|
SECTIONT'W® Previous Investigations
<br /> • remained below detection hnuts in MW-20 during the groundwater sampling performed in
<br /> 1994
<br /> o In 1994, N"inyo and Moore abandoned the following monitoring wells due to declining
<br /> water levels MW-1 through MW-8 and MW-10 In addition, eight groundwater
<br /> monitoring wells (MW-9, MVS 11, MW-13, MW-14, MW-16, MVI-19, NNV-20, and
<br /> MW-24)were temporarily decommissioned by lowering the top of the well casings due to
<br /> future planned onsite construction activities
<br /> o In 1995, Geocon performed environmental engineering services that included restoring
<br /> groundwater sampling capability for eight groundwater monitoring wells that were
<br /> temporarily decommissed A groundwater monitoring/vapor extraction test well VW 1
<br /> was also installed in 1995 Two vapor extraction test monitoring wells (VM-1 and VM-2)
<br /> and two new groundwater monitoring wells MW-25 and MW-26 were installed by
<br /> Geocon m 1996 A corrective action plan was prepared(Geocon, 1996)
<br /> o Three quarters of groundwater monitoring were performed by Geocon in 1996
<br /> Monitoring wells MW-9, MW-11, MW-12, MW-13, MW-14, MW-16, MW-19, MW-20,
<br /> MW-24, and VW-1 were sampled for TPH g, TPH-d, BTEX, and MTBE Groundwater
<br /> monitoring wells MW-25 and MW-26 were sampled during the last quarter of sampling in
<br /> 1996 Groundwater concentrations of TPH g, TPH-d, BTEX, and MTBE generally
<br /> decreased from the first monitoring event to the current monitoring in monitoring wells
<br /> MW-9 and MW-11, fluctuated in MW-12, MW-13, MW 19, MW-20, and MW-24, and
<br /> increased in MW-14, and MVV-16
<br /> o Groundwater monitoring was performed by Professional Service Industries in May,
<br /> September, December of 1997 and March 1998 Groundwater concentrations of TPH-g,
<br /> TPH-d, BTEX and MTBE continuer) to decrease in monitoring wells MW-9, MW-11,
<br /> MW-12, MW-13, MW-14, MW-16, MW-19, MW-20, MW-24, VW-1, MW-25, and
<br /> MW-26 Concentrations of TPH-d, toluene and xylene fluctuated and concentrations of
<br /> TPH g and benzene decreased in VM-2
<br /> In summary, 21 groundwater monitoring wells have been installed at the Shop 10 site Twelve of the Z wA(5
<br /> groundwater monitoring wells are currently located on site and rime of the groundwater monitoring cl ro\(AV
<br /> wells have been abandoned A total of 125 groundwater samples have been collected and
<br /> p analyzed
<br /> (through the March 1998 groundwater sampling event ) for TPH-g and BTEX. A total of 99
<br /> groundwater samples have been analyzed for TPH-d and a total of 82 groundwater samples have been
<br /> analyzed for MTBE At the Shop 10 site, a total of 241 soil samples were collected and analyzed for
<br /> TPH g and BTEX, and a total of 68 soil samples were analyzed for TPH-d Results of soil and
<br /> groundwater analysis are included in Table 2-1 and 2-2, respectively The frequency of concentrations
<br /> of TPH g, TPH-d, BTEX, and MTBE detected above laboratory reporting limits in groundwater are
<br /> e 's ® t%1 B9T97 OOMALSrOCKTOMREPORr 0=7 AVG-9 A%SW 2-3
<br />
|