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® = = = M = == = = =I= = M = = = <br />Table 1 (Continued) <br />Predicted Vapor Phase VOC Concentrations in Lower Vadose Zone Soil <br />Equivalent to Maximum Groundwater Concentrations at the PQL and MDL <br />Analytes(s) <br />Henry's <br />Constant <br />KH(b) <br />(Dimensionless) <br />Henry's <br />Constant <br />kH(b) <br />(atm-mYrnol) <br />Regulated <br />Groundwater <br />Concentration <br />at PQL(c) <br />(µg/L) <br />Vapor <br />Concentration <br />Equivalent to <br />PALO) <br />(µg/l-) <br />Vapor <br />Concentration <br />Equivalent to <br />PQLO) <br />(ppbv) <br />Regulated <br />Groundwater <br />Concentration <br />at MDUO <br />(µg/L) <br />Vapor <br />Concentration <br />Equivalent to <br />MDUN <br />(µg/L) <br />Vapor <br />Concentration <br />Equivalent to <br />MDUN <br />(ppbv) <br />1,1,1,2 -Tetrachloroethane <br />0.016tg1 <br />0.00039 <br />0.50 <br />0.008 <br />1.164 <br />0.34 <br />0.0054 <br />0.786 <br />1,1,2,2 -Tetrachloroethane <br />0.0203 <br />0.0000500 <br />1.0 <br />0.0203 <br />2.955 <br />0.59 <br />0.0120 <br />1.747 <br />Tetrachloroethene <br />0.923 <br />0.0227 <br />0.50 <br />0.4615 <br />67.176 <br />0.44 <br />1 0.4061 <br />59.112 <br />Toluene <br />0.269 <br />0.00661 <br />0.50 <br />0.1345 <br />35.676 <br />0.32 <br />0.0861 <br />22.838 <br />1,2,3-Trichlorobenzene <br />0.1300 <br />0.0032(d) <br />0.50 <br />0.0650 <br />8.760 <br />0.46 <br />0,0598 <br />8.059 <br />1,2,4-Trichlorobenzene <br />0.0934 <br />0.0023(d) <br />0.50 <br />0.0467 <br />6.294 <br />0.41 <br />0.0383 <br />5.162 <br />1,1,1 -Trichloroethane <br />0.112 <br />0.00276 <br />0.50 <br />0.0560 <br />10.256 <br />0.19 <br />0.0213 <br />3.901 <br />1,1,2 -Trichloroethane <br />0.0476 <br />0.00117 <br />0.50 <br />0.0238 <br />4.359 <br />0.43 <br />0.0205 <br />3.755 <br />Trichloroethene <br />0.363 <br />0.00892 <br />0.50 <br />0.1815 <br />33.798 <br />0.36 <br />0.1307 <br />24.339 <br />Trichlorofluoromethane <br />4.47 <br />0.111d1 <br />0.50 <br />2.2350 <br />397.7 <br />0.42 <br />1.8774 <br />334.1 <br />1,2,3-Trichloropropane <br />0.00851gi <br />0.0002 <br />1.0 <br />0.0085 <br />1.410 <br />0.55 <br />0.0047 <br />0.779 <br />1,2,4-Trimethylbenzene <br />15.83 <br />0.39(e) <br />0.50 <br />7.9150 <br />1,608. <br />0.18 <br />2.8494 <br />579.1 <br />1,3,5-Trimethylbenzene <br />15.02 <br />0.37te1 <br />0.50 <br />7.51 <br />1,526. <br />0.28 <br />4.21 <br />855.7 <br />Vinyl chloride <br />28.3 <br />0.695 <br />0.50 <br />14.15 <br />5,527. <br />0.16 <br />4.53 <br />1,770. <br />Xylenes (total) <br />0.2558 <br />0.0063te1 <br />0.50 <br />0.1279 <br />29.470 <br />0.48 <br />0.1228 1 <br />28.295 <br />Ico. ia/ nnarytas are rur vvL4 tired Tor uocrH Method czours Tor groundwater. vapor concentrations are applicable to USEPA Methods TO -14A or TO -15, assuming use of mass spectroscopy. <br />(b) Henrys Law Constants used in this calculation are dimensionless (KH) derived experimentally within the temperature range 293-298 deg K. Henrys Constants (kH) with units atm m3/mole are also presented. Their numerical <br />relationship Is given by the conversion KH = 40.6 kH, Most values presented were taken from USEPA (1997). Other values were taken from other sources as noted. <br />(c) The Practical Quantification Limit (PQL) and Method Detection Limit (MDL) are based on USEPA Method 82608 for analysis of VOCs in groundwater. <br />(d) Value of kH is taken from Shiu (1981). <br />(e) Value of kH is taken from Heath at al., (1993). <br />(f) Value of KH is taken from USEPA (1991), adapted from Howe at al., (1986). <br />(g) Value of KH is computed from the analyte's molecular weight, MW (g/mole); vapor pressure, VP (atm); water solubility, S (mg/Q; Universal Gas Constant, R (atm m3/mole NC); and temperature, T (IK); from the relationship: KH = <br />(VP + Mw) / (SRT). Computed values of KH are used to supplement the lack of data in the literature for those VOCs whose vapor pressure and solubility in water are extreme, rendering KH less reliable. <br />(h) Value of kH is taken from Mabey at al., (1982). <br />(i) Data unavailable or inadequate. <br />Q) Typical values for vapor phase PQL for USEPA Method TO -14A or TO -15 analytes are 0.8 to 3.0 ppbv; some vapor concentrations are less than PQL, as noted. <br />(k) Typical values for vapor phase MDL for USEPA TO -14A or TO- 15 analytes are 0.5 to 1.0 ppbv; some vapor concentrations are less than the MDL, as noted. <br />Prediced Vapor Equivs to GW PQL and MCL.doc Page 4 of 4 <br />