Edmonds UNOCAL / Chevron Cleanup

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  However, as a result of the ongoing state budget woes continued funding for this next two-year period has been withdrawn by Ecology.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.

 

 

UNOCAL EDMONDS BULK FUEL TERMINAL MTCA CLEANUP UPDATE, June 2011

By Greg Glass

 

Starting the Feasibility Study.  Chevron submitted a Draft Year 2 Ground Water Monitoring Report to Ecology on January 25, 2011.  After compiling review comments from Ecology, WSDOT, and ECAC, David South, Ecology’s site manager, convened a stakeholder meeting on May 25, 2011 to discuss that draft report and related matters.

 

After the stakeholder meeting, Ecology issued a formal determination that the Lower Yard Interim Actions did not constitute a final site cleanup, based on continued exceedances of cleanup levels at multiple Point of Compliance ground water monitoring wells.  That letter (see separate posting under Additional Info on the left of the blog) dated May 27, 2011 started a 90 day period for Chevron to prepare and submit a work plan for a Feasibility Study (FS) that will identify and evaluate various alternatives to achieve final site cleanup.  The Draft FS Work Plan is thus due by August 26, 2011.  David South forecast that reviews of the FS Work Plan would not be completed until December 2011, indicating that a revised Final Work Plan would be ready around February 2012.  Allowing for completion of Draft and Final Feasibility Study Reports, selection of a cleanup alternative and preparation of a Cleanup Action Plan by Ecology, and required design studies, it now appears likely that further physical cleanup actions in the Lower Yard will not occur before 2014.

 

Chevron’s Year 2 Ground Water Monitoring report included a proposal to continue ground water monitoring activities at the site.  Quarterly sampling of the POC wells, and bi-annual sampling of interior wells, was proposed.  Sampling of POC wells for the first quarter of 2011 occurred in March (see summary below); second quarter sampling of both POC and interior wells will occur in June.  ECAC considers it critically important to continue ground water monitoring so that trends in TPH contamination can be effectively evaluated.  Several comments on the proposal for continued ground water monitoring are still being discussed with Ecology and Chevron.

 

It was clear at the completion of the two years of post-Interim Action ground water monitoring that Lower Yard cleanup was not complete.  Before the formal initiation of the FS process, Chevron prepared a Draft Aquifer Testing Work Plan, submitted to Ecology on November 19, 2010.  The Final Work Plan was submitted on January 25, 2011 and field work for tidal influence and aquifer testing was completed in May.  The extensive Lower Yard excavations and backfilling changed the characteristics of soils throughout much of the Lower Yard.  The FS evaluations of ground water cleanup options will require an updating of aquifer properties; this aquifer testing program is a first example of identifying and filling data gaps for completing the FS.  Full evaluations of the data collected in this field program will occur within the FS.

 

Petroleum product (LNAPL) has been consistently found at one monitoring well, MW-510.  Chevron will submit a plan to Ecology by June 30, 2011 to further investigate the extent of NAPLs in this area near the former slops pond. Except in unusual circumstances, NAPLs must be removed for site cleanup to be considered complete.  Field work to carry out the NAPLs Work Plan investigations is expected to occur in August 2011.  Final NAPLs cleanup actions are expected to be part of the FS evaluations.

 

Ground Water Monitoring Results, 1^st Quarter 2011.  Chevron’s May 12, 2011 monthly progress report to Ecology included a summary of the results of ground water monitoring that occurred in March (first quarter 2011 sampling).  Under Chevron’s proposed scope for continued ground water monitoring, samples were collected and analyzed in Q1 2011 only for the 21 Point of Compliance (property boundary) wells.

 

Product (LNAPL) was still found at well MW-510 in the vicinity of the former slops pond location; therefore, no ground water sample was collected for analysis at that well.

 

The total TPH concentrations at the Point of Compliance (POC) perimeter wells continue to show multiple exceedances of default cleanup levels at locations spread across most of the Lower Yard property boundary.  LM-2 at the northern corner of Detention Basin 1 had the highest total TPH concentration (3,925 ug/L) among sampled wells in the last round of the two-year post-Interim Action monitoring program, in October 2010.  It still had the highest concentration among wells sampled in March 2011, at 2,625 ug/L.  Chevron collected an additional sample at LM-2 in December 2010 to check the high value reported in October 2010; the December total TPH of 2,405 ug/L confirmed the general trend toward higher concentrations in recent sampling rounds.  MW-129R, near the southeast corner of DB-1, had 2,275 ug/L total TPH; it has exceeded 2,000 ug/L for 9 of the last 10 sampling rounds.  Wells MW-135 and MW-136, at 695 and 643 ug/L total TPH, had substantially decreased concentrations from previous rounds and reflected the greatest reductions.  Along the western boundary, MW-104 at 1,214 ug/L showed a substantial increase from the last 3 rounds, and continued an “up-and-down” (seasonal?) pattern.  MW-147 at 1,524 ug/L continued a pattern of frequent higher concentrations at that location, except for lower mid-summer values (seasonality?).  Additional years of monitoring will be required to confirm any seasonal patterns in ground water TPH concentrations.

 

 As part of its review of Chevron’s Year 2 Ground water Monitoring report, ECAC prepared tables summarizing the TPH results for two years of ground water monitoring.  That summary is provided below and gives results by sampling date and by well over 11 rounds of sampling.  Ecology will meet with ARCADIS, Chevron’s consultant, in late June 2011 to make final revisions to the Year 2 Ground Water Monitoring report in response to reviewer comments, as discussed at the May 25^th stakeholder meeting.  That report will become primarily a data report rather than an evaluation and interpretation report.

