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751.
The effect of nitrate concentration on sulfide-driven autotrophic denitrification in marine sediment 总被引:3,自引:0,他引:3
Copepods have been widely used to evaluate toxicity of metals present in marine environments. However, a technical difficulty is to understand the possible routes of metal uptake and to identify in which tissues or organs metals are being accumulated. Traditional techniques are hard to be employed once each organ has to be analyzed separately. Autoradiography is an alternative technique to circumvent this limitation, since metal distribution in tissues can be visualized and quantified, even in small organisms like copepods. In the present study, accumulation and distribution of 64Cu in the copepod Calanus hyperboreus was studied using autoradiography. Copepods were exposed for 2 h to copper (2.3 mg L−1; 1.08 MBq 64Cu mg−1 Cu) and then allowed to depurate for 2 h in clean seawater. Total 64Cu was determined by gamma-spectrometry after a metal exposure and a depuration period. 64Cu distribution was determined based on images generated by autoradiography. Metal accumulation was observed on all external surfaces of the copepods, being accumulated mostly on the ventral region, followed by dorsal, urossoma and internal regions. After depuration, radioactivity levels had a decrease in the sum of external body surface. Our results show that copper uptake by C. hyperboreus is fast and that a non-negligible proportion of the accumulated metal can reach internal tissues, which may lead to detrimental physiological effects. Moreover, whole-body autoradiography was demonstrated to be an efficient technique to study copper accumulation and body distribution in a very small organism such as the copepod C. hyperboreus. 相似文献
752.
753.
Hanlim Lee Young J. Kim Jinsang Jung Chulkyu Lee Klaus-Peter Heue Ulrich Platt Min Hu Tong Zhu 《Journal of environmental management》2009
During the CAREBEIJING campaign in 2006, imaging differential optical absorption spectroscopy (I-DOAS) measurements were made from 08:00 to 16:00 on September 9 and 10 over Beijing, China. Detailed images of the near-surface NO2 differential slant column density (DSCD) distribution over Beijing were obtained. Images with less than a 30-min temporal resolution showed both horizontal and vertical variations in NO2 distributions. For DSCD to mixing ratio conversion, path length along the lines of I-DOAS lines of sight was estimated using the light-extinction coefficient and Ångstrom exponent data obtained by a transmissometer and a sunphotometer, respectively. Mixing ratios measured by an in-situ NO2 analyzer were compared with those estimated by the I-DOAS instrument. The obtained temporal and spatial variations in NO2 distributions measured by I-DOAS for the two days are interpreted with consideration of the locations of the major NOx sources and local wind conditions. I-DOAS measurements have been applied in this study for estimating NO2 distribution over an urban area with multiple and distributed emission sources. Results are obtained for estimated temporal and spatial NO2 distributions over the urban atmosphere; demonstrating the capability of the I-DOAS technique. We discuss in this paper the use of I-DOAS measurements to estimate the NO2 distribution over an urban area with multiple distributed emission sources. 相似文献
754.
发展循环经济是安徽省实现又好又快发展的必然选择。本文阐述了安徽省发展循环经济的科学内涵,分析了安徽省发展循环经济的重大意义。针对安徽省发展循环经济面临的主要问题,提出促进安徽省循环经济发展的财政政策选择方案。 相似文献
755.
756.
曝气生物流化池生物强化处理高氨氮制革废水研究 总被引:3,自引:0,他引:3
以曝气生物流化池(ABFT)I艺为核心,通过投加高效菌酶添加剂(简称菌荆)的方法对高氨氮制革废水进行生物强化处理研究.结果表明,在菌剂投加量为0.4 kg/m3,总水力停留时间为32 h(其中生化处理段水力停留时间为29 h)条件下,菌剂投加10 d后氨氮的去除率可达80.2%,25 d后系统即可稳定运行;出水氨氮平均为4.8 mg/L,去除率为98.8%;出水COD平均为137 mg/L,去除率为76.4%.无机碳化合物和生长因子对硝化反应有促进作用,使氨氮的去除率提高约6.6%.该结果显示了ABFT工艺在处理高氨氮制革废水上具有明显优势. 相似文献
757.
采煤塌陷水域是淮南矿区一种特殊地表水体。选择了具有代表性的有一定塌陷时间的谢桥矿塌陷水域,监测分析其水质理化指标、常规离子和重金属元素。结果表明:塌陷水域水质状况具有季节性变化。水域受到了一定程度的污染,DO丰富,COD含量偏高,水域呈弱碱性,pH值较为稳定,部分理化指标随时间增长有累计效应。常规离子含量顺序为HCO3->Mg2+>SO42->Ca2+>Cl->Na+>K+>F-。与国家地表水质量标准(GB3838-2002)比较,水域重金属元素除了Hg严重超标外, 其他As、Se、Cd、Cr、Cu、Pb、Zn等均不超标,未对水域构成重金属污染。通过对谢桥矿区塌陷水域水质进行分析评价,为其及周边矿区塌陷水域综合应用提供了一定的理论依据。 相似文献
758.
Tong Cao Min Wang Yinghao Yu Shuiliang Guo Yan Liu Yang Cao 《Environmental pollution (Barking, Essex : 1987)》2009,157(4):1270-1278
In order to better understand the spatial and temporal distribution pattern of metals and sulfur present in Shanghai, moss bags with Haplocladium microphyllum (Hedw.) Broth. were suspended at 14 local monitoring stations from April through June 2006 in Shanghai, the largest city in China. The results showed that the concentrations of S, Cu, Pb, and Zn in the moss bags after exposure were higher at the sites in the industrial district and most urban districts and lower at the sites in suburban areas, and well correlated with SO2 API and PM10 API in the air both in terms of space and time. The present study provided evidence that the moss H. microphyllum is suitable for bio-monitoring air pollution with moss bags and further confirmed that the moss-bag method is a simple, inexpensive and useful technique. 相似文献
759.
氨浸出含锌烟尘制取活性氧化锌 总被引:3,自引:0,他引:3
采用氨浸出法处理含锌烟尘,浸出液在微波-超声波联合作用下蒸氨得碱式碳酸锌沉淀,再经煅烧制得活性氧化锌.实验结果表明:在总氨浓度为9.0 mol/L、浸出温度为40 ℃、浸出液初始pH为 11.0~11.5、搅拌转速为400 r/min、浸出剂体积与含锌烟尘质量比为4、浸出时间为60 min的浸出条件下,锌的浸出率为83.3%.浸出液经过两段净化除杂后,在超声波功率50 W、微波辐射(微波功率随温度的设定而自动变化)的联合作用下,使溶液体系恒温90 ℃,进行蒸氨,沉淀得到前驱体碱式碳酸锌,经煅烧,得到平均直径为0.4 μm、晶型为六方晶系、片状的活性氧化锌. 相似文献
760.
通过间歇曝气的运行方式,对高浓度氨氮低碳废水进行短程硝化-反硝化脱氮过程的研究.在生物驯化过程中考察亚硝酸盐氮的积累,并验证短程硝化即亚硝化的可行性.实验结果表明,短程硝化-反硝化过程满足高氨氮低碳废水的生物脱氮要求,亚硝化率达到98.0%以上.采用16S rRNA基因克隆文库分子生物学分析方法对系统中的硝化菌群进行分析,发现系统中主要存在将氨氧化成亚硝酸根的氨氧化菌(AOB)及亚硝酸盐还原菌. 相似文献