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长江口南支表层沉积物中多环芳烃分布特征及生态风险 总被引:4,自引:0,他引:4
2008年5月和8月先后2次采集长江口南支表层沉积物样品,采用高效液相色谱进行多环芳烃测定,研究其分布、来源与生态风险。结果表明:长江口南支表层沉积物中PAHs总量在8.9~312.2ng.g-1;PAHs组成以芘、菲、苯并[b]荧蒽、苯并[a]蒽、苯并[a]芘为主,各站芘的含量均最高,本研究PAHs总含量与长江口、黄河口和鸭绿江口近期的调查数据相近,但明显低于珠江口和闽江口数据,以及长江口潮滩沉积物中PAHs数据;PAHs环数组成以中、高环为主,表明长江口南支PAHs主要来源于相对高温条件下不完全燃烧过程。采用平均效应中值商法评价长江口南支PAHs生态风险结果表明,调查区域PAHs产生生态风险的概率较小(<10%)。 相似文献
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白洋淀土壤中多环芳烃的分布特征及来源 总被引:4,自引:0,他引:4
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。 相似文献
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贵阳市表层土壤中多环芳烃的分布特征及来源解析 总被引:3,自引:0,他引:3
运用高效液相色谱仪对贵阳市区及近郊的表层土壤中16种多环芳烃(PAHs)进行了定量分析,对其分布特征、污染水平以及来源进行了探讨.结果表明:土壤中PAHs含量为61~ 1560 μg·kg-1,城区土壤样品中PAHs含量为247~1560 μg·kg-1,郊区土壤样品中PAHs含量为61 ~339 μg· kg-1,土壤中4环、5环PAHs含量较高,在土壤PAHs含量中占有绝对优势;参照国外环境标准,对区域表层土壤PAHs的污染现状进行了评价,结果显示,贵阳市表层土壤受到一定程度的PAHs污染.利用相关系数法和典型源三角图法对PAHs的可能来源进行了解析,发现贵阳市的土壤主要受到燃煤排放以及混合污染源——燃煤与汽车尾气排放PAHs的联合污染. 相似文献
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利用气相色谱-质谱法(GC-MS)测定了白洋淀表层沉积物16种优控多环芳烃的含量,应用统计分析、分子异构体比值、空间插值等方法分析其组成特征、空间分布,进行了风险评价。结果表明,白洋淀表层沉积物中16种优控多环芳烃总量在1.79~1618.90 ng·g-1,均值为411.12 ng·g-1。多环芳烃组成以4环和5环为主,分别占总含量的42.22%和28.21%,单体含量最高的是苯并[b]荧蒽,占比为16.47%,最低的为苊,占比仅为0.26%。说明白洋淀多环芳烃来源于本地输入,较少受到气团输送的影响。多环芳烃空间分布为淀区中心浓度高,四周浓度低,污染尤以淀中心西北部和南部为重,包括安新大桥、烧车淀、采蒲台,其次是寨南和端村。源解析显示,白洋淀表层沉积物多环芳烃含量受木材秸秆等生物质燃烧、煤炭燃烧和石油燃烧的综合影响。生态风险评价结果显示,约1/3的采样点位超过效应区间低值,存在潜在的生态危害。比较2007、2008、2009、2016年的检测数据发现,多环芳烃的平均含量有所下降,可能与淀中村人口密度下降和煤改电有关。 相似文献
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太子河水体中多环芳烃分布与污染源解析 总被引:3,自引:0,他引:3
利用振荡提取-硅胶柱净化-HPLC荧光(FLD)/二级阵列检测器(DAD)检测法测定了太子河水中USEPA16种优控多环芳烃(PAHs)的含量。结果表明,枯水期(4月)、丰水期(7月)和平水期(10月)太子河水中PAHs总浓度分别为454.5~1379.7、1801.6~5868.9和367.0~5794.5ng.L-1,同国内外河流相比,太子河水中PAHs污染较严重,且具有明显的季节分布特征,丰水期PAHs浓度远高于枯水期。丰水期、平水期和枯水期太子河水中均以2~3环PAHs为主,但不同季节代表性PAHs的种类不同。污染来源分析表明,枯水期太子河水中PAHs主要来源于石油污染,丰水期和平水期主要来源于石油源和燃烧源的混合源。 相似文献
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轮作制度对水稻生长季节稻田氧化亚氮排放的影响 总被引:10,自引:3,他引:7
通过盆栽试验(3次重复),研究了3种主要轮作制度对稻田水稻生长季节N2O排放的影响。结果表明,在水稻-小麦轮作中,水稻生长季节稻田N2O-N的排放量为4.2kg·hm-2,显著大于双季稻-小麦轮作中早稻的排放量2.2kg·hm-2;但两者的季节平均排放通量无明显差异,分别为117和118μg·m-2·h-1。同时,两者都显著大于双季稻-小麦中的晚稻和持续淹水体系中的水稻生长季节稻田N20的平均排放通量,分别为67.0和42.1μg·m-2·h-1,在前作为旱作小麦的2种水稻生长季节中,大于91%的稻田N2O排放量都集中在水稻生长前半期;在前作为水稻的晚稻生长季节中,稻田N2O排放量的91%集中在中期烤田及收获前水分落干阶段,轮作制度和前作水分状况极大地影响稻田N2O的排放。 相似文献
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The main research results of nitrous oxide (N2O) emission from paddy fields in China were summarized. Paddy fields are an important source of N2O emission. Denitrification process exists not only in the upper flooded cultivated layer in paddy fields but also in the underground saturated soil layer. The cropping system with rice–wheat rotation and the water regime with mid-season aeration (MSA) in paddy fields of China are not only the controlling factors of N2O emission but also the main factors influencing methane (CH4) emission. There is a trade-off relationship between N2O and CH4 emissions from paddy fields. Straw amendment reduced N2O emission but promoted CH4 emission. Therefore, effects of both CH4 and N2O emissions from rice fields on the global warming potential (GWP) should be taken into consideration when any mitigation options are to be established. 相似文献
