Laserfiche WebLink
' 20 September 2002 <br /> AGE-NC Project No 98-0432 <br /> Page 3 of 4 <br /> 3 1 GROUND WATER ELEVATION, FLOW DIRECTION AND GRADIENT <br /> The depth to ground water measured in the monitoring wells ranged from 16 22 to 17 78 feet below <br /> ' the top of the well casing (btoc) (Table 1) The ground water elevations at the site ranged from <br /> 20 22 feet (MW-4) to 20 56 feet (MW-6) above mean sea level (MSL), the average ground water <br /> elevation decreased 0 7 feet since the previous monitoring event in April 2002 <br /> tThe ground water flow direction was inferred to be towards the north,at a gradient of approximately <br /> 0 002 ft/ft near the former UST locations,steepening to approximately 0 003 ft/ft at the northern end <br /> ' of the site (Figure 3) <br /> ' 32 GROUND WATER ANALYTICAL RESULTS <br /> TPH-d was detected in the ground water sample collected from well MW-2 at a concentration of <br /> ' 52 microgram per liter (µg/1) <br /> MTBE detected was in water samples MW-1,MW-2 and at the detection limit in sample MW-5 by <br /> EPA Method 8260 at concentrations of 4,600 µg/1, 130 µg/1 and 0 51 µg/l, respectively <br /> ' No additional petroleum hydrocarbon compounds were detected in the samples analyzed Analytical <br /> results from ground water samples are summarized in Tables 2 and 3 The laboratory reports (MAI <br /> Laboratory ID 0207165-001 A to 006A),quality assurance and quality control(QA/QC)reports and <br /> ' chain-of-custody forms are included in Appendix B <br /> ' 4.0. SUMMARY AND CONCLUSIONS <br /> The following conclusions were drawn from the results of this investigation <br /> ' 0 During the July 2002 monitoring event, the ground water flow direction was north, which <br /> was similar to the prevailing northerly flow direction at the site, the gradient ranged between <br /> ' 0 002 ft/ft in the area of the former USTs to 0 003 ftJft at the northern end of the site <br /> • TPH-d was detected only in sample MW-2 — <br /> ' 0 MTBE was detected in samples MW--1,MIXS2 at concentrations as high as 4,600 µg/l,a low - <br /> detection of 0 51 µg11 was detected in sample MW-5 13 0 piI G <br /> .y <br /> ' Advanced Geo Environmental,Inc <br /> 1 <br />