卤代有机污染物抑制甲状腺激素代谢酶活性的研究进展

甲状腺激素(thyroid hormones,THs)对生物体细胞的正常发育和分化至关重要,甲状腺激素失调可引起中枢神经系统、肺、心血管和其他器官的异常发育。研究表明,环境中的卤代有机污染物(halogenated organic contaminants,HOCs)及其代谢产物具有甲状腺激素干扰效应。抑制参与THs代谢的生物酶,例如磺基转移酶(sulfotransferases,SULTs)和脱碘酶(deiodinases,DIs),是HOCs及其代谢产物干扰THs正常功能的重要方式。本文重点综述了HOCs对不同甲状腺激素代谢酶的抑制效应的研究,讨论了环境计算化学和预测毒理学方法在该领域的重要应用,期望为HOCs干扰甲状腺激素酶代谢活性的深入研究提供借鉴与参考。     

Effective removal of Cd2+ and Pb2+ pollutants from wastewater by dielectrophoresis-assisted adsorption

Dielectrophoresis (DEP) process could enhance the removal the Cd²⁺ and Pb²⁺ with less absorbent. The removal rates of both Cd²⁺ and Pb²⁺ increased with the increase of voltage. The overall removal rate of Cd²⁺ and Pb²⁺ in the binary system is higher than that of Cd²⁺ or Pb²⁺ in the single system. DEP could cause considerable changes of the bentonite particles in both surface morphology and microstructure. Dielectrophoresis (DEP) was combined with adsorption (ADS) to simultaneously and effectively remove Cd²⁺ and Pb²⁺ species from aqueous solution. To implement the process, bentonite particles of submicro-meter size were used to first adsorb the heavy metal ions. These particles were subsequently trapped and removed by DEP. The effects of the adsorbent dosage, DEP cell voltage and the capture pool numbers on the removal rate were investigated in batch processes, which allowed us to determine the optimal experimental conditions. The high removal efficiency, 97.3% and 99.9% for Cd²⁺ and Pb²⁺, respectively, were achieved when the ions are coexisting in the system. The microstructure of bentonite particles before and after ADS/DEP was examined by scanning electron microscopy. Our results suggest that the dielectrophoresis-assisted adsorption method has a high capability to remove the heavy metals from wastewater.     

野外测量条件对石油污染地下水常规水化学参数的影响

通过原位水质监测仪监测某石油类污染地下水的6项常规水化学指标,研究不同测量方式、不同测量深度对其产生的影响。结果表明:受石油污染的地下水水面以下0.5 m处,原、异位测量的水温、p H值、溶解氧、氧化还原电位、浊度均有不同程度的差异。在对比研究期内,可观测到这种差异最大可达:水温5~6℃,p H值0.2,溶解氧3.0 mg/L,氧化还原电位11 m V,浊度55 NTU。这种地下水环境条件的改变,必然会引起一系列水文地球化学、生物地球化学反应的变化。原位测量水深0.5~4 m范围内,水温随深度增加逐渐增大,最大变幅0.16℃;p H随深度增加变化不大;DO受温度和生化耗氧作用影响,随深度增加而降低;ORP与DO变化趋势大致相同,最大减幅达62 m V;电导率随地下水深度增加其值不变;最大浊度值113 NTU出现在水深4 m处。     

环境空气中短链氯化石蜡研究进展

短链氯化石蜡(SCCPs)是碳链长度为10至13个碳原子的正构烷烃氯代衍生物。SCCPs具有持久性、生物累积性、长距离迁移能力、以及毒性作用。SCCPs已被《关于持久性有机污染物的斯德哥尔摩公约》增列为持久性有机污染物审查范围内,引起了全球关注。SCCPs在环境各介质及生物体内均有检出,近年来,在室内空气和灰尘中也检出了大量SCCPs,其已成为人体暴露的一个重要来源。本文就大气环境及室内空气与灰尘中氯化石蜡(CPs)的采样与分析方法、污染水平与来源,及人体暴露概况进行了综合阐释,以期为我国大气和室内环境中CPs的研究工作提供参考。     

基于GIS的西辽河流域生态安全空间分异特征

生态安全评价与预警研究具有空间特性、非线性和随机性,研究过程中必须处理大量的空间信息,而空间分析和空间数据管理正是GIS的优势,它使各环境要素的分布态势及彼此之间的拓扑关系一目了然,并且图文并茂地展示全流域的生态安全格局.在充分研究西辽河流域生态环境的基础上,讨论了基于GIS的西辽河生态安全空间差异的评价方法.①拟定“压力-状态-响应”(P-S-R)指标体系,实地调查并收集资料;②数字化流域,运用模糊AHP和综合比较法赋权并量化计算;③建立西辽河流域生态安全指数GRID数据库,通过GIS的空间Interpolate运算和Assembly分析,阐述生态安全的空间分异特征.     