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Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by gas chromatography–mass spectrometry. Twenty samples were collected from the surface sediments of Haizhou Bay in this survey. This research aimed to identify the PAHs' contamination level, composition pattern, pollution sources, and assess the ecological risk of PAHs. The results showed that the sum of PAH concentrations ranged from 116.6 ng g?1 to 2414.9 ng g?1 (mean: 662.42 ng g?1), which is higher than the reported values for different wetlands worldwide. Three- and four-ring PAHs (accounts for more than 70% of the total PAH content) were predominant in the wetland sediment. The PAHs source distribution in the surface sediments were determined using diagnostic ratio and PCA/MLR. Consequently, multiple PAHs sources were found. Of the total PAH, 79.25% was derived from vehicular emission, 20.75% from coal combustion. The effect range low/effect range median (ERL/ERM) values indicated a low toxicity risk level. However, the fluoranthene concentrations exceeded the ERL level, and even the ERM level, in some stations. The mean effects range–median quotient (M-ERM-Q) suggests a low ecological risk for the PAHs in the sediments. 相似文献
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Dao-lai Zhang Na Liu Ping Yin Zhi-gang Zhu Jing-fang Lu Xue-hui Lin Xue-jun Jiang Xian-wei Meng 《Wetlands Ecology and Management》2017,25(1):105-117
We characterized 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments of natural mangrove habitats in China, as well as assessed their sources and the risks they pose. Our results indicate that the total concentrations of the 16 PAHs ranged from 3.16 to 464.05 ng g?1 dw (mean value of 72.80 ng g?1 dw), which were generally lower than those in other coastal environments in China and in other countries. The compositional patterns were dominated by four-ring PAHs, including fluoranthene, pyrene, benzo[a]anthracene and chrysene. Petrogenic sources, specifically, petroleum spills, were the dominant sources of PAHs in the surficial sediments of mangroves in China. Selected ratios of PAHs from two-tailed Pearson correlation analysis and principal-component analysis for different sites also indicate pyrolytic sources of PAHs. Results of the ecological risk assessment show little negative effect of most of the PAHs in the surface sediments. Overall, the data obtained in this study reveal relative low PAHs pollution in the mangrove swamps of China. 相似文献
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Sixteen polycyclic aromatic hydrocarbons (PAHs) were investigated in urban soils of Ahvaz metropolis to assess the contamination, distribution, potential sources, and related health risks for local residents. For this purpose, a total of 39 topsoil samples from different parts of the city were collected and analyzed for PAHs using gas chromatography–mass spectrometry. PAHs analysis revealed that 4 -rings PAHs are the dominant compounds. Distribution maps revealed that outlet roads of the city and an area in city center, particularly an industrial area at Southwest of the city, West Saheli street, Pasdaran Blvd, Ahvaz-Ramhormoz Police Station, Khorramshahr bus terminal, and Daneshgah Square, are the contamination hotspots. PAHs diagnostic ratios and principal component analysis (PCA) showed both petrogenic and pyrogenic sources for these compounds, although, the results indicated the dominance of pyrogenic (combustion) origin, particularly traffic emission, incomplete combustion of fossil fuels and gasoline emissions. Furthermore, calculation of toxic equivalents and cancer risk showed a high carcinogenic risk especially through dermal contact and ingestion pathways; however, compared with adults, children faced more cancer risk in their daily life through their unconscious ingestion and dermal contact pathway. 相似文献
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Yueling Qi Anita Awino Owino Victorine Anyango Makokha Yun Shen Di Zhang 《人类与生态风险评估》2016,22(5):1183-1196
