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3.1.1 Fourth Quarter 1994 Results The VOCs detected during the fourth quarter 1994 monitoring event show that Freon 12, methylene chloride, chloroform, and PCE were found at concentrations of 8.4, 2.0, trace, and 4.3 gg/L, respectively. These results are generally similar to those found during historical monitoring (see Appendix A for historical monitoring data). Chloroform was detected for the first time at a trace amount from the sample from MW-5 during the fourth quarter 1994. Semivolatile organic compounds, organochlorine pesticides, polychlorinated biphenyls (PCBs), and chlorophenoxy herbicides (i.e., COCs) were not detected in MW-5 or any of the other wells (MW-4 and SB-1). As part of the water quality monitoring component of the EMP (described in the Article 5 Monitoring Program [EMCON, 1992] and the WQPS Report [EMCON, 1993]), the Kendall Rank Correlation test for trend was used to evaluate the correlation between time and monitoring parameter concentrations in MW-5. The trend analysis can also be used to assess the nature of the release. The Kendall Rank Correlation test for trend, also called the Mann-Kendall test, is a nonparametric, rank correlation method. The test is described in statistical literature (Gilbert, 1987; Hollander and Wolfe, 1973), and its use is recommended by the U.S. EPA (Loftis, et al., 1989). The trend analysis results are included in Appendix B. The results of the Mann-Kendall test for MW-5 are summarized below: Electrical Conductivity(EC) Upward trend pH No trend Total Dissolved Solids(TDS) Upward trend Chloride Upward trend Sulfate No trend Nitrate-nitrogen No trend Freon 12 Downward trend Freon 11 No trend Methylene Chloride Upward trend PCE Upward trend Bicarbonate Upward trend Total alkalinity Upward trend Total Organic Carbon(TOC) Downward trend Iron Downward trend Zinc No trend SAC\N.\PJ0\0939\09390031.9BG-94\sdg:1 Rev.0 420/95 0939.003.19 3-2