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Surface water samples also are to be analyzed for the following constituents of concern (COCs) every 5 years. • Total organic carbon a Cyanide • Carbonate • Sulfide • Bicarbonate • Oil and Grease • Total alkalinity • Chemical oxygen demand • Metals Dissolved oxygen MONITORING RESULTS GROUNDWATER Groundwater monitoring data for the third quarter of 2000 is presented in Table 1. Appendix E contains a tabular summary of the historical monitoring data. Concentration limits were updated this quarter, and monitoring results were compared to the limits presented on Table 1. In several instances the concentration limits could not be updated because the false positive rate is greater than 5%. An analysis of variance (ANOVA)test was performed and the results showed a variance in Chloride, EC and Nitrate in MW-3, and Nitrate in MW-2. There were no significant increasing trends in these constituents. The ANOVA is not a very powerful test, and there are no increasing trends, so the County believes these wells are still unimpacted. QUARTERLY MONITORING AND FIELD PARAMETERS A comparison of the quarterly field parameter results to the concentration limits in Table 1 shows that there are no exceedences this quarter where concentration limits could be determined. The constituents that concentration limits could not be determined, further testing seems to show that these are also not exceedences. VOLATILE ORGANIC COMPOUNDS (VOC'S) During the third quarter monitoring event Acetone and Napthalene were detected in MW-2, and 1,1-Dichloroethene, and Trichloroethene were detected in MW-3. Because Acetone is a common ' laboratory solvent, the County believes this detection to be laboratory error and does not warrant a retest. Also,the County does not believe a retest is warranted for well MW-2 because Napthalene is a single non-laboratory contaminant trace detection, and as thus does not need to be retested. Detections of 1,1-Dichloroethene and Trichloroethene in MW-3 have both occurred in the past. The County is preparing an Evaluation Monitoring Plan as requested by the Regional Board to address the detections of 1,1-Dichloroethene and Trichloroethene. A report will be submitted on the constituent of concern monitoring as soon as the results are available. Further monitoring will determine the extent of contamination of these constituents. Surface Water First storm samples were taken during the first quarter monitoring event. Also, during the first quarter monitoring event, the five year COC's for surface water were analyzed. During the third quarter monitoring event,no water was present for sampling. I ' 6