郑州市环境空气中VOCs的污染特征及健康风险评价

挥发性有机物（VOCs）不但是引发霾和光化学烟雾等环境问题的重要原因,达到一定浓度时还对人类健康造成威胁.为研究中原地区环境空气中VOCs 污染状况,探查VOCs 对人群健康产生的风险,以中原地区核心城市-郑州为代表,于2012年─2013 年间,在郑州市区内布点,以苏玛罐采样/气相色谱-质谱法分析测定了VOCs 的时空分布,并使用健康风险评价四步法进行健康风险评价.郑州市环境空气中VOCs 年均浓度分布特征：以烷烃和芳香烃为主,分别占总量的23.8%和19.5%;年平均质量浓度,芳香烃类为131 μg·m^-3、烷烃类为118 μg·m^-3,酮类为84.3 μg·m^-3、卤代烷烃类为67.8 μg·m-3;单体化合物以丙酮（66.2 μg·m-3）、乙醇（27.5 μ·m-3）、正十-烷（24.4 μg·m-3）和甲苯（17.2 μg·m-3）质量浓度最高,污染程度在国内居于中等水平.VOCs 季均浓度分布特征：夏季高于冬季,但各类化合物在两季的浓度差异较大.VOCs 日均浓度变化特征：烷烃类和芳烃类化合物于10：00 出现浓度峰值,浓度变化趋势与交通量变化具有相关性.健康风险评价结果为：非致癌风险大于1,会对人群健康造成-定的非致癌危害;苯、四氯化碳、1,2-二氯乙烷、1,1,2-三氯乙烷、六氯丁二烯的致癌指数超过EPA 致癌风险值,但未超出OSHA 致癌风险.     

纳米材料对污水/污泥厌氧消化系统影响的研究进展

随着纳米技术的广泛应用,越来越多的纳米材料进入污水/污泥中,对污水/污泥的厌氧消化过程产生一定的影响。综述了纳米材料特性利用在厌氧消化过程中产生的影响(吸附还原重金属,作为电子供体提高厌氧消化效能,降解难降解有机物,减少硫化氢等),以及纳米材料可能对厌氧消化系统微生物的影响(释放金属离子毒性,通过吸附作用包被微生物细胞,破坏细胞膜,引起遗传物质损伤等)。提出最大限度降低纳米材料对厌氧消化系统微生物危害以及利用纳米材料特性促进污水/污泥厌氧消化过程的可行性。     

The effect of two different biochars on remediation of Cd-contaminated soil and Cd uptake by Lolium perenne

Biochar can be widely used to reduce the bioavailability of heavy metals in contaminated soil because of its adsorption capacity. But there are few studies about the effects of biochar on cadmium uptake by plants in soil contaminated with cadmium (Cd). Therefore, an incubation experiment was used to investigate the effects of rice straw biochar (RSBC) and coconut shell biochar (CSBC) on Cd immobilization in contaminated soil and, subsequently, Cd uptake by Lolium perenne. The results showed that the microbial counts and soil enzyme activities were significantly increased by biochar in Cd-contaminated soil, which were consistent with the decrease of the bioavailability of Cd by biochar. HOAc-extractable Cd in soil decreased by 11.3–22.6% in treatments with 5% RSBC and by 7.2–17.1% in treatments with 5% CSBC, respectively, compared to controls. The content of available Cd in biochar treatments was significantly lower than in controls, and these differences were more obvious in treatment groups with 5% biochar. The Cd concentration in L. perenne reduced by 4.47–26.13% with biochar. However, the biomass of L. perenne increased by 1.35–2.38 times after adding biochar amendments. So, Cd uptake by whole L. perenne was augmented by RSBC and CSBC. Accordingly, this work suggests that RSBC and CSBC have the potential to be used as a useful aided phytoremediation technology in Cd-contaminated soil.

