Isolation and characterization of a diverse group of phenylacetic acid degrading microorganisms from pristine soil

A diverse range of microorganisms capable of growth on phenylacetic acid as the sole source of carbon and energy were isolated from soil. Sixty six different isolates were identified and grouped according to 16S rRNA gene RFLP analysis. Subsequent sequencing of 16S rDNA from selected strains allowed further characterization of the phenylacetic acid degrading population isolated from soil. Nearly half (30) of the isolates are Bacillus species while the rest of the isolates are strains from a variety of genera namely, Arthrobacter, Pseudomonas, Rhodococcus, Acinetobacter, Enterobacter, Flavobacterium, and Paenibacillus. Sixty-one of the sixty-six strains reproducibly grew in defined minimal liquid culture medium (E2). All strains isolated grew when at least one hydroxylated derivative of phenylacetic acid was supplied as the carbon source, while 59 out of the 61 strains tested, accumulated ortho-hydroxyphenylacetic acid in the assay buffer; when pulsed with phenylacetic acid. Oxygen consumption experiments failed to indicate a clear link between phenylacetic acid and hydroxy-substituted phenylacetic acid in isolates from a broad range of genera.     

城市河涌受污染底泥的固化/稳定化处理

为了给河涌疏浚底泥的资源化提供技术支持,以广州市车陂涌表层受污染底泥为研究对象,用水泥、石灰、粉煤灰、膨润土等材料对底泥进行固化/稳定化处理实验。通过无侧限抗压强度、污染物在模拟自然条件下(中性)的释放特征、毒性浸出实验(酸性条件)对固化/稳定化处理效果进行综合分析。结果表明:经合适的处理后,固化体抗压强度能高于300 kPa;固化体自然条件下重金属的释放量明显减少,固化/稳定化处理能够有效减缓和减少固化体的二次污染;毒性浸出实验结果表明,河涌底泥经固化/稳定化处理后其重金属浸出能力显著降低。     

Degradation of nonylphenol by anaerobic microorganisms from river sediment

We investigated the degradation of nonylphenol monoethoxylate (NP1EO) and nonylphenol (NP) by anaerobic microbes in sediment samples collected at four sites along the Erren River in southern Taiwan. Anaerobic degradation rate constants (k1) and half-lives (t1/2) for NP (2 microg/g) ranged from 0.010 to 0.015 1/day and 46.2 to 69.3 days respectively. For NP1EO (2 microg/g), the ranges were 0.009-0.014 1/day and 49.5-77.0 days respectively. Degradation rates for NP and NP1EO were enhanced by increasing temperature and inhibited by the addition of acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, heavy metals, and phthalic acid esters. Degradation was also measured under three anaerobic conditions. Results show the high-to-low order of degradation rates to be sulfate-reducing conditions > methanogenic conditions > nitrate-reducing conditions. The results show that sulfate-reducing bacteria, methanogen, and eubacteria are involved in the degradation of NP and NP1EO, with sulfate-reducing bacteria being a major component of the river sediment.     

Evaluation of effluent toxicity and ambient toxicity in a polluted lowland river

The impact of an industrial effluent containing high loads of calcium, cadmium, lead chloride and sulphate, on a river ecosystem was assessed using a combination of an effluent toxicity test, an ambient toxicity test and an ecological survey. Only this combination of techniques made it possible to discriminate between the effects of the discharge and those of the background pollution. Each of the individual techniques detected essential effects which the other failed to reveal. With the physical and chemical measurements, important increases of several components were measured at all sampling sites downstream of the discharge. With the ecological survey, however, no large changes in water quality could be determined at the sampling sites, due to the high degree of pollution present upstream of the discharge. Reproduction of Daphnia magna, exposed to sublethal effluent dilutions, was followed over two generations. The offspring of the first generation were shown to have an increased sensitivity to the effluent, compared to the first generation that was born from previously unexposed mothers. Besides the toxicity of the effluent, the acute and chronic toxicity of its main component, CaCl(2), was also determined. The results of the CaCl(2)-tests and toxicity data from literature for the suspected toxicants were transformed to Toxic Units (TU). Using the sum of the TUs we investigated the possibility of predicting effluent toxicity to Daphnia magna. Effluent toxicity was under-estimated by calculating the sum of the TUs of the individual components. Dilution of the effluent to a level at which the measured toxicant concentrations comply with European regulations still showed significant effects on Daphnia reproduction.     

