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Mr. Dave Henry - 2 - 29 Tuly 1999 Sebastiani Vineyards, Inc. Soil Sampling Methods and Equipment (Page 14) The Workplan suggests soil samples may be retained for analytical purposes and describes the methods to be used for collection and analysis. It is not necessary to collect soil samples during the installation of the monitoring wells, except for the purposes of lithologic description. Vertical profiling of the soil column as part of a source investigation is not the purpose of this field program. If analyses are to be conducted, then they should only be performed on the samples collected from the upgradient well for the purpose of defining background concentrations of specific inorganic compounds. Development/Groundwater Monitoring Wells (Page 14) The Workplan states that the groundwater monitoring wells will be developed, if necessary, but does not indicate what conditions would warrant development. All of the monitoring wells must be developed to avoid potential i U dity pioblerns rviul the g-ioundwatcr sampiG;. in addition, Clcv lopmient should be conducted at a minimum of 48 hours after installation, to allow sufficient time for the formation of the cement annular seal. Equipment Decontamination Procedures/Groundwater Monitoring Wells (Page 16) The Workplan states that bailers will be decontaminated between sampling events. Use of disposable bailers may be more economical than the labor needed to decontaminate the bailer between each usage. In addition, the rope used to lower the bailer for sample collection should be not be used between wells, but should be discarded. Quality Assurance/Quality Control Procedures (Page 16) The Workplan states that quality assurance and quality control (QA/QC) measures will be conducted in the laboratory setting. However, the Workplan does not indicate whether QA/QC measures will be implemented for the field program. It is recommended that analysis of one duplicate sample from one well and/or collection of one field blank be performed once a year(representing approximately 10 percent of the samples collected cumulatively on an annual basis). Trip blanks are not necessary as volatile compounds are not being considered for analysis. Groundwater Analytical Protocols and Groundwater Monitoring Wells (Page 16) The Workplan indicates that groundwater samples will be collected for analysis of total dissolved solids (TDS),bicarbonate, chloride, sulfate, nitrate as nitrogen, and sodium. This list of compounds is inconsistent with that which is required in the revised Waste Discharge Requirements (WDRs). The WDRs require that nitrate as nitrogen, TDS, specific conductivity, and pH be analyzed on a quarterly basis for groundwater samples from each of the monitoring wells. In addition, standard minerals are to be performed semiannually. Other than nitrate and TDS, this suite of compounds requires that analysis for calcium, magnesium, sodium, chloride, sulfate, total alkalinity(alkalinity series), and hardness be performed on the groundwater samples. Quarterly Monitoring Reports (Page 17) The Workplan indicates that the quarterly monitoring program, as required in the WDRs, will be implemented, following collection of the initial samples. This suggests that each of the wells will be sampled five times during the first year. It is recommended that the initial sampling program, as proposed in the Workplan (see previous paragraph),be eliminated and that the quarterly program be implemented for a total of only four sampling events during the first year after well installation. c:\ckwfiles\wineries\winememos\winemem00l