     

Fenton试剂催化氧化法处理模拟酸性红B染料废水

采用Fenton试剂催化氧化处理用酸性红B配制的模拟偶氮染料废水,考察了影响处理效果的主要因素,并探讨了酸性红B降解的动力学.实验结果表明,Fenton试剂催化氧化处理酸性红B废水的最佳工艺条件为:H2O2加入量49.0 mmol/L,Fe2+加入量2.0 mmol/L,反应温度25℃,初始废水pH 3～6.在此最佳工艺条件下反应5min时,酸性红B去除率为99.8％,COD去除率为62.3％;反应60 min后,酸性红B去除率为99.9％,COD去除率为80.0％.Fenton试剂催化氧化降解酸性红B的反应符合二级反应动力学规律.     

Pollution characteristics of organic and elemental carbon in PM2:5 in Xiamen, China

Xiamen,located on the southeastern coastal line of China,is undergoing rapid urbanization and industrialization,so its air quality has a trend of degradation.However,studies on level,temporal and spatial changes of fine particles (PM2.5) and their carbonaceous fractions are scarce.In this article,abundance,sources,seasonal and spatial variations,distribution of organic carbon (OC) and elemental carbon (EC) in PM2.5,were studied at suburban,urban and industrial sites in Xiamen during four season-representative months in 2009-2010.PM2.5 samples were collected with middle volume sampler and were analyzed for OC and EC with thermal optical transmittance (TOT) method.Results showed that the annual average PM2.5 concentrations were 63.88-74.80 μg/m3 at three sites.While OC and EC concentrations were in the range of 15.81-19.73 μg/m3 and 2.74-3.49 μg/m3,respectively,and clearly presented the summer minima and winter maxima in this study.The carbonaceous aerosol accounted for 42.8％-47.3％ of the mass of PM2.5.The annual average of secondary organic carbon (SOC) concentrations in Xiamen were 9.23-11.36 μg/m3,accounting for approximately 56％ of OC.Strong correlations between OC and EC was found in spring (R2 = 0.50) and autumn (R2 = 0.73),suggesting that there were similar emission and transport processes for carbonaceous aerosols in these two seasons,while weak correlations were found in summer (R2 = 0.33) and winter (R2 = 0.41).The OC/EC ratios in PM2.5 varied from 2.1 to 8.7 with an annual average of 5.7,indicating that vehicle exhaust,coal smoke and biomass burning were main source apportionments of carbonaceous fractions in Xiamen.     

邯郸市大气复合污染特征的监测研究

利用邯郸市4个大气环境监测站点的PM2.5、PM10、O3等在线连续观测数据,对2013年全年的PM2.5、PM10、O3的浓度水平、变化规律和PM2.5/PM10的变化情况进行了分析,并从地形、气象、污染物排放及冬、夏季逐时PM2.5、O3和各类气体污染物浓度之间的关系等方面进行了研究.结果表明:12013年PM2.5、PM10的年均浓度分别为139和238μg·m-3,分别是国家二级标准的4.0倍和3.4倍.PM2.5、PM10日均浓度超过标准的天数均在280 d左右,全年3/4以上天数均超标.其颗粒物污染程度甚至超过北京、天津、长三角和珠三角等超大城市或城市群,属于严重超载的红色预警地区.整个采暖期PM2.5、PM10平均浓度分别为209和322.1μg·m-3,为非采暖期平均浓度的2倍和1.6倍;同时,采暖期PM2.5/PM10平均值为63%,高出非采暖期10%,采暖期细颗粒物污染问题特征明显.22013年O3日最大8小时平均浓度的最大值为238μg·m-3,是国家二级标准的1.5倍,超标天数为53 d,超标率为14.5%;最大时均浓度为288μg·m-3,是国家二级标准的1.4倍,超标小时数为148h,占全年有效数据的1.7%;与北方城市相比,其污染程度超过北京、天津等,略低于洛阳污染水平.3邯郸市大气复合污染的形成,除了区域大气环流与特殊地形叠加影响外,还主要归因于相对较高的人为源大气污染物排放,因此,要想走出复合污染的困局,减排是硬道理,解决灰霾污染需开展颗粒物、NOx、SO2等污染物的协同控制.     

