ARCHIVED REPORTS XR0000190 - Laserfiche WebLink

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California Department of Transportation February 24, 2000 P ry Shop 10 Maintenance Station, Stockton, California Project No 103872-02 In well MW-13, TPH-G decreased in concentration from 450 go to 300 gg/l Benzene de- creased from 85 µg11 to 7 3 µg/1, ethylbenzene increased from non detect levels to 37 µg/1, and total xylenes decreased from 9 0 gg/l to non detect TPH-D could not be analyzed for sample MW-19 due to broken containers upon lab arrival of samples TPH-G decreased in well VM-1 from 8,820 gg/l to 1,500 µg/l and TPH-D decreased from 700 gg/l to non-detect levels Concentrations of benzene decreased from 3,890 µg/1 to 192 µg/1, eth- ylbenzene has decreased from 1,000 µg/l to 58 µg/l, and of total xylenes have decreased from t1,220 gg/l to 120 µg/l A duplicate sample designated as VM-21, was taken at VM-1 The duplicate analysis results were within range of the primary sample Well VM-2 was paved over and could not be sampled According to laboratory analytical data for 8260B, other VOCs that were detected during the icurrent groundwater sampling event are 1,2-dichloroethane, 1,2,4-trimethylbenzene, 1,3,5- trimethylbenzene, isopropylbenzene, naphthalene, n-propylbenzene, tert-butylbenzene 6. RECOMMENDATIONS Based on the results of the Fourth Quarter 1999 groundwater monitoring analytical results, which indicated elevated concentrations of TPH-G, TPH-D and/or BTEX, Ninyo & Moore recom- mends that quarterly groundwater monitoring continue at the site 7. LIMITATIONS The environmental services described in this report have been conducted in general accordance 1 with current regulatory guidelines and the standard-of-care exercised by environmental consult- ants performing similar work in the project area No other warranty, expressed or implied, is shop IQ doc 5