Heavy metal accumulation in Littoraria scabra along polluted and pristine mangrove areas of Tanzania

The periwinkle Littoraria scabra was collected at polluted and pristine mangrove sites along the Tanzanian coastline, including Msimbazi, Mbweni (i.e. Dar es Salaam) and Kisakasaka, Nyamanzi and Maruhubi (i.e. Zanzibar). Periwinkles were morphologically characterized, sexed and their heavy metal content was determined using ICP-MS. Analysis revealed that L. scabra from polluted areas contained higher soft tissue heavy metal levels, were significantly smaller and weighed less compared to their conspecifics from the unpolluted mangroves. The current morphological observations may be explained in terms of growth and/or mortality rate differences between the polluted and non-polluted sites. Although a variety of stressors may account for these adverse morphological patterns, our data suggest a close relationship with the soft tissue heavy metal content. Compared to soft tissue heavy metal levels that were measured in L. scabra along the same area in 1998, most metals, except for arsenic, chromium and iron have decreased dramatically.     

青萍生长特征及其对受污染河水的修复效果

以浮萍优势品种青萍（Lemna minor）为研究对象,开展受污染河水修复。分析了青萍在不同营养盐浓度条件下的生长特征,探讨了青萍对受污染河水的修复效果。在表面积为0.0095 m2的限制空间条件下,青萍在1、2和5 mg总氮（TN）/L营养液中的生长特征都能较好地服从Logistic生长模型,受制约的临界鲜重（FW）分别为1.20、1.36和1.36 g;青萍对受污染河水中氮磷污染物具有较好的去除效果,氨氮（NH＋4-N）的平均去除率、平均去除量和平均去除速率分别为56.87%、1.22 mg/d和0.0466 mg/（g FW·h）,正磷酸盐（PO3-4-P）的平均去除率、平均去除量和平均去除速率分别为66.95%、0.25 mg/d和0.0088 mg/（g FW·h）。根据相关性分析,进水NH＋4-N和PO3-4-P浓度与其对应去除量之间极显著相关;青萍FW与NH＋4-N去除速率之间显著负相关,但与PO3-4-P去除速率之间不存在显著相关性;NH＋4-N进水浓度与去除速率相关性不显著,但PO3-4-P进水浓度与去除速率显著正相关。     

Removal and degradation of aromatic compounds from a highly polluted site by coupling soil washing with photocatalysis

The possible application of two environmental remediation technologies - soil washing and photocatalysis - to remove and decompose various aromatic pollutants present in excavated soils of a contaminated industrial site has been investigated. Aqueous solutions containing the non-ionic surfactant Brij 35 were used to extract the contaminants from the soil samples. The photocatalytic treatment of the obtained washing wastes, performed in the presence of TiO(2) suspensions irradiated with simulated sunlight, showed a slow abatement of the toxic compounds due to the relevant concentrations of organics in the waste. A neat improvement of the process performances, obtained by operating in the presence of added potassium peroxydisulfate, suggests a feasible treatment route.     

本源微生物菌剂修复城市污染河流

通过丰湖河投菌过程中和总投菌后两周的各水质指标分析,对本源微生物菌剂作用城市重污染河流过程进行了探讨和研究。结果表明,在2010年11月20日全河布菌后,以COD下降后上升的情况作为补菌时间的判断依据,实现菌种效力最大化。继2010年11月25日、27日和30日3次补菌后上游至下游硐桥、久泰桥和益民水闸处COD的去除率分别达到52.7%、68.8%和61.6%,氨氮和总磷有所去除。水色由深灰绿色转变为深绿色,浮油减少,臭味明显消除。表明此法在冬季水温较低的天然河流条件下,不需大型设备便可较快修复水质,具有较好的经济环境效益。     

潮汐式生态滤床在平原河网地区污染河流治理中的应用

以梁塘河治理措施中的主体工程潮汐式生态滤床为研究对象,考察其对平原河网地区污染河流中的N、P及有机污染物等的去除效果,并通过高通量测序技术分析潮汐式生态滤床混合层的微生物群落组成。结果表明,以潮汐式生态滤床为主体的治理工程运行稳定,河流水质趋好,且在受到污染冲击后,水质能迅速恢复。潮汐式生态滤床对[NH₄⁺-N]有很好的去除效果,[NH₄⁺-N]去除率最高为99.42%,平均去除率为80.94%。潮汐式生态滤床对TP和I_Mn也有一定的去除效果,平均去除率为34.37%和35.65%。潮汐式生态滤床内部硝化作用明显,微生物群落分析结果表明,滤床内主要的优势菌属是norank_f_norank_o_Chloroplast (1.72%~12.61%) 和硝化螺旋菌属 (Nitrospiria,1.75%~8.75%) 。norank_f_norank_o_Chloroplast作为第一优势菌属,其相对丰度远超其他菌属,且随着滤床的持续运行,具有硝化作用的硝化螺旋菌属相对丰度增长显著。微生物群落相似性和差异性分析结果表明,滤床微生物群落结构稳定,不受季节、温度的影响,尽管运行时长对滤床内部群落组成造成一定差异,但并不存在显著性。本研究以梁塘河水系为例开展水环境生态治理,一方面旨在提升梁塘河水环境质量,另一方面也为平原河网地区,尤其是位于城区的平原河网地区河流生态治理提供示范参考。     

