土壤,植物样品中多环芳烃（PAHs）分析方法研究

土壤、植物和籽实样品分别用四氢呋喃、甲醇、乙酸乙酯以超声技术提取。提取液经旋转浓缩蒸发仪浓缩,经硅胶柱净化后,由高效液相色谱（ＨＰＬＣ）分离,萤光检测分析。对于土壤、植物和籽实样品,其方法回收率根据各个ＰＡＨ化合物的理化性质不同分别为４５．６８－９３．４２、７７．５９－１０８．１３和７９．１１－９８．９６％,结果表明,二氯甲烷、四氢呋喃适合作为土壤样品的提取剂;甲醇、乙酸乙酯分别适合于植物和籽实样     

两种植物条件下土壤中矿物油和多环芳烃（PAHs）的生物修复研究

选择苜蓿草和水稻为供试植物,以污染物水平、有机以、专性细菌和真菌为调控因子,进行土壤中矿物油和PAHs的生物修复研究,结果表明,投肥对苜蓿草土壤中矿物油降解有促进作用,但对水稻土壤中矿物油降解无明显作用,投肥均使苜蓿草和水稻土壤中多环芒烃总量（11种列于美国EPA黑名单上的多环芳烃）降解率提高,这一降解促进效果在水稻土壤中好于苜蓿草土壤,有机肥量与苜蓿草根际土著真菌、细菌数量明显呈正相关,但仅与水稻根际土著细菌数量呈明显正相关,两种土壤中实测真菌和细菌总数均与试验投加专性真菌和细菌量无关,水稻土和苜蓿草土壤中3环多环芳烃的降解随投肥量增大而降解率提高,其在水稻土蓑中的效果好于苜蓿草土壤,投肥怪4环多环芳烃的降解并未产生有效作用。     

土壤－植物系统中多环芳烃和重金属的行为研究

对土壤中多环芳烃和重金属的行为研究表明,与对照相比,０—２０ｃｍ以上表土层存在多环芳烃和重金属积累,２０ｃｍ以下土层未发现积累;与春、秋两次采样结果相比,土壤中多环芳烃的含量有所下降,表明土壤微生物对多环芳烃有一定降解作用,且其降解程度与土壤－植物系统的生态结构有关．菲在地下水中检出浓度较高,表明这一污染物有向下迁移的可能性．此外,柳树对土壤中重金属Ｃｄ的积累有明显的削减与净化作用．本研究表明,严格限制污水中多环芳烃和重金属的污染负荷以及设计合理的生态结构是避免多环芳烃和重金属在土壤中积累的关键．     

多环芳烃类化合物在土壤上的吸附

研究了几种多环芳烃化合物在土壤上的吸附行为．通过一个连续投药－取样试验装置,在没有任何其它有机试剂干扰的情况下,测定了荧蒽与菲在土壤上的吸附量．研究表明,这两种多环芳烃化合物在土壤上的吸附量与土壤有机质含量之间呈显著相关．对多环芳烃化合物的分子结构及理化特性,如辛醇－水分配系数、溶解度等参数与ＬｏｇＫｏｃ关系的研究发现多环芳烃化合物的ＬｏｇＫｏｃ与化合物的水溶性、辛酸－水分配系数以及分子结构中的苯环数线性相关．     

土壤中多环芳烃源解析技术研究进展

多环芳烃是一类广泛存在于各种环境介质中的持久性有机污染物。针对土壤中多环芳烃的污染现状, 为了更加全面明确地识别污染源, 进而能从源头上对多环芳烃的产生与排放加以控制, 综合论述了国内外土壤中多环芳烃定性和定量源解析技术的研究进展; 在介绍各种多环芳烃污染源解析模型的原理和特点的同时, 通过对比国内外相关研究的实例说明各解析方法的使用前提和适用范围, 讨论了源解析技术进步对污染物控制、治理的意义和重要性; 并对土壤中多环芳烃源解析技术研究未来的发展趋势作出展望, 为区域环境治理和能源利用结构调整等相关决策地制定提供参考依据。     