微囊藻毒素-LR的提取与测定

采用固相萃取结合液相色谱的方法,对可能有微囊藻毒素污染的某水库中的藻体和水样分别进行提取分析,在藻体中检测出微囊藻毒素LR,并确定产毒的藻种为水华微囊藻。同时对微囊藻毒素LR的测定方法进行了一定探讨。     

牦牛粪便对川西北高寒草甸土壤养分的影响

川西北高寒草甸是我国四大牧区之一,也是"长江上游生态屏障"建设的重要"生态功能区"之一.近年来牦牛粪便被大量出售,显著地改变了生态系统的养分循环.通过模拟牛粪堆积,研究了牦牛粪便养分释放及其对周围土壤养分(NO3--N、NH4--N、速效K、无机P、有机C、全N和全P)在不同时间和距离条件下的影响.结果表明,在研究区域内,牛粪对草地生态系统具有较强的养分(N、P)贡献能力,据初步统计,其值大致为N素699～932 kg hm-2,P素为110～147 kg hm-2;牛粪养分在夏季具有较快的分解速率,在3 mo左右之后基本分解殆尽;粪便在短期内能显著提高粪下土壤养分的含量,其中,对No3--N含量的提高最为明显,在2 mo左右之后其含量达到初始态的8.4倍,在实验后期,粪便对土壤养分的影响作用逐渐消失;粪便在夏季对周围10 cm内土壤的养分(NO3--N、NH4+N、速效K和无机P)含量能产生显著影响(P<0.05),但影响范围难以达到周围30 cm左右.与通常结论不同的是,在整个实验周期内,牦牛粪便并没有显著提高土壤有机C、全N和全P的含量.图4表1参31     

Removal of multicomponent VOCs in off-gases from an oil refining wastewater treatment plant by a compost-based biofilter system

Waste gases from oil refining wastewater treatment plants are often characterized by the presence of multicomponent and various concentrations of compounds. An evaluation of the performance and feasibility of removing multicomponent volatile organic compounds (VOCs) in off-gases from oil refining wastewater treatment plants was conducted in a pilot-scale compost-based biofilter system. This system consists of two identical biofilters packed with compost and polyethylene (PE). This paper investigates the effects of various concentrations of nonmethane hydrocarbon (NMHC) and empty bed residence time (EBRT) on the removal efficiency of NMHC. Based on the experimental results and practical applications, an EBRT of 66 s was applied to the biofilter system. The removal efficiencies of NMHC were within the range of 47%–100%. At an EBRT of 66 s, the average removal efficiency of benzene, toluene, and xylene were more than 99%, 99%, and 100%, respectively. The results demonstrated that multicomponent VOCs in off-gases from the oil refining wastewater treatment plant could be successfully removed in the biofilter system, which may provide useful information concerning the design criteria and operation of full-scale biofilters.     

Matrix-bound phosphine in Antarctic biosphere

Phosphine (PH(3)) is a natural gaseous carrier of phosphorus in its geochemical cycles, and it might be of importance to the phosphorus balance of natural ecosystem. For the first time phosphine levels were investigated in the Earth's coldest, driest, and most southerly Antarctic biosphere. Matrix-bound phosphine (MBP) was found in sea animal guanos, ornithogenic sediments and soils. Phosphine concentrations varied with different sea animal guanos. Average phosphine concentrations in empire penguin, gentoo penguin, sea lion, skua and gull guanos were 2.54+/-1.28 ng kg(-1), 6.21+/-2.15 ng kg(-1), 9.12+/-4.66 ng kg(-1), 11.90+/-1.29 ng kg(-1) and 14.55+/-6.74 ng kg(-1), respectively. The contents of phosphorus in these various matrixes have an important effect on MBP concentrations. The levels of phosphine appeared an increasing tendency with the content of TP, IP and OP in sea animal guanos, ornithogenic sediments or soils. The correlation between PH(3) and Fe, Mn, Al in these matrixes was also analyzed and discussed. Phosphine showed an obviously positive correlation with Fe in sea animal guanos. However, excessively high Fe, Al and Mn may inhibit the formation of PH(3) in the ornithogenic soils or sediments in the Antarctic biosphere.     

铅锌冶炼厂渣堆场周边土壤铅污染特征

金属冶炼过程留下的废渣经过雨水冲刷及渗滤液等的作用使残留在废渣中的重金属发生迁移转化,导致渣堆场下及周边土壤受到重金属污染。了解冶炼厂渣堆场下及周边土壤重金属污染状况对场地修复及土地利用规划均有重大意义。本研究调查了湖南某铅锌冶炼厂渣堆场0~4 km内三个采样区0~20 cm表层土壤及0~100 cm深度土壤中铅的污染状况,采用单项污染指数法进行铅污染评价,并分析了铅纵向迁移随深度变化和横向迁移随距离变化的分布特征。结果表明,铅锌冶炼厂渣堆场下及周边0~1 km范围内土壤受到了铅污染,渣堆场下、距渣堆场10 m处及1 km处表层土壤中重金属铅的质量分数分别可达775.25、645.33和309.80 mg·kg^-1,超过了当地土壤中铅的背景值,也超过了土壤二级质量标准甚至三级质量标准。三个采样区的铅污染指数分别为2.6、2.1及1.03,污染等级均为Ⅱ级,污染程度为轻度污染。三个采样区土壤中铅污染主要集中于0~20 cm土壤层中,铅的质量分数分别达775.25,645.33和309.80 mg·kg^-1,20~100 cm土壤层中铅的质量分数低于0~20 cm的,分别在88.48~120.96 mg·kg-1、235.01~380.16 mg·kg^-1及309.80~59.32 mg·kg^-1之间。渣堆场下土壤中的铅从0~20cm土壤层往下至20~100cm土壤层迁移量远小于距渣场10 m处及1 km处的。三个采样区表层0~20 cm土壤层中铅的变化规律为距渣堆场0 m（渣堆场下）〉距渣堆场10 m〉距渣堆场1 km〉距渣堆场4 km,质量分数随距离增加而降低。20~40 cm及40~60 cm土壤层中铅的变化规律为距渣堆场10 m〉距渣堆场1 km〉距渣堆场0 m处（渣堆场下）〉距渣堆场4 km,60~80 cm及80~100 cm土壤层的变化规律为距渣堆场10 m〉距渣堆场0 m处（渣堆场下）〉距渣堆场1 km〉距渣堆场4 km,铅的质量分数随距离的增加先升高后降低。