 

Feel free to contact:  HYPERLINK "mailto:gglassenviro@comcast.net" gglassenviro@comcast.net

 

 

	UNOCAL Edmonds Former Bulk Fuel Terminal
	Summary of Ground Water Monitoring Results
	Round 1 through Round 11 (Oct 2008 - Oct 2010)
	TPH Exceedances of Default Ground Water Cleanup Levels:
	Summary by Sampling Round
			POC Wells [n=21]
			number	low	high	max location
	Sampling Round			(ug/L)	(ug/L)
	Oct 2008		6	909	8,330	MW-501
	Dec 2008		4	968	5,407	MW-510
	Feb 2009		10	595	16,380	MW-510
	Apr 2009		9	779	22,930	MW-510
	June 2009		9	915	25,090	MW-510
	Aug 2009		7	1,066	18,080	MW-510
	Oct 2009		11	715	2,720	MW-147 (a)
	Jan 2010		8	845	3,105	MW-104 (a)
	Apr 2010		7	908	2,015	MW-129R (a)
	Jul 2010		8	592	2,275	MW-129R (a)
	Oct 2010		7	924	3,925	LM-2 (a)
			Interior Wells [n=19]
			number	low	high	max location
				(ug/L)	(ug/L)
	Oct 2008		9	701	1,697	MW-502
	Dec 2008		5	562	1,438	MW-502
	Feb 2009		6	748	2,005	MW-143
	Apr 2009		6	534 [533]	1,503	MW-502
	June 2009		5	512 [413]	1,175	MW-143
	Aug 2009		3	539 [561]	847 [755]	MW-514
	Oct 2009		4	534 [594]	1,013	MW-507
	Jan 2010		5	544	1,230	MW-502
	Apr 2010		4	646	1,565 [1,875]	MW-143
	Jul 2010		3	534	1,585	MW-143
	Oct 2010		2	575	615	MW-507
	(a)	LNAPLs detected at MW-510, no sample collected for
		lab analysis
	[533]	A second TPH concentration in brackets is for a field
		duplicate sample

 

 

UNOCAL Edmonds Former Bulk Fuel Terminal                 Summary of Ground Water Monitoring Results:  POC Wells   Round 1 through Round 11 (Oct 2008 - Oct 2010)                             TPH Exceedances of Default Ground Water Cleanup Levels:   Summary by Perimeter Well Over 11 Sampling Rounds                     number low high         (ug/L) (ug/L)   POC Well [n=21]  (a)                     MW-150   1 715                 MW-149R   1 775                 MW-524   0                   MW-147   8 968 2,720               MW-523   0                   MW-8R   0                   MW-522   3 779 955               MW-20R   2 866 1,087               MW-104   5 916 3,105               MW-101   0                   MW-518   10 697 [709] 1,403               MW-139R   0                   MW-510 (b)   11 3,980 25,090 (b)               LM-2   8 915 3,925               MW-108   0                   MW-109   0                   MW-129R   9 1,675 4,425               MW-501   5 592 8,300               MW-500   6 595 3,000               MW-135   8 845 2,625               MW-136   9 1,535 3,725                                       NOTES                       (a) POC wells are listed in spatial order, from southwest     to southeast site boundary                 (b) LNAPLs detected on and after October 2009 at MW-510,     no sample collected for lab analysis                 [709] A second TPH concentration in brackets is for a     field duplicate sample           UNOCAL Edmonds Former Bulk Fuel Terminal                 Summary of Ground Water Monitoring Results:  Interior Wells   Round 1 through Round 11 (Oct 2008 - Oct 2010)                             TPH Exceedances of Default Ground Water Cleanup Levels:   Summary by Interior Well Over 11 Sampling Rounds                     number low high         (ug/L) (ug/L)   Interior Well [n=19]  (a)                     MW-143   6 770 2,005               MW-519   0                   MW-520   1 731                 MW-521   0                   MW-511   0                   MW-512   6 534 [533] 748               MW-513   8 534 [594] 932               MW-514   11 575 1,578               MW-515   1 947 [975]                 MW-516   1 801                 MW-517   0                   MW-502   8 512 [413] 1,700               MW-503   0                   MW-504   1 701                 MW-505   0                   MW-506   0                   MW-507   8 562 1,142               MW-508   1 745 [645]                 MW-509   0                                           NOTES                       (a) Interior wells are listed in approximate spatial order,     from southwest to southeast of Lower Yard (in     original MNA plume layout, west-central-east plumes,     from upgradient to downgradient)                 [533] A second TPH concentration in brackets is for a     field duplicate sample

LOWER YARD 2007-2008 CLEANUP (INTERIM ACTIONS): LONG-TERM GROUND WATER MONITORING PROGRAM UPDATE, December 2010

By Greg Glass 

 

Two Year Ground Water Monitoring Program Ends.  The final round of sampling wells at the UNOCAL Edmonds site (Round 11) occurred in October 2010; the results were reported to Ecology by Chevron on December 6^th.  What happens next?  Ecology and Chevron held a stakeholders meeting on November 16^th to discuss the plans and approximate schedules for further activities.

 

After extensive Interim Actions in the Lower Yard to remove contamination, wells throughout the Lower Yard were sampled for two years to track trends in ground water quality (including natural attenuation of residual contamination) and see if the cleanup levels for site ground water were met at the Points of Compliance (the site perimeter) by the end of that period.  Interim Actions removed and treated large quantities of contaminated ground water, excavated and removed large quantities of contaminated soils, and removed floating product (LNAPLs) from large portions of the Lower Yard.  The ground water monitoring data, including Round 11 results, show that despite the extensive cleanup actions multiple Point of Compliance wells have not yet achieved cleanup levels.

 

A ground water monitoring report will be submitted to Ecology by Chevron by the end of January 2011.  We hope that report will provide evaluations and interpretations of the data as a starting point for the development of further actions.  Because the Interim Actions already completed cannot be deemed Final Cleanup Actions, a Feasibility Study will be prepared by Chevron to identify and evaluate alternatives for additional cleanup actions to meet site cleanup standards.  After completion of the Feasibility Study, Ecology will develop a Cleanup Action Plan and select a preferred alternative.  Ecology and Chevron have agreed on this standard MTCA process to develop final cleanup actions.  Further Interim Actions to address parts of the remaining contamination problems are not being considered.

 

The Feasibility Study process will start with development and review of a Work Plan, which will probably be submitted in the first half of 2011.  The Feasibility Study schedule will likely include deliverables along the path to a final report; for example, a list of alternatives to be evaluated should be submitted for early review.  There will be opportunities for stakeholders to review and comment on the Work Plan, a Draft Feasibility Study report, and a Draft Cleanup Action Plan.  At the November 16^th stakeholders meeting Ecology offered a preliminary estimate that completion of a Feasibility Study and Cleanup Action Plan may take two years.  That would mean the final cleanup actions could start in 2013.  The development schedule for the multi-modal Edmonds Crossing transportation hub, according to the Washington State Department of Transportation, does not conflict with this schedule.