多环芳烃在土壤中的行为

多环芳烃（PAHs)在土壤中达到吸附平衡时存在“快”和“慢”两个吸附过程,植物能够从土壤中吸收低分子量的PAHs并向植物的地上部分迁移转化,但PAHs在植物体内主要的累积方式是植物地上部分的空气污染,微生物对PAHs的降解依然是去除PAHs的主要方式,主要通过微生物产生的酶的作用,本文详细分析了影响PAHs生物去除的各种因素。     

污染土壤中多环芳烃的共代谢降解过程

1　前　言多环芳烃是一类普遍存在于环境中的重要有机污染物 ,因其致癌性、致畸性、致突变性而被认为是危险物质。由于其水溶性低 ,辛醇 水分配系数高 ,因此 ,该类化合物易于从水中分配到生物体内、沉积层中。土壤成为多环芳烃的重要载体 ,多环芳烃污染土壤的生物修复也因此倍受关注。多环芳烃在土壤中有较高的稳定性 ,其苯环数与其生物可降解性明显呈负相关关系。很少有能直接降解高环数多环芳烃的微生物。研究表明 ,高分子量的多环芳烃的生物降解一般均以共代谢方式开始[1 3] 。共代谢作用可以提高微生物降解多环芳烃的效率 ,改变微生物碳…     

表面活性剂对土壤中多环芳烃生物有效性影响的研究进展

表面活性剂能够改变多环节烃(Polycyclic aromatic hydrocarbons,PAHs）在土壤中的溶解度、吸附/解吸平衡和与土壤微生物的相互作用,从而改变PAHs的生物有效性,表面活性剂主要通过降低土壤-水之间的界面张力,增加PAHs的溶解度、促进PAHs的运输等方式来加强PAHs的生物有效性,但由于表面活性剂本身对微生物的毒害作用或无毒的表面活性剂优先作为微生物的生长基质,可能会对PAHs的生物有效性起到抑制作用,另外,表面活性剂对土壤中不同形态的PAHs生物有效性的影响不同,表面活性剂、PAHs和土壤微生物的类型浓度以及土壤的物理化学条件等都对PAHs的生物有效性有影响。     

白洋淀土壤中多环芳烃的分布特征及来源

采用气相色谱质谱联用仪检测了白洋淀表层(0～20 cm)和亚表层(20～30或农田30～40 cm)土壤中16种多环芳烃的含量。结果表明：表层土壤中多环芳烃总量的变化范围为146.0～645.9 ng·g^-1,平均含量为417.4 ng·g^-1;亚表层土壤中多环芳烃总量的变化范围为43.0～394.5 ng·g^-1,平均含量为152.4 ng·g^-1。表层土壤中多环芳烃含量与有机碳含量相关性不显著,亚表层土壤中多环芳烃含量与有机碳含量呈显著正相关(P<0.01),这可能表明了土壤埋藏改造过程中PAHs与土壤有机相结合程度不断加强,以及土壤中不同环数多环芳烃的环境行为差异,总体上看,与高环(≥4环)多环芳烃相比,萘、菲等低环(2～3环)多环芳烃更容易向下层迁移。PAHs的源解析分析表明,白洋淀表层土壤的多环芳烃表现出显著的以生物质和煤燃烧为主的源特征,这与淀区的人为活动,如秸秆燃烧等相关。     

植物法生物修复PAHs和矿物油污染土壤的调控研究

选择苜蓿草为供试植物,以污染物含量水平、专性细菌和真菌及有机肥为调控因子,进行了植物法生物修复多环芳烃(PAHs)和矿物油污染土壤的调控研究。结果表明,PAHs和矿物油的降解率与有机肥含量呈正相关,增加有机肥5%,可提高矿物油降解率17.6%～25.6%,PAHs降解率9%.在植物存在条件下,土壤微生物降解功能增强。多环芳烃总量的平均降解率比无植物对照土壤提高2.0%～4.7%.投加特性降解真菌可不同程度地提高土壤PAHs总量和矿物油的降解率。真菌对萤蒽、芘和苯(a)蒽/(艹屈)的降解有明显促进作用。而细菌能明显提高苊稀/芴、蒽和苯(a)萤蒽/苯(k)萤蒽的降解率。     

