兰州市大气颗粒物多环芳烃的恒能量同步荧光光谱特征研究

通过传统单波长激发/发射荧光光谱法与恒能量同步荧光光谱法进行对比,对大气颗粒物中多环芳烃(PAHs)进行了定性定量分析,采用恒能量同步荧光光谱法在不同能量差下建立了15种典型PAHs成分的恒能量同步荧光法的标准谱库.在各PAHs在最佳能量差下进行定量分析,结果表明,除苊荧光信号响应较差外,其余PAHs的LOD和LOQ分别为0.0580～3.18、0.232～12.7 ng·mL~(-1).15种PAHs的空白和一定浓度下的加标回收率范围在82.8%～120.0%,相对标准偏差范围在0.51%～5.87%之间,以恒能量同步荧光光谱进行了兰州地区大气颗粒物中15种PAHs分布特征分析.     

~（110m）Ag在鲤鱼体内的转移、积累与分布

为了探讨水中１１０ｍＡｇ在鲤鱼体内的行为，将鲤鱼喂养在１１０ｍＡｇ比活度为３．７×１０２Ｂｑ／Ｌ、３．７×１０３Ｂｑ／Ｌ、３．７×１０４Ｂｑ／Ｌ水中，于喂养后隔一定时间取样解剖，测各组织器官的放射性，结果表明，鲤鱼通过鳃和消化管将１１０ｍＡｇ很快吸收到体内，并随血液运输到全身各处，主要分布在软组织中。在相同喂养时间内，鱼体各组织器官１１０ｍＡｇ积累量随水中１１０ｍＡｇ比活度增加而增加。鳃、消化管、心脏、肌肉、骨骼等组织器官中１１０ｍＡｇ积累量随喂养时间呈单峰曲线变化；肝胰脏中１１０ｍＡｇ积累量随喂养时间则直线上升。它们对１１０ｍＡｇ的积累能力依次为：肝胰脏＞鳃＞消化管＞心脏＞肌肉＞骨骼。     

2-氯苯甲酸好氧降解菌的降解特性

分离出 2株以 2 -氯苯甲酸为唯一碳源的细菌W1和W2 ,这 2株菌对 2 -氯苯甲酸的降解均表现为一级动力学反应。W1降解酶系为诱导酶 ,对 2 -氯苯甲酸的降解动力学常数为 -0 .1 34h- 1;W2降解酶系为非诱导酶 ,对 2 -氯苯甲酸的降解动力学常数为 -0 .0 388h- 1。W1还能够降解 4 -氯苯甲酸、苯、甲苯和邻苯二酚 ,但不能降解 3-氯苯甲酸、2 ,4 -二氯苯甲酸、乙苯、丙苯和萘。W1菌体质粒和染色体提取实验表明 ,其降解基因位于染色体上。     

大气环境中OH自由基测定

采用自旋捕集技术和电子自旋共振法结合测定大气环境中ＯＨ自由基，首先用自旋捕集剂将ＯＨ自由基捕集，生成比较稳定的自然旋加合物，，然后带回实验室处理测定，该法为开展大气光化学研究提供了一种采样方便，利于实测的方法，据３个采样点的实测结果表明，相对误差约为３５％，比文献所示结果略大。     

Simultaneous measurements of arsenic and sulfide using diffusive gradients in thin films technique (DGT)

Diffusive gradients in thin films technique (DGT) is a dynamically passive sampling technique which has been applied increasingly to the environmental monitoring field. In the preliminary period, the DGT with zirconium hydroxide-silver iodide as the binding phase (ZrO-AgI DGT) has been developed for the determination of sulfide (S(II)). On this basis, this paper developed its determination method for inorganic arsenite (As(III)) to further realize the simultaneous and high-resolution measurements of labile inorganic As and S(II) in sediments. ZrO-AgI binding gel had a strong ability in adsorbing and fixing As(III), showing a linear increase in the initial 12.5 min. After saturation of S(II) on ZrO-AgI binding gel, the adsorption rate and adsorption capacity of As(III) reduced by 8 and 14%, respectively. A stable elution rate (89.1 ± 2.2%) was obtained by extraction of As(III) on the binding gel using a mixture solution of 1.0 M NaOH and 1.0 M H₂O₂ (1:1). The DGT capacity of As(III) determined by the ZrO-AgI DGT was 23.6 μg cm^?2. DGT uptakes of As(III) were independent of pH (4.0–9.0) and ionic strength (0.01–100 mM), and they did not interfere with each other during the uptake process. Simultaneous measurements of labile As and S(II) in four sediment cores of Taihu Lake (China) with ZrO-AgI DGT showed that they had similarly vertical distributions in the top 16-mm layer in one core and in the whole profile up to the 35 mm depth in two cores. It likely reflected a simultaneous release of As and S(II) in sediments by synchronous reduction of As-hosted oxidized iron and sulfate, respectively. The simultaneous decreases of labile As and S(II) from their co-precipitation (e.g., As₂S₃) were not obvious in deeper sediment layer through the measurement with ZrO-AgI DGT.     

