Tree bark as a passive air sampler to indicate atmospheric polybrominated diphenyl ethers (PBDEs) in southeastern China

The different barks were sampled to discuss the influence of the tree species, trunk circumference, and bark thickness on the accumulation processes of polybrominated diphenyl ethers (PBDEs) from air into the bark. The results of different PBDE concentrations indicated that barks with a thickness of 0–3 mm collected from weeping willow, Camphor tree, and Masson pine, the trunk circumferences of which were 100 to 150 cm, were better PBDEs passive samplers. Furthermore, tree bark and the corresponding air samples were collected at Anji (AJ), Hangzhou (HZ), Shanghai (SH), and Wenling (WL) to investigate the relationship between the PBDE concentrations in bark and those in air. In addition, the significant correlation (r ²?=?0.906; P?<?0.05) indicated that atmospheric PBDEs were the principle source for the accumulation of PBDEs in the barks. In this study, the log K _BA (bark–air partition coefficient) of individual PBDE congeners at the four sites were in the range from 5.69 to 6.79. Finally, the total PBDE concentration in WL was 5 to 20 times higher than in the other three cities. The result indicated that crude household workshops contributed a heavy amount of PBDEs pollution to the environment, which had been verified by the spatial distribution of PBDEs levels in barks collected at Wenling (range, 26.53–1317.68 ng/g dw). The good correlation between the PBDE concentrations in the barks and the air samples and the variations of the PBDE concentrations in tree barks collected from different sites reflected that the bark could be used as a passive sampler to indicate the atmospheric PBDEs.     

Hazardous substances in indoor dust emitted from waste TV recycling facility

Various hazardous substances contained in waste TV sets might be released into environment via dust during recycling activities. Two brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and tetrabromobisphenol A (TBBPA), and five kinds of heavy metals (Cu, Pb, Cd, Cr, and Ni) were detected in indoor dust collected from two workshops (TV dismantling workshop and subsequent recycling workshop). PBDEs concentrations in dust from waste wires recycling line (722,000 ng/g) were the highest among the studied sites, followed by those in manual dismantling–sorting line (117,000 ng/g), whereas TBBPA concentrations were the highest in manual dismantling–sorting line (557 ng/g) and printed circuit board (PCB) recycling line (428 ng/g). For heavy metals, Cu and Pb were the most enriched metals in all dust samples. The highest concentration of Pb (22,900 mg/kg) was found in TV dismantling workshop-floor dust. Meanwhile, Cu was the predominant metal in dust from the PCB recycling line, especially in dust collected from electrostatic separation area (42,700 mg/kg). Occupational exposure assessment results showed that workers were the most exposed to BDE-209 among the four PBDE congeners (BDE-47, BDE-99, BDE-153, and BDE-209) in both workshops. The hazard quotient (HQ) indicated that noncancerous effects were unlikely for both BFRs and heavy metals (HQ?<?1), and carcinogenic risks for Cd, Cr, and Ni (risk?<?10^?6) on workers in two workshops were relatively low.     

Biodegradation of methyl red by Bacillus sp. strain UN2: decolorization capacity,metabolites characterization,and enzyme analysis

Azo dyes are recalcitrant and refractory pollutants that constitute a significant menace to the environment. The present study is focused on exploring the capability of Bacillus sp. strain UN2 for application in methyl red (MR) degradation. Effects of physicochemical parameters (pH of medium, temperature, initial concentration of dye, and composition of the medium) were studied in detail. The suitable pH and temperature range for MR degradation by strain UN2 were respectively 7.0–9.0 and 30–40 °C, and the optimal pH value and temperature were respectively 8.0 and 35 °C. Mg²⁺ and Mn²⁺ (1 mM) were found to significantly accelerate the MR removal rate, while the enhancement by either Fe³⁺ or Fe²⁺ was slight. Under the optimal degradation conditions, strain UN2 exhibited greater than 98 % degradation of the toxic azo dye MR (100 ppm) within 30 min. Analysis of samples from decolorized culture flasks confirmed biodegradation of MR into two prime metabolites: N,N′dimethyl-p-phenyle-nediamine and 2-aminobenzoic acid. A study of the enzymes responsible for the biodegradation of MR, in the control and cells obtained during (10 min) and after (30 min) degradation, showed a significant increase in the activities of azoreductase, laccase, and NADH-DCIP reductase. Furthermore, a phytotoxicity analysis demonstrated that the germination inhibition was almost eliminated for both the plants Triticum aestivum and Sorghum bicolor by MR metabolites at 100 mg/L concentration, yet the germination inhibition of parent dye was significant. Consequently, the high efficiency of MR degradation enables this strain to be a potential candidate for bioremediation of wastewater containing MR.     

