Zinc tolerance and accumulation in Pteris vittata L. and its potential for phytoremediation of Zn- and As-contaminated soil

A field investigation and pot experiments were conducted to determine the potential of arsenic (As) hyperaccumulator, Pteris vittata L., to remediate sites co-contaminated with zinc (Zn) and As. We found that P. vittata L. had a very high tolerance to Zn and grew normally at sites with high Zn concentrations. In addition, P. vittata L. could effectively take up Zn into its fronds, with a maximum of 737 mg kg(-1) under field conditions. In pot experiments, the accumulated Zn concentration increased significantly as the Zn treatment was raised from 0 to 2000 mg kg(-1), with a maximum Zn accumulation of 0.22 mg pot(-1). Although the concentration of As in P. vittata L. was reduced by the addition of Zn, total frond accumulation of As was elevated when the Zn treatment was increased from 0 to 1000 mg kg(-1), with a maximum As accumulation of 8.3 mg pot(-1) in the presence of 1000 mg kg(-1) Zn. The high Zn tolerance, relatively high ability to accumulate Zn, and great capacity to accumulate As under conditions of suppression by high Zn suggest that P. vittata L. could be useful for the remediation of sites co-contaminated with Zn and As.     

Polycyclic aromatic hydrocarbons (PAHs) in the aerosol in Beijing, China, measured by aminopropylsilane chemically-bonded stationary-phase column chromatography and HPLC/fluorescence detection

We developed a useful analytical method for the determination of polycyclic aromatic hydrocarbons (PAH) concentrations in the aerosol of China. We used an accelerated solvent extraction (ASE) method for the extraction of PAHs from the aerosol samples, in order to reduce the extraction time and the solvent volume used. The optimum purification method was developed, with aminopropylsilane chemically-bonded stationary-phase column chromatography, in order to remove many co-extractives which cannot be removed by conventional purification methods using silica-gel column chromatography. HPLC/fluorescence detection (FLD) was adopted as the analytical method, because it has very high sensitivity to PAH and it is easy to install, operate, and maintain as compared with GC/MS. With the analytical method developed in this study, the recovery and precision (RSD) for most of the PAHs ranged from 75% to 129% and from 2.8% to 22.7%, respectively. The concentrations of PAHs in the aerosol samples collected from October 2003 to April 2005 in Beijing, China were determined using the newly developed method. SigmaPAHs, which is the sum of the concentrations of all detected PAHs, was 177.8 +/- 239.9 ng m(-3) (n = 64). The SigmaPAHs concentration in the heating season (305.1 +/- 279.0 ng m(-3), n = 33) was 7.2 times higher than that in the non-heating season (42.3 +/- 32.0 ng m(-3), n = 31). These strong seasonal variations in atmospheric PAH concentration are possibly due to coal combustion for residential heating in winter.     

A/DAT-IAT生物膜法处理高含盐废水

以含盐量为60 000mg/L(以NaCl计)的模拟工业废水为研究对象,利用A/DAT-IAT生物膜反应器,研究A/DAT-IAT工艺对投加悬浮填料后高含盐废水的处理,并以CODCr、NH4 -N、PO43--P等作为指标评价处理效果.试验结果表明,在总水力停留时间(HRT)为13 h、pH=7,5、25℃条件下,进水ρ(CODCr)、ρ(NH4 -N)和ρ(PO43--P)分别为907.4～1 210.0 mg/L、86.2～99.7 mg/L和3.6～5.1 mg/L.CODCr、NH4 -N和PO43--P的平均去除率分别为73.9%、38.6%和93.5%,平均出水SS为198 mg/L,其中CODCr和PO43--P的去除效果较好.研究表明,A/DAT-IAT生物膜法较其他活性污泥法有了较大的提高.     

北京市重点地区γ辐射水平监测与评价

北京市在奥运行动规划中,明确将放射性辐射作为环境治理的重点.在野外数据采集的基础上,运用地理信息系统(GIS)技术,对北京市重点地区(重点居民区、文物保护区、风景旅游区、奥运场馆区)环境的γ辐射水平进行了监测与评价.结果表明,所调查的4个地区,在总体上放射性辐射水平都不高,其人均年有效剂量当量最高为0.595 mSv,与国家对公众个人的标准(GB 8703-88)剂量值1 mSv比较,仅为限制剂量当量值的60%,均属于环境本底水平.     