控制环境与健康风险:美国环境标准制度功能借鉴

传统观念下,环境与健康分属两个不同领域,美国作为最早遭遇环境与健康问题的国家,经过多年努力,形成了建立以保障公共健康为核心的环境标准体系和环境与健康风险评估框架,实现了对环境与健康风险的有效控制。美国对环境污染物的界定主要取决于其对公共健康的影响,将污染物分为普遍及对公共健康危害较大的污染物、一些污染范围较小或对公共健康危害较小的污染物两类,且采取不同的标准制定方法。在标准制定方面,主要是将有关科学共识转化为可执行的环境标准。为了避免环境标准的不确定性带来的不利影响,建立了包括科学论证、公开透明、周期性审查等较为严格的环境标准制定程序。美国赋予环境标准制度以控制环境与健康风险的功能,并通过建立以保障公共健康为核心的环境标准体系,实现对环境与健康风险有效控制的执法路径,对解决中国目前存在的环境标准价值缺失、体系割裂、内容缺失等问题,实现环境标准的功能再造具有较强的借鉴意义。     

新型负载型光催化剂的制备及其光催化活性研究

以硝酸钙和磷酸为原料,采用均匀沉淀法制备了羟基磷灰石(HAP);以HAP为载体,采用浸渍-提拉法制得负载型光催化剂TiO2／HAP,并用其对酸性媒介红B进行光催化氧化实验;探讨了HAP煅烧温度和TiO2负载量对TiO2／HAP光催化活性的影响,并利用XRD、FT—IR和TEM对载体及TiO2／HAP催化剂进行了表征。实验结果表明,煅烧温度、TiO2负载量对HAP吸附性能及催化活性有较大的影响;TiO2／HAP的催化活性明显优于TiO2／玻片的催化活性。     

Speciation of organic phosphorus in a sediment profile of Lake Taihu I: Chemical forms and their transformation

Organic phosphorus(nonreactive P,NRP)is a major component of P in sediments,but information about its chemical forms and dynamic transformation is limited.The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu,a freshwater and eutrophic lake in China,were investigated.Five forms of NRP in the sediments were extracted based on a chemical fractionation technique,including easily labile NRP(NaHCO3-NRP),reactive metal oxide-bound NRP(HCl-NRP),humic acid-associated NRP(NaOH-NRPHA),fulvic acid-associated NRP(NaOH-NRPFA)and residual NRP(Res-TP).There were notable transformations with increasing sediment depth from the labile NaHCO3-NRP and NaOH-NRP pools to the recalcitrant HCl-NRP and Res-TP pools,which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded.Further analyses showed that the relative changes in contents of organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP.The results highlighted the importance of abiotic processes in regulating the diagenesis of organic P and its stability in sediments.     

Assessment on contaminations in sediments of an intake and the inflow canals in Taihu Lake,China

As the second largest freshwater lake in China, Taihu Lake provides water supply to approximately 32 million inhabitants around the lake. However, dramatically increased pollution has threatened the safety of drinking water supply in recent years. In the present study, we investigated the contaminations of nutrients and heavy metals in the sediments of an intake and inflow canals in Gonghu Bay, Taihu Lake. Moreover, we also examined the impact of human activities on spatial distribution characteristics of contaminations. Our results showed that the intake presented relatively lower concentrations of phosphorus and nitrogen compared with inflow canals. However, the concentrations of Cr, Ni, Cu, Zn and Pb in the sediments of the intake exceeded the lowest effect level (LEL) values, indicating a potential risk to drinking water resource. In addition, the concentrations of Ni in the sediments of Tianji Canal and Jinshu Canal exceeded the severe effect level (SEL) value. More importantly, the concentrations of Cu in the sediments of Tianji Canal exceeded three times of the SEL value. Multivariate statistical analysis confirmed that the domestic sewage primarily contributed to the nutrient accumulation, and the leakage of electronic trash dominated the enrichment of metals in the sediments. Taken together, more effort should be made to ensure the security of water resources in Taihu Lake, especially for the treatment of domestic sewage and industrial wastewater.     

外源稀土对土壤中稀土和重金属可交换态的影响

通过土壤旱作和淹水2种培养方式,研究了不同时期添加外源稀土对黄褐土中稀土和重金属Fe、Mn、Zn可交换态含量的影响.研究结果表明,稀土处理显著提高土壤中可交换态含量,其分配系数也随之增大,但绝大部分仍维持在10%以下.淹水条件下交换态稀土的含量比旱作高,但随培养时间的延长逐渐降低.随稀土处理浓度的升高,交换态稀土组成逐渐向外源稀土成分靠近,并在200mg·kg^-1以上达到相对稳定土壤中交换态Fe、Mn、Zn的含量随稀土处理浓度的升高呈线性升高,其中稀土对Mn的作用最强.