 

Some additional site data collection can be anticipated as part of the next steps.  Chevron will be submitting a proposed plan to Ecology soon for continuing ground water monitoring during the Feasibility Study process.  The excavation and backfilling of large portions of the Lower Yard has changed the materials in the shallow ground water zone; a proposal for a tidal influence (hydraulics) study is expected to be submitted soon.  Further data collection to clarify the sources and extent of remaining contamination, to support Feasibility Study development and evaluation of alternatives, may also be needed.

 

Round 11 Ground Water Monitoring Results.  In addition to TPH, Round 11 included analyses for benzene, cPAHs, and natural attenuation parameters in all sampled wells.  Those additional parameters had been dropped from several preceding rounds when the monitoring program was revised after the first year.  The complete analyses in Round 11 provide a snapshot of conditions at the end of the two-year monitoring program.  Evaluations of the natural attenuation parameters should be included in the ground water monitoring report due in January 2011.

 

The overall picture of ground water TPH at the site was largely confirmed in Round 11, although there were notable changes at a few wells.  Product continues to be observed at MW-510 at the former slops pond location.  Wells MW-129R, MW-135, and MW-136 in the southeast Lower Yard had total TPH between 1,685 and 2,625 ug/L.  Well LM-2, at the north end of Detention Basin 1, had the highest TPH concentrations (omitting MW-510 with NAPLs, which was not sampled) in Round 11 at 3,925 ug/L.  Three additional Point of Compliance wells along the western site boundary – MW-149R, MW-147, and MW-518 – had total TPH values between 645 and 1,730 ug/L.  [Depending on TPH composition, the TPH cleanup levels are between about 500 and 700 ug/L].

 

As noted in previous rounds, the interior of the Lower Yard has only minor levels of residual ground water contamination compared to perimeter wells.  Only two wells, MW-507 and MW-514, slightly exceeded 500 ug/L.

 

Notable changes in Round 11 included the following:

 

An almost 90% decrease in TPH at MW-143, in the southwest Lower Yard near the toe of the Upper Yard.  The Round 11 TPH result was only 169 ug/L, compared to over 1,500 ug/L in the two previous rounds.

A new maximum TPH concentration for the two years of monitoring at LM-2.  The Round 11 value of 3, 925 ug/L is more than 75% higher than the previous maximum value in October 2009.  Chevron noted in its December 6^th submittal to Ecology that it planned to resample LM-2 in December to verify this result.

MW-147, along the western site boundary, had TPH at 1,730 ug/L, more than 2.5 times the previous Round 10 value.

 

Thus, monitoring results continue to show some instances of sharp “up-and-down” patterns in wells rather than steadily decreasing TPH concentrations reflecting typical attenuation processes.

 

The time trends for selected wells, grouped geographically, over all 11 rounds of sampling are provided below as visual summaries of ground water TPH concentrations at the site since completion of the extensive Lower Yard Interim Actions.

 

Check Monitoring Well Maps on the left for help in identifying the well locations.

 

 

 

 

 

 

 

 

 

 Feel free to contact:  ( HYPERLINK "mailto:gglassenviro@comcast.net" gglassenviro@comcast.net)

LOWER YARD 2007-2008 CLEANUP (INTERIM ACTIONS): LONG-TERM GROUND WATER MONITORING PROGRAM UPDATE, October 2010

 

By Greg Glass 

 

The results from Round 10 sampling of ground water monitoring wells at the UNOCAL Edmonds site were submitted to Ecology by Chevron on September 13, 2010.  Round 11 sampling, the last planned sampling event for the 2-year post-cleanup ground water monitoring program, will occur later in October.  We expect a Year 2 ground water monitoring report to be completed early in 2011.  It is already clear that some of the wells will not be in compliance with ground water cleanup levels for TPH.  The monthly progress report submitted to Ecology by Chevron on October 7, 2010 noted that Ecology and Chevron have already begun discussing further cleanup activities for the site.

 

The results of Round 10 sampling conform to the general established pattern seen in recent sampling rounds.  MW-510, at the location of the former slops pond along the western site boundary, continues to have product (NAPLs) detected.  Of all of the wells with continued elevated TPH concentrations, MW-510 is the one for which the source seems clearest:  residual slops pond contamination.  MW-510 may not be located at the point of maximum residual slops pond contamination.

 

Most of the interior wells are at low TPH concentrations.  The exception is MW-143 in the southwestern Lower Yard, which had total TPH of 1,585 ug/L in Round 10.  There are no monitoring wells being sampled upgradient of MW-143; the source of the continuing TPH contamination is unclear.

 

Four of the perimeter (point of compliance) monitoring wells exceeded 1,000 ug/L in Round 10.  [TPH cleanup levels depend on the composition of total TPH and will generally be in the 500 to 700 ug/L range].  LM-2, at the northern corner of Detention Basin 1, had 2,075 ug/L total TPH.  The interior wells upgradient of LM-2 do not show elevated TPH concentrations, and DB-1 was cleaned out in an interim remedial action with no significant residual contamination detected.  The source for ongoing LM-2 contamination is unclear, but may possibly be related to the slops pond contamination demonstrated at MW-510.

 

Three additional perimeter wells exceeding 1,000 ug/L in Round 10 are located in the southeastern corner of the Lower Yard.  MW-129R had the highest total TPH concentration in Round 10, at 2,225 ug/L.  MW-135 and MW-136 were at 1,625 and 1,575 ug/L, respectively.  The contamination at MW-129R may be related to operations at the former asphalt warehouse, where asphalt was pumped in a line located in a trench in the warehouse floor.  Alternatively, past disposal practices along the edge of DB-1 may have contributed to contamination near MW-129R.  No wells upgradient of MW-129R, MW-135, or MW-136 are currently being sampled.

 

In summary, then, recent sampling rounds show the major remaining areas of interest for perimeter (point of compliance) wells to be near the slops pond (MW-510), along the southeastern portion of the Lower Yard (MW-129R, MW-135, and MW-136), and at the northern side of DB-1 (LM-2).  The primary interior location of interest is at MW-143, in the southwestern part of the Lower Yard near the toe of the Upper Yard slope.

