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! Quarterly Groundwater Monitoring Report
<br /> 1 Frontier Transportation
<br /> 0199-068
<br /> February 11, 1999
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<br /> Groundwater collected from MW-1, MW-2, MW-4, MW-5, MW-6, and MW-7 identified
<br /> ' no detectable (<500 Ag/L) dissolved TPH-d concentrations using EPA method 8015. In
<br /> monitoring well MW-3, groundwater analysis identified an increase in TPH-d concentrations from
<br /> 600 yg/L in September 1998 to 1,300 Mg/L in December 1998. However, the elevated TPH-d
<br /> ' concentration identified in MW-3 is not representative of true dissolved diesel concentrations.
<br /> Laboratory analysis results reported the TPH-d concentration as a diesel and motor oil mixture
<br /> and not exclusively as diesel.
<br /> Laboratory analytical results identified no detectable dissolved concentrations of TPH-g
<br /> ' above 50 µg/L from groundwater samples collected from MW-5, MW-6, and MW-7 using EPA
<br /> method 8015. TPH-g concentrations attenuated significantly in MW-3 from 26,000µg/L in
<br /> September 1998 to 4,300 mg/L in December 1998. Monitoring wells MW-1, MW-2, and MW-4
<br /> identified a slight increase in TPH-g concentrations from <50µg/L to 130 ugfL, 120 ug/L to 180
<br /> µg/L, and 80 ug/L to 110 ,ug/L, respectively, since the previous monitoring episode performed in
<br /> September 1998. Please see Figure 6, TPH-g isoconcentration map.
<br /> Less than detectable concentrations of BTEX were identified in groundwater samples
<br /> collected from MW-2, MW-4, MW-5, M.W-6, and MW-7 using EPA method 8260. Monitoring
<br /> well MWA observed an increase in BTEX from non-detectable concentrations in September 1998
<br /> to <17.5 µg/L in December 1998. Groundwater analyzed from MW-3 identified a maximum
<br /> BTEX concentration of 2,036 pg/L, an attenuation of 66% from 5,971 mg/L as identified in
<br /> September 1998. Benzene was identified in MW-3 exclusively, however, EPA method 8260
<br /> detection limits for benzene were <5 µg11_. See Figure 7 for Benzene Isoconcentration Map. In
<br /> future groundwater monitoring episodes, BTEX will be analyzed by EPA method 8020 with
<br /> detection limits of<0.5 ug/L for BTE and <1 ,ug/L for X.
<br /> MTBE was identified in groundwater from three monitoring wells only. Groundwater
<br /> samples collected from monitoring wells MW-1, MW-3, and MW-4 identified increased MTBE
<br /> concentrations at 379 ug1L, 3,700 µg/L, and 42 pg/L, respectively, using EPA method 8260.
<br /> MTBE was identified at 38 ug/L in MWA, 13,600 ,Lcg/L in MW-3 (by EPA method 8020), and
<br /> <10µg/L in MW-4 in September 1998. Of the remaining EPA method 8260 analytes from
<br /> groundwater sample analysis, only the following were identified at greater than detectable
<br /> concentrations (See Table 2).-
<br /> MW-1
<br /> ):MW-1 4 10
<br /> AgIL as 1,2,4-Tnmethylbenzene. _
<br /> • MW-2 -4 5 g.g/L as methyl chloride, 6 Ag/L as n-Propylbenzene, and 11 �tg/L as
<br /> 1,2,4-Trimethylbenzene.
<br /> • MW-3 -► 520 µg/L as Acetone, 26 4g/L as Isopropylbenzene, 150 ug/L as
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