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Iiy� fes) . 18 June 1997 AGE-NC Project No. 95-0109 Page 5 of 6 concentrations and pH. Nitrate was detected at concentrations from 9 to I I ppm. Ammonium was detected at concentrations up to 16 ppm. Phosphate was detected at concentrations ranging from 9.8 ppm to 12.3 ppm. Potassium was detected at concentrations from 119 ppm to 159 ppm. Soil pH ranged from 7.3 to 8.1. Analytical results are summarized on Table 5. The laboratory report and chain-of-custody form are included in Appendix D. 3.7. ANALYTICAL RESULTS OF SOIL SAMPLES TPH-g was detected in soil samples collected from probing P-20 at concentrations ranging from 120 parts per million (ppm, reported as milligrams per kilogram) to 4,900 ppm. TPH-g was detected in probing P-21 at concentrations ranging from 210 ppm to 770 ppm. BTE&X were detected at concentrations as high as 510 ppm (P20-25). Benzene was detected at 23 ppm in sample P20-35. Analytical results of soil samples are summarized in Table 6. The laboratory report (MAI sample No. 78001 through 78007) and chain-of-custody form are included in Appendix D. . 4.0. CONCLUSIONS Based upon data collected during the June 1997 sampling event, AGE concludes the following: • Ground water flow direction continues to be south-southwest near the northern portion of the site, shifting to south-southeast near the southern portion of the site. • Petroleum hydrocarbons were not detected in wells MW-6 or MW-12 during the June 1997 sampling, which indicates the dissolved hydrocarbon plume has not migrated up-gradient or down-gradient of previously known limits. • Between March and June 1997, concentrations of petroleum hydrocarbons increased in wells MW-7, MW-8, MW-9, MW-11 and MW-14. • TPH-g and benzene concentrations in soil samples collected from probe boring P-21 were substantially less than concentrations detected in samples collected from surrounding probe borings P-16 and P-18. Probe borings P-16 and P-18 were advanced in September and December 1995, respectively. • TPH-g and benzene concentrations in soil samples collected from probe boring P-20 were greater than concentrations detected in probe boring P-14, advanced at the site in September 1995. • Microbiological plate counts and nutrient concentrations in soil have shown little change . from the previous sampling event. It appears that the northern portion of the site has Advanced CeoEnvironmental,Inc.