Adsorption of chlorpyrifos on Almería soils

• Published in: Science of the total environment 1992-08, Vol.123, p.541-549
• Main Authors: VALVERDE GARCIA, A, SOCIAS VICIANA, M, GONZALEZ PRADAS, E, VILLAFRANCA SANCHEZ, M
• Format: Article
• Language: English
• Subjects: adsorption; Applied sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; chlorpyrifos; clorpirifos; Exact sciences and technology; pesticide; Pollution; residu; residues; residuos; Soil and sediments pollution; soil sorption; soils; sorcion del suelo; sorption du sol
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/0048-9697(92)90176-S

The adsorption of the insecticide chlorpyrifos on the eight most representative soils of Almería Province (Spain) from aqueous solution at 30°C was studied. The adsorption isotherms were derived from batch equilibration experiments. Chlorpyrifos concentrations in the solution phase were determined, after extraction with petroleum ether, by gas liquid chromatography (GLC) with a nitrogen phosphorus detector (NPD) and an electron capture detector (ECD). The adsorption isotherms may be classified as S-type of the Giles classification, and the adsorption constants were calculated with the Freundlich isotherm. Comparisons between adsorption capacities of the soils were done using the X 0.1 values (quantities of chlorpyrifos adsorbed at a actual equilibrium concentration of 0.1 mg · 1 −1) calculated from the Freundlich equation. These X 0.1 values ranged from 22.2 up to 71.1 mg · kg −1. Correlations between X 0.1 values and soil properties show that the adsorption process of chlorpyrifos seems to be conditioned by the electrical conductivity and clay content.