HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bowman, B. T. Articles by Sans, W. W. Search for Related Content PubMed Articles by Bowman, B. T. Articles by Sans, W. W. Agricola Articles by Bowman, B. T. Articles by Sans, W. W.

Partitioning Behavior of Insecticides in Soil-Water Systems: I. Adsorbent Concentration Effects¹

ABSTRACT

Adsorption studies were conducted to determine whether adsorbent concentration (soil-solution ratio) affected insecticide adsorption by soils and clays. Adsorption isotherms were obtained for several insecticides in Bondhead sandy loam and Ca-saturated illite suspensions using adsorbent concentrations that were varied over several orders of magnitude. There was no evidence that altering adsorbent concentration exerted any influence on partitioning of insecticides between the adsorbent and solution phases. The centrifugation process, which in effect greatly increased adsorbent concentration at the bottom of the centrifugation tube, did not change the partitioning of the insecticides between the two phases. Dieldrin (1,2,3,4,10,10-hexachloro-exo-6,7-epoxyl, 4,4a,5,6,7,8,8a-octahydro-1,4-endo,exo-5,8-dimethanophthalene), unlike the other insecticides, exhibited strong concentration-dependent adsorption by glass surfaces, which invalidated the use of the normal "blank" (no adsorbent) sample for determining the initial solute concentration. Since glass adsorption appeared quite irreversible in aqueous solution, a sequential blank/sample adsorption technique was adopted whereby the stock solution was initially equilibrated in the glass bottle, then a small aliquot was removed for analysis before adding the adsorbent for its equilibration period. This technique produced consistent adsorption data that showed no evidence of being influenced by adsorbent concentration.

Key Words: soil-solution ratio • isotherm • adsorption • parathion • dieldrin • chlorpyrifos • fensulfothion sulfone

¹ Contribution from the Research Centre, Canada Agriculture, University Sub Post Office, London, Ontario, N6A 5B7.

² Research scientist and research assistant, respectively.

Received for publication January 27, 1984.