title: Studies on bound (14)C-chlorsulfuron residues in soil.
abstract: The cause for phytotoxicity of bound residues of chlorsulfuron (2-chloro-N-[[4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl]benzenesulfonamide) to rotational crops is unknown. This study was conducted to determine the formation of nonextractable (bound) residues of chlorsulfuron in soil, and the distribution of bound residues in different organic matter fractions. The results showed that over 150 days, the extractable fraction of (14)C-residues decreased to 25.1% of applied chlorsulfuron, while bound residues concurrently increased to 47.1%. The distribution of (14)C-bound residues in soil organic matter fractions followed an order of humic acid (HA) < humin < fulvic acid (FA). Although the most bound residues were detected in the FA fraction, the amount associated with the humin fraction increased with time. After soil treatment by autoclaving, it was found that bound (14)C-chlorsulfuron residues became available again in the soil. One of the released products was 2-amino-4-hydroxyl-6-methyl-1,3,5-triazine (identified by GC-MS), which is a degradation product of chlorsulfuron.
authors.affiliation: Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, People's Republic of China.
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: Guo
authors.forename: Jinhe
authors.initials: J
authors.lastname: Sun
mesh_terms: D001578:Benzopyrans / Q000032:analysis; D002250:Carbon Radioisotopes; D005591:Chemical Fractionation; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000032:analysis*; D006358:Hot Temperature; D006812:Humic Substances / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D011312:Pressure; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D013449:Sulfonamides; D014227:Triazines / Q000032:analysis*
chemical_list: D001578:Benzopyrans; D002250:Carbon Radioisotopes; D006540:Herbicides; D006812:Humic Substances; D010573:Pesticide Residues; D012987:Soil; D012989:Soil Pollutants; D013449:Sulfonamides; D014227:Triazines; C001861:humin; C037137:chlorsulfuron; C005023:fulvic acid