序批式生物膜反应器和序批式反应器处理硝酸盐氮污染河水

在序批式反应器(SBR)中添加ZH组合填料构成序批式生物膜反应器(SBBR),并以SBR为对比,研究了2种工艺对污染河水中硝酸盐氮的去除效果。结果表明,(1)进水硝酸盐氮浓度分别为15、20和30 mg/L时,2种工艺对COD的去除率均大于90%,对COD的去除能力均较强,进水硝酸盐氮的增加对COD的去除效果影响不大;第1个缺氧段是COD的主要去除段,此阶段COD的去除率达到80%以上。(2)随进水硝酸盐氮浓度的增加,SBBR中NO3--N和TN的去除率分别从99.73%和99.24%降至79.75%和65.56%;SBR中NO3--N和TN的去除率分别从99.91%和99.51%降至55.57%和41.73%。(3)随进水硝酸盐氮浓度的提高,两反应器内亚硝酸盐氮的积累量增大;进水硝酸盐氮浓度为15、20和30 mg/L时,SBBR中的亚硝酸盐氮最大积累浓度分别为2.90、6.82和10.72 mg/L;SBR中亚硝酸盐氮最大积累浓度分别为4.35、9.47和11.89 mg/L。SBBR中亚硝酸盐氮的积累明显低于SBR。     

太子河水系印染行业重点污染河段优先控制污染物的确定

通过对太子河水系印染行业重点污染河段-海城河三期水样的采集以及水样中有机污染物的检测分析,获取了48种有机污染物的平均浓度水平,其中浓度较高的是苯酚(28.18 μg/L)、邻苯二甲酸二(2-乙基己基)酯(22.30 μg/L)和苯乙酮(8.818 μg/L)。结合流域的实际污染状况,采用"改进潜在危害指数法",对海城河检测出的有机污染物进行加权综合评分计算,按照综合分数值大小,对其进行排序,提出了44种优先控制污染物名单,其中包括酯和酞酸酯类7种、含氮杂环类7种、胺及苯胺类5种、氯苯类6种、硝基苯类5种、苯酚类7种、苯及其他取代苯类5种、多环芳烃类2种,大部分污染物与印染行业废水排放有着密切关系。     

Dechlorination of polychlorinated biphenyl congeners by anaerobic microorganisms from river sediment.

The microbial dechlorination of seven kinds of polychlorinated biphenyls (PCBs) by anaerobic microorganisms from river sediment was investigated. Dechlorination rates were found to be affected by the chlorine level of PCB congeners; dechlorination rates decreased as chlorine levels increased. Dechlorination rates were fastest under methanogenic conditions and slowest under nitrate-reducing conditions. The addition of individual electron donors (acetate, pyruvate, and lactate) enhanced the dechlorination of PCB congeners under methanogenic and sulfate-reducing conditions but delayed the dechlorination of PCB congeners under nitrate-reducing conditions. PCB congener dechlorination also was delayed by the addition of various polycyclic aromatic hydrocarbons (PAHs) under three reducing conditions and by surfactants, such as brij30, triton SN70, and triton N101. The results suggest that methanogen, sulfate-reducing bacteria, and nitrate-reducing bacteria all are involved in the dechlorination of PCB congeners.     

受污染城市河道沉积物磷吸附特征及其影响因素

采集了典型受污染城市河道——陕西省新河不同季节的沉积物,研究其磷吸附特征及影响因素,并考察其缓冲外源污染的能力,评估其磷释放风险。结果显示,沉积物平均粒径在秋季小于夏季和春季,pH为7.64~8.88;沉积物总磷 (TP) 为870~2 173 mg·kg⁻¹;计算了沉积物磷富集系数,明确了新河部分点位为重度污染类型。吸附动力学研究结果表明：0~2 h沉积物对磷的吸附量在正负之间波动;2~4 h吸附量迅速增加,吸附速率也达到了峰值;之后吸附量增加趋势变缓,并在48 h达到平衡。绘制吸附等温线,可知沉积物的磷吸附-解吸平衡质量浓度 (EPC₀) 为0.39~2.21 mg·L⁻¹,高于同时段上覆水中磷的质量浓度,具有释放风险;磷最大缓冲容量MBC和Freundlich常数K_F呈现秋季>>夏季>春季的规律;经D-R模型拟合,绝大多数样品的吸附能为8.45~11.18 kJ·mol⁻¹,说明吸附机制为离子交换。相关性分析结果表明,沉积物的磷吸附速率常数与钙的相对含量呈显著相关 (P<0.05) 。EPC₀与沉积物的总磷和易释放态磷含量呈显著相关 (P<0.01) ,与沉积物平均粒径和有机质显著相关 (P<0.05) ,与pH显著相关 (P<0.05) 。本研究结果可为受污染城市河道治理提供参考。     

