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OUR <br /> transport rate of approximately 100 ft/year in the B-zone, indicate the need for B-zone <br /> implementation of ERD as soon as possible. We believe that funds expended in such an effort <br /> would result in a very large cost savings as compared to implementing more difficult and costly <br /> remedial measures in the future if B-Zone ERD implementation is postponed. <br /> Response 1: <br /> The Phase V Plan includes collecting additional contaminant concentration and biogeochemical <br /> data allowing for a more thorough assessment of the rate at which natural attenuation is occurring <br /> in the B-zone. The Trust has committed to providing the RWQCB with a letter format update on <br /> the progress of natural degradation within the B-zone during A-zone injections. This letter will be <br /> submitted after the baseline data and first two quarters of groundwater monitoring data have been <br /> collected, approximately seven to eight months after implementation of ERD in the A-zone begins. <br /> If it is determined at that time that progress is not being made within the B-zone or that the <br /> magnitude of the concentrations are of concern, then a proposal for implementing ERD injections <br /> or other technologies will be provided at that time. <br /> Comment 2: <br /> We also wish to go on record informal disagreement with the following statements made in the <br /> Detailed Plan, which seem aimed at minimizing the significance ofB-Zone contamination: <br /> Third paragraph on page 3, Section 1.2 - <br /> "Review of the time concentration graphs presented in Appendix A shows the steady decline <br /> of VOC concentrations in each of the B zone wells with many of them being at or below MCLS <br /> at this time. " <br /> Second paragraph on 6, Section 2.2.1 - <br /> "In addition, total Hazardous Substances in well MW-205B have generally decreased since <br /> December 2001. " <br /> We believe that the site data do not support the conclusions made in the above statements, and we <br /> request that these statements be removed from the Detailed Plan. <br /> Response 2: <br /> It is LFR's professional opinion that the majority of the B-zone wells at the Site have shown a <br /> steady decline of VOC concentrations over time. As such, this statement will not be changed. <br /> Going forward, concentration trends for each monitoring well will be evaluated using the <br /> Mann-Kendall statistical analysis method. The results of this evaluation will be presented in the <br /> aforementioned report scheduled to be submitted approximately seven months after the A-zone <br /> ERD injections. Regarding conditions at well MW-20513, LFR believes that the data could be <br /> interpreted in a number of ways and, as such, LFR will remove that statement from the document. <br /> 1tr-Farr-RTC-141un LPL-PhV-06750(fina1).dm:d 2 <br />