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81.
Li Lu 《Environmental pollution (Barking, Essex : 1987)》2009,157(6):1794-1799
Reducing the transfer of contaminants from soils to plants is a promising approach to produce safe agricultural products grown on contaminated soils. In this study, 0-400 mg/kg cetyltrimethylammonium bromide (CTMAB) and dodecylpyridinium bromide (DDPB) were separately utilized to enhance the sorption of PAHs onto soils, thereby reducing the transfer of PAHs from soil to soil solution and subsequently to plants. Concentrations of phenanthrene and pyrene in vegetables grown in contaminated soils treated with the cationic surfactants were lower than those grown in the surfactant-free control. The maximum reductions of phenanthrene and pyrene were 66% and 51% for chrysanthemum (Chrysanthemum coronarium L.), 62% and 71% for cabbage (Brassica campestris L.), and 34% and 53% for lettuce (Lactuca sativa L.), respectively. Considering the impacts of cationic surfactants on plant growth and soil microbial activity, CTMAB was more appropriate to employ, and the most effective dose was 100-200 mg/kg. 相似文献
82.
作者把气相色谱仪(GC)与自行研制的光离子化检测器(PID)联用,实现了大气中痕量烃类化合物的直接测定,给出了仪器的构成和性能指标及测量结果. 相似文献
83.
84.
通过采集了2004~2006年北京市昌平区四个季节中大气PM10样品,采用超声抽提方法,使用GC/MS分析了该区PAHs含量和组成.结果显示,三年中四个季度的18种PAHs总量范围分别为21.64~656.39ng/m3、31.94~164.33ng/m3和7.294~209.3ng/m3,其中致癌性极强的苯并[a]芘含量范围为2.69~36.95 ng/m3、1.44~6.6ng/m3和0.256~8.625ng/m1,其变化趋势与PAHs总量有较好的相关性.PAHs的浓度是冬季>秋季>夏季>春季,这与夏季时雨水冲刷和阳光照射强度大导致PAHs光解,冬季时燃煤排放大等影响因素有关.文章还使用多种方法判断昌平区大气PM10中的PAHs主要来源于燃煤和汽车尾气,其它污染源贡献较小. 相似文献
85.
86.
Impact of Bioaugmentation with a Consortium of Bacteria on the Remediation of Wastewater-Containing Hydrocarbons (5 pp) 总被引:1,自引:0,他引:1
Domde P Kapley A Purohit HJ 《Environmental science and pollution research international》2007,14(1):7-11
Goals, Scope and Background It has been observed that hydrocarbon treated wastewaters still contain high COD and a number of intermediates. This suggests
that the required catabolic gene pool for further degradation might be absent in the system or, that its titer value is not
significant enough. By providing the desired catabolic potential, the overall efficiency of the treatment system can be improved.
This study aims to demonstrate this concept by bioaugmentation of a lab-scale reactor treating refinery wastewater with a
consortium having the capacity to complement the alkB genotype to the available microbial population.
Methods Two reactors were set up using activated biomass collected from a refinery treatment plant and operated at a continuous mode
for a period of 8 weeks. The feed to both reactors was kept constant. Crude oil was spiked regularly. One reactor was bioaugmented
with a consortium previously described for crude oil spill remediation. The efficiency of the bioaugmented reactor was demonstrated
by reduced COD. The changes in the microbial population over a period of time were analyzed by RAPD. Catabolic activity of
the biomass in both reactors was monitored by PCR. The presence of the catabolic loci was confirmed by Southern Hybridization.
Results and Discussion 52.2% removal of COD was observed in the bioaugmented reactor while only 15.1% reduction of COD was observed in the reactor
without bioaugmentation. The change in microbial population can be seen from the 4th week, which also corresponds to improved
catabolic activity. The presence of the bedA locus was seen in all samples, which indicates the presence of aromatic degraders,
but the appearance of the alkB locus, from the 6th week onwards, which was observed only in the samples from the bioaugmented
reactor. The results suggest that the gene pool of the bioaugmented reactor has catabolic loci that can degrade accumulated
intermediates, thus improving the efficiency of the system.
