不同添加浓度DEHP在黑土中的降解特点及对酶活性的影响

王蕾; 枉靖宜; 张颖; 王磊; 张福庆; 马超然; 王旭; 王天琦; 李世民

doi:10.19336/j.cnki.trtb.2021020601

不同添加浓度DEHP在黑土中的降解特点及对酶活性的影响

Degradation Characteristics of DEHP Added into Mollisols at Different Concentrations and Its Effect on Enzyme Activities

摘要

摘要:
目的本研究以邻苯二甲酸二-（2-乙基己基）酯（DEHP）为目标化合物，采用室内培养试验的方法，对不同浓度梯度的DEHP在黑土中的降解过程和对土壤酶活性影响进行了研究。
方法在DEHP降解试验中，使添加到黑土中的DEHP浓度分别为0 mg kg⁻¹、5 mg kg⁻¹、10 mg kg⁻¹、20 mg kg⁻¹、40 mg kg⁻¹，每个处理设置3次重复，于3 d、7 d、14 d、21 d、28 d、35 d采集土壤样本，利用气相色谱－质谱联用（GC-MS）的检测方法，对DEHP、邻苯二甲酸单-（2-乙基己基）酯（MEHP）和邻苯二甲酸（PA）进行定量分析。在土壤酶活性试验中，使添加到黑土中的DEHP浓度分别为0 mg kg⁻¹、30 mg kg⁻¹、50 mg kg⁻¹、100 mg kg⁻¹、300 mg kg⁻¹、500 mg kg⁻¹，每个处理设置3次重复，于3 d、7 d、14 d、21 d、28 d、35 d分别采用靛蓝比色法、3,5-二硝基水杨酸比色法和高锰酸钾滴定法对不同添加浓度DEHP的黑土的脲酶、蔗糖酶和过氧化氢酶活性进行测定。
结果培养第35 d，DEHP的平均降解率达到39.95%，MEHP的平均积累率达到89.25%，未发现PA。随着DEHP添加浓度的增加，脲酶和蔗糖酶活性受到抑制，35 d内的平均抑制率分别为22.6%和33.5%。
结论将DEHP添加到黑土中并培养，在短时间内（至少35 d），DEHP降解后浓度减少，毒性可能降低，但DEHP降解产生的降解产物MEHP仍然具有生态毒性甚至毒性更强，因此总体环境毒性并未降低。此外，黑土受到DEHP的污染，在一段时间以后其脲酶和蔗糖酶会受到抑制作用。

Abstract:
Objective The degradation process of Di-(2-Ethylhexyl) phthalate (DEHP) and its effects on soil enzyme activities were investigated in a lab incubation experiment.
Method DEHP was added into mollisols at 0, 5, 10, 20, and 40 mg kg⁻¹ with three replications. Soil samples were collected at the 3^rd, 7^th, 14^th, 21^st, 28^th and 35^th days of incubation, and the concentrations of DEHP, Mono -(2-ethylhexyl) phthalate (MEHP), and phthalic acid (PA) were analyzed by gas chromatography-mass spectrometry (GC-MS). In the experiment of soil enzyme activities, DEHP was added to mollisols at 0, 30, 50, 100, 300, and 500 mg kg⁻¹ with three replications. Methods of indigo colorimetry, 3,5-dinitrosalicylic acid colorimetry, and potassium permanganate titration were used to determine the activities of urease, sucrase, and catalase.
Result On the 35^th day, the average degradation rate of DEHP was 39.95 %, the average accumulation rate of MEHP was 89.25 % and PA was not found. The activities of urease and sucrase were inhibited with the increase in the concentration of DEHP and their inhibition percentages were 22.6% and 33.5%.
Conclusion The concentration of DEHP and its toxicity could decrease in a short time incubation experiment of DEHP added to mollisols (at least 35 days). However, MEHP as degradation product of DEHP was still ecologically toxic or even more toxic, means that the overall environmental toxicity was not decreased. In addition, the activities of urease and sucrase would be inhibited in mollisols contaminated by DEHP.

HTML全文

参考文献(28)

施引文献

资源附件(0)