 

The high variability, or “up and down” pattern, in total TPH concentrations at some wells has been noted in several previous postings.  Examples of wells where relatively low TPH results have been followed by concentrations more than 5 times higher occur at locations across the site:

 

MW-147 351 ug/L in August 2009, then 2,720 ug/L in October 2009 (x7.7)

 

MW-104 464 ug/L in August 2009, then 3,105 ug/L in January 2010 (x6.7)

 

MW-143 258 ug/L in October 2009, then 1,585 in July 2010 (x6.1)

 

LM-2 386 ug/L in August 2009, then 2,225 ug/L in October 2009 (x5.8)

 

MW-502 199 ug/L in August 2009, then 1,230 ug/L in January 2010 (x6.2)

 

MW-501 442 ug/L in April 2009, then 3,385 ug/L in August 2009 (x7.7)

 

 

A brief examination of results at these wells suggests that the variations reflect something other than simple seasonality or a relationship to ground water levels.

 

Feel free to contact:  ( HYPERLINK "mailto:gglassenviro@comcast.net" gglassenviro@comcast.net)

 

 

 

 

LOWER YARD 2007-2008 CLEANUP (INTERIM ACTIONS): LONG-TERM GROUND WATER MONITORING PROGRAM UPDATE, June 2010

By Greg Glass 

The ninth round of ground water sampling was performed in April 2010, with lab results reported to Ecology by Chevron on June 17^th.  With only 2 more scheduled rounds of sampling (in July and October), we are nearing the end of the planned two-year, post-Interim Action excavations ground water monitoring program.  A Year 2 ground water monitoring report will be prepared after the October 2010 results are compiled.

Given the results so far, with product (LNAPLs) consistently being observed in one well and multiple perimeter (Point-of-Compliance, or POC) wells still above ground water TPH cleanup levels, Chevron has started some preliminary work on how the residual contamination could be addressed.

Round 9 results continue to reflect the same general pattern seen previously.  The Interior wells as a group show less TPH contamination than the perimeter wells.  Well MW-510 at the location of the former slops pond still has observable LNAPLs.  Six additional perimeter (POC) wells are above the (default) ground water TPH cleanup levels:  Southeast Lower Yard wells MW-136, MW-135, and MW-129R; well LM-2 at the northwest corner of DB-1; and west-side wells MW-518 and MW-147.  Apart from MW-510, the highest TPH concentration in a POC well is 2,015 ug/L at MW-129R.  The highest Interior well TPH concentration is at MW-143 at 1,565 ug/L [and 1,875 ug/L for a duplicate sample]; only 3 additional Interior wells exceeded the TPH cleanup level, all at less than 850 ug/L.

A preliminary look at some monitoring results, and a little math:

After removal of most of the source(s) of TPH contamination, the residual ground water TPH levels at a well would be expected to decrease fairly steadily over time; an exponential decay model is often used as a first approximation for this time trend.  The UNOCAL Edmonds data over the first 9 sampling rounds show examples of such patterns, as well as highly variable patterns that do not reflect such steady decreases.  For example, compare the total TPH results for these three wells:

MW-518      MW-143   LM-2

10/2008    1,142 <400   <389

12/2008    1,162 <386   <389

  

2/2009      1,403 2,005   1,835

4/2009      1,202    770   1,355

6/2009         675                      1,175                    915                                                                                                                                                    

8/2009      1,066    421      386

10/2009    1,007    258   2,225

1/2010        924    975                 1,625

4/2010        908        1,565 [1,875]      1,585

TPH at MW-518 shows a fairly steady decline over time, with one lower reading on 6/2009; MW-143 and LM-2 have much more “up and down” patterns.  The interpretation of the highly variable time trends may need to consider whether there are ongoing sources affecting TPH concentrations at the wells, the possible effects of seasonal changes in infiltration and ground water levels, varying ground water flow directions seasonally, or other factors causing deviations from a “steadily decreasing concentrations” model.

Detailed evaluations and interpretations of the monitoring data are some months in the future.  It is interesting to note that MW-143 is on the upgradient side of Lower Yard ground water flow directions, and that LM-2 may (at least at times) be downgradient of MW-510 where LNAPLS and elevated TPH levels have been observed.  Most of the POC wells with higher residual TPH concentrations are also seen to have relatively higher TPH-heavy oil (TPH-O) levels.  The highest TPH-O concentration in the ground water monitoring program so far has been at MW-510; perhaps elevated TPH-O levels are a marker for the past (or continuing?) proximity of LNAPLs or near-saturated soil TPH as a source of ground water contamination.

A quick summary of the progress in ground water cleanup, post-Interim Actions, is provided by comparing the Round 9 TPH results (in ug/L) to the maximum TPH for any round, for selected wells:

POC wells:

MW-136 1,535 / 3,725 41.21%

MW-135 1,035 / 2,625 39.43%

MW-129R       2,015 / 4,425           45.54%

LM-2 1,585 / 2,225 71.24%  ***

MW-518  908 / 1,403 64.72%  ***

W-147 1,128 / 2,720 41.47%

Interior wells:

MW-143 1,565 [1,875] / 2,005    78.05%  [93.52%]  ***

MW-512 670 / 748 89.57%  ***

MW-513 487 / 932 52.25%

MW-514 646 / 1,578     40.94%

MW-502 844 / 1,697     49.73%

MW-507 406 / 1,142     35.55%

The maximum values for Interior wells appear to be lower than those for perimeter (POC) wells; maybe this is a result of the greater removal of ground water from the interior of the site during soil excavations.  For both groups of wells, the percentages of maximum TPH still present in Round 9 show two clusters, one around 40% and one around 70% or higher (noted by ***).

Returning to the simple model of exponential decay in TPH concentrations over time, and assuming the reductions illustrated by remaining percentages as shown above reflect 18 months (the duration of monitoring so far), the exponential decay parameter can be estimated and from that the duration until TPH has been reduced to any specified fraction.  [NOTE: using the full 18 months in these calculations, even when the maximum TPH occurred some months into the monitoring program, is conservative in that it gives a high-bound number for the months required to reach any specified level of TPH.  Using less than 18 months would mean a faster reduction in TPH concentrations].

An exponential decay function reduces a starting concentration (in our case, the maximum TPH over the first 9 rounds of sampling) by a factor related to time, t, and a decay constant, k.  After t units of time, e^-kt of the starting concentration remains.  If we let t equal 18 months, the percentages shown above for Round 9 versus previous maximum TPH concentration let us calculate k.  For example, for a percentage of 45%

    e^-kt = e^-k*18 = 0.45

and then

    

    k = 0.044, approximately

For a TPH cleanup level of about 500 ug/L, reductions from a starting value of 1,500 to 3,000 ug/L would mean remaining fractions of 0.33 to 0.167 (or a 3-fold to a 6-fold reduction).  For a TPH cleanup level of about 700 ug/L, those same remaining fractions would mean starting concentrations of 2,100 to 4,200 ug/L.  These are roughly the starting (maximum) TPH values shown above.