Conclusions In this study, improvement of efficiency of bioremediation was demonstrated by addition of catabolic loci that are responsible
for degradation. Bioaugmentation was carried out in biomass that was collected from an ETP (effluent treatment plant) treating
hydrocarbon containing wastewater to study the strategies for improvement of the treatment system. Biostimulation, only marginally
improved the efficiency, when compared to bioaugmentation. The improved efficiency was demonstrated by COD removal. The presence
of the alkB locus suggests the importance of a catabolic gene pool that acts on accumulated intermediates. It is well documented
that straight chain aliphatics and intermediates of aromatic compounds after ring cleavage, accumulate in refinery wastewater
systems, thereby hindering further degradation of the wastewater. Supplementation of a catabolic gene pool that treats the
lower pathway compounds and alkanes will improve the overall efficiency. In this study, results suggest that the alkB locus
can also be used to monitor the degradative mode of the activated biomass.
Recommendations and Perspective . Pollution from petroleum and petroleum products around the globe are known to have grave consequences on the environment.
Bioremediation, using activated sludge, is one option for the treatment of such wastes. Effluent treatment plants are usually
unable to completely degrade the wastewater being treated in the biological unit (the aerator chambers). The efficiency of
degradation can be improved by biostimulation and bioaugmentation. This study demonstrates the improved efficiency of a treatment
system for wastewater containing hydrocarbons by bioaugmentation of a consortium that supports degradation. Further experiments
on a pilot scale are recommended to assess the use of bioaugmentation on a large scale. The use of molecular tools, like DNA
probes for alkB, to monitor the system also needs to be explored. 相似文献
87.
Paumen ML Borgman E Kraak MH van Gestel CA Admiraal W 《Environmental pollution (Barking, Essex : 1987)》2008,152(1):225-232
During acute exposure, polycyclic aromatic compounds (PACs) act mainly by narcosis, but during chronic exposure the same compounds may exert sublethal life cycle effects. The aim of this study was therefore to evaluate the chronic effects of sediment spiked PACs on the emergence of the midge Chironomus riparius. Three isomer pairs were selected, and 28-day LC50 values and 50% emergence times (EMt50) were determined. Concentration-response relationships were observed for phenanthrene, acridine, phenanthridine and acridone. Anthracene and phenanthridone had no effect on total emergence, but did cause a delay in emergence. Calculated porewater LC50 values correlated well with logKow values, suggesting narcosis as mode of action. In contrast, effect concentrations for delay in emergence (EMt50) deviated from narcosis, suggesting a specific mode of action during chronic exposure. It is concluded that emergence is a powerful endpoint to detect life cycle effects of PACs on a key sediment inhabiting invertebrate. 相似文献
88.
底泥中多环芳烃(PAHs)提取方法评析 总被引:5,自引:0,他引:5
总结了底泥中多环芳烃(PAHs)提取的处理流程和国内外多种提取方法,比较了几种在我国较为常用的提取方法的效率.同时还提出了PAHs分离纯化的方法和步骤,并指出了提取过程中影响实验回收率的几个因素. 相似文献
89.
一个新的拓扑指数用于芳烃化合物溶解度、分配系数及生物毒性的研究 总被引:19,自引:0,他引:19
在分子拓扑理论的基础上,提出了一个新的拓扑指数Yx,并用Yx研究了芳烃化合物的溶解度、分配系数及生物毒(活)性,给出了相关方程。结果表明,新方法计算方便,物理意义明确,预测值与相应的实验值较吻合。 相似文献
90.
三峡大坝每年周期性“蓄水-放水”,形成水位落差巨大的消落带,库区内污染物环境地球化学行为随之发生变化.以冬季淹没期消落带多环芳烃为研究对象,采集成对大气(n=16)、植物(n=12)和土壤样品(n=12),采用气相色谱/质谱法(GC/MS),分析USEPA 16PAHs浓度水平,解析来源,估算大气地表、大气-植物等多介质交换通量.结果表明:大气、土壤和植物中PAHs浓度为5.65~13.47ng/m3、70.86~13 5.44ng/g和78.23~1084.72ng/g,平均值分别为(8.58±2.78) ng/m3、(90.10±22.18) ng/g和(360.36±309.54) ng/g.大气中PAHs以2~3环为主(62.3%),植物中PAHs以3~4环为主(73.7%),土壤中PAHs以3环和5环为主(52.1%).特征分子比值法揭示煤、生物质燃烧是植物PAHs的主要来源,以石油为主的化石燃料燃烧是大气和土壤PAHs主要来源.“一室模型”表明,植物吸收PAHs的主要途径为植物-气相之间动态平衡限制下的气沉降.“逸度模型”表明,3... 相似文献