title: Cosorption of zinc and glyphosate on two soils with different characteristics.
abstract: Agricultural application of large amounts of glyphosate [N-(phosphonomethyl)-glycine] may affect soil metal behaviors to some extend, because glyphosate can react with many kinds of metals to form metal complexes. Cosorption of Zn and glyphosate on a Red soil (RS, Udic Ferrosols) and a Wushan soil (WS, Anthrosol) was studied. In comparison with the WS, the RS has less adsorption capacity for Zn and higher for glyphosate. The presence of glyphosate decreased Zn adsorption on the two soils, which are resulted from the decreased equilibrium solution pH caused by the added glyphosate, and also the formation of water-soluble complexes of glyphosate with solution Zn(2+) that had lower affinity to soil surface in comparison with Zn(2+) itself. Such effect is more significant on the RS than on the WS, mainly because of the less adsorption quantity of Zn on the former one. On the contrary, the presence of Zn increased the adsorption quantities of glyphosate on the RS and WS, which is resulted from the decreasing pH value of the equilibrium solution caused by Zn(2+) exchange with H(+) ions of soil surface. Such results suggest that glyphosate in field may increase the mobility and bioavailability of Zn and correspondingly increase its environmental risk.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Yu-Jun
authors.initials: YJ
authors.lastname: Wang
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Zhou
authors.forename: Rui-Juan
authors.initials: RJ
authors.lastname: Sun
authors.forename: Long
authors.initials: L
authors.lastname: Cang
authors.forename: Xiu-Zhen
authors.initials: XZ
authors.lastname: Hao
mesh_terms: D000327:Adsorption; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis; D015386:Hazardous Substances; D006540:Herbicides; D006863:Hydrogen-Ion Concentration; D011522:Protons; D012987:Soil; D012989:Soil Pollutants; D015032:Zinc / Q000032:analysis* / Q000737:chemistry; D017967:Zinc Compounds; D000097797:Glyphosate
chemical_list: D005998:Glycine; D015386:Hazardous Substances; D006540:Herbicides; D011522:Protons; D012987:Soil; D012989:Soil Pollutants; D015032:Zinc; D017967:Zinc Compounds; D000097797:Glyphosate