南岭山地湖泊多环芳烃的大气沉降历史记录

高大山脉对大气环流具有阻挡或屏障作用.通过分析测定南岭山地湖泊沉积物中多环芳烃(PAHs)的垂直分布,结合210Pb定年,探讨了大气PAHs污染在南岭山地的沉积历史.结果显示,沉积物中的PAHs主要以低环数化合物为主,其中尤以菲的含量为最高.在剖面深度0～28 cm范围内,总多环芳烃的含量范围为86～778 ng/g.自1970年开始,PAHs含量持续增加,其中20世纪80、90年代中后期PAHs含量略有降低;在2000年后,沉积柱中的PAHs含量呈急剧增加之势态.多环芳烃在大气迁移过程中发生了组成分异,沉积物中相对富集轻组分(低环数)PAHs,与颗粒物结合的大气干湿沉降是PAHs向偏远山地积的主要途径.     

应用单体碳同位素分析技术探析农田土壤中多环芳烃的植物降解过程

长期以来,研究者在探讨土壤中多环芳烃(PAHs)的降解及修复过程中,缺乏简便有效的手段对化合物的降解动态进行定量研究。前人尝试用投加实验、对比采用降解措施前后污染物的浓度变化、模型计算等方法研究PAHs的降解过程,其结果常互相矛盾,或不能真实反映复杂的实际环境。本文应用单体碳同位素技术对农田土壤中多环芳烃的植物降解过程进行定量表征,采集了某地农田表土作为供试土壤,选择玉米作为供试作物,开展了作物对土壤中PAHs降解及消除过程的研究。气相色谱-质谱分析结果表明,培养所用的玉米原始土及分4批收集的空白土、根际土、非根际土样品中16种PAHs的浓度总和(∑PAHs)平均分别为380.8 ng/g、(281.5±34.7) ng/g、(272.2±11.6) ng/g和(299.8±37.9) ng/g;玉米生长期间,各土壤样品 的∑PAHs均比原始土壤有所下降,但除3环化合物(苊烯、苊、芴、菲、蒽)外,其他化合物并未随玉米的生长表现出显著趋势。与玉米根、叶倾向于富集低环PAHs化合物相对应,可以判断植物对土壤中的低环化合物去除作用最为显著。各采样时期玉米根际土、非根际土和空白土壤样品中多环芳烃单体化合物的碳同位素分馏值(δ¹³C)在-34.31‰~-23.95‰之间,且除芘外的其他化合物的δ¹³C值随时间呈现逐步变轻的趋势,波动值位于-0.6‰~-9.0‰之间;本文对于PAHs单体化合物,尤其是4、5环化合物,在玉米降解过程中的碳同位素分馏与浓度变化之间未发现明显关系。考虑3环以下的PAHs化合物更倾向于被降解和清除,且其碳、氢同位素分馏情况更容易被观察到,因此稳定同位素分析更有助于探明该类单体多环芳烃污染物在环境中的迁移、转化规律。     

东海泥质区表层沉积物中多环芳烃的分布特征及物源

以 GC/MSD内标法定量测定了东海近岸和远岸泥质沉积区 18个表层沉积物中多环芳烃 (PAHs)的含量,探讨了多环芳烃在这些泥质区的分布特征、影响因素及来源.结果显示 ,近岸泥质区多环芳烃含量普遍较高,介于 180.3～ 424.8 ng/g(干重 )之间;冲绳海槽次之,含量为 211.7 ng/g ;济州岛西南泥质区最低,含量介于 117.1～ 211.7 ng/g之间.东海泥质区多环芳烃的分布主要受控于离物源的远近、沉积物粒度、有机碳含量以及东海环流体系.东海泥质区的多环芳烃主要来源于热成因,大气干湿沉降和河流输入是其进入泥质区的主要途径.东海泥质区多环芳烃的污染程度中等.     

