TABLE B-2 Number of Detects and Likely Source for Analytes Detected More than Occasionally in 2007 and 2009
|Analyte||Number of detectsa||Likely major source or use|
|Chloromethane||66||54||Natural sources (ATSDR 1998, 1999)|
|Toluene||63||56||Petroleum-based fuel combustion|
|Hexane||65||53||Petroleum-based fuel combustion|
|Pentane||65||NA||Petroleum-based fuel combustion|
|Propylene||32||55||Petroleum-based fuel combustion|
|2-Butanone (MEK)||20||53||Solvent, combustion|
|n-Heptane||60||36||Petroleum-based fuel combustion|
|Octane||46||NA||Petroleum-based fuel combustion|
|Isopropyl alcohol||NA||27||Solvent, disinfectant|
|Methyl tert-butyl ether (MtBE)||29||0||Anti-knock fuel additive|
|Isooctane||17||NA||Anti-knock fuel additive|
|Cyclohexane||NA||8||Petroleum-based fuel combustion|
NOTE: NA = not analyzed.
aTotal possible detects 66 in 2007 and 57 in 2009 except 4-ethyltoluene.
for many analytes at all the measurement locations at JBB, and there did not appear to be any consistent gradients in concentration, although differing gradients exist for some analytes at some times.
During 2007, 18, 21, and 21 PCDD/F nominal 24-hour samples were collected at the guard tower/transportation field, H-6 housing/CASF, and mortar pit locations, respectively, on 20 sampling days (TO-9 method; 60 samples total). Two of the samples for the H-6 housing/CASF and mortar pit locations were obtained on the same day (about 2 hours and 20 minutes apart in starting time, respectively), and on 2 of the 20 sampling days the guard tower/transportation field was not sampled. All samples were analyzed for the seventeen 2,3,7,8-chlorinated PCDD/F congeners, with all congeners detectable in 41 or more of the 60 samples except 1,2,3,7,8,9-hexaCDF (detected in 14/60 samples).
The 2009 sampling data for PCDD/PCDFs included 19, 17, and 18 PCDD/F nominal 24-hour samples at the