非流体介质中多环芳烃污染的微生物固定化修复技术

非流体介质中多环芳烃(PAHs)污染的修复是目前环境工作者所面临的艰巨而紧迫的任务.由于非流体介质环境的特殊性,常规修复方法难以高效地发挥作用,传统微生物修复技术采用的游离微生物也存在许多弊端.而微生物固定化能大幅度地提高参加反应的微生物浓度,避免优势菌受土著菌的恶性竞争,增强微生物的耐环境冲击性.微生物固定化技术在一定程度上克服了传统工艺的不足,因而广泛应用于流体介质(废水等)和半流体介质(泥浆等)环境污染的修复.在概述固定化微生物技术的特点和分析国内外研究进展的基础上,指出将该技术应用于非流体介质中PAHs污染的原位修复领域的可行性,并论述了需要解决的关键科学问题,提出了利用微生物固定化技术修复非流体介质中PAHs污染的未来研究课题.     

多环芳烃降解菌筛选及其降解特性

通过选择性富集培养,从辽河油田稠油污染土壤4号土样中,获得了能以高浓度菲(2000mg·L^-1)为唯一碳源和能源快速生长的优势菌系和优良菌株ZL5．16S rDNA核苷酸序列分析表明,ZL5菌株归类于鞘氨醇单胞菌属,分得的菌系和菌株有较强的降解菲能力,120h混合菌系降解了投加菲的95．28％,菌株降解了69．24％,但它们对芘的降解能力均较低,外加碳源葡萄糖可提高菌系和菌株的菲、芘降解能力,加量多。提高幅度大,但超过一定量。降解速率开始下降,表现出抑制效应。所以,应用时需控制适宜的浓度。     

Polycyclic Aromatic Hydrocarbons (PAHs) Pollution in Agricultural Soil in Tianjin,China

Representative soil samples (n = 60) collected from suburban agricultural land in Tianjin were analyzed to determine 16 PAHs in this study. Accelerated solvent extraction, GPC (Gel Permeation Chromatography), and SPE (Solid Phase Extraction) clean-up procedures were employed for PAH preparation prior to analysis with gas chromatography–mass spectrometry. The concentrations of the total PAHs (T-PAHs) ranged from 228.6 ng/g to 14722.1 ng/g with the mean value of 613.1 ng/g. Bap concentrations in many sites exceeded the suggested standards. Spatial variation of PAHs in soil was illustrated; the pollution status and comparison to other cities were also investigated. Severe PAH soil pollution was observed in some sites near urban areas. Higher PAH concentrations were detected at the downwind side of the urban areas, indicating the influence of human activities. Two indicative ratios (Fl/(Fl+Pyr, Baa/(Baa+Chr)) and principal component analysis were used to identify the possible sources of PAHs. These suggested that coal combustion was still the most important source of PAHs in Tianjin, which coincided well with the previous studies. These data can be further used to assess the health risk associated with soils polluted by PAHs and can help local government find proper ways to reduce PAHs’ pollution in soils.     

Characteristics of PAHs adsorption on inorganic particles and activated sludge in domestic wastewater treatment

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in a domestic wastewater treatment plant (WWTP) was investigated in a 1 year period. In order to understand how PAHs were removed at different stages of the treatment process, adsorption experiments were conducted using quartz sand, kaolinite, and natural clay as inorganic adsorbents and activated sludge as organic adsorbent for adsorbing naphthalene, phenanthrene, and pyrene. As a result, the adsorption of PAHs by the inorganic adsorbents well followed the Langmuir isotherm while that by the activated sludge well followed the Freundlich isotherm. By bridging equilibrium partitioning coefficient with the parameters of adsorption isotherm, a set of mathematical models were developed. Under an assumption that in the primary settler PAHs removal was by adsorption onto inorganic particles and in the biological treatment unit it was by adsorption onto activated sludge, the model calculation results fairly reflected the practical condition in the WWTP.     