太原市大气总悬浮颗粒物中正构烷烃和多环芳烃空间分布及来源分析

收集了太原市不同功能区的大气总悬浮颗粒物样品,经超声波提取分离得到正构烷烃、多环芳烃,经色谱-质谱分析表明,太原市大气颗粒物中正构烷烃主要来源于化石燃料的燃烧,少量为自然排放源。含量较高的不带取代基的多环芳烃有8种,其年平均浓度为1.50μg/m3,其中苯并(a)芘的年平均浓度为74.7ng/m3。多环芳烃的浓度分布为一电厂化工区>太钢工业区>桃园三巷商业居民区>太行仪表厂文化区。利用三角图与烟尘、汽车尾气样品中的多环芳烃特征相比较,认为太原市大气颗粒物中的多环芳烃主要来源于煤的燃烧。     

北京密云房山地区土壤中多环芳烃的组成与分布特征

选择北京城近郊房山与密云地区的土壤进行了多环芳烃的定量分析，同时探讨了多环芳烃在土壤中的分布特征与来源。研究结果显示：密云、房山两地土壤中多环芳烃的含量值具有明显差异，提示了两地工业活动影响强度的不同；各采样区土壤中多环芳烃总量的平均值在45．98～388．23ng／g变化，根据多环芳烃的特征参数可以推测研究区土壤中的多环芳烃主要来自于化石燃料的不完全燃烧。     

多环芳烃在水稻籽粒中的分布及其与环境介质含量的关系

介绍了江西南昌某郊区采集的成熟期(2008年9月)和收割期(2008年10月)的水稻籽粒中多环芳烃(PAHs)的富集情况,并与同时期的环境介质(土壤、空气气相以及颗粒物)中多环芳烃的含量及分布情况作了相关性分析。结果表明,研究区水稻籽粒中16种多环芳烃(∑PAHs)总量平均为(74.8±13.6)ng/g,水稻土壤中∑PAHs含量平均为(203.7±14.3)ng/g,空气气相样品中∑PAHs含量平均为68.25 ng/m3,以3环和4环多环芳烃为优势化合物;颗粒物样品中∑PAHs含量平均为42.28 ng/m3,以4环、5环和6环多环芳烃为优势化合物。各介质多环芳烃含量在国内同类地区中均位于中等偏下水平。将多环芳烃在水稻籽粒和各个介质之间的生物富集系数与化合物的辛醇分配系数KOC、KOA作对数变换后比较,发现水稻籽粒中多环芳烃的分布与水稻土和空气颗粒物中的多环芳烃没有太大关系;而与空气气相中的多环芳烃关系较明显,证实了前人得到的气相化合物对植物体内化合物的分配起着主要贡献的研究结论。     

祁连山七一冰川雪冰和冰川融水中正构烷烃和多环芳烃的分布特征及来源研究

2008年6月,在祁连山七一冰川采集雪坑、冰川融水和冰川末端冰样,经过大孔吸附树脂富集后,用GC-MS对样品中的正构烷烃(nC14～nC32)和多环芳烃进行了分析.结果表明,正构烷烃的含量在冰川融水中最高,雪坑次之,冰中最低;多环芳烃的含量在雪坑中最高,冰中最低,冰川融水界于二者之间.正构烷烃与多环芳烃都具有很强的疏水性,在固-液相分配过程中倾向于保留在残留固相中.由于冰川融水样品距冰川末端约1km,沿途地表土壤和植被会贡献部分正构烷烃,所以冰川融水中正构烷烃的含量最高.与正构烷烃不同,多环芳烃较易挥发,而且易被沿途土壤和植被所吸附,导致冰川融水中多环芳烃的含量降低.冰川末端冰中正构烷烃与多环芳烃的含量都很低,可能是由于冰川末端冰年代比较古老,受人类活动的污染较轻.正构烷烃的碳优势指数(CPI值)表明,七一冰川中的正构烷烃主要来自高等植物蜡和化石燃料燃烧产物的混合物,多环芳烃的荧蒽/芘(Fla/Pyr)和菲/蒽(Phe/Ant)比值表明,七一冰川冰雪和冰川融水中检测到的多环芳烃主要来自化石燃料的不完全燃烧.     

