|
I
<br /> 2.2 Quarterly Monitoring Results
<br /> A summary of the analytical results of the samples collected during the quarter is displayed in
<br />' Table 1 while the complete analytical reports are presented in Appendix B Table 2 presents a
<br /> chronological record of the sampling results of all previous sampling events at the site All
<br /> I sample numbers correspond to the well from which they were taken except for two quality
<br /> assurance samples Sample MW-12 is a field decontamination procedure check sample collected
<br /> after sampling monitor well MW-1 and sample MW-13 is a duplicate of primary sample MW-1
<br /> Both of the quality assurance samples were analyzed only for BTEX compounds
<br /> TABLE 1
<br /> Analytical Results Summary
<br /> Second Quarter 1993
<br />' Well TPH-G Benzene Toluene Ethylbenzene Xylene Total Lead Fecal Coliform
<br /> (µglL) (Ag/L) (ug/L) (IeglL) (deg/L) (mg/L) (MPN/100 ml)
<br /> MW-1 ND5 o ND,0 ND,o ND,, ND,, NA NA
<br /> IMW-2 150 1 3 ND,o ND,0 ND,U NA NA
<br /> MW-3 400 ND,, ND,a ND,u ND,n NA NA
<br />' MW-4 ND,, ND,,, ND,o ND,U ND,U NA NA
<br /> MW-5 ND,, ND,0 ND,,, ND,0 ND,0 NA NA
<br /> MW-6 NDS 0 ND,o ND,0 N1310 ND,, NA NA
<br /> MW-12 NA ND,o ND,u ND,0 ND,, NA NA
<br /> MW-13 NA ND,,, ND,, ND,0 ND,U NA NA
<br /> Tank-61893 78 ND,, ND,o 1 ND,o ND,, NA NA
<br /> ND = Nori-detectable at the level of detection noted NA = Not analyzed
<br />' As shown on Table 1, the only hydrocarbon compounds found in the groundwater at the site
<br /> during this quarter were benzene at 1 3 µg/L and TPH-G at 150 µg/L in MW-2 and TPH-G at
<br /> I 400 µg/L in MW-3 As shown on Table 2, groundwater quality trends at the site indicate that
<br /> chemical concentrations have significantly decreased from previous quarter results in all wells
<br /> except for TPH in MW-3 In particular, benzene, the only BTEX compound that has been
<br />' historically found in significant concentrations at the site, has currently dropped to non-detectable
<br /> results in all wells except MW-2 While this drop in concentration may be a seasonal anomaly,
<br /> the trend is very clear
<br />' Regarding the QA samples, good repeatability of the laboratory analysis was found between the
<br /> field duplicate (MW-13) and the primary well sample (MW-1) as BTEX concentrations were not
<br />' detected in either sample The decontamination check sample (MW-12), collected after sampling
<br /> MWA, showed no detectable compounds present in field equipment after completion of a
<br /> standard field decontamination procedure
<br /> I
<br />' SMRPTMAREG2QTRwP 4 08IM93
<br />
|