This study was conducted to investigate the occurrence, distribution, and source of 16 polycyclic aromatic hydrocarbons (PAHs) in the Hanjiang River Basin and the Danjiangkou (DJK) Reservoir. The concentrations of total PAHs in surface water, sediments, and bank soils ranged from 9.42 to 137.94 ng/l, 86.23 to 2514.93 ng/g, and 133.17 to 671.93 ng/g dry weight, respectively. The composition pattern of PAHs showed that 3-ring PAHs were dominated in all of the samples, while the proportion of high molecular weight PAHs (5- to 6-ring PAHs) in sediments and bank soil samples was almost three times higher than water. The source apportionment analysis showed that most of the PAHs in water were derived from sources of petroleum and combustion, while combustion was the predominant source of PAHs in sediments and bank soils. The methods based on toxic equivalency factors, risk quotient, and incremental lifetime cancer risk were used to assess the ecosystem risk and potential health risk of PAHs. The risk assessments showed that PAHs in the DJK Reservoir were out of potential health risk, but the ecological risk for majority of 16 PAHs was in the moderate level. 相似文献
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Jan Dolfinga 《FEMS microbiology letters》1998,167(2):271-274
Biological halogenation of aromatic compounds implies the generation of reducing equivalents in the form of e.g. NADH. Thermodynamic calculations show that coupling the halogenation step to a step in which the reducing equivalents are oxidized with a potent oxidant such as O2 or N2O makes the halogenation reaction thermodynamically feasible without the input of additional energy in the form of e.g. NADH. In a current model on the halogenation of tryptophan to 7-chloro-l-tryptophan NADH and O2 are proposed as co-substrates in a reaction in which the aromatic compound is oxidized via an epoxide as intermediate. The thermodynamic calculations thus indicate that such a route hinges on mechanistic insights but has no thermodynamic necessity. Furthermore the calculations suggest that halogenation of tryptophan and other aromatic compounds should be possible with N2O, and possibly even with nitrate replacing O2 as the oxidant. 相似文献
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真菌对土壤N2O释放的贡献及其研究方法 总被引:1,自引:4,他引:1
N2O是一种重要的温室气体,而土壤作为N2O的重要来源之一,其N2O主要产生于硝化和反硝化作用的生物过程.研究表明细菌和古菌是这些生物过程的主要参与者,然而在特定土壤生态系统中,真菌在N循环过程中起主要作用.但真菌对土壤N2O释放贡献的研究报道甚少.本文阐述了土壤真菌N2O产生机制的研究进展,介绍了自养硝化、异养硝化和反硝化过程的发生机理、关键微生物和功能基因.详细介绍了与真菌有关的N2O产生过程,真菌的异养硝化作用和反硝化作用,并且比较了真菌和细菌反硝化系统的差异.此外,本文重点总结了研究土壤真菌N2O产生的主要方法,包括选择抑制剂法、15N标记、分离和纯培养以及免培养的分子生态学方法,对各种方法的优势和弊端进行了探讨,并对今后的研究工作提出了展望. 相似文献
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《Chemical Speciation and Bioavailability》2013,25(4):243-248
AbstractThis study was conducted to examine the impact of vehicular traffic on the contamination status of urban traffic sites in Beijing with respect to polycyclic aromatic hydrocarbons (PAHs). The soil and Pinus pinea needle samples were collected at 12 sites on Three Ring Road in Beijing, China, from July 2009 to March 2010. Total PAH concentrations at traffic sites ranged from 113.86 to 2226.24 ng g?1 with an average value of 658.71 ± 742.41 ng g?1 in soil samples and 112.03 to 2016.80ng g?1 with an average value of 680.29 ± 485.61 ng g?1 in needle samples. The PAH pattern was dominated by two- and three-ring PAHs (contributing >80% to the total PAHs) at all the 12 traffic sites. Seasonal variations of PAHs compounds indicated the PAHs concentrations in autumn and winter were higher than those in spring and summer due to temperature effects. This work indicates that the low ring PAHs were the major profile at the roadside of a busy street with heavy traffic in Beijing. 相似文献