Immobilization of self-assembled pre-dispersed nano-TiO2 onto montmorillonite and its photocatalytic activity

The immobilization of pre-dispersed Ti O_2 colloids onto the external surface of the clay mineral montmorillonite(Mt) was accomplished and regulated via a self-assembly method employing the cationic surfactant cetyltrimethylammonium bromide(CTAB). The role of CTAB in the synthesis process was investigated by preparing a series of Ti O_2-CTAB-Mt composites(TCM) with various CTAB doses. The results indicated that a uniform and continuous Ti O_2 film was deposited on the external surface of montmorillonite in the composite synthesized with 0.1 wt.% of CTAB, and the TCM nano-composites showed much higher values for specific surface area, average pore size and pore volume than the raw montmorillonite clay. Then, the formed TCM materials were applied in photocatalytic degradation of 2,4-dichlorophenol(2,4-DCP) in aqueous solution. The degradation efficiency reached as high as 94.7%. Based on the degradation intermediates benezoquinone, fumaric acid and oxalic acid identified by LC–MS analysis, a mechanism for the photocatalytic oxidation of 2,4-DCP on Ti O_2/Mt nano-composites is proposed.     

Immobilization of self-assembled pre-dispersed nano-TiO2 onto montmorillonite and its photocatalytic activity

The immobilization of pre-dispersed TiO₂ colloids onto the external surface of the clay mineral montmorillonite (Mt) was accomplished and regulated via a self-assembly method employing the cationic surfactant cetyltrimethylammonium bromide (CTAB). The role of CTAB in the synthesis process was investigated by preparing a series of TiO₂-CTAB-Mt composites (TCM) with various CTAB doses. The results indicated that a uniform and continuous TiO₂ film was deposited on the external surface of montmorillonite in the composite synthesized with 0.1 wt.% of CTAB, and the TCM nano-composites showed much higher values for specific surface area, average pore size and pore volume than the raw montmorillonite clay. Then, the formed TCM materials were applied in photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) in aqueous solution. The degradation efficiency reached as high as 94.7%. Based on the degradation intermediates benezoquinone, fumaric acid and oxalic acid identified by LC–MS analysis, a mechanism for the photocatalytic oxidation of 2,4-DCP on TiO₂/Mt nano-composites is proposed.     

Yangtze Three Gorges Reservoir, China: A holistic assessment of organic pollution, mutagenic effects of sediments and genotoxic impacts on fish

Besides obvious benefits,the Three Gorges Dam's construction resulted in new pollution scenarios with the potentials to threaten the Three Gorges Reservoir(TGR) ecosystem.In order to record organic contamination,to find links to ecotoxicological impacts and to serve as reference for ensuing monitoring,several sites in the TGR area were screened applying the triad approach with additional lines-of-evidence as a holistic assessment method.Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011 and 2012 to determine organic pollution levels,mutagenic potentials and genotoxic impacts.Two regional hot-spots near the cities of Chongqing and Kaixian were identified and further investigated in 2013.Only polycyclic aromatic hydrocarbons(PAHs) could be detected in sediments in 2011(165–1653 ng/g),emphasizing their roles as key pollutants of the area.Their ubiquity was confirmed at Chongqing(150–433 ng/g) and Kaixian(127–590 ng/g) in2013.Concentrations were comparable to other major Chinese and German rivers.However,the immense sediment influx suggested a deposition of 216–636 kg PAH/day(0.2–0.6 mg PAH/(m2·day)),indicating an ecotoxicological risk.PAH source analysis highlighted primary impacts of combustion sources on the more industrialized upper TGR section,whereas petrogenic sources dominated the mid-low section.Furthermore,sediment extracts from several sites exhibited significant activities of frameshift promutagens in the Ames fluctuation assay.Additionally,significant genotoxic impairments in erythrocytes of P.vachellii were detected(Chongqing/Kaixian),demonstrating the relevance of genotoxicity as animportant mode of action in the TGR's fish.PAHs,their derivatives and non-target compounds are considered as main causative agents.     

印染废水处理系统中的主要细菌群体和功能

云南印染厂位于昆明西郊滇池畔,排放的印染废水经生化处理后汇入滇池,使水体受到污染。为此,我们对云南印染厂活性污泥处理系统中主要微生物类群及功能进行了研究,为进一步改善处理系统结构,增强净化功能提供依据。