中国机动车排放清单的建立

以中国2002年各省统计年鉴中关于机动车及道路信息的数据为基础,并根据COPERTⅢ模型计算出的2002年中国各省区各种机动车类型在城区、郊区和高速公路3种行驶工况下的排放因子,应用GIS技术建立了40km×40km的高空间分辨率的中国机动车排放源清单.结果表明,2002年中国机动车排放CO、NO_x、NMVOC和PM₁₀的排放总量分别为2 815×10⁴、305×10⁴、461×10⁴和111×10⁴t,主要来源于摩托车和汽油小客车的排放.污染物排放量的空间分布显示出其排放集中于经济发达地区,10.8%、2.2%、9.7%和5.3%的国土面积分别排放了84%的CO、55%的NMVOC、48%的NO_x和48%的颗粒物,并呈现出东部高于西部、沿海高于内地的趋势,其中长江三角洲、珠江三角洲和京津地区的排放相对较强.     

恶臭假单胞菌Pseudomonas putida 5-x细胞壁膜系统的Cu2+吸附性能

对1株从电镀废水中分离出的革兰氏阴性菌恶臭假单胞菌P.putida 5-x的细胞表面组分对Cu²⁺的吸附性能进行了分析研究.结果表明,分离的P.putida 5-x细胞壁膜的Cu²⁺吸附容量是完整细胞的5倍之多.细胞表面组分如肽聚糖层、细胞外膜和细胞内膜在P.putida 5-x细胞壁膜的Cu²⁺吸附过程中都发挥了作用.肽聚糖层、细胞外膜和内膜在P.putida 5-x细胞壁膜中的含量依次为细胞内膜>外膜>肽聚糖层,而它们的Cu²⁺吸附容量的大小依次为肽聚糖层>外膜>内膜.在P.putida 5-x细胞壁膜对Cu²⁺的吸附过程中,肽聚糖层贡献了不到15%的吸附容量,而细胞外膜和内膜分别贡献了30%～35%和25%～30%.P.putida 5-x细胞外膜中的磷脂含量明显比其它报道的革兰氏阴性细菌的细胞外膜高,这可能是P.putida 5-x细胞外膜具有较高Cu²⁺吸附容量的主要原因,并由此导致P.putida 5-x细胞壁膜的高Cu2+吸附容量.     

Quantitation of Hydroxyl Radicals from Photolysis of Fe(III)-Citrate Complexes in Aerobic Water (5 pp)

Background For their high photoreactivity, Fe(III)-carboxylate complexes are important sources of H2O2 for some atmospheric and surface waters. Citrate is one kind of carboxylate, which can form complexes with Fe(III). In our previous study, we have applied Fe(III)-citrate complexes to degrade and decolorize dyes in aqueous solutions both under UV light and sunlight. Results have shown that carboxylic acids can promote the photodegradation efficiency. It is indicated that the photolysis of Fe(III)-citrate complexes may cause the formation of some reactive species (e. g. H2O2 and ·OH). This work is attempted to quantify hydroxyl radicals generated in the aqueous solution containing Fe(III)-citrate complexes and to interpret the photoreactivity of Fe(III)-citrate complexes for degrading organic compounds. Methods By using benzene as the scavenger to produce phenol, the photogeneration of ·OH in the aqueous solution containing Fe (III)-citrate complexes was determined by HPLC. Results and Discussion In the aqueous solution containing 60.0/30.0 mM Fe(III)/citrate and 7.0 mM benzene at pH 3.0, 96.66 mM ·OH was produced after irradiation by a 250W metal halide light (l ≥ 313 nm) for 160 minutes. Effects of initial pH value and concentrations of Fe(III) and citrate on ·OH radical generation were all examined. The results show that the greatest photoproduction of ·OH in the aqueous solution (pH ranged from 3.0 to 7.0) was at pH 3.0. The photoproduction of ·OH increased with increasing Fe(III) or citrate concentrations. Conclusion In the aqueous solutions containing Fe(III)-citrate complexes, ·OH radicals were produced after irradiation by a 250W metal halide light. It can be concluded that Fe(III)-citrate complexes are important sources of ·OH radicals for some atmospheric and surface waters. Recommendations and Outlook It is believed that the photolysis of Fe(III)-citrate complexes in the presence of oxygen play an important role in producing ·OH both in atmospheric waters and surface water where high concentrations of ferric ions and citrate ions exist. The photoproduction of ·OH has a high oxidizing potential for the degradation of a wide variety of natural and anthropogenic organic and inorganic substances. We can use this method for toxic organic pollutants such as organic dyes and pesticides.     