徐州土壤多环芳烃的环境地球化学迁移特征

选择江苏徐州黄棕壤进行不同深度层位多环芳烃含量的定量分析,研究并探讨了多环芳烃在土壤深度剖面中的地球化学迁移特征。研究结果显示,多环芳烃在徐州土壤剖面中主要集中在地表0~20 cm内。其中低环多环芳烃化合物的迁移能力较强,4~6环等高环化合物相对较难迁移,主要残留于地表生态系统环境中。     

某化工场地土壤与地下水中多环芳烃的分布特征及迁移规律

选取某化工场地作为研究对象,采集不同深度的原状土壤样品和原状地下水样品,对土壤样品和地下水样品的16种优控多环芳烃进行定量分析,研究不同种类的多环芳烃在包气带和饱和带中的分布特征和迁移规律.研究表明,在平面上,多环芳烃在土壤和地下水中的污染高值区与生产车间分布基本一致;在垂向上,土壤中的16种多环芳烃集中分布在杂填土层,低环和中环的多环芳烃更易向下迁移,并在黏土层产生一定的富集,仅有最低环的萘通过包气带迁移至饱和层中,饱和层中的萘一部分在地下水中扩散,一部分仍继续垂向迁移至更深层的土壤中.通过特定分子间的浓度比值,初步判定场地土壤中的多环芳烃来源为原油的不完全燃烧.     

长江三角洲典型农用地土壤多环芳烃的空间分布及源解析——以华东某地区为例

为研究长江三角洲典型农用地土壤多环芳烃的组成及来源,系统采集华东某地区农用地表层土壤样77个,对16种优先控制的多环芳烃(PAHs)单体含量进行测定。结果表明:研究区农用地土壤中Σ16PAHs浓度范围为18.60~1278.67μg/kg,平均浓度为233.57μg/kg;PAHs组成以2环至4环的中低环组分为主,占85.05%;同分异构体比值法和主成分分析法显示研究区农用地土壤中多环芳烃主要来源于石油泄漏及煤与生物质燃烧。     

Solvent–water extraction method for the evaluation of polycyclic aromatic hydrocarbons bioavailability in coal–tar-contaminated soils

A solvent–water extraction method was proposed as an assessment tool to estimate the bioavailability of polycyclic aromatic hydrocarbons in coal–tar-contaminated soils. The approach taken was to measure the percent of polycyclic aromatic hydrocarbons extracted by a solvent–water mixture and comparing the results with the percent of polycyclic aromatic hydrocarbons degraded in a soil slurry reactor. Five soil samples from three former manufactured gas plant sites and a coal–tar disposal site which were operated between 1880 and 1947, and 1945 and 1950, respectively, in Iowa, USA were used in this study. Extraction experiments were conducted using acetone–water or ethanol–water mixtures with solvent volume fractions ranging from 1.0 to 0.4 (v/v). The percent of polycyclic aromatic hydrocarbons extracted from the various soils decreased as the volume fraction of the solvent in the solvent–water mixture was reduced. An acetone–water mixture of 0.6 was found to be appropriate in correlating the percent of polycyclic aromatic hydrocarbons degraded to the percent of polycyclic aromatic hydrocarbons extracted. For the first correlation, the percent extracted and the percent biodegraded were modified by using the molecular weights and log K _ow of polycyclic aromatic hydrocarbons, respectively. For the second correlation, the equation relating the percent extracted and the percent biodegraded was modified using soil properties such as organic carbon content and percent of clay and silt. Although the experiments were conducted for a limited number of soils, the extraction method appeared to be a good starting point in estimating the bioavailability of polycyclic aromatic hydrocarbons in coal–tar-contaminated soils.     

Levels of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in sediment of bitumen deposit impacted area

Polycyclic aromatic hydrocarbons and polychlorinated biphenyls were investigated in sediment of bitumen deposit impacted area of Agbabu, Nigeria, to determine the present level of contamination with these toxic compounds prior to exploitation. Samples were collected during the dry season (March) and the wet season (August) of year 2008. Analysis was carried out with gas chromatography using mass spectrometry detector for polycyclic aromatic hydrocarbons and flame ionization detector for polychlorinated biphenyls. In the dry season sum of concentration of PAHs ranged from zero to 0.12 ± 0.06 ppm, while in the wet season the minimum was 0.18 ± 0.07 ppm and the maximum was 1.04 ± 0.16 ppm. Most of these values were higher than sum of polycyclic aromatic hydrocarbons concentrations of 1–10 μg/kg indicating that they were likely to come from anthropogenic sources. Average concentrations of PAHs such as naphthalene and benzo (a) pyrene obtained in sediment in the wet season in some of the stations were higher than recommended limits. The linear regression analysis between sum of concentrations and percentage organic carbon showed no significant correlation in sediment in the dry season (r² = 0.0025) and in the wet season (r² = 0.1345). The predominance of 4–6 ringed polycyclic aromatic hydrocarbons and the ratios between pairs of individual polycyclic aromatic hydrocarbons showed that they are likely to have come from pyrolytic sources. No polychlorinated biphenyl congener was detected in the samples.     