CuO / 过硫酸氢钾体系催化氧化苯酚简

本论文通过直接沉淀法制备了CuO催化剂,结合过硫酸氢钾,在常温常压下催化氧化处理苯酚模拟废水。采用电子显微镜（SEM）、X射线粉末衍射（XRD）对催化剂进行了表征,并研究了反应过程中各影响因素对降解效率的影响。实验结果表明,在催化剂用量为0.2 g/L,氧化剂浓度为0.25 g/L,pH值为7,反应时间为60 min的条件下,浓度为50 mg/L的苯酚降解率可达100%,TOC去除率达84%。进一步实验表明,催化剂具有良好的重复使用能力。最后,通过自由基捕捉实验,考察了体系中的自由基种类,并根据实验结果,讨论了CuO/过硫酸氢钾体系的催化降解机理。     

水生植物酸碱预处理对厌氧发酵联产氢气-甲烷的影响简

采用酸碱预处理乌梁素海典型沉水植物龙须眼子菜和挺水植物芦苇,通过厌氧发酵动力学分析、还原糖变化及微观结构解析,研究酸碱预处理对水生植物厌氧发酵联产氢气-甲烷的影响。实验结果表明,酸碱预处理后水生植物厌氧发酵联产氢气-甲烷两阶段累积产气量、氢气及甲烷含量均显著提高,酸处理效果优于碱处理。采用0.5 mol/L HCl预处理龙须眼子菜效果最佳,最大氢气、甲烷含量分别达42.65%和52.82%,产氢气速率为4.118 mL/h,产甲烷速率最高达14.199 mL/h。芦苇经1 mol/L HCl预处理效果最佳,最高氢气、甲烷含量分别为32.22%和65.26%。扫描电镜微观结构分析表明,酸碱预处理可显著破坏芦苇、龙须眼子菜的纤维素结构,有效增加植物与微生物接触面积,有利于厌氧发酵联产氢气-甲烷工艺的快速启动和稳定运行。     

基于GIS的太湖流域主要生态风险源危险度综合评价研究

以太湖流域主要生态风险源为评价对象,充分考虑多类型多等级风险源作用强度的差异性,构建了风险源危险度评价模型,并在此基础上依据风险源发生机率、强度及作用范围等建立了太湖流域洪涝、干旱、极端气象、土壤侵蚀及污染排放等主要生态风险源的危险度评价指标体系。在ArcGIS技术支持下,创建了太湖流域1 606个网格和24个县市的风险源危险度统计数据库,采用AHP权重法确定指标权重,运用叠加分析、空间分析等技术方法最终实现太湖流域单要素及综合生态风险源危险度的定量评价。结果表明流域内生态风险源的分布存在明显的空间分异规律。其中,高生态风险源危险区集中分布在环太湖北部一带,面积约占流域面积的1172%;较高危险区主要呈“西北 北 东北 东”半环状分布格局,所占面积约2452%,危险度较低的区域集中在流域西南部的苕溪流域一带,面积占1566%。此外,不同区域主导生态风险源组成亦不同,约599%的区域是以污染排放为主导生态风险源,主要分布在镇江 宜兴 长兴 安吉一线以东的地区;2545%的区域主导生态风险源为干旱,主要集中在镇江 宜兴 长兴 安吉一线以西;1244%的区域是以洪涝灾害为主导风险源,集中分布在湖州、宜兴等地;而以水土流失、极端气象灾害作为主导风险源地区相对较为分散,所占比例较小     

