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BATCH VERSUS COLUMN METHOD FOR DETERMINING DISTRIBUTION OF ORGANICS BETWEEN SOIL AND WATER PHASES

 

作者: J. JOHNSON,   W. FARMER,  

 

期刊: Soil Science  (OVID Available online 1993)
卷期: Volume 155, issue 2  

页码: 92-99

 

ISSN:0038-075X

 

年代: 1993

 

出版商: OVID

 

数据来源: OVID

 

摘要:

The batch equilibrium and a continuous flow (column) procedures were compared to determine if similar pesticide distribution coefficients could be obtained for the two methods. Using a low infiltration rate of 2.7 cm day−1, essentially identical values were obtained by the two methods for the distribution of napropamide and lindane between the sorbed and solution phases in a Pachappa sandy loam. Values for Kocof 421 and 1300 L kg−1were measured for napropamide and lindane, respectively, at 20°C. Distribution coefficients decreased with increasing temperature. In the column experiments, similar values for the distribution coefficients were obtained regardless of whether the amounts of pesticide sorbed were determined by direct extraction of the soil or by the difference between quantities added to the columns and the quantities of solute in the effluent. Both linear and Freundlich isotherm models were used to calculate distribution coefficients. The soil column breakthrough curves were reproducible in duplicate runs for both napropamide and lindane. When distribution coefficients were estimated using a chemical retardation factor from the column experiments, the coefficients were consistently larger than those determined by the batch equilibrium method.

 

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