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991.
多环芳烃(PAHs)是具有三致效应的一类典型持久性有机污染物,具有较高的生态风险.随着工业不断发展,地表水已成为PAHs重要的汇.由于其疏水性特征,PAHs易附着在地表水悬浮颗粒物表面,逐渐积累并可以随地表水长距离迁移而扩大其污染区域,对人体健康和生态环境造成威胁.因此,对地表水悬浮颗粒物中PAHs长时间尺度的时空分布特征和输入源的定量解析研究,可为生态管控和环境政策的制订,提供重要理论依据.对典型地表水悬浮颗粒物中16种优控PAHs长期监测数据进行分析,采用Mann-Kendall趋势检验法评估了PAHs时间变化趋势和突变点;利用小波分析研究其周期变化规律;采用特征比值法和正定矩阵因子分解(PMF)模型分析PAHs的来源,并从拟合优度、因子交换现象和PMF基础运行重现性等方面评估了源解析结果的不确定性.∑16PAHs含量时间变化分析表明,研究区域地表水悬浮颗粒物中∑16PAHs含量呈现显著递减趋势(P<0.05),平均值最大为6 239μg·kg-1(2006年),最小为2 760μg·kg-1  相似文献   
992.
<正>定矩阵因子分解模型(PMF)自1993年开发至今,其在环境中持久性有毒物质(PTS),尤其是多环芳烃(PAHs)源解析中的应用取得了重大研究进展。简要介绍了PMF模型的基本原理,在综述该模型用于土壤/沉积物、大气及水体中PAHs源解析现状的基础上,结合其在实际工作的应用,评述了其在环境中PAHs源解析方面的应用潜力及发展前景。  相似文献   
993.
Cytochrome P450 (CYP450) genes play an important role in catalyzing oxidative metabolism of toxicants. Recently, CYP1 subfamily were discovered and reported in fish, however, little is known regarding the CYP2 isoforms in fish. In the present study, the cDNA fragments of CYP 1B1 and 1C1 and CYP2Aa, 2Y3, and 2K of rare minnow were cloned and exhibited a high amino acid sequence identity compared with their zebrafish orthologs. Basal expression showed CYP1C1 and CYP 2Aa expression were observed in all eight tissues analyzed (liver, gill, intestine, kidney, spleen, brain, skin, and muscle). CYP 1A, and 1B1 expression was found in all tissues except for muscle and skin. However, CYP 2Y3 was expressed in liver, spleen, intestine and muscle whereas CYP 2 K in liver, kidney and intestine. 4 and 100 μg L−1 Benzo[a]pyrene (BaP) induced patterns showed that CYP 1A, 1B1 and 1C1 expression in liver, gill, and intestine was strongly up-regulated (p < 0.05). Furthermore, CYP 2Y3 was strongly induced in liver from BaP treatments (p < 0.05). The high induction on mRNA level of CYP1s and CYP 2Y3 by BaP could be associated with catalyzing detoxification and indicated that CYP2s may also be potential biomarker to screen AHR agonist. The high responsiveness of CYP1 and 2 genes suggested Chinese rare minnow is feasible to screen and assess pollution with AHR agonist.  相似文献   
994.
XQH1.00地震安全性评价工作程序包具先进性、灵活性、可靠性和实用性。编制者对危险性分析、人造地震动和土层反应等主要程序作了一系列改进,使之具有较强的计算性能。其中,人造地震动采用了自己研究提出的新技术——即时域迭加技术和反应谱整体逼近技术。该软件包采用菜单方式,实行人机对话和各种表格图件全部汉化。图件的输出可使用打印机和绘图仪,具有优良的服务性能。  相似文献   
995.