Two-stage fuzzy-stochastic robust programming: a hybrid model for regional air quality management

In this study, a hybrid two-stage fuzzy-stochastic robust programming (TFSRP) model is developed and applied to the planning of an air-quality management system. As an extension of existing fuzzy-robust programming and two-stage stochastic programming methods, the TFSRP can explicitly address complexities and uncertainties of the study system without unrealistic simplifications. Uncertain parameters can be expressed as probability density and/or fuzzy membership functions, such that robustness of the optimization efforts can be enhanced. Moreover, economic penalties as corrective measures against any infeasibilities arising from the uncertainties are taken into account. This method can, thus, provide a linkage to predefined policies determined by authorities that have to be respected when a modeling effort is undertaken. In its solution algorithm, the fuzzy decision space can be delimited through specification of the uncertainties using dimensional enlargement of the original fuzzy constraints. The developed model is applied to a case study of regional air quality management. The results indicate that reasonable solutions have been obtained. The solutions can be used for further generating pollution-mitigation alternatives with minimized system costs and for providing a more solid support for sound environmental decisions.     

Distribution and dissipation pathways of nonylphenol polyethoxylates in the Yellow River: Site investigation and lab-scale studies

Spatial distribution of nonylphenol polyethoxylates (NPEOs) and nonylphenol (NP) was investigated in a field study in Lanzhou Reach of the Yellow River. NPEOs and their metabolites were found in the river, with the maximum dissolved concentrations of 6.38 nmol/L for NPEOs, 0.19 nmol/L for nonylphenol ethoxy acetic acids (NPECs) and 0.79 nmol/L for NP, respectively. The maximum concentrations in the sediment and suspended particle samples were 1.50 and 5.09 nmol/g for NPEOs and NP, respectively. The effects of particles, light and microorganism on the dissipation of NPEOs in the river water were investigated based on lab-scale experiments. When natural particles were removed, 72% and 22% degradation of NPEOs were achieved at 120 h in non-sterile and sterile conditions with light, respectively. Different concentrations of NPECs were also observed in these experiments. When suspended particle matters (SPMs) were present, about 38-50% of NPEOs were sorbed to the particulate phase in only 1 h. As a result, the degradation of NPEOs and production of NPECs were inhibited. However, the combined sorption and degradation in the presence of SPMs resulted in lower dissolved NPEO concentrations than those in the absence of SPMs. Biodegradation was the most important pathway for NPEOs degradation in the river water, while NPECs seemed to be produced through both biological and abiological pathways.     

“2+26”城市2017年冬防减排效果及其潜在原因分析——以衡水市为例

近年来我国大气重污染频发,严重影响民生,其中以京津冀最为严重.2017年"总理基金"启动,同年冬防效果显著.衡水市作为"2+26"城市之一,空气质量排名常年处于倒数十名之内.经过2017年的冬防,空气质量明显改善,衡水市大气污染的改善在"2+26"城市中很具有代表性.本文以衡水作为切入点,利用后向轨迹和浓度权重轨迹分析(CWT)探讨了2017年衡水冬防效果及潜在源区变化,分别从气象轨迹和本地排放初探了潜在原因.结果表明,2017年冬防效果显著,PM_(2.5)浓度降低33%,优良天数增加32 d,重污染天数减少22 d.PM_(10)浓度降低41%,优良天数增加40 d.2017年冬季PM_(2.5)潜在源区由2016年同期衡水北部及以北地区向衡水南部及以南地区转移.PM_(10)潜在源分布变化与PM_(2.5)相似.两年气象条件的对比结果表明,气象变化较小,对潜在源分布影响不大,本地排放是潜在源区分布变化的主要原因,其中衡水北部工业锅炉和扬尘减排量显著高于衡水南部.研究表明,2017年衡水冬防效果显著,相比于气象条件,本地排放对大气颗粒污染及来源影响更大,本研究可为"2+26"城市大气颗粒污染研究提供参考.