009 Annual Groundwater Monitoring Report (February 12, 2010).  Review comments were submitted to Ecology on April 19, 2010.
• 2010 Annual Groundwater Monitoring Report (January 25, 2011).  Review comments were provided to Ecology as a document markup on May 20, 2011.
• Aquifer Testing Work Plan (January 25, 2011).  Review comments were discussed with WSDOT’s consultant (Landau Associates) and Ecology.

 

In addition, ECAC received copies of Chevron’s monthly progress reports as submitted to Ecology.  The results for each round of ground water sampling were attached to these monthly progress reports and formed the basis for ECAC’s ongoing review of the ground water monitoring program and site ground water status.

 

 

Meetings.  ECAC met periodically with its technical consultant to discuss the status of site cleanup activities, evaluations of recent sampling results, and plans for community updates via the weblog.  Ecology, Chevron and its consultant ARCADIS, and ECAC, along with WSDOT and its consultant (Landau Associates), continued the cooperative approach established earlier through the Technical Work Group to identify and discuss issues as they arose.  ECAC participated in meetings with this group at ARCADIS’ offices in Seattle on three occasions during the grant period:  October, 2009; November, 2010; and May, 2011.  At these meetings, review comments and technical issues for several site reports (see above) were discussed, cumulative ground water monitoring data were reviewed, and the status of the site and schedules for future activities were discussed.

 

 

Long-Term Ground Water Monitoring Program Data Reviews.  The post-Interim Action two-year ground water monitoring program started with round 1 sampling in October 2008.  A total of 40 wells was sampled and analyzed each round, with additional wells observed for ground water elevations and product occurrence.  During the current grant period results from sampling rounds 5 through 11 of the planned two-year program were reported by Chevron (as attachments to monthly progress reports to Ecology).  The first round of additional sampling from Q1 2011 was also completed.  ECAC reviewed the results from each round as they were reported and prepared summary reports to be posted on ECAC’s website (see below). Time trend plots were prepared for selected sets of wells to visualize and track trends in ground water TPH concentrations; those time trend plots were periodically posted on the website.  At the completion of the planned two-year post-Interim Action ground water monitoring program, TPH results were summarized by sampling round (n=11) and by monitoring well (n=40) in a set of tables to provide an easily accessible overview of ground water quality status at the site.  Those summary tables were also posted at the website.  A number of patterns were observed in the two-year data set.  Some wells, mostly within the interior of the Lower Yard, showed progressive decreases in TPH concentrations over time; by the end of the two-year period, few interior wells exceeded cleanup levels.  A subset of the perimeter (point of compliance) wells showed consistent exceedances of cleanup levels over time, with several having non-decreasing or even increasing TPH concentrations.  Those trends are difficult to reconcile with natural recovery processes and may indicate ongoing TPH sources.  Another subset of wells showed marked “up-and-down” patterns in TPH concentrations over time, with low TPH levels at a point in time followed by exceedances of cleanup levels in later rounds.  Short-term results at such variable wells are thus not necessarily indicative of longer-term compliance.  Petroleum product (LNAPLs) has been consistently observed at one perimeter monitoring well, MW-510, located near the former asphalt plant “slops pond”.

 

 

Weblog.  During the previous grant period, ECAC established a website (www.ecac-unocal.org) as a primary means of keeping the community informed about the status of site cleanup, issues needing resolution, and opportunities to participate and comment on the overall cleanup process.  By June 30, 2011 there have been more than 3,000 hits on this blog site.  The results of 8 rounds of ground water sampling, occurring between June 2009 and March 2011, were reported during the current grant period.  After each round’s results were reviewed, summary information was posted on the ECAC website.  Additional information posted included time trend plots of TPH concentrations at wells, an example calculation of time-to-compliance based on exponential decreases in TPH concentrations over time, summary tables of TPH exceedances of cleanup levels by round and by well, copies of technical review comments submitted by ECAC for various site reports, site status and schedules information discussed at technical Work Group meetings, and the 2007-2009 PPG Evaluation Report.  The website also includes a map showing the Lower Yard and all monitoring well locations and a set of historic airphotos of the UNOCAL Edmonds site and its surroundings.  Ecology’s Determination Letter of May 27, 2011, stating that the 2007-2008 Interim Actions were not final cleanup actions and including a list of key issues for site ground water, was also posted on the website to communicate the latest information on site status.  A preliminary anticipated schedule for completion of a Feasibility Study and Cleanup Action Plan, suggesting that further cleanup activities would not occur before 2014, was also noted on a website posting.

 

 

SITE STATUS AS OF JUNE 30, 2011

 

Attempts at floating product (LNAPLs) recovery in the Lower Yard date back to 1987.  After a series of more limited and localized cleanup actions, the 2007-2008 Interim Actions completed an extensive excavation program to remove contaminated soils, while also removing free product and removing and treating a large quantity of contaminated ground water during excavation dewatering.  The excavation areas and volumes of soils removed were considerably larger than identified during planning of the Interim Actions, based on site characterization information.  Buried drums with product and assorted debris were found buried in the southeast Lower Yard, an area without significant historic operations associated with Bulk Fuel Terminal operations.

 

Some TPH-contaminated soils remain in the Lower Yard, including soils with TPH below the selected remediation level of 2,975 ppm, a few locations with TPH levels marginally above that remediation level, and more substantially contaminated soils near the WSDOT storm drain line.  It is also possible that one or more areas with elevated TPH concentrations have not yet been detected (as substantial portions of the southeast Lower Yard were not identified before excavations began).

 

The post-Interim Action ground water monitoring program has identified continuing TPH contamination above cleanup levels at multiple locations across the Lower Yard.  One well, MW-510 located near the former slops pond adjacent to the asphalt plant, has repeated observations of LNAPLs presence.  Approximately one-third of the perimeter (point of compliance) monitoring wells, at multiple locations along the property boundary, exceed the TPH cleanup levels for the site, and several of those have non-decreasing or increasing concentration trends.  Ground water flow directions are outward from the property boundary, suggesting some degree of continued offsite migration of ground water contamination, some 20 years after site operations ended in 1991.  The non-decreasing TPH trends at some wells, as well as the presence of LNAPLs, suggest that there may still be some uncontrolled sources of petroleum contamination at the site which could result in a prolonged duration of ground water contamination.  The “up-and-down” trends in TPH concentrations at several wells, including at least one well in the interior of the Lower Yard, still need to be understood, especially with respect to seasonal effects of ground water elevations and remaining sources.  In general, ground water in the interior of the Lower Yard has lower TPH concentrations compared to those perimeter wells with elevated levels.

 

Ecology has determined that a Feasibility Study needs to be completed for the Lower Yard to identify and evaluate alternatives for further cleanup actions.  Chevron has begun the steps needed to prepare that report.  It is likely that additional site characterization information will need to be collected to address data gaps and support completion of the Feasibility Study.  Ecology will prepare a Cleanup Action Plan by 2013, which will be released for public comment.  Final cleanup actions are now deemed likely to occur in 2014.  The Draft Work Plan for the Feasibility Study is scheduled to be submitted to Ecology in August 2011.  Ecology expects to complete its review of that Work Plan by the end of 2011.

 

With further PPG support from Ecology, ECAC intends to continue to review all ground water monitoring data, the Draft Feasibility Study and Draft Cleanup Action Plan, and all additional site characterization results, and to inform the community through ECAC’s website and encourage citizen participation in the cleanup process.