Soil sorption of acidic pesticides: modeling pH effects |
| |
Authors: | Spadotto Claudio A Hornsby Arthur G |
| |
Institution: | Embrapa Environment. C.P. 69, 13820-000 Jaguariúna, SP, Brazil. spadotto@cnpma.embrapa.br |
| |
Abstract: | A model of acidic pesticide sorption in soils was developed from theoretical modeling and experimental data, which initially considered a combination of a strongly acidic pesticide and a variable-charge soil with high clay content. Contribution of 2,4-D (2,4-dichlorophenoxy) acetic acid] anionic-form sorption was small when compared with molecular sorption. Dissociation of 2,4-D was not sufficient to explain the variation in Kd as a function of pH. Accessibility of soil organic functional groups able to interact with the pesticide (conformational changes) as a function of organic matter dissociation was proposed to explain the observed differences in sorption. Experimental 2,4-D sorption data and K(oc) values from literature for flumetsulam N-(2,6-difluorophenyl)-5-methyl 1,2,4] triazolo 1,5-a] pyrimidine-2-sulfonamide] and sulfentrazone N-2,4-dichloro-5-4-(difluromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl] phenyl] methanesulfonamide] in several soils fit the model. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|