SITE INFORMATION AND CORRESPONDENCE FILE 2

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Rodger Liston Darpetro Inc. 749 E. Charter Way, Stockton, California Page 2 of 3 1 . A clear statement of the objectives for the monitoring program ; 2 . A monitoring schedule for each well in the current monitoring well network with a rational for the monitoring schedule for each well that is not proposed to be sampled on a quarterly basis; 3 . Purge procedures to be utilized for each well or set of wells that will ensure that the samples collected will be representative of aquifer conditions; 4. A proposed quality assurance and quality control (QA/QC) program to ensure collection of highly reliable data to meet the objectives of the monitoring program . The QA/QC program should include a detailed description of the decontamination techniques to be utilized for all equipment used for purging the monitoring wells or collecting samples, and appropriate laboratory blanks to be utilized to detect cross contamination of samples; and 5. The techniques utilized to obtain the DTW measurements . The protocols submitted had no statement of the monitoring objectives. The objectives influence selection of purging and sampling techniques , which wells will be sampled and how often , what chemical analyses will be performed on which samples , etc. In the context of an accepted site conceptual model (SCM), the monitoring objectives could help with the evaluation of requests to drop wells from the monitoring program periodically. As noted in the 16 April 2004 letter, CGG has been selecting four wells to exclude from sampling each monitoring event. EHD has no written plan showing how such exclusions can be made while meeting the monitoring objectives for the site, and cannot approve continuation of this practice without the plan : CGG did not include a proposed schedule for sampling the wells rn the protocols. Until a proposed schedule has been received and accepted by EHD, all wells must be sampled each monitoring event. The purge procedures described in the protocols included use of bailers and/or an electric pump. EHD was informed on 29 April 2004 that Mr. Don Light of Del-Tech had been retained by CGG to conduct future monitoring events on your site. Mr. Light requested approval for his use of a Waterra system , Del-Tech's primary method for purging and sampling monitoring wells, on your site. The protocols make no mention of a Waterra system and how it would be utilized to purge and sample the wells. If CGG is planning to use the Waterra system , it should most certainly be included in the monitoring and sampling plan . The protocols make no mention of procedures to be followed to purge and sample wells with water over the screen interval versus those with the water table in the screen interval . The ground water monitoring and sampling plan should address these and any other pertinent issues . The protocols make no mention of procedures to be utilized for quality assurance and quality control on your site. The protocols submitted , which have been included in all recent quarterly monitoring reports, have obviously not been adequate to ensure collection of data having a high degree of confidence. EHD wants to have the plan your consultant will be following to ensure that all aspects of the monitoring and sampling plan are carried out properly. What procedures will be followed to detect cross contamination by any likely source? How will the equipment be decontaminated? What equipment will be utilized for decontamination , i.e. 5-gal buckets, 35-gal or 55-gal drums? Brushes, sponges, or high pressure steam? Will sample blanks be utilized , if so when ? The protocols do describe how depth to water (DTW) measurements will be collected, but do not state that the surveyed elevation points on the well casings are the high points on the well casing that the protocols state the DTWs are measured from . Please document this in the revised ground water monitoring and sampling plan .