Intention, Goal, Scope, Background The effect of chloride concentration and pH on the UV oxidation systems was examined. Phenol and methanol were used as organic substances. The treatment of these chemicals by UV oxidation using a newly developed lab scale pretest UV-Free Surface Reactor (UV-FSR) with and without Cl– addition at different pH values, is evaluated. Results of this study indicated that the Cl– concentration of the water and the chemical structure of the substances is more important than the pH of the water. There was no AOX at the beginning of the experiments, but a de-novo synthesis of AOX was observed during the batch experiments. This is caused by the high chloride content of the wastewaters. It can be supposed that OHradicals oxidize some chloride-ions to form chlorine, which further reacts with organic compounds. During the treatment, these AOX compounds which are produced from the beginning of the reaction are destroyed again. Evaluations of these experiments were done according to TOC and AOX results. Approximately 80% and 99% TOC removal efficiencies were obtained for the treatment of Phenol and Methanol-containing wastewaters, respectively. Objective In the literature, there are no relevant publications concerning the AOX formation of wastewater by wet oxidation- iron catalysed or by application of UV. For that reason, the main objectives of this study were: 1. to see the influence of chloride concentration and pH on the AOXde-novo formation with newly developed UV-Free Surface Reactor (UV-FSR), 2. to make a comparison of different AOPs, 3. to observe the effect of the chloride concentration on the TOC degradation efficiency, 4. to optimise reaction conditions. Methods In synthetic wastewaters, Methanol (CH3OH) and Phenol (C6H5 OH) are used as pollutants. The concentration of each substance was 1000 mg/l and COD values were calculated theoretically. The H2O2 addition was calculated according to the COD with a convenient stoichiometric factor (e.g. 1). During experiments, the pH was always kept constant with the addition of either 25% H2SO4 or 33% NaOH depending on the experimental conditions. Each substance was treated with the addition of 1000 mg/l Cl–, 10000 mg/l Cl– and without Cl– addition at pH 3, pH 7 and pH 10, respectively. NaCl was used as a Cl– source. Adsorbable Organic Halogenides (AOX) were determined using a TOX analyser (European Standard EN 1485 H 14, 1996). TOC measurements were carried out using an Elementar High TOC Analyzer equipped with an auto sampler. The H2O2 concentration was measured according to German Standard Methods (DIN 38409, Part 15, 1987). Results and Discussion The first step was to determine the effect of pH on the AOX formation in the process. Therefore, experiments were carried out at three different pHs: acidic (pH 3), neutral (pH 7) and basic (pH 10) conditions at a constant initial Methanol concentration of 1000 mg/l and a hydrogen peroxide concentration of 3185 mg/l (1 x stoichiometric). All results were evaluated according to applied pH. At these conditions, the amount of H2O2 (53 ml / 10 l) concentration was nearly zero after 1 hour batch treatment of Methanol. There was no AOX at the beginning of the experiments, but the AOX value increased after 6–18 min. At the end of 1 hour batch treatment this produced AOX was treated again. The maximum AOX production was obtained with the addition of 10000 mg/l Cl–, whereas there is no AOX production during the experiment when Cl– was not used. In all studies, however, TOC values decreased to almost zero after 1 hour batch treatment. After the experiments with Methanol, Phenol treatment was carried out at different pHs as a second experiment. pH was kept constant with the addition of either H2SO4 or NaOH depending on the experimental conditions. During experiments with Phenol, the colour of the water changed from colourless to a yellowish- red. After 1 hour treatment, the colour of the water was red. Therefore, these experiments were continued until the water became colourless again, and this took about 5 hours. Although there was no AOX at the beginning of the experiments, it increased after 30 min to 1 hour oxidation with the addition of 1000 mg/l Cl– and 10000 mg/l Cl–. There was no AOX production during the experiments when Cl– was not added. At the end of 5 hours of treatment, formed AOX was degraded and the TOC concentration decreased from 766 mg/l to approximately 200 mg/l. Conclusion. These experiments of this study showed that the effects of Cl– concentration of the water and the chemical structure of the substances is more than that of the pH on the AOX formation. During the batch experiments, a de-novo synthesis of AOX was observed very impressively due to the high chloride content of the wastewaters. It can be implied that OH-radicals oxidize some chloride-ions to form chlorine, which further reacts with organic compounds so that AOXde-novo is formed. At the end of the reaction times these AOX compounds are also destroyed. Recommendation and Outlook It is more cost effective to use these processes for only purposes such as toxicity reduction, enhancement of biodegradability, decolourisation and removal of micropollutants. However, the most important point is the optimization of the reaction conditions for the process of concern. The AOP applied can be used, for instance, for AOX reduction and TOC removal of industrial wastewaters.  相似文献   
996.
