酞酸酯污染对土壤脲酶与磷酸酶的动态影响

Dynamic Effects of PAEs on Soil Urease and Phosphatase

[目的]为酞酸酯类化合物污染土壤的生态毒理评价提供参考依据。[方法]采用室内模拟污染土壤,研究了邻苯二甲酸二(乙基-己基)酯(DEHP)和邻苯二甲酸二丁酯(DBP)两种酞酸酯类化合物对农田土壤脲酶与磷酸酶活性及其反应动力学参数的动态影响。[结果]较高土壤处理浓度的DBP与DEHP对脲酶和磷酸酶均表现明显的抑制效应,其抑制作用有随处理浓度的增加而加强,酶活性的恢复也受DBP与DEHP污染程度影响,此外脲酶活性受DBP与DEHP影响程度大于磷酸酶。高浓度的DEHP对土壤酶活性的影响较DBP有一定的滞后效应。对两种酶的K_m与V_(max)、以及V_(max)/K_m等动力学参数分析表明,随土壤污染程度增加,DBP与DEHP降低了酶促反应速率、酶与底物亲和力以及酶促反应初速度。[结论]2种酶活性变化能反映DBP与DEHP在土壤中的污染程度,但酶促反应动力学参数较酶活性变化更宜作为DBP与DEHP污染土壤的生态毒理评价指标。

[Object]The study aimed to supply a reference for evaluating ecotoxicology of soil contaminated with phthalate acid esters （PAEs）.[Method]The dynamic effects of DBP and DEHP on activities and kinetics parameters of urease and phosphatase in agro-soil contaminated artificially with DBP and DEHP were studied.[Result]The activities of urease and phosphatase were both inhibited significantly by higher contents of DBP and DEHP in soils compared with CK.The inhabitations increased with increasing DBP and DEHP contaminations in soils.The restoration terms of enzyme activities were related with contaminated levels of DBP and DEHP in soils.Urease activity was more susceptive of DBP or DEHP than phoshatase.Compared with DBP,lag phenomena of inhabitation with both enzymes were found in high contaminated soils with DEHP.The further analysis on enzyme kinetics parameters,including K_m,V_（max） and V_（max）/K_m,showed that significant changes were presented compared with the controls.[Conclusion]As eco-toxicological evaluating indexes on soil contaminated with DBP and DEHP,the kinetics parameters of urease and pbosphatase were more suitable than the activities of the enzymes.