Oxidation of polycyclic aromatic hydrocarbons by horseradish peroxidase in water containing an organic cosolvent

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that are toxic, mutagenic, and carcinogenic. We investigated the horseradish peroxidase (HRP)-catalyzed oxidation of PAHs in water containing N,N-dimethylformamide. Four PAHs (anthracene, phenanthrene, pyrene, and fluoranthene) were investigated using single-PAH and mixed-PAH systems. The results provide useful information regarding the preferential oxidation of anthracene over other PAHs regardless of the reaction time, enzyme dosage, and hydrogen peroxide concentration. The removal of PAHs was found to be very strongly correlated with the ionization potential (IP), and much greater PAH oxidation was observed at a lower IP. The oxidation of anthracene was specifically pH- and temperature-dependent, with the optimal pH and temperature being 8.0 and 40 °C, respectively. The redox mediators 1-hydroxybenzotriazole and veratryl alcohol promoted the transformation of anthracene by HRP; 9,10-anthraquinone was the main product detected from the anthracene oxidation system. The results of this study not only provide a better understanding of the oxidation of PAHs by utilizing a plant biocatalyst, but also provide a theoretical basis for establishing the HRP-catalyzed treatment of PAH-contaminated wastewater.     

CALPUFF模型在大气环境容量测算中的应用研究

本研究利用CALPUFF空气质量扩散模式模拟了凉山州2007年气象场和s02浓度场,通过现状监测结果与模拟结果的比较评述了模型的适用性;并根据西昌市现状污染源和虚拟污染源情况,通过CALPUFF模拟建立大气污染物传递矩阵,结合线性优化模型测算了西昌市大气环境容量。     

First trimester maternal serum placenta growth factor (PIGF)concentrations in pregnancies with fetal trisomy 21 or trisomy 18

Placenta growth factor (PIGF), an angiogenic factor belonging to the vascular endothelial growth factor family, pregnancy-associated plasma protein A (PAPP-A) and free β-human chorionic gonadotrophin (β-hCG) were measured in maternal serum from 45 pregnancies with trisomy 21, 45 with trisomy 18 and 493 normal controls at 10–13 completed weeks of gestation. In the normal pregnancies maternal serum PIGF levels increased exponentially with gestation. The median multiple of the median (MoM) PIGF concentration in the trisomy 21 group (1.26 MoM) was significantly higher (p<0.0001) than in the control group (1.00 MoM). In the trisomy 18 group the median PIGF was lower (0.889 MoM) but this did not quite reach significance (p=0.064). The corresponding median MoM values for PAPP-A were 1.00 MoM for the controls, 0.49 MoM for trisomy 21 and 0.16 MoM for trisomy 18. The median MoM values for free β-hCG were 1.00 MoM for the controls, 2.05 MoM for trisomy 21 and 0.38 MoM for trisomy 18. In the control group there was a small but significant correlation of PIGF with free β-hCG (r=+0.1024) and PAPP-A (r=+0.2288). In the trisomy 18 group there was a significant association between PIGF and free β-hCG (r=+0.2629) but not with PAPP-A (r=+0.0038). In the trisomy 21 group there was a small but significant association with PAPP-A (r=+0.1028) but not with free β-hCG (r=+0.0339). The separation of affected and unaffected pregnancies in maternal serum PIGF is small, and therefore it is unlikely that measurement of PIGF would improve screening for these abnormalities provided by the combination of fetal nuchal translucency and maternal serum PAPP-A and free β-hCG. Copyright © 2001 John Wiley & Sons, Ltd.     

Technology of comprehensive disposal and utilization of municipal solid waste (MSW)

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萍乡市农用土壤重金属含量及其分布特征分析

以江西省萍乡地区农用土壤为研究对象,分析研究了萍乡市农用土壤中重金属的含量、分布特征。结果表明:萍乡地区农用土壤中重金属的平均含量均未超过国家土壤环境质量二级标准,但其中锌、镍、铬、铜、镉、砷、铅、锰、汞的含量均超过了江西省土壤重金属相应元素的背景值。从空间分布来看,在全市5个县区布置的29个测点中,有14个测点的重金属含量超标;其中上栗县有8个测点超标,明显多于其他县区,出现了不同的污染特征。     

