Welcome: Don Winters and Mark Eliasen Welcome and thank you for coming.
Ecology reply: Yes this is correct. There have been four phases of investigation and soil removal in addition to soil and groundwater sampling. These phases have been successful in removing significant amounts of contamination. However, some contamination remains on site. Sound Environmental Strategies (SES), the current consultants at the Pace site propose to complete the investigation, prepare a Cleanup Action Plan, and to conduct two pilot tests. The two pilot tests are to evaluate two new methods to cleanup the specific chemicals of concern (contaminants) at this site. These two methods are proven successful at other sites. The pilot tests are to evaluate these two methods here at this site with this soil and these site conditions. I am optimistic that these two methods will be effective in removing the remaining contamination. If not, then Ecology will require other cleanup methods.
2. We have been told that the groundwater is contaminated with vinyl chloride. What other contaminants have been found on the site and at what level?
Ecology reply: I do not have the site file with me. My memory is that the chemicals of concern (contaminants) are primarily vinyl chloride and dichloroethenes. There may be other chemicals associated with vinyl chloride (VC) such as tetrachloroethene or perchloroethene (PCE), trichloroethene (TCE) and dichloroethenes (DCE) in addition to petroleum substances such as diesel and volatile organics such as benzene. During the earlier investigations there has been a lot of chemical laboratory analyses and much of the contamination found earlier has been excavated and removed from the site. One of the tasks of the new proposed work is to review all the past work and to make sure there are not data gaps and chemicals of concern at the site. If data gaps are identified, then Ecology will require more investigation and laboratory analysis to identify the chemicals of conern and their extent and then to evaluate cleanup tasks. So the proposed work includes completing the investigation for data gaps and other chemicals of concern at this site.
3. By how much does the contamination exceed the permitted levels? Is it only slightly above the threshold or is it a major issue?
Ecology reply: Compared to other sites, I would estimate that this site is above cleanup level for vinyl chloride greater than slightly and less than major or significant. Yes it will require cleanup. A site hazard assessment is currently being completed and this will rank this site relative to other known hazardous sites within Washington state. When this work is completed I will forward it to you.
4. What is the name of the company that Pace has hired to clean up the site? What cleanup process are they proposing? Please be specific. Will they be removing more soil?
Ecology reply: Currently, Sound Environmental Strategies (SES), a Seattle consulting firm is working at the former Pace site in addition to Hart Crowser, another Seattle consulting firm. SES has proposed to conduct two pilot tests. One involving zero valent iron injection to address the vinyl chloride in situ, meaning within the soil and groundwater in the substrate below the surface at the property located in the northwest area of the property. The second is a biodegradation process using microbes to assist in breaking down vinyl chloride into neutral chemical subparts at the north-central part of the site. If you like I will be happy to send you a copy of the proposed pilot test work plan. The Pilot Test Work Plan is currently available for review at Ecology's Bellevue office and you need to call for an appointment to Sally Alexander at 425-649-7239. Note, Ecology will observe the pilot testing and results, then we will have information if one or both of these methods are successful at this site. Then we will be able to prepare a cleanup action plan.
In regard of removing more soil, we need to complete these pilot tests and to complete the site investigation first, in order to evaluate what are the best methods for the remainder cleanup that needs to be completed at this site. The question if more soil needs to be excavated, my answer at this time is I do not think so and I need to wait until the site investigation and pilot tests are completed.
5. There have been several environmental firms working on the site over the years. They have drilled monitoring wells and removed lots of soil. Have they made progress or are we about where we started?
Ecology reply: Significant progress has been achieved at this site, however, there remains pockets of contamination at the site. The proposed work outlined in the former Pace National Site fact sheet and the proposed Agreed Order describes the work to be conducted to address the remaining contamination at this site.
6. Has the company estimated how long the process will take?
Ecology reply: The pilot testing results will assist us to make an estimate for the proposed cleanup. Based on other sites, I would make a guess-estimate of one to two years plus compliance monitoring to confirm that the cleanup is completed.
7. How will the State determine when the site is clean enough to require no further action?
Ecology reply: Washington state uses the Model Toxics Control Act (MTCA), our state cleanup process to set cleanup levels for each media (soil, groundwater, air, surface water or wetlands what ever applies to a site) and to set points of compliance to determine that cleanup is completed for each and all media and that the cleanup process has achieved the requirements. The MTCA process includes all state and federal regulations that apply to this site. The last step of the MTCA process is compliance monitoring and this is to confirm that cleanup levels are achieved and sustained. For example for ground water, cleanup levels need to be achieved for four consecutive quarters, then Ecology confirms the site groundwater is cleaned up.