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. 30 April 2003 AGE-NC Project No 95-0184 Page 4 of 5 I ■ The ground water was inferred to flow generally northward across much of the site at a gradient of approxunately 0 009 f1/fl (Figure 2), however, the ground water was inferred to flow toward the east in the southeastern portion of the site • Detectable concentrations of TPH-g were found in all of the ground water wells sampled BTEX compounds were found in all ground water samples with the exception of samples collected from MW-7,these samples contained one or more analytes at concentrations above California's Maximum Contaminant Levels (MCLS) • No free product was measured during this sampling event,however,most of the well screens are drowned and are not likely to produce direct evidence of free product • MTBE was detected in samples from wells MW-1 through MW-4, VW-2B, VW-3Aand VW-4 at concentrations ranging from 2 6 µg11 in sample MW-1 to 510µg/1 in sample VW-4 I 1 • 1,2-DCA was detected in samples MW'; MW-4, V 2B, VW-3, VW-4, VW-SB and VW-5C, at concentrations ranging from gg/L(MW- )to 550µg/1(VW-2B) EDB was detected in samples MW-4,VW-2B and VW-5B at concentrations of 19 µg/1, 340 Ag/1 and 260 µg/1, respectively i • The concentrations of MTBE, EDB and 1,2-DCA in the ground water samples exceed the DHS MCLS for drinking water 4s p 9 Not4V'rt"- • Naththalene, 1,2,4-tnmethylbenzene, 1,3,5-tnmethylbenzeneond n-propylbenzene were detected in ground water samples at concentrations above the DHS-recommended drinking water action levels • The vertical and lateral extent of impacted soil and ground water has not yet been defined 5.0. RECOMMENDATIONS Based upon data collected from the site, AGE recommends • Continued quarterly ground water monitoring The first quarter 2003 monitoring event was performed in March 2003 the report is in preparation ' • Two of four proposed cone-penetrometer test (CPT) soil borings were advanced to a 0 YL4) 2-V43 maximum depth of 180 feet bsg on 13 to 15 November 2001 to assess the vertical and lateral 5 h D Sd extent of impacted soil and ground water, to define hydrogeologic flow units at the site, and i e,+#4--r to optimize locations of additional monitoring and extraction wells, however, ground water r ved was still impacted at 180 feet AGE is preparing an addition to the onginal Work Plan Addendum -February 2002 to advance the two remaining CPT borings to 200 feet bsg "0 del GUorJeC !Olm,�-to vlels�ect Advanced GeoEnvironmental,Inc. c1r� 'r- 61) r)i?e p(d pT