Record Display for the EPA National Library Catalog


Main Title Paraquat Sorption as a Function of Particle Size in Natural Sediments.
Author Karickhoff, Samuel W. ; Brown., David S. ;
CORP Author Environmental Research Lab., Athens, Ga.
Year Published 1977
Report Number EPA/600/J-78/013;
Stock Number PB-282 232
Additional Subjects Particle size distribution ; Pyridinium compounds ; Herbicides ; Sediments ; Adsorption ; Isotherms ; Numerical analysis ; Water pollution ; Paraquat herbicide ; Bipyridinium/dimethyl ; Reprints
Library Call Number Additional Info Location Last
NTIS  PB-282 232 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 10p
The distribution of sorbed paraquat (1,1'-dimethyl-4,4'-bypyiridinium ion) as a function of particle size (sand through clay) was determined on five natural sediments. Paraquat concentrations in individual size fractions varied as much as two orders of magnitude within a given sediment, showing a pronounced preference for the fine silt and clay fractions. Adsorption isotherms were measured for individual size separates on one sediment. Paraquat distributions in the whole sediment agreed well with those computed using the isotherm coefficients determined on individual size separates. Paraquat sorbs by ion exchange, and sorption partition coefficients showed a definite correlation with the cation exchange capacity (CEC) of individual size fractions. However, exchange sites in different fractions differed in their effectiveness in sorbing paraquat, with the fine silt and clay exchange sites being more effective than those of the larger separates.