Adsorption of atrazine and metolachlor in three soils from Blue Creek wetlands, Waterville, Ohio
Adsorption of atrazine and metolachlor in three soils from Blue Creek wetlands, Waterville, Ohio
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DOI：
10.1007/s10112-000-0001-4
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发表时间：
2000-04
期刊：
影响因子：
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通讯作者：
A. Spongberg;Lou Ganliang
中科院分区：
文献类型：
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作者：
A. Spongberg;Lou Ganliang
阿特拉津和甲草胺是俄亥俄州西北部农业活动中广泛使用的农药。吸附系数通常用来模拟农药的命运和运输。许多物理化学参数，如有机质、粘土含量、pH值和离子强度，都会影响农药的吸附。通过间歇实验研究了吸附动力学和吸附等温线。探讨了腐植酸、溶液pH和离子强度对阿特拉津和异丙甲草胺吸附的影响。24 h后，阿特拉津和异甲草胺在3种土壤中均达到吸附平衡。吸附等温线用Freundlich方程描述。阿特拉津的Freundlich系数（Kf）为0.14 ~ 4.47 (L kg - 1)，异草胺的Freundlich系数（Kf）为0.04 ~ 5.30 （L kg - 1）。吸附量大小依次为斯隆壤土、德尔雷壤土、奥特基细砂。两种农药的Koc值差异很大：斯隆壤土中异丙草胺>，德尔雷壤土中阿特拉津≥异丙草胺，奥托基细沙中阿特拉津>异丙草胺。除有机质含量外，粘土对Del Rey壤土和Ottokee细砂的吸附也起着关键作用。两种农药在pH值为5时均有较高的吸附。当pH值降低到3和增加到11时，吸附减少。吸附量随离子强度的增加而增加。
Atrazine and metolachlor are extensively used pesticides in agricultural activities in northwest Ohio. Adsorption coefficients are often used to model pesticide fate and transport. Many physical-chemical parameters, such as organic matter, clay content, pH, and ionic strength, affect pesticide adsorption. Adsorption kinetics and adsorption isotherms were studied by batch experiment. Effects of humic acid, solution pH, and ionic strength on atrazine and metolachlor adsorption were also approached. After 24 h, both atrazine and metolachlor reached adsorption equilibrium in three local soils. Adsorption isotherms were described by Freundlich equations. The Freundlich coefficient (Kf) ranged from 0.14 to 4.47 (L kg−1) for atrazine, and 0.04 to 5.30 (L kg−1) for metolachlor. Adsorption capacity decreased in the order Sloan loam > Del Rey loam > Ottokee fine sand. Koc values varied considerably for both pesticides: metolachlor > in Sloan loam, atrazine ≥ metolachlor in Del Rey loam, and atrazine > metolachlor in Ottokee fine sand. In addition to organic matter content, clay played a key role in adsorption in the Del Rey loam and Ottokee fine sand. Higher adsorption was observed at pH 5 for both pesticides. As pH decreased to 3 and increased to 11, adsorption decreased. Adsorption increased as ionic strength increased.