So here is the payoff:  our simple exponential decay model, with the parameter value k derived from the reductions so far in ground water TPH values [as a range of k values], lets us estimate the number of months after the start of the ground water monitoring program when the reductions needed to hit the 500 to 700 ug/L range of cleanup levels will be achieved.

MONTHS REQUIRED

Target fraction remaining:

Round 9 fraction    k parameter 0.33 0.25 0.167

0.40         0.051 21.7 27.2 35.1

0.45        0.044 25.2 31.5 40.7

0.50        0.039 28.4 35.5 45.9

0.65        0.024 46.2 57.8 74.6

0.70        0.020 55.4 69.3 89.5

0.75        0.016 69.3 86.6 111.9

These simply calculated values should be considered illustrative, and not predictive; as noted above, the simple exponential decay model may not be applicable at all wells, especially those that are still being influenced by ongoing sources of TPH.

What does this table show?  For wells that have achieved reductions to 40 to 50% by Round 9, about 22 to 28 months would be needed for a 3-fold reduction from a starting concentration, 27 to 36 months for a 4-fold reduction, and 35 to 46 months for a 6-fold reduction.  Appropriate ranges can also be read off for cases where reductions so far are less, to only 65 to 75% of starting values; obviously, the months needed to achieve 3-fold to 6-fold reductions are longer in those cases.  These results suggest that the POC wells will not all be in compliance at the end of the 24-month monitoring program.  And remember that by using 18 months for our exponential decay formula we end up with upper-bound values for the months required.

Feel free to contact:  ( HYPERLINK "mailto:gglassenviro@comcast.net" gglassenviro@comcast.net)

MEMORANDUM: Technical Review Comments, 2009 Annual Groundwater and Geochemical Parameter Monitoring Report, Former UNOCAL Edmonds Terminal (February 12, 2010)

GREGORY L. GLASS

7558 Brooklyn Avenue NE

Seattle, Washington  98115

Environmental Consultant    tel:  (206) 523-1858

DATE:  April 19, 2010

TO:  David South, Ecology/NWRO      

I have reviewed ARCADIS’ February 12, 2010 “2009 Annual Groundwater and Geochemical Parameter Monitoring Report for the Former UNOCAL Edmonds Terminal”.  On behalf of ECAC, I am submitting the following technical review comments.  Please contact me if you have any questions or if further discussions would be useful.

This report does more to summarize and describe the empirical ground water monitoring results than to evaluate them and further our understanding of site ground water contamination.  The extended text summaries of the monitoring results for each of the first 7 rounds of sampling would be better presented as tables.  As an illustration, I have drafted 3 summary tables of the ground water TPH results for rounds 1 through 7 (see separate .xls file, with 3 worksheets).  The first table lists the number of wells exceeding the default ground water TPH CULs (east and west Lower Yard) and the ranges of those exceedances, in ug/L, for POC and Interior wells by sampling round.  The second and third tables summarize the number of TPH default CUL exceedances, by well (POC wells on the second table and Interior wells on the third table), with the range of those exceedances noted.  The ordering of wells in these two tables follows the spatial layout of the wells, making it easier to visualize the results across the entire Lower Yard.  Tables of this type, which summarize all of the TPH results for the first 7 sampling rounds “on a page” (by round, or by well), highlight several features of the ground water monitoring results to date; they tell the story better than extended text summaries.

The final paragraph in the Conclusions section (Section 7, page 31) states:  “Overall, the groundwater IHS concentrations at the site have remained below the specified CULs at most monitoring locations following the interim actions.”  This statement is not supported by the data.  As shown in the attached tables, 25 out of 40 wells have had exceedances of the default TPH CULs over the first 7 sampling rounds:  14 of 21 POC wells (67%), and 11 of 19 Interior wells (58%).  Almost half of the POC wells (10 of 21, or 48%) have had TPH exceedances for 4 or more (i.e., the majority) of the first 7 sampling rounds.  In the last of the 7 rounds included in this report, in October 2009, 11 of 21 POC wells (52%) still exceeded for TPH.  The data summaries presented in the attached tables also show that TPH contamination overall has been higher, and more persistent, in the POC wells compared to the Interior wells.

TPH cleanup levels (CULs) are determined based on the composition of TPH types in a ground water sample.  The CULs that are cited in this report (e.g., see Table 1), and that have been used in reporting on each sampling round as results were submitted to Ecology, are based on average historic compositions for portions of the Lower Yard; they are in reality default CULs (a point I have noted in previous comments).  Final CULs and compliance evaluations should be based on the actual TPH composition of ground water samples.

In that regard, it is interesting to note the effect that a change in analytical labs (see Section 3.3, page 7, bottom paragraph) before the February 2009 sampling round had on the reported TPH composition for multiple wells, and particularly the shift toward higher TPH-D contributions.  CULs will shift lower as the TPH-D component becomes more dominant.  The change in analytical labs achieved a primary goal of lower TPH detection limits.  The apparent change in TPH composition associated with this change in labs is not noted in the report but is worthy of discussion with respect to causes and implications for CULs.

Recent re-evaluations of ground water/surface water interactions at the site, and measured ground water elevation data sets, have led to some revisions in the model for ground water flows at the site.  Ground water contour maps are provided; a discussion of the revised model for ground water/surface water interactions would also be very useful, to update the site conceptual model for ground water.  A number of measured ground water elevations have been determined to be questionable (anomalous) and are not used in developing ground water contours; they are so identified on the contour plots.  A discussion of the possible causes for such anomalous water elevation measurements, and corrective actions to minimize their future occurrence, would be a useful addition to the report.  A similar discussion of anomalous measurements of field parameters would also be useful.

The ground water monitoring system, with 40 wells being sampled for chemical analyses, consists of a mixture of older wells and wells installed just prior to the first sampling round in October 2008.  Were all 40 wells developed or redeveloped before the first round of sampling?  It is interesting to note that the initial results for TPH were anomalously low at a number of wells (e.g., MW-129R, a new well, and MW-136, an older well) considering the total record over the first 7 rounds of sampling.  Inclusion of such low initial TPH results in time trend analyses can have a substantial impact on the results (as would the inclusion of any “anomalous” data).  It is of interest to consider whether the initial monitoring data are representative of “equilibrium” conditions, with respect to soil excavations, ground water removal during excavations, and well development activities.

