Sakaliene Ona, Papiernik Sharon K, Koskinen William C, Spokas Kurt A
Lithuanian Institute of Agriculture, Vilnius, Lithuania.
J Environ Sci Health B. 2007 Aug;42(6):641-7. doi: 10.1080/03601230701465601.
This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine approximately amitrole approximately simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log K(ow)) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides.
本研究旨在测定8种除草剂（甲草胺、杀草强、莠去津、西玛津、麦草畏、咪唑乙烟酸、咪唑喹啉酸和二甲戊灵）在立陶宛各地采集的7种农业土壤中的吸附系数。所测得的吸附系数用于预测这些除草剂渗入地下水的敏感性。采用放射性标记除草剂，通过批次平衡研究测定土壤-水分配系数。在大多数土壤中，吸附遵循以下一般趋势：二甲戊灵>甲草胺>莠去津，杀草强和西玛津大致相当，咪唑喹啉酸>咪唑乙烟酸>麦草畏，这与疏水性（log K(ow)）趋势一致，但杀草强除外。对于几种除草剂，在有机碳含量和砂含量适中的土壤中，吸附系数和计算得出的阻滞因子最低（预计最易淋溶）。对于有机碳含量高的土壤，计算得出的除草剂阻滞因子较高。在假设无除草剂降解且无优先水流的饱和条件下，估计的淋溶时间受土壤质地对预测水流的影响比受除草剂吸附作用的影响更大。预计所有除草剂在高黏土和低砂含量的土壤中淋溶最慢，而在高砂含量和低有机质含量的土壤中淋溶最快。除草剂管理对于波罗的海地区农业生产和盈利能力的持续提高至关重要，这些结果将有助于确定需要改进管理措施以减少农药对水污染的关键区域。