土壤有机质是影响多环芳烃(PAHs)环境行为的一个重要因素,不同有机质组分结合的PAHs生物有效性和环境风险有所不同.本文对6个野外污染土壤中15种优控PAHs的含量和组成及其在土壤轻组(LF)和重组(HF)中的分配特征进行了研究,并采用苯并[a]芘(BaP)毒性当量浓度(TEQBaP)评价了全土、LF和HF中PAHs的生态风险.结果表明,6个土样中15种PAHs总量范围为8.31×102~2.97×104μg/kg,4环PAHs百分含量最高,范围为35.7%~59.6%.6个土样LF中PAHs总量范围为2.38×104~1.17×105μg/kg,HF中PAHs总量范围为3.75×102~2.12×104μg/kg.虽然土壤中LF质量百分比只有1.0%~9.8%,但其结合的PAHs量却占土壤中PAHs总量的5.9%~60.6%.LF中15种PAHs总TEQBaP值范围为2.99×102~1.68×104μg/kg,分别是全土和HF的2.7~33.2倍和3.6~69.5倍.在PAHs污染土壤修复和生态风险评估中,应重视LF中PAHs.对LF中PAHs量占土壤中PAHs总量百分比较高的土壤,可以通过分离LF的方法来修复污染土壤.  相似文献   
997.
嵊泗海域是舟山渔场的重要组成部分,属于国家海洋特别保护区.为了解嵊泗海域表层沉积物中16种优控PAHs(多环芳烃)的污染特征及潜在风险,于2017年6月采集了嵊泗海域18个站点的表层沉积物样品,采用气相色谱-质谱联用技术确定PAHs质量分数及其分子组成,运用特征分子比值法和主成分分析法识别PAHs来源,并采用质量基准法与质量标准法对沉积物中PAHs潜在生态风险进行评价.结果表明:①除了Ace与Act外,其他14种PAHs均被检出.除A1站点外,w(Phe)最高,w(Flra)次之.检出的PAHs以3环和4环为主,占总量的71.21%,不同环数PAHs占比大小依次为3环> 4环> 5环> 2环> 6环.w(∑14PAHs)范围为46.38~196.36 ng/g,平均值为109.40 ng/g.整体分布上,嵊泗海域表层沉积物中w(∑14PAHs)呈近岸高于远岸的分布特征.②嵊泗海域表层沉积物中PAHs以煤炭、柴油和生物质等燃烧源为主,部分站点同时受到燃烧源与石油源影响.③各站点的w(∑14PAHs)均低于ERL和OEL,表明嵊泗海域潜在生态风险较小.④与国内外其他区域相比,嵊泗海域表层沉积物中w(∑14PAHs)处于较低污染水平,尚不足以对当地渔业生态环境造成负面影响,但作为我国重要"蓝色粮仓",仍应加强其陆源排放监管.   相似文献   
998.