The time trend analyses use log-scaled concentrations and linear time.  Such log-linear regressions are equivalent to an exponential decay model for concentrations over time.  How was time of sampling entered into the regressions?  What time is represented by the y-intercept value (i.e., what is time zero)?  The fitted curves would support an estimate of the time-to-meet-CULs for any decreasing concentration trends; that information is not explicitly presented in the report.  (Note that such time estimates can be highly dependent on the chosen model, and can differ markedly for regressions using linear concentration versus log-concentration values).  The time-to-meet-CULs is not meaningful for cases of increasing time trends for concentration.  With respect to the status of site ground water and the likelihood of meeting CULs at the end of the two-year monitoring program, however, the mere occurrence of increasing concentration trends is notable at this point in the monitoring program.

The period of sampling available for this initial time trends evaluation is obviously limited.  It should be noted that it covers sampling rounds from October to October, and thus includes somewhat more than one annual hydrologic cycle.  This could be important if there is seasonality in ground water contaminant response (requiring a seasonal trends analysis).  With the limited available data set, it could be interesting to see if there is a general systemic response (i.e., across most wells with more than de minimis TPH concentrations) to changes in ground water levels, which could imply a seasonality component to trends.  Plotting TPH data for multiple wells for the ECAC blog, I have noted that multiple wells seem to show similar up-and-down patterns in TPH over sampling rounds.

The development of a ground water mound in the southeast Lower Yard after completion of soil excavations and backfilling is noted.  The potential significance (including vertical gradients) of that ground water mound for TPH concentrations measured in the two most directly downgradient wells, MW-500 and MW-501, is one aspect of the relationship between ground water elevations and ground water chemistry that should be discussed.

In contrast to relatively simple models of steadily decreasing concentrations of TPH over time, as a result of natural attenuation processes, some wells at this site have shown a pattern of highly variable and “jumpy” TPH concentrations over time.  Such patterns include exceedances of TPH default CULs after one or more rounds of concentrations well below CULs.  These variable patterns are of even more interest assuming source materials have been removed through the extensive Lower Yard Interim Actions.  Given variable TPH patterns over time at some wells (see, for example, MW-104, MW-143, LM-2, MW-135, MW-136 MW-500, MW-501, MW-502, MW-507), time trend analyses will be sensitive to the exact time periods included in the analysis and may have quite limited predictive power.  To give but one example, the time trend analysis for MW-104 (Appendix I) gives a (non-statistically significant) decreasing trend, but the round 8 TPH concentration of 3,105 ug/L substantially exceeds any result from rounds 1 through 7.  The presentation of time trends in this report would be improved by additional discussion of these characteristics of the ground water data set over the first 7 rounds, and cautions against over-reliance on the predictive validity of the results.

There are a number of monitoring wells where reported TPH concentrations are all, or nearly all, not-detected for the first 7 sampling rounds (e.g., MW-109, MW-511, and MW-524).  In the discussion of natural attenuation (geochemical) parameters in Section 5, it would be interesting to compare the geochemical profiles for these wells with de minimis levels of TPH to the profiles at other wells with higher TPH concentrations in support of the interpretation of ground water geochemistry.

Minor Edits

The date on the draft report cover shows 2009, but should be 2010.

Section 3.1, page 4.  The list of wells included as interior monitoring wells (n=19), at the bottom of the page, actually lists 20 wells.  MW-518, a POC well included in the list of POC wells on page 4, is included under interior monitoring wells in error and should be deleted.

Section 3.3, page 6.  The 56 on-site wells noted in the first sentence includes 8 piezometers that were installed in late July 2009 (see Section 3.4.6.1) and therefore were only available for gauging starting in August 2009.  Since the text in Section 3.4 identifies 49 wells being gauged prior to the installation of those piezometers, it would avoid potential confusion if the text in the first paragraph of Section 3.3 distinguished between the 49 wells (including one offsite well, MW-301) and the 8 piezometers, and noted when the gauging program expanded from 49 to 57 locations.

Section 3.3, page 7.  At the end of the top paragraph, a statement can be added to note that the time for collecting water level information at each well in each round is listed in Table 2, and the total time for completing a round of water elevation measurements can therefore be determined from the data in Table 2.

Section 3.3, page 7.  The bottom paragraph says samples were sent to a new analytical lab (Lancaster Laboratories) starting with the January 2009 event.  The next event after December 2008 was not in January 2009 but in February 2009 (see Section 3.4.3).  This should be corrected in the text.  (Perhaps January 2009 reflects the time for completion of making new lab arrangements, not the date for the first sampling event when the new lab was used?)

Section 3.4, page 8.  In the first line of the second paragraph, “grounding” should be changed to “mounding”.

Section 3.4.8, page 13.  The LNAPL thickness reported as “0.01 inch” should be “0.01 feet”.  See Table 2 – LNAPL (apparent) thicknesses are given in units of feet.  As the sentence on page 13 notes, the LNAPL thickness at MW-510 in October 2009 was measured from 6.71 feet to 6.72 feet amsl.

Section 3.6.2, page 17 (subsection 3.6.2.2).  For the December 2008 sampling round summary, the text notes 5 interior wells above TPH CULs, 6 with detectable TPH below CULs, and 9 below the TPH detection limits.  Those 3 categories sum to 20 interior wells instead of 19.  Revise the counts as necessary.

Section 3.6.3.1, page 18.  The counts for POC wells appear to be in error and should be checked.  There are 10 wells with TPH above CULs and 8 with TPH above detection limits but below CULs.

Section 3.6.4.1, page 20.  The number of POC wells is mis-stated as 19; there are 21 POC wells.  The well counts in this subsection should be checked to be sure all 21 POC wells are included.

Section 3.6.6.1, page 23.  In the second paragraph the number of POC wells is mis-stated as 19; there are 21 POC wells.

Section 6, page29.  On the third line from the bottom, delete the second redundant “were”.

The symbols used for monitoring wells on figures appear to have several errors that should be corrected.  The list of POC wells (n=21) is given in Section 3.1, Monitoring Well Network (page 4).  The symbols for POC wells and other, non-POC wells are not correct in some cases; for example, on Figure 18, MW-151 (a non-POC well, see Section 3.1) is shown with a POC symbol, MW-129R (a POC well, see Section 3.1) is shown with a non-POC symbol, and MW-523 (a POC well, see Section 3.1) is shown with a non-POC symbol.  All wells on all figures were not checked for our review, but corrections across all figures should be made as needed.

