Sorption, desorption and leaching potential of sulfonylurea herbicides in Argentinean soils

Authors
Azcarate, Mariela Pamela; Montoya, Jorgelina Ceferina; Koskinen, William C.
Publication Year
2015
Language
English
Format
article
Status
Published version
Description
The sulfonylurea (SUs) herbicides are used to control broadleaf weeds and some grasses in a variety of crops. They have become popular because of their low application rates, low mammalian toxicity and an outstanding herbicidal activity. Sorption is a major process influencing the fate of pesticides in soil. The objective of this study was to characterize sorption–desorption of four sulfonylurea herbicides: metsulfuron-methyl (methyl 2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoylsulfamoyl)] benzoate), sulfometuron-methyl (methyl 2-[(4,6-dimethylpyrimidin-2-yl)carbamoylsulfamoyl]benzoate), rimsulfuron (1-(4,6- dimethoxypyrimidin-2-yl)-3-(3-ethylsulfonyl-2-pyridylsulfonyl)urea) and nicosulfuron (2-[(4,6-dimethoxypyrimidin-2-yl) carbamoylsulfamoyl]-N,N-dimethylnicotinamide) from different soil horizons of different landscape positions. Sorption was studied in the laboratory by batch equilibration method. Sorption coefficients (Kd-SE) showed that rimsulfuron (Kd-SE D 1.18 to 2.08 L kg -1) and nicosulfuron (Kd-SE D 0.02 to 0.47 L kg -1) were more highly sorbed than metsulfuron-methyl (Kd-SE D 0.00 to 0.05 L kg -1) and sulfometuron-methyl (Kd-SE D 0.00 to 0.05 L kg -1). Sorption coefficients (Kd-SE) were correlated with pH and organic carbon content. All four herbicides exhibited desorption hysteresis where the desorption coefficients (Kd-D) > Kd-SE. To estimate the leaching potential, Koc and ground-water ubiquity score (GUS) were used to calculate the half-life (t1/2) required to be classified as “leacher” or “nonleacher”. According to the results, rimsulfuron and nicosulfuron herbicides would be classified as leachers, but factors such as landscape position, soil depth and the rate of decomposition in surface and subsurface soils could change the classification. In contrast, these factors do not affect classification of sulfometuron-methyl and metsulfuron-methyl; they would rank as leachers.
Fil: Azcarate, Mariela Pamela. INTA. Estación Experimental Agropecuaria Anguil; Argentina
Fil: Montoya, Jorgelina Ceferina. INTA. Estación Experimental Agropecuaria Anguil; Argentina
Fil: Koskinen, William C. Department of Agriculture. Agricultural Research Service. Soil and Water Management Research Unit; Estados Unidos
Source
Journal of environmental science and health, Part B 50 : 229–237. (2015)
Subject
Sorción
Herbicidas de Sulfonilurea
Lixiviación
Horizontes del Suelo
Suelo
Sorption
Pesticide Toxicity
Leaching
Soil Horizons
Sulfonylurea Herbicides
Argentina
Access level
Restricted access
License
Repository
INTA Digital (INTA)
Institution
Instituto Nacional de Tecnología Agropecuaria
OAI Identifier
oai:localhost:20.500.12123/2109