中国典型河湖水体铅的水生生物安全基准与生态风险评价

采用物种敏感度排序法(SSR)对我国铅的淡水水生生物安全基准进行推导,并以太湖为例进行了流域水生生物安全基准推导。对于难以获得的本土生物毒性数据,开展了相应的毒性试验。获得了我国国家与太湖流域铅的水生生物安全基准值,基准最大浓度(CMC)分别为63.92、104.26μg·L-1,基准连续浓度(CCC)分别为1.21、4.06μg·L-1。同时,对我国主要河流以及太湖流域进行了铅的生态风险评价,联合概率曲线法显示影响5%水生生物种类的概率分别为66.22%和43.19%,熵值法则显示中国主要河流存在较大的铅暴露风险,因此,我国铅的潜在生态风险较大,主要河流与太湖流域存在铅污染问题。     

Cadmium accumulation characteristics of floricultural plant Cosmos bipinnata*

The artificially high soil cadmium (Cd) concentration screening method was used to screen Cd-hyperaccumulators from floricultural plants. Among the five species of floricultural plants screened, Cosmos bipinnata showed the characteristics of Cd-accumulators. A pot experiment was conducted to further study Cd accumulation characteristics of C. bipinnata. The results showed that the biomass, chlorophyll content, superoxide dismutase activity, peroxidase activity and soluble protein content of C. bipinnata first increased and later decreased with the increase in soil Cd concentration, but the carotenoid content and catalase activity of C. bipinnata reduced. Cd contents in roots, stems, leaves and shoots of C. bipinnata increased with increasing soil Cd concentration. When the soil Cd concentration was 50?mg?kg^?1, the Cd content in shoots was up to 112.62?mg?kg^?1, which was higher than the Cd-hyperaccumulator critical value. The root and shoot bioconcentration factors exceeded 1 in various Cd treatments, but the translocation factors were less than 1. When the soil Cd concentration was 50?mg?kg^?1, the Cd accumulation in shoots achieved the maximum of 224.30?μg plant^?1. Therefore, considering the tolerance and accumulation of Cd, C. bipinnata is a Cd-accumulator that could be used to remediate Cd-contaminated urban soil.     

新型单级A/O程序无回流复合膜生物反应器处理氨氮废水的试验

采用单级A/O程序复合膜生物反应器(HSMBR)处理高氨氮废水,研究在低DO浓度下系统对有机物、氨氮和总氮的去除效率。研究结果表明:在低DO浓度下,CODCr、氨氮的平均去除率分别为94.4%和92.8%。由于进水CODCr/TN值仅为2.01,则使得总氮平均去除率仅为69.4%,但是当系统亚硝化累积率从60.5%～67.1%提高到83.5%～86.4%时,系统总氮去除率提高了17.7%。另外,维持低DO浓度可以实现亚硝酸型同时硝化反硝化反应。     

Process analysis of characteristics of the boundary layer during a heavy haze pollution episode in an inland megacity, China

Ground observation data from 8 meteorological stations in Xi'an, air mass concentration data from 13 environmental quality monitoring sites in Xi'an, as well as radiosonde observation and wind profile radar data, were used in this study. Thereby, the process, causes and boundary layer meteorological characteristics of a heavy haze episode occurring from 16 to 25 December 2013 in Xi'an were analyzed. Principal component analysis showed that this haze pollution was mainly caused by the high-intensity emission and formation of gaseous pollutants (NO₂, CO and SO₂) and atmospheric particles (PM_2.5 (fine particles) and PM₁₀ (respirable suspended particle). The second cause was the relative humidity and continuous low temperature. The third cause was the allocation of the surface pressure field. The presence of a near-surface temperature inversion at the boundary layer formed favorable stratification conditions for the formation and maintenance of heavy haze pollution. The persistent thick haze layer weakened the solar radiation. Meanwhile, a warming effect in the urban canopy layer and in the transition zone from the urban friction sublayer to the urban canopy was indicated. All these conditions facilitated the maintenance and reinforcement of temperature inversion. The stable atmospheric stratification finally acted on the wind field in the boundary layer, and further weakened the exchange capacity of vertical turbulence. The superposition of a wind field with the horizontal gentle wind induced the typical air stagnation and finally caused the deterioration of air quality during this haze event.     

CIBR污泥吸附有机物机理及应用

通过吸附实验考察连续流间歇生物反应器(CIBR)中污泥对有机物的吸附效果及吸附类型,分析好氧、缺氧和厌氧环境对污泥吸附有机物能力的影响,进而探讨污泥的吸附能力在CIBR实现有机物高效去除中的作用.实验结果表明,污泥对有机物的吸附主要是物理吸附.好氧/缺氧/厌氧环境对活性污泥及其灭活污泥吸附有机物能力影响不大,各环境下平均吸附率分别达到54.09％和48.62％.污泥良好的吸附能力及其先吸附后生物降解的特性,保证了CIBR混合液中COD值始终低于30 mg/L.