  UNOCAL Edmonds Former Bulk Fuel Terminal

Summary of Ground Water Monitoring Results

Round 1 through Round 7 (Oct 2008 - Oct 2009)

TPH Exceedances of Default Ground Water Cleanup Levels

POC Wells [n=21] Interior Wells [n=19]

number    low    high    max location number    low    high

    Sampling Round (ug/L)    (ug/L) (ug/L)    (ug/L)

    Oct 2008 6    909    8330    MW-501 9    701    1697

    Dec 2008 4    968    5407    MW-510 5    562    1438

    Feb 2009 10    595    16380    MW-510 6    748    2005

    Apr 2009 9    779    22930    MW-510 6    534 [533]    1503

    June 2009 9    915    25090    MW-510 5    512 [413]    1175

    Aug 2009 7    1066    18080    MW-510 3    539 [561]    847 [755]

    Oct 2009 11    715    2,720 (a)    MW-147 (a) 4    534 [594]    1013

    NOTES

    (a)    LNAPLs detected at MW-510, no sample collected for lab analysis

    [533]    A second TPH concentration in brackets is for a field duplicate sample

UNOCAL Edmonds Former Bulk Fuel Terminal

Summary of Ground Water Monitoring Results:  POC Wells

Round 1 through Round 7 (Oct 2008 - Oct 2009)

TPH Exceedances of Default Ground Water Cleanup Levels

number    low    high

(ug/L)    (ug/L)

    POC Well [n=21]  (a)

    MW-150 1    715

    MW-149R 1    775

    MW-524 0

    MW-147 5    968    2720

    MW-523 0

    MW-8R         0

    MW-522 3    779    955

    MW-20R 2    866    1087

    MW-104 4    916    1,915 [2,046]

    MW-101 0

    MW-518 6    1007    1403

    MW-139R 0

    MW-510 (b) 7    3980    25,090 (b)

    LM-2         4    915    2225

    MW-108 0

    MW-109 0

    MW-129R 5    1675    4425

    MW-501 4    815 [785]    8300

    MW-500 5    595    3000

    MW-135 4    1695    2625

    MW-136 5    1622    3725

    NOTES

    (a)    POC wells are listed in spatial order, from southwest to southeast site boundary

    (b)    LNAPLs detected in October 2009 at MW-510, no sample collected for lab analysis

    [2,046]    A second TPH concentration in brackets is for a field duplicate sample

UNOCAL Edmonds Former Bulk Fuel Terminal

Summary of Ground Water Monitoring Results:  Interior Wells

Round 1 through Round 7 (Oct 2008 - Oct 2009)

TPH Exceedances of Default Ground Water Cleanup Levels

number    low    high

(ug/L)    (ug/L)

    Interior Well [n=19]  (a)

    MW-143 3    770    2005

    MW-519 0

    MW-520 1    731

    MW-521 0

    MW-511 0

    MW-512 4    534 [533]    748

    MW-513 6    534 [594]    932

    MW-514 7    825    1578

    MW-515 1    947 [975]

    MW-516 1    801

    MW-517 0

    MW-502 6    512 [413]    1700

    MW-503 0

    MW-504 1    701

    MW-505 0

    MW-506 0

    MW-507 7    562    1142

    MW-508 1    745 [645]

    MW-509 0

    NOTES

    (a)    Interior wells are listed in approximate spatial order, from southwest to southeast of Lower Yard

(in original MNA plume layout, west-central-east plumes, from upgradient to downgradient)

    [533]    A second TPH concentration in brackets is for a field duplicate sample

LOWER YARD 2007-2008 CLEANUP (INTERIM ACTIONS): LONG-TERM GROUND WATER MONITORING PROGRAM UPDATE, March 2010

By Greg Glass 

Chevron submitted a report to Ecology on February 12, 2010 summarizing and discussing the ground water monitoring data collected for the first year after Interim Action cleanup activities were completed (“2009 Annual Groundwater and Geochemical Parameter Monitoring Report”).  The analytical results from the first seven sampling rounds (October 2008 through October 2009) at 40 monitoring wells (21 Point of Compliance “perimeter” wells and 19 additional “interior” wells) are included in this report.

The Year 1 ground water monitoring report includes discussions of ground water elevations and flow directions, ground water contaminant chemistry, time trends in contaminant concentrations, and natural attenuation (geochemical) indicator parameters.  ECAC will be submitting review comments on this report to Ecology in the near future.

The results from Round 8 ground water sampling, conducted in January 2010, were submitted to Ecology by Chevron on March 12^th.  Three additional sampling rounds are planned for April, July, and October 2010 to complete the scheduled two-year post-Interim Action ground water monitoring program.

The monitoring well at the former slops pond location – MW-510 – continued to show measurable levels of product, and therefore no lab analyses were performed for that well in Round 8.  The apparent product thickness at MW-510 increased in Round 8 to approximately 1.5 inches.

Overall, the perimeter well system continues to show higher TPH concentrations than the interior wells.  One perimeter well, MW-104 on the western site boundary near the tidal basin on Willow Creek, had a new maximum TPH concentration in Round 8; at 3,105 ug/L total TPH this was also the maximum value reported for any sampled well in Round 8.  Monitoring wells showed a mixture of increasing and decreasing TPH concentrations in Round 8 compared to Rounds 6 and 7.  As noted in earlier postings, meaningful trend analyses should be based on much longer records than just two successive sampling rounds a few months apart.  Numerous wells have shown an up-and-down pattern for TPH rather than a steady increase or decrease over time.

Of the 14 wells along the western site boundary, between LM-2 at Detention Basin 1 (DB-1) and MW-150 in the far southwestern corner, 9 had total TPH concentrations less than 360 ug/L.  Besides MW-510 (product) and MW-104 (3,105 ug/L), the 3 additional wells in this area with higher TPH ranged between approximately 900 and 1,600 ug/L.

Wells in the southeastern Lower Yard continued to show elevated TPH levels.  The two wells (MW-500 and MW-501) closest to the ground water mound that developed after soil excavations were completed in the southeastern Lower Yard had low TPH concentrations in Round 8, well below Cleanup Levels.  Well MW-129R (southeast corner of DB-1), with 2,475 ug/L total TPH, had the second highest result of any Round 8 wells.  Wells MW-135 and MW-136, farther to the southeast, had TPH of 845 and 1,545 ug/L, respectively.