董磊  汤显强  林莉  郦超  黎睿  吴敏 《环境科学》2018,39(6):2588-2599
持久性有机污染物(POPs)在我国地表水和沉积物等环境介质中被广泛检出,对生态环境和人类健康具有潜在的风险.针对现阶段长江经济带核心区域(武汉段)POPs的污染状况信息严重缺乏的问题,本文以使用量较大且环境中检出高的PAHs和PAEs为研究对象,通过对2016年长江武汉段干流15个采样点丰水期水体和沉积物中16种PAHs和6种PAEs污染物含量水平、分布特征和污染来源的系统分析.结果表明,长江武汉段2016年丰水期水体和沉积物中ΣPAHs浓度分别为20.8~90.4 ng·L~(-1)(均值40.7 ng·L~(-1))和46.1~424.0 ng·g~(-1)(均值191.8 ng·g~(-1)),ΣPAEs浓度分别为280.9~779.0 ng·L~(-1)(均值538.6 ng·L~(-1))和1 346.2~7 641.1 ng·g~(-1)(均值3 699.5 ng·g~(-1)).PAHs和PAEs含量均低于国家地表水环境质量标准规定的限值,污染程度小.长江武汉段水体中PAHs以2~3环为主,沉积物中PAHs以2~3环和4环为主,水体和沉积物中PAEs以DEHP和DBP为主.基于比率及主成分分析,长江武汉段水体与沉积物中PAHs主要的来源为煤和生物质燃烧,以及石油来源;水体和沉积物中PAEs的主要来源于塑料和重化工工业,以及生活垃圾.水体及沉积物中两类典型POPs(PAHs和PAEs)对人类健康会产生潜在有害影响,需加强监控.研究成果可为长江(武汉段)环境保护提供基础数据和技术支撑.  相似文献   
999.
多环芳烃(PAHs)是焦化废水的特征污染物,不同的焦化废水处理工艺会影响其归趋行为与削减量.基于此,本文追踪了焦化废水厌氧/好氧/好氧(A/O~2)和厌氧/好氧/水解/好氧(A/O/H/O)处理工艺中PAHs的分布行为,使用气质联用色谱(GC-MS)检测并分析了两种工艺中各单元反应器内废水及污泥样品的PAHs浓度,通过通量衡算,评估工艺系统处理效果的差异性.结果表明,两种工艺的前置A厌氧池对PAHs的削减不明显,PAHs在A池富集的浓度远高于O池及H池,低环PAHs经水相从A池进到O池后得到有效降解,高环PAHs则大部分富集于污泥相中,风险比较大,应该区别处理;A/O/H/O工艺对低环的PAHs生物削减率略高于A/O~2工艺,对4环以上的PAHs,A/O/H/O则表现出更明显的降解有效性,理解为A/O/H/O工艺的H池促进了大分子有机物的水解,对PAHs具有针对性.综合研究结果认为,A/O/H/O工艺表现出比A/O~2更明显的降解PAHs的优势.  相似文献   
1000.
为了解钢铁工业区对土壤环境的影响以及土壤的污染状况,采集上海典型钢铁工业区下风向的14个表层土壤样品,应用气相色谱-质谱联用仪(GC-MS)检测了样品中16种优控PAHs(多环芳烃)的含量水平,分析了钢铁工业区下风向土壤中PAHs的组成分布特征,并利用比值法和主成分分析法对土壤中的PAHs进行溯源.结果表明,钢铁工业区下风向土壤中∑16 PAHs(16种优控PAHs的含量)范围为167.0~2 355.0 μg/kg,∑7PAHs(7种具有致癌作用的PAHs的含量)在∑16 PAHs中平均比例为50.4%,近距离样区(< 1 km)表层土壤中∑16 PAHs平均值最高,为1 057.7 μg/kg,远距离样区(5~10 km)污染相对较轻,平均值为381.4 μg/kg;宝3、宝6和宝9采样点于钢铁工业区烧结工艺的下风向,导致宝3采样点∑16 PAHs最高,为2 355.0 μg/kg,宝3、宝6和宝9采样点土壤中PAHs含量依次降低;表层(0~20 cm)土壤中PAHs单体含量最高的为荧蒽,致癌性最强的苯并[a]芘含量范围为10.0~194.0 μg/kg,环数组成以4环为主,平均比例为46.3%,其次是5~6环,二者平均比例为39.9%,随着距离工业区越远,4环的组成比例越高,5~6环比例降低;比值法和主成分分析法结果显示土壤中PAHs主要来源于石油、煤的燃烧和机动车尾气的排放.研究显示,钢铁工业对多环芳烃贡献较大,下风向土壤中总多环芳烃的含量和高环多环芳烃比例都呈现明显的随距离递减特征,石油、煤的燃烧和机动车尾气的排放是其多环芳烃的最主要来源.   相似文献   
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