南京大气细粒子中重金属污染特征及来源解析简

利用2011年1月、4月、7月和10月在南京市区和北郊采集的气溶胶样品,研究了南京大气细粒子中Zn、Pb、Hg、As和Cd 5种重金属的污染水平,通过元素相关性分析和因子分析方法,对细粒子中这些重金属的污染来源进行了初步解析。结果表明,南京大气细粒子及其重金属污染严重,北郊普遍比市区严重;As严重超标,Cd在南京北郊超标约5倍,Zn在市区与北郊的质量浓度均高于其他重金属元素。每种重金属的浓度均随季节而变化。市区细粒子中,As和Zn可能主要与燃煤、轮胎灰尘和建筑扬尘等有关,Pb、Hg和Cd主要来自交通尘、城市垃圾焚烧等。北郊细粒子中,As、Hg和Zn主要来源于燃煤、钢铁冶炼等工业,Pb和Cd主要与农作物秸秆燃烧、汽车尾气、道路扬尘等影响有关。     

国内成功运营的餐厨垃圾处理厂臭气排放特征研究简

选择目前国内成功运营的餐厨垃圾资源化处理厂为采样点,采用气相色谱-质谱联用（GC/MS）技术对该厂的主要工段,如卸料室、破碎室、湿热反应器出气口、好氧发酵仓、厌氧发酵区以及厂界的臭气进行了定性和定量的分析。结果表明,6个采样点共检测出包括芳香烃、硫化物、卤代物、烯烃、烷烃、醇、醛、酮和酯在内的9类66种物质,各采样点臭气总浓度分别为：11.738、18.390、30.917、25.097、4.737和2.635 mg/m³。其中湿热反应器出气口处恶臭气体浓度最高,其芳香烃、硫化物、卤代物、烯烃、烷烃、酮及酯类物质均高于其他检测点,需对该工段进行重点监测和控制。恶臭排放特征分析表明,各点的H₂S浓度均超过嗅觉阈值,除厂界外甲硫醇和二甲二硫检测值均超过嗅觉阈值。     

Degradation characteristics and metabolic pathway of 17alpha-ethynylestradiol by Sphingobacterium sp. JCR5

A 17alpha-ethynylestradiol (EE2)-degrading bacterium was isolated from the activated sludge of the wastewater treatment plant (WWTP) of an oral contraceptives producing factory in Beijing, China. On the basis of its morphology, biochemical properties and the 16S rDNA sequence analysis, this strain was identified as Sphingobacterium sp. JCR5. This strain grew on EE2 as sole source of carbon and energy, and metabolized up to 87% of the substrate added (30 mgl-1) within 10 d at 30 degrees C. In addition to EE2 the strain could be cultivated on steroidal estrogens like estrone (E1), 17beta-estradiol (E2), estriol (E3) and mestranol (MeEE2), the intermediates of contraceptive medicine processing and on some aromatic compounds. Mass spectrum analysis of the EE2 degradation showed that in the first step it is oxygenized to E1, 2-hydroxy-2,4-dienevaleric acid and 2-hydroxy-2,4-diene-1,6-dioic acid, which are the main catabolic intermediates. The former was analogous to the pathway of a previously reported testosterone-degrading bacterium Comamonas testosteroni TA441 and the latter is a metabolite with a different cleavage position of 3-hydroxy-4,5-9,10-disecoestrane-1(10),2-diene-5,9,17-trione-4-oic acid from the former.     

Degradation of phenol by Acinetobacter strain isolated from aerobic granules

Aerobic granules effectively degrade phenol at high concentrations from which no Acinetobacter species, that can effectively degrade high concentrations of phenol, have ever been isolated from aerobic granules. The phenol-fed aerobic granule studied was made by merging several smaller granules, each with a core of proteins and nucleic acids surrounded by an outer layer enriched with polysaccharides. In the present study, a strain of Acinetobacter sp. was isolated from the phenol-fed aerobic granules and was identified using DNA sequencing. The fluorescent in situ hybridisation combined with the confocal laser scanning microscope test revealed that the isolated Acinetobacter strain was mainly distributed in the core regime of granule. Batch tests revealed that the suspended Acinetobacter strain could effectively degrade phenol at an initial phenol concentration of up to 1000 mg l(-1) with no cell growth taking place at a phenol concentration of 1500 mg l(-1). The Haldane model describes the inhibitory kinetics of the phenol degradation data. The suspended Acinetobacter strain had a propensity to attach to the surface of sterilized polyurethane foam at a concentration of 12.3mg dry cells mg(-1) dry foam. The immobilized cells could not only degrade phenol at a rate similar to the suspended cells at phenol concentration of 500 mg l(-1), but also effectively degraded phenol at 1500 mg l(-1). The polysaccharides outer layer protected the Acinetobacter strain from phenol's toxicity; while the strain may also contribute to bioaggregation of the granule for its high propensity to attach to solid surface.     

