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RECORD NUMBER: 23 OF 28

OLS Field Name OLS Field Data
Main Title QSARs for Predicting Biotic and Abiotic Reductive Transformation Rate Constants of Halogenated Hydrocarbons in Anoxic Sediment Systems.
Author Peijnenburg, W. J. G. M. ; 't Hart, M. J. ; den Hollander, H. A. ; van de Meent, D. ; Verboom., H. H. ;
CORP Author Environmental Research Lab., Athens, GA. Office of Research and Development. ;Rijksinstituut voor de Volksgezondheid en Milieuhygiene, Bilthoven (Netherlands). Lab. for Ecotoxicology, Environmental Chemistry and Drinking Water.
Publisher c1991
Year Published 1991
Report Number EPA/600/J-92/145;
Stock Number PB92-166792
Additional Subjects Structure activity relationships ; Reaction kinetics ; Water pollution ; Halogen organic compounds ; Molecular structure ; Abiotic environment ; Biorhythms ; Sediment water interfaces ; Reduction(Chemistry) ; Physical properties ; Environmental persistence ; Bioaccumulation ; Degradation ; Reprints ; Quantitative Structure-Activity Relationship ; Chemical reaction mechanisms
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NTIS  PB92-166792 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 08/22/1992
Collation 20p
Abstract
Quantitative structure-activity relationships (QSARs) are developed relating biotic and abiotic pseudo-first-order disappearance rate constants of halogenated hydrocarbons in anoxic sediments to a number of readily available molecular descriptors. Based upon knowledge of the underlying reaction mechanisms, four descriptors were selected: carbon halogen bond strength, the summation of the Hammett (aromatics) and Taft (aliphatics) sigma constants and the inductive constants (aromatics) of the additional substituents, carbon-carbon bond dissociation energy (aliphatics), and steric factors of the additional substituents. Comparison of the abiotic and biotic QSARs clearly showed the close similarities between both processes. By correlating the rate constants for reduction of a number of halocarbons obtained in a number of distinct sediment samples to the organic carbon content of the samples, the QSARs were made operative for predicting rates of reduction of given halocarbons in given sediment-water systems. The correlations were enhanced by taking into account the fraction of the compounds sorbed to the solid phase. (Copyright (c) 1991 Elsevier Science Publishers B.V.)