Microbial community changes in contaminated soils in response to phenanthrene amendment

Leachate and reclaimed wastewater have become the important sources of polycyclic aromatic hydrocarbons in soils. However, the information on bioremediation of leachate and reclaimed wastewater-contaminated soils is still lacking. Identification of changes in microbial structure or of enriched genera related to biodegradation could aid identification of particular organisms or consortia capable of degrading polycyclic aromatic hydrocarbons in these contaminated soils. In this study, terminal restriction fragment length polymorphism, coupled with 16S Ribosomal ribonucleic acid clone library analysis, was applied to investigate the composition of bacterial community in leachate-contaminated soil or grassland soil irrigated reclaimed wastewater and the response to phenanthrene amendment. Results showed that phenanthrene amendment had significant but different impacts on microbial community structure, dependent on soil source. Several greatly enriched terminal restriction fragments with phenanthrene biodegradation were identified. Moreover, genus rhizobacteria, possibly linked to phenanthrene biodegradation, was firstly reported in this study. This work might provide some new insights into bioremediation of polycyclic aromatic hydrocarbons-contaminated soils.     

Biodegradation of polycyclic aromatic hydrocarbon by a halotolerant bacterial consortium isolated from marine environment

The biodegradability of polycyclic aromatic hydrocarbons such as naphthalene, fluorene, anthracene and phenanthrene by a halotolerant bacterial consortium isolated from marine environment was investigated. The polycyclic aromatic hydrocarbons degrading bacterial consortium was enriched from mixture saline water samples collected from Chennai (Port of Chennai, salt pan), India. The consortium potently degraded polycyclic aromatic hydrocarbons (> 95%) at 30g/L of sodium chloride concentration in 4 days. The consortium was able to degrade 39 to 45% of different polycyclic hydrocarbons at 60 g/L NaCl concentration. Due to increase in salinity, the percent degradation decreased. To enhance polycyclic aromatic hydrocarbons degradation, yeast extract was added as an additional substrate at 60g/L NaCl concentration. After the addition of yeast extract, the consortium degraded > 74 % of polycyclic aromatic hydrocarbons at 60 g/L NaCl concentration in 4 days. The consortium was also able to degrade PAHs at different concentrations (5, 10, 20, 50 and 100 ppm) with 30 g/L of NaCl concentration. The polycyclic aromatic hydrocarbons degrading halotolerant bacterial consortium consists of three bacterial strains, namely Ochrobactrum sp., Enterobacter cloacae and Stenotrophomonas maltophilia.     

Distribution behavior of polycyclic aromatic hydrocarbons in roadside soil at traffic intercepts within developing cities

A study of polycyclic aromatic hydrocarbons pollution in roadside soil was conducted in developing city environment of northern India during autumn and winter season to ascertain the contamination levels and their distribution behavior in soil. The concentration of polycyclic aromatic hydrocarbons was determined at ten locations of Jalandhar city, Punjab in India at 1, 2 and 3 m distances from roadside in soil covering all the major traffic intercepts within city. The samples were extracted in acetone and dichloromethane (1:1) using soxhlet extraction. The extracts were then filtered on a silica gel micro column to remove impurities and elute was subjected to GC-FID. The total average concentration (city average) was found to be 4.04 ?g/g and 16.38 ?g/g during winter and autumn respectively. DiBenzo (ah) Anthracene and Benzo (a) Pyrene were the individual polycyclic aromatic hydrocarbons found in highest concentration at all the intercepts ranging between 0.008 to 28.4 ?g/g during winter and 0.01 to 252.55 ?g/g during autumn. Average concentration of non-carcinogenic and carcinogenic polycyclic aromatic hydrocarbons during winter and autumn was found to be 2.1 and 6.4 and 4.74 and 35.08 ?g/g respectively. The average ratio of non-carcinogenic and carcinogenic Polycyclic Aromatic Hydrocarbons was found to be 1:3 during winter, and 1:7.6 during autumn at most of the intercepts. Total carcinogenic polycyclic aromatic hydrocarbons concentration was found quite high (80 %) in comparison to non-carcinogenic polycyclic aromatic hydrocarbons (20 %) at most of the intercepts.     

