title: Surface runoff losses of copper and zinc in sandy soils.
abstract: Increased anthropogenic inputs of Cu and Zn in soils have caused considerable concern relative to their effect on water contamination. Copper and Zn contents in surface soil directly influence the movement of Cu and Zn. However, minimal information is available on runoff losses of Cu and Zn in agricultural soils, and soil-extractable Cu and Zn in relation to runoff water quality. Field experiments were conducted in 2001 to study dissolved Cu and Zn losses in runoff in Florida sandy soils under commercial citrus and vegetable production and the relationship between soil-extractable Cu and Zn forms and dissolved Cu and Zn concentrations in runoff water. Five extraction methods were compared for extracting soil available Cu and Zn. Concentrations of dissolved Cu and Zn in runoff were measured and runoff discharge was monitored. Mean dissolved Cu in field runoff water was significantly correlated with the extractable Cu obtained only by 0.01 mol L(-1) CaCl2, Mehlich 1, or DTPA-TEA methods. Dissolved Zn in runoff water was only significantly correlated with extractable Zn by 0.01 mol L(-1) CaCl2. The highest correlations to dissolved Cu in runoff were obtained when soil-available Cu was extracted by 0.01 mol L(-1) CaCl2. The results indicate that 0.01 mol L(-1) CaCl2-extractable Cu and Zn are the best soil indexes for predicting readily released Cu and Zn in the sandy soils. Both runoff discharge and 0.01 mol L(-1) CaCl2-extractable Cu and Zn levels had significant influences on Cu and Zn loads in surface runoff.
authors.affiliation: Dep. of Natural Resource Sciences, College of Natural Resource and Environmental Sciences, Zhejiang Univ., Huajiachi Campus, Hangzhou 310029, China.
authors.forename: Mingkui
authors.initials: M
authors.lastname: Zhang
authors.forename: Zhenli
authors.initials: Z
authors.lastname: He
authors.forename: David V
authors.initials: DV
authors.lastname: Calvert
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Stoffella
authors.forename: Xiaoe
authors.initials: X
authors.lastname: Yang
mesh_terms: D000383:Agriculture; D003300:Copper / Q000032:analysis*; D004784:Environmental Monitoring; D011891:Rain; D012989:Soil Pollutants / Q000032:analysis*; D012995:Solubility; D014872:Water Movements; D015032:Zinc / Q000032:analysis*
chemical_list: D012989:Soil Pollutants; D003300:Copper; D015032:Zinc