邻苯二甲酸二异辛酯在番茄根际土壤中的持留动态

利用分室根箱法模拟根际微域环境的试验结果表明,无论初始浓度高低,邻苯二甲酸二异辛酯(DEHP)在土壤中的持留都可较好地用一级反应动力学方程进行描述,初始浓度越高,持留半寿期越短．土壤中DEHP浓度的增加可引起土壤脱氢酶活性的增加．但在DEHP初始浓度低、中、高3种情况下都表现出在根际土壤(0～5mm)中DEHP的残留浓度比非根际土壤(25～30mm)中的残留浓度稍高,持留的半寿期(t1/2)稍长的趋势,说明植物的生长并没有加速DEHP的降解．不添加DEHP的根室土壤中DEHP浓度始终都维持在一个较低的水平上,处理之间没有显著差异,且植物组织中DEHP的含量很低,处理之间也没有显著差异,说明DEHP在土壤中随水溶液的扩散和由于植物根系生长活动引起的迁移是微不足道的．

The dynamics of di-(2-ethylhexyl) phthalate in tomato-rhizospheric soil

A root-chamber method was used to simulate the rhizospheric environment and to investigate the dynamics of di-(2-ethylhexyl) phthalate (DEHP) in rhizospheric soil. The results showed that a first-order kinetics equation could be used to describe the disappearance of DEHP in soil. With the increase in initial concentrations of DEHP in soil, the dispearance half time decreased. The increase in DEHP concentration in soil resulted in the increase in dehydrogenase activity in soil, implying that DEHP stimulated the soil microbial activity and resulted in the acceleration of biodegradation. A tendency was found that the residual concentrations of DEHP in rhizospheric soil was slightly higher than in non-rhizospheric soil at the same time, suggesting that plant growth might not markedly influence the degradation of DEHP. The DEHP concentrations in root chamber soil without additional DEHP did not change markedly during the experiment, and there was not marked difference between the treatments. The DEHP concentrations in plants were much low and no marked difference was observed between the treatments. These results suggested that the diffusion of DEHP with water movement and migration resulted from plant growth activity was marginal.