The highest TPH concentrations at interior wells occurred at MW-502 (1,230 ug/L) and MW-143 (975 ug/L).  Both of these wells are close to the Upper Yard hillside, on the upgradient side of much of the Lower Yard ground water flowpaths.  Only two additional interior wells marginally exceeded 500 ug/L TPH.  Well MW-507, located in the north-central Lower Yard, continued its pattern of alternating increasing and decreasing TPH concentrations in successive rounds; in Round 8 it was at only 383 ug/L TPH, compared to three previous values over 1,000 ug/L.

The analytical results for Round 9 ground water sampling are expected to be available by mid-June 2010.  No decisions on the need for additional cleanup actions are expected from Ecology until after the results from the complete two-year ground water monitoring program are evaluated.

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

Feel free to contact: ( HYPERLINK "mailto:gglassenviro@comcast.net" gglassenviro@comcast.net)

  

LOWER YARD 2007-2008 CLEANUP (INTERIM ACTIONS): LONG-TERM GROUND WATER MONITORING PROGRAM UPDATE, December 2009

By Greg Glass

Ecology approved modifications to the ground water monitoring program on December 7^th.  The frequency of sampling will be reduced from six times per year to quarterly; the next sampling event will occur in January 2010, with results reported around mid-March.  The final round in October 2010 will include all of the analytical constituents that have been measured up to now, including geochemistry parameters for natural attenuation evaluations.  That will provide a complete “snapshot” of ground water conditions at the end of the planned two-year monitoring program.  The next three of four quarterly rounds will have a reduced set of analytical parameters, including TPH but dropping the natural attenuation parameters and PAHs.  With the extensive excavations that occurred during the 2007-2008 Lower Yard Interim Actions, the “source – plume” model assumed for monitored natural attenuation evaluations for ground water is no longer representative of site conditions, a conclusion shared by all parties involved with the site.

The reduced frequency for ground water sampling will provide a total of 11 rounds of data instead of the 13 originally planned.  Sampling will still cover a two-year period and provide a means to address seasonality effects, if any, on ground water contaminant concentrations.  Statistical evaluations of the complete data set – for example, tests of trends in ground water TPH concentrations at individual wells – will have to take into account the change in sampling frequency.

The results from Round 7 ground water sampling, conducted in October 2009, were submitted to Ecology by Chevron on December 9^th.  Time trend plots for total TPH concentrations at selected wells for Rounds 1 through 7 are provided below; see the monitoring well map to locate individual wells.  These time trend plots will be updated periodically to visually summarize some of the ground water data.

Well MW-510, located at the former slops pond, had measurable product (LNAPL) observed in the October 2009 sampling event.  No ground water sample was submitted for laboratory analysis because the presence of product indicated TPH concentrations would be significantly elevated; well MW-510 has had the highest TPH levels of any well sampled through Round 6.  The results to date indicate further remedial action will likely be needed for the former slops pond.

Consistent with previous results, the Round 7 data show generally higher TPH levels along perimeter (Point of Compliance) wells than in the interior of the site.  Ten of the 21 POC wells (not counting MW-510) exceeded [default] cleanup levels for TPH in Round 7.  [NOTE:  the default cleanup levels based on assumed TPH composition are 706 ug/L on the west side and 506 ug/L on the east side of the Lower Yard].  Several wells, including POC wells LM-2, MW-147, and MW-522 along the western margin of the Lower Yard, had their maximum TPH levels so far in Round 7.  Two wells marginally exceeded the [default] TPH cleanup level for the first time in Round 7, both located at the far southwestern corner of the Lower Yard (MW-149R and MW-150).

Several wells have shown markedly inconsistent or intermittent patterns for TPH contamination through the first 7 rounds of sampling.  Examples include MW-147, LM-2, MW-522, and MW-501 (all included in time trend plots below).  These patterns point to the need for caution in assuming that TPH concentrations will remain low after one or two successive low rounds, whether the reason(s) for the intermittent patterns are identified or not.  A similar intermittent pattern was noted from the long-term ground water monitoring record prior to extensive Lower Yard excavations at other wells, including MW-136.

In the southeast Lower Yard, 4 of 5 wells (MW-129R, MW-500, MW-135, MW-136) continue to show elevated TPH concentrations (approximately 1,500 to 2,600 ug/L).  The exception is MW-501, where TPH dropped from over 3,300 ug/L in Round 6 to less than 150 ug/L in Round 7.  That well also had an anomalously high ground water elevation, associated with the ground water mound in the southeast Lower Yard after excavations and backfilling.  The variability in TPH at southeast Lower Yard wells may be influenced by this ground water mounding.

 

In the northern part of the Lower Yard MW-510 remains highly contaminated (product observed in Round 7).  TPH at well LM-2 has varied over time but had its highest concentration yet (2,225 ug/L) in the most recent sampling round.  Well MW-507, located in the site interior just south of DB-1, has had an alternating pattern in TPH between about 500 and 1,100 ug/L.  (Note:  two versions of the time trend plot for northern wells are provided below.  The second one with a change in Y-axis scaling makes the trends at LM-2 and MW-507 easier to see, without the dominating effect of MW-510).

Southwest of the slops pond, along the western site perimeter, 5 POC wells exceed the [default] cleanup level for TPH.  Two wells in the far southeast corner had TPH between 700 and 800 ug/L, exceeding the [default] cleanup level for the first time (MW-149R and MW-150, not included in the time trend plot below).  The highest TPH occurred at MW-147, at over 2,700 ug/L – a new maximum level for that well and, except for MW-510, the highest to date along the western site boundary.  Wells MW-518 and MW-522 have been comparatively more consistent than MW-147 over time.

 

Most wells in the interior of the site have had TPH concentrations below cleanup levels.  At interior wells with higher TPH levels, the concentrations have been more consistent, even slowly declining, through Round 7 (for example, MW-512, MW-513, MW-514).  MW-502, located near the WSDOT storm drain line where remaining soil TPH contamination has been documented, has been somewhat more variable.

 

Chevron is expected to submit a Year 1 ground water monitoring program evaluation report early in 2010.  

Feel free to contact:   ( HYPERLINK "mailto:gglassenviro@comcast.net" gglassenviro@comcast.net)