镉芘单一和复合污染对龙葵土壤微生物和土壤酶的影响

发布时间：2017-12-27 14:21

本文关键词：镉芘单一和复合污染对龙葵土壤微生物和土壤酶的影响　出处：《西北农林科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：污水灌溉是我国最重要的废水利用方式之一,但由于不合理的污灌所导致的土壤重金属、PAHs污染已成为我国目前面临的主要环境问题之一,给生态系统造成了严重的危害,因此,开展对污灌区重金属和PAHs污染土壤的研究显得至关重要,本文通过模拟陕西省咸阳市污灌区农田土壤进行研究,以镉(Cd)作为重金属的代表物和芘(pyrene)作为PAHs代表物,对单一和复合污染的土壤蔗糖酶、土壤脲酶、土壤碱性磷酸酶的酶活性和土壤细菌、真菌、放线菌的数量进行探究,旨在为污灌区污染土壤对微生态环境的影响以及环境质量评价提供有益的参考。试验研究结果表明:(1)土壤重金属Cd对土壤酶活性的影响,在五次采样试验过程中,对土壤蔗糖酶和土壤碱性磷酸酶均起到激活作用;除第40天对土壤脲酶是抑制作用外,其他时间各处理对土壤脲酶均起到激活作用。(2)土壤有机污染物芘对土壤酶活性的影响,在五次采样试验中,对土壤碱性磷酸酶起到激活作用;对于土壤脲酶,0-40天,除中等浓度(50mg·kg-1)是激活作用外,其他处理均起到抑制作用,而40-80天,则起到激活作用;对于土壤蔗糖酶,中等浓度(50mg·kg-1)在第40天、低和高浓度(10mg·kg-1和250mg·kg-1)在第80天时激活作用外,其他则起到抑制作用。(3)Cd、芘复合污染对土壤酶活性的影响,在五次采样试验中,除低浓度(Cd1mg·kg-1+芘10mg·kg-1)对土壤碱性磷酸酶是抑制作用外,其他均表现出激活作用;对于土壤脲酶,0-40天表现出抑制作用,而40-80天表现出激活作用;对于土壤蔗糖酶,低浓度在第40、80天,中等浓度(Cd5mg·kg-1+芘50mg·kg-1)在第40天,高浓度(Cd25mg·kg-1+芘250mg·kg-1)在第80天是激活作用外,其他均表现出抑制作用。(4)Cd、芘单一污染对细菌的最小抑制率均出现在第40天,而复合污染则出现在第80天;对真菌和放线菌的最小抑制率均出现在第40天;第80天只有土壤真菌的抑制率全部在50%以上,而土壤中放线菌和细菌数量基本恢复到接近对照水平并保持稳定,由此可见放线菌、细菌在污染环境中易形成耐性菌种。
[Abstract]:Sewage irrigation is one of China's most important water use, but because of the unreasonable irrigation caused by soil heavy metals, PAHs pollution has become one of the main environmental problems faced by our country, the ecosystem caused serious harm, therefore, to carry out research on heavy metals and PAHs contaminated soil is crucial in this paper, through the study of soil irrigated farmland in Xianyang city of Shaanxi province in the simulation, cadmium (Cd) is a representative of pyrene and heavy metals (pyrene) as the representative of PAHs, the single and compound pollution of soil invertase, urease, alkaline phosphatase activity and soil bacteria, fungi, actinomycetes the number of inquiry, to influence of sewage irrigation area soil on micro ecological environment and environmental quality assessment to provide a useful reference. The test results show that: (1) effects of heavy metal Cd in soil on soil enzyme activities, in five samples during the experiment, the soil invertase and alkaline phosphatase play activation; in addition to the fortieth days of soil urease inhibition, other time of different treatments on soil urease play activation. (2) effects of soil pyrene on soil enzyme activities, in the five sampling test, activation to the soil alkaline phosphatase; for soil urease, 0-40 days, in addition to medium concentration (50mg - kg-1) is activated, other treatments had inhibitory effect, and is 40-80 days. To activate; for soil invertase, medium concentration (50mg - kg-1) on the fortieth day, the low and high concentration (10mg - kg-1 and 250mg - kg-1) activation in eightieth days, the other is to restrain. (3) effects of Cd and pyrene combined pollution on soil enzyme activities, in five sampling tests, in addition to low concentration (Cd1mg - kg-1+ pyrene 10mg - kg-1) on soil alkaline phosphatase is inhibited, the other showed activation; for soil urease, 0-40 days inhibited, and 40-80 days show activation; for soil invertase, low concentration in fortieth, eightieth days, the medium concentration (Cd5mg - kg-1+ 50mg - kg-1 pyrene) in fortieth days, high concentration (Cd25mg - kg-1+ 250mg - kg-1 pyrene) in eightieth days is activated, the other showed inhibitory effect. (4) Cd and pyrene single pollution on bacterial minimum inhibitory rates in fortieth days, and the combined pollution appeared in eightieth days; the minimum inhibition of fungi and actinomycetes were appeared in fortieth days; eightieth days only inhibition of soil fungi was all above 50%, and the number of lines placed in soil bacteria and bacteria recovered to near control levels and maintain stability, thus actinomycetes, bacteria in polluted environment is easy to form tolerance strains.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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