Molecular characterization of phenanthrene-degrading methanogenic communities in leachate-contaminated aquifer sediment

The existence of polycyclic aromatic hydrocarbons in the various environments has aroused great environmental concerns due to their potential hazards to human health. The presence of polycyclic aromatic hydrocarbons in aquifer is particularly sensitive where groundwater is used as a source of potable water. Anaerobic biodegradation of polycyclic aromatic hydrocarbons is an attractive option for remediation of contaminated aquifer sediment. Bacterial and archaeal community structures of phenanthrene-degrading aquifer sediment under methanogenic condition were investigated using clone library analysis in combination with microcosm study. The bacterial members were all affiliated with ??-Proteobacteria. Phylum Euryarchaeota was the predominant archaeal group, represented by genera Methanosarcina, Methanobacterium and Thermogymnomonas. Both bacteria (genera Citrobacter and Pseudomonas) and archaea (genus Methanosarcina) might have links to phenanthrene degradation process. This work might provide some new insights into developing strategies for the isolation of the putative polycyclic aromatic hydrocarbons degraders under methanogenic condition and bioremediating polycyclic aromatic hydrocarbons in leachate-contaminated aquifer sediment.     

Organic-Inorganic Interaction Recorded by Polycyclic Aromatic Steranes in Continental Epithermal Ore Deposits

Continental epithermal ore deposits are commonly associated with sedimentary organic matter, oils or solid bitumen. These organics embedded in mineral deposits can convey valuable information of the ore genesis. However, the extent to which the formation of ore minerals was recorded by organic compounds remains largely unknown, as also is how metal-rich ores interfere with the molecular proxies in the temperature regime envisaged for hydrothermal activity. The molecular compositional changes of ...     

Ultrasonic wave extraction and simultaneous analysis of polycyclic aromatic hydrocarbons (PAHs) and phthalic esters in soil

A method is developed for detection of polycyclic aromatic hydrocarbons(PAHs) and Phthalic Acid Esters(PAEs) in soil samples. Ultrasonic Wave Extraction under airtight circumstances is adopted to extract the analytes in soil samples with n-hexane–acetone(V:V=1:1) as extraction solvent. This method has several advantages, including high extraction efficiency, short time, convenience and simplicity. It can be used to detect polycyclic aromatic hydrocarbons(PAHs) and Phthalic Acid Esters(PAEs) in soil.     

湿地生态系统中的多环芳烃研究进展

湿地是人类最重要的生存环境之一,但由于人类活动的干扰,湿地正遭受不同程度的污染,湿地功能也处在不断退化之中。如何保护并合理利用湿地,已成为人类共同面临的一个严峻问题。对湿地生态系统中的多环芳烃(PAHs)的国内外研究热点问题进行概括总结,介绍了湿地中PAHs的污染状况、来源解析、分布特征、修复技术、对生物的毒害及风险评价等研究的主要进展,讨论了湿地中PAHs变化趋势,此外还提出了目前湿地PAHs研究中一些亟待解决的问题:如何确定分散污染源的贡献率问题,进而提出有针对性的防治措施;提高高活性微生物的环境适应能力;研究人类活动影响的比例,并预测未来的变化趋势;PAHs污染生态风险阈值的研究。并对该领域未来可能的发展趋势进行了展望。     

持久性有机污染物对环境的影响及对策

概述了《斯德哥尔摩公约》中规定的12种持久性有机污染物及六六六、多环芳烃等持久性有机污染物,以及持久性有机污染物对土壤、水体、农产品及大气的污染状况,并在借鉴国内外先进经验的基础上,根据中国的国情提出了5项对策.