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SORPTION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN TO SOILS FROM WATER/METHANOL MIXTURES
Walters, R. W. AND A. GuiseppiElie. SORPTION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN TO SOILS FROM WATER/METHANOL MIXTURES. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 22(7):819-825, (1988).
Sorption of 14C-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to soils from water/methanol mixtures has been evaluated by batch shake testing. Uncontaminated soils from Times Beach, MO, were used in these experiments and ranged in fraction organic carbon (U+0192oc from
0.0066 to 0.077. Volume fraction methanol in the liquid phase (U+0192sa; at U+0192s of 0.5, sorption equilibrium for low-U+0192oc soils was achieved within 1 day, while sorption to the high-U+0192oc soil required as long as 30 days to reach equilibrium. For U+0192s of 1.0 and the high-U+0192oc soil, sorption equilibrium was attained in about 10 days. Sorption isotherms were linear, and when sorption partition coefficients (KD, mL/g) were converted to Km (mol/g), these latter values were log-linearly related to fa. K, values for two soils, when normalized on U+0192oc, gave values of Km,oc that collapsed onto a single line having the equation determined by linear regression analysis: log Km,oc = -4.97U+0192s + 5.30 with r2 = 0.98 and s = 0.20. log Koc, the logarithm of the aqueous-phase partition coefficient normalized on foc, for TCDD extrapolated from this relationship
is 6.6 ± 0.7. The slope of the log-linear relationship is related to the effect off, on TCDD solubility and on TCDD-soil and solvent-soil interactions. Data
presented here suggest that the latter solvent-soil interactions may not increase TCDD accessibility to soil organic matter to the same extent as that reported for less hydrophobic organic solutes.
Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Product Published Date: 07/01/1988
Record Last Revised: 02/06/2009
OMB Category: Other