Probabilistic risk assessment for zinc in some commercial dishwashing detergents: the nitrification processes in US POTWs

A US patent was issued to a commercial dishwashing detergent composition in which soluble zinc is used to protect glassware from corrosion. Some of the consumed detergents are discharged as wastewater and treated in publicly owned treatment works (POTWs). A probabilistic risk assessment was conducted to quantitatively determine the risk of zinc in the detergents to the nitrification processes in US POTWs. The procedure for POTW local limit development designed by the US Environmental Protection Agency (EPA) was used as a reference when conducting the risk assessment. The assessment took into account the background zinc concentrations in POTW influents and potential shock loading patterns, and was conducted at different market penetration rates (MPRs) for the US market of detergents based on the patented formula. The assessment involved several conservative factors including conservative determination of primary treatment efficiency, bioavailability, inhibition concentration, configuration of the nitrification process, as well as background zinc concentration in wastewater. With the conservative factors in the assessment, it was found that zinc in detergents does not present a significant risk to the nitrification processes in POTWs at a MPR up to 10%. It was noted that additional analyses would be required when the MPR is higher than 10% to adequately account for the effects of the conservative factors on the result of the assessment.     

Impacts of climatic and atmospheric changes on carbon dynamics in the Great Smoky Mountains National Park

We used the Dynamic Land Ecosystem Model (DLEM) to estimate carbon (C) storage and to analyze the impacts of environmental changes on C dynamics from 1971 to 2001 in Great Smoky Mountain National Park (GRSM). Our simulation results indicate that forests in GRSM have a C density as high as 15.9kgm(-2), about twice the regional average. Total carbon storage in GRSM in 2001 was 62.2Tg (T=10(12)), 54% of which was in vegetation, the rest in the soil detritus pool. Higher precipitation and lower temperatures in the higher elevation forests result in larger total C pool sizes than in forests at lower elevations. During the study period, the CO(2) fertilization effect dominated ozone and climatic stresses (temperature and precipitation), and the combination of these multiple factors resulted in net accumulation of 0.9Tg C in this ecosystem.     

采用双氰胺甲醛缩聚物混凝去除水中酸性红B染料的研究

以双氰胺和甲醛为原料制备了聚合双氰胺甲醛,并对其进行红外光谱表征.采用聚合双氰胺甲醛与硫代硫酸钠共同作用对酸性红B染料溶液进行混凝脱色实验.对比了单独使用聚合双氰胺甲醛,以及聚合双氰胺甲醛与硫代硫酸钠共同作用的脱色效果.探讨了硫代硫酸钠和聚合双氰胺甲醛的用量以及pH值对脱色率的影响.结果表明,投加硫代硫酸钠可以明显地提高聚合双氰胺甲醛的脱色率,增大絮凝范围,使絮凝剂对pH值的变化有很强的适应性,pH值为7～12的范围内,脱色率均能维持在96%以上.此外,还对混凝脱色的机理进行了研究.     

一种未见报道的厌氧氨氧化菌分子生物学鉴定

以(NH4):SO4和NaNO2作为基质,富集厌氧氨氧化污泥.提取厌氧氨氧化污泥中细菌总DNA,纯化后使用特异性引物对厌氧氨氧化菌16S rDNA进行PCR扩增.扩增产物连接到pMD19-T载体,将载体转化到感受态细胞大肠杆菌JM109中,并对其16S rDNA基因进行测序.将测序结果进行系统发育树分析,发现富集得到的厌氧氨氧化菌与Candidatus Anammoxoglobus propionicus进化关系比较接近,是一种尚未见报道的厌氧氨氧化菌.     

电子垃圾焚烧排放的二噁英对周围大气环境的影响

为了研究电子垃圾焚烧产生的二噁英对周围环境的影响,同时在E1和E2采样点分别采集9个大气样品.E1周围分布大量的电子垃圾焚烧点,E2则位于E1南9 km处,周围无其他明显的二噁英排放源.所采样品用同位素稀释法进行分析测定,结果表明,E1和E2大气样品中二噁英的平均质量浓度分别为127.37、22.37 pg/m3,平均毒性当量浓度分别为8.777、1.305 pg I-TEQ/m3.八氯代二苯并呋喃(OCDF)、八氯代二苯并二噁英(OCDD)、七氯代二苯并呋喃(1,2,3,4,6,7,8-HpCDF)和七氯代二苯并二噁英(1,2,3,4,6,7,8-HpCDD)对2,3,7,8位氯代的二噁英的总浓度贡献较大,而五氯代二苯并呋喃(2,3,4,7,8-PeCDF)则对总毒性当量浓度贡献最大,其贡献率超过40%.在E1和E2两个采样点,二噁英在气相中的比例均随着氯原子取代数的增加而降低.两采样点相似的二噁英分布模式和气固分配,说明E2大气中二噁英主要来自于E1电子垃圾焚烧产生的二噁英.     

溴代二噁英类化合物的环境研究进展

溴代二噁英类化合物是一类剧毒环境污染物,主要来源于溴系阻燃剂与含溴系阻燃剂聚合物的生产、使用和回收等过程.随着溴系阻燃剂的广泛使用,溴代二噁英类化合物的环境和健康风险日益增加,对其环境问题的研究已成为当今环境科学的一大热点,而中国在此方面的研究还相当薄弱.介绍了溴代二噁英类化合物的结构性质,综述了溴代二噁英类化合物的分析方法、污染来源和环境分布,重点探讨了溴代二噁英类化合物的生成机制,介绍了生成溴代二噁英类化合物的影响因素,讨论并总结了当前研究中溴代二噁英类化合物污染来源解析与生成机制所存在的问题,最后展望了未来溴代二噁英类化合物的环境研究趋势.