Degradation and Binding of Atrazine in Surface and Subsurface Soils
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- 作者：Elena Blume ; Marianne Bischoff ; Thomas B. Moorman ; and Ronald F. Turco
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2004
- 出版时间：December 1, 2004
- 年：2004
- 卷：52
- 期：24
- 页码：7382 - 7388
- 全文大小：159K
- 年卷期：v.52,no.24(December 1, 2004)
- ISSN：1520-5118
文摘
Understanding the dissipation rates of chemicals in unsaturated and saturated zones of subsurfacesoils will help determine if reductions of concentrations to acceptable levels will occur. Chemicalproperties and microbial biomass and activity were determined for the surface (0-15 cm), lower root(50-105 cm), and vadose (175-220 cm) zones in a Huntington silty clay loam (Fluventic Hapludoll)collected from an agricultural field near Piketon, OH. The rates of sorption, mineralization, andtransformation (formation of bound residues and metabolites) of atrazine were determined. Microbialactivity was estimated from the mineralization of 14C-benzoate. We observed decreased levels ofnutrients (total organic carbon, N, and P) and microbial biomass with depth, while activity as measuredwith benzoate metabolism was higher in the vadose zone than in either the surface or the root zones.Sorption coefficients (Kf) declined from 8.17 in the surface to 3.31 in the vadose zone. Sorption waspositively correlated with organic C content. Rates of atrazine mineralization and bound residuesformation were, respectively, 12-2.3-fold lower in the vadose than in the surface soil. Estimatedhalf-lives of atrazine ranged from 77 to 101 days in the surface soil, but increased to over 900 daysin the subsurface soils. The decreased dissipation of atrazine with increasing depth in the profile isthe result of decreased microbial activity toward atrazine, measured either as total biomass or aspopulations of atrazine-degrading microorganisms. The combination of reduced dissipation and lowsorption indicates that there is potential for atrazine movement in the subsurface soils.Keywords: Microbial biomass and activity; sorption; subsurface microbiology; mineralization; kinetics