藻类对多环芳香烃(PAHs)的富集和代谢

概述了藻类对PAHs的富集和代谢的研究进展。环境中多环芳香烃(PAHs)的污染能导致严重的健康问题,利用生物特别是微生物去除污染环境中的PAHs是一项新的技术。藻类对PAHs的富集与有机污染物的类型、藻类的种类及藻类的生物量有关,活细胞和死细胞对PAHs均有富集能力。还阐述了PAHs在真菌、细菌和藻类体内代谢的途径以及代谢过程中起关键作用的酶,PAHs在藻类中的代谢途径和细菌及真菌都不同,谷胱甘肽转移酶(GST)在藻类代谢PAH过程中起重要作用,但细胞色素P450酶所起的作用则不详。     

植物根对土壤中PAHs的吸收及预测

研究了多种植物根对土壤中多环芳烃(PAHs)的吸收作用,阐述了根系吸收与土壤污染强度、污染物性质、植物组成等的关系,并用实验数据检验了限制分配模型对植物吸收土壤中PAHs的预测性能。供试土壤中菲和芘的起始浓度分别为0~457和0~489mg/kg;45d后,随土壤中菲和芘浓度提高,根中菲和芘含量明显增大,根系富集系数则减小。不同植物根中菲和芘含量和根系富集系数与根的脂肪含量呈显著正相关。由于芘的Kow较大,同种植物根中芘含量、芘的根系富集系数则远大于菲。经45d处理,尽管土壤中菲浓度变化很大(从不足1mg/kg到约45mg/kg),限制分配模型能较好地预测供试植物根中菲的含量,黑麦草和菜心根中菲含量的预测误差低于81%。作为限制分配模型预测植物吸收的关键参数,不同植物根吸收菲的αpt值与根脂肪含量显著正相关。     

The degradation of three-ringed polycyclic aromatic hydrocarbons by wood-inhabiting fungus Pleurotus ostreatus and soil-inhabiting fungus Agaricus bisporus

The degradation of two isomeric three-ringed polycyclic aromatic hydrocarbons by the white rot fungus Pleurotus ostreatus D1 and the litter-decomposing fungus Agaricus bisporus F-8 was studied. Despite some differences, the degradation of phenanthrene and anthracene followed the same scheme, forming quinone metabolites at the first stage. The further fate of these metabolites was determined by the composition of the ligninolytic enzyme complexes of the fungi. The quinone metabolites of phenanthrene and anthracene produced in the presence of only laccase were observed to accumulate, whereas those formed in presence of laccase and versatile peroxidase were metabolized further to form products that were further included in basal metabolism (e.g. phthalic acid). Laccase can catalyze the initial attack on the PAH molecule, which leads to the formation of quinones, and that peroxidase ensures their further oxidation, which eventually leads to PAH mineralization.A. bisporus, which produced only laccase, metabolized phenanthrene and anthracene to give the corresponding quinones as the dominant metabolites. No products of further utilization of these compounds were detected. Thus, the fungi's affiliation with different ecophysiological groups and their cultivation conditions affect the composition and dynamics of production of the ligninolytic enzyme complex and the completeness of PAH utilization.     

Cometabolic degradation of dibenzofuran by Comamonas sp. MQ

In this study, strain MQ belonging to the genera Comamonas was used to cometabolically degrade dibenzofuran (DBF) with naphthalene, phenanthrene, benzene, toluene, biphenyl and nitrobenzene, respectively, for the first time. Strain MQ could cometabolically degrade DBF in the growing system using naphthalene as a substrate and the K_i value of strain MQ on naphthalene and DBF was 90.26 mg L^?1 and 68.34 mg L^?1, respectively. The degradation rate of DBF by naphthalene-cultivated strain MQ cells (0.080 mmol L^?1 h^?1) was 1.05, 1.11, 1.13, 1.18 and 1.27-fold higher than that cultivated by phenanthrene, benzene, toluene, biphenyl and nitrobenzene, respectively. Examination of metabolites indicated that naphthalene-cultivated strain MQ cells degraded DBF to 2-hydroxy-4-(3′-oxo-3′H-benzofuran-2′-yliden)but-2-enoic acid (HOBB) and subsequently to salicylic acid via the lateral dioxygenation and meta cleavage pathway. In contrast, biphenyl-cultivated strain MQ cells degraded DBF to monohydroxydibenzofuran through the lateral dioxygenation without meta cleavage pathway. These results suggested that strain MQ could be useful in the bioremediation of environments contaminated by heterocyclic compounds mixtures with polycyclic aromatic hydrocarbons.