透水坝原位净化山溪性污染河流

针对苕溪流域山溪性河流锦溪水质污染的现状,结合河流水文特征在河道内建设了三级透水坝,考察其对河流水质原位净化的效果。结果表明,透水坝有利于减缓山溪性河流的水速,对水流所携带的悬浮颗粒进行拦截、沉降,对河水浊度的平均去除率约为25%,并可将河水溶解氧（DO）提高1 mg/L以上。透水坝对河流水质的净化效果呈现明显的季节波动,夏季对COD、NH3-N、TN和TP的去除率最高,可维持在20%以上。秋季污染物去除效果有所下降,可能是由于水体中硝化-反硝化菌活性降低、水生植物同化吸收能力有限造成。将来可在透水坝壅水区内优化搭配种植挺水与沉水植物,改善其对氮磷的去除效果。     

生物膜处理城市河道污染水体的挂膜试验研究

以城市河道污染水体为研究对象,通过水体中土著微生物的富集过程,利用自行设计的生物接触氧化装置进行动态挂膜试验研究.讨论了挂膜过程系统对污染物去除效果的变化、生物膜及其生物相的变化;同时考察了填料上SS以及VSS的变化;分析了影响填料挂膜的各种因素,提出了判断生物膜成熟的依据.     

曝气充氧和人工造流技术修复河道污染水体

基于模拟河道反应器,考察了曝气充氧及人工造流技术对污染水体的修复效果。结果表明,河道本身具有一定的自净能力,自然运行条件下对COD、TP、NH₃-N和TN的去除率分别为7.44%、4.88%、5.70%和10.60%。通过对模拟河道进行曝气充氧,最佳气水比条件下对COD、TP、NH₃-N和TN的去除率分别为15.33%、10.45%、6.78%和21.18%。在曝气基础上通过设置人工阻流板,对COD、TP、NH₃-N和TN的去除率分别为26.82%、16.07%、9.51%和23.80%。结果初步显示,通过曝气充氧和人工造流技术的集成应用研究,对污染水体具有明显有效的修复作用。     

Aerosol properties,in-canopy gradients,turbulent fluxes and VOC concentrations at a pristine forest site in Amazonia

Aerosol physical and chemical properties were measured in a forest site in central Amazonia (Cuieiras reservation, 2.61S; 60.21W) during the dry season of 2004 (Aug–Oct). Aerosol light scattering and absorption, mass concentration, elemental composition and size distributions were measured at three tower levels (Ground: 2 m; Canopy: 28 m, and Top: 40 m). For the first time, simultaneous eddy covariance fluxes of fine mode particles and volatile organic compounds (VOC) were measured above the Amazonian forest canopy. Aerosol fluxes were measured by eddy covariance using a Condensation Particle Counter (CPC) and a sonic anemometer. VOC fluxes were measured by disjunct eddy covariance using a Proton Transfer Reaction Mass Spectrometer (PTR-MS). At nighttime, a strong vertical gradient of phosphorus and potassium in the aerosol coarse mode was observed, with higher concentrations at Ground level. This suggests a source of primary biogenic particles below the canopy. Equivalent black carbon measurements indicate the presence of light-absorbing aerosols from biogenic origin. Aerosol number size distributions typically consisted of superimposed Aitken (76 nm) and accumulation modes (144 nm), without clear events of new particle formation. Isoprene and monoterpene fluxes reached respectively 7.4 and 0.82 mg m^?2 s^?1 around noon. An average fine particle flux of 0.05 ± 0.10 10⁶ m^?2 s^?1 was calculated, denoting an equilibrium between emission and deposition fluxes of fine mode particles at daytime. No significant correlations were found between VOC and fine mode aerosol concentrations or fluxes.     

不同复合人工湿地对高污染河流有机污染物的去除

为了研究复合人工湿地对高污染河流污水中有机污染物的去除效果及规律,实验构建了不同水力负荷下的潜流+潜流、潜流+表面流、潜流+潜流+表面流、表面流+表面流等人工湿地单元组合成的5个复合人工湿地.连续运行一年以来,各复合人工湿地对BOD5、COD和SS的去除效果分别为91.9%~94.7%、69.3%~75.8%和92.3%~93.9%,相对于多级表流湿地,多级潜流湿地更利于有机污染物和悬浮物的去除;BOD5、COD和SS主要在各复合湿地的第一级湿地单元内得到去除;复合人工湿地对COD去除效果秋夏季两季好,春冬两季差;复合人工湿地能有效去除悬浮态BOD5和COD,出水中部分溶解态有机物难以有效降解.