春季香溪河库湾CODMn时空分布及其影响因子初探

于2012年春季在香溪河库湾合理布置断面观测,分析水体高锰酸盐指数(CODMn)的时空分布特征,并对CODMn与水体中叶绿素a、溶解氧(DO)、水体垂向稳定系数、总氮(TN)和溶解性硅酸盐(D Si)进行相关分析,以期为香溪河流域有机污染的治理提供支持和指导。结果表明：春季香溪河库湾CODMn浓度变化范围为1.40～5.36 mg/L,4月CODMn均值明显高于3月和5月,为366 mg/L,整个春季CODMn浓度从下游至上游呈现明显增大的趋势。相关分析发现,春季水华暴发期间,CODMn与叶绿素a显著正相关(分别为072和074),而在未暴发水华的3月二者的相关性不显著。浮游植物和水体稳定系数是影响CODMn变化的主要因素。倒灌异重流使得高含氮、低CODMn浓度的长江干流水体进入库湾下游并稀释CODMn浓度。CODMn与DO在3月和5月的弱相关关系为香溪河CODMn特殊的分布特征提供了其它合理的解释,其分布特征受多种因素的共同影响。春季库湾上游有机污染趋于恶化,限制支流特别是上游污染物的排放是改善有机污染现状的有效途径     

恩施地区生态足迹和生态承载力评价

以恩施地区2010年统计数据为依据,对其2010年的生态足迹、生态承载力、生态盈余进行计算和分析,并将生态足迹、生态承载力、生态盈余和万元GDP生态足迹分别与恩施地区贫困村分布密度进行空间耦合。研究表明：（1）恩施地区人均生态盈余为0467 hm2,人均生态承载力为0947 1 hm2,人均生态足迹为048 hm2;（2）贫困村分布密度最高的来凤县、建始县人均生态盈余很少,而贫困村分布密度最低的利川市、咸丰县、宣恩县、鹤峰县,人均生态足迹最高和最低的县分别是咸丰县、宣恩县,鹤峰县的生态承载力最高,人均生态盈余最高的是宣恩县、鹤峰县,万元GDP生态足迹最高和最低的分别是利川市,巴东县;（3）通过生态足迹的研究,提出了恩施贫困地区需放大生态比较优势,〖JP2〗因地制宜,努力将生态盈余转化为直接的经济增长,使之能够有效的帮助贫困地区脱贫致富     

石墨气体扩散电极的制备与性能优化

电极的制备工艺及参数直接影响电极材料的活性。主要考察了C/PTFE质量比、碾压压力、煅烧温度、造孔剂NH4HCO3及稀土掺杂等因素对电极产出H2O2的影响规律。研究结果表明,电极最佳制备条件为:石墨和PTFE质量比为2∶1、石墨、造孔剂和稀土元素质量比为6∶1∶1、碾压压力10 MPa、煅烧温度330℃。在pH=3、电解质Na2SO4浓度为0.05mol/L条件下,电解2 h后,改性电极产生的H2O2从95 mg/L提高到350 mg/L,提高了268.4%。     

Stability of 6:2 fluorotelomer sulfonate in advanced oxidation processes: degradation kinetics and pathway

Perfluorooctane sulfonate (PFOS), a widely used mist suppressant in hard chrome electroplating industry, has been listed in the Stockholm Convention for global ban. 6:2 Fluorotelomer sulfonate (6:2 FTS) acid and salts have been adopted as alternative products in the market, but no data about their abiotic degradation has been reported. In the present study, the degradability of 6:2 FTS potassium salt (6:2 FTS-K) was evaluated under various advanced oxidation processes, including ultraviolet (UV) irradiation, UV with hydrogen peroxide (H₂O₂), alkaline ozonation (O₃, pH = 11), peroxone (O₃/H₂O₂), and Fenton reagent oxidation (Fe²⁺/H₂O₂). UV/H₂O₂ was found to be the most effective approach, where the degradation of 6:2 FTS-K followed the pseudo-first-order kinetics. The intermediates were mainly shorter chain perfluoroalkyl carboxylic acid (C₇ to C₂), while sulfate (SO₄ ^2?) and fluoride (F^?) were found to be the final products. The high yields of SO₄ ^2? and F^? indicate that 6:2 FTS-K can be nearly completely desulfonated and defluorinated under UV/H₂O₂ condition. The degradation should firstly begin with the substitution of hydrogen atom by hydroxyl radicals, followed by desulfonation, carboxylation, and sequential “flake off” of CF₂ unit. Compared with PFOS which is inert in most advanced oxidation processes, 6:2 FTS-K is more degradable as the alternative.