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881.
882.
Mutagenicity of surface water in Lake Taihu was monitored by genotoxicological methods. The goal is to determine the situation concerning the contamination by mutagens, their distribution in the lake, and the potential effect on public health. In this study, the micronucleus test of Vicia faba root tip, a standard monitoring technique now in China, was carried out to make a preliminary screening of environmental mutagens in 39 representative sites of the lake. Highly significant differences in MCN permillage (average number of micronuclei per 1000 cells) and PI (pollution index) values were found among these sites. From the results, a rough distribution of the contamination could be obtained: mainly concentrated in the north-west area of the lake from several tributaries flowing into the lake. In order to provide further evidence, organic extracts from four entrances and one outlet of the five major tributaries were examined by the micronucleus test of human peripheral lymphocytes. The results were in accord with those of the micronucleus tests using Vicia faba. The tests also revealed that the intensity and mechanism of the pollutants were diverse in the different sources. 相似文献
883.
Spatial analysis for spring bloom and nutrient limitation in Xiangxi bay of three Gorges Reservoir 总被引:6,自引:0,他引:6
The spatial and temporal dynamics of physical variables, inorganic nutrients and phytoplankton chlorophyll a were investigated in Xiangxi Bay from 23 Feb. to 28 Apr. every six days, including one daily sampling site and one bidaily
sampling site. The concentrations of nutrient variables showed ranges of 0.02–3.20 mg/L for dissolved silicate (Si); 0.06–2.40
mg/L for DIN (NH4N + NO2N + NO3N); 0.03–0.56 mg/L for PO4P and 0.22–193.37 μg/L for chlorophyll a, respectively. The concentration of chlorophyll a and inorganic nutrients were interpolated using GIS techniques. The results indicated that the spring bloom was occurred
twice in space during the whole monitoring period (The first one: 26 Feb.–23 Mar.; the second one: 23 Mar.–28 Apr.). The concentration
of DIN was always high in the mouth of Xiangxi Bay, and PO4P was high in the upstream of Xiangxi Bay during the whole bloom period. Si seems no obvious difference in space in the beginning
of the spring bloom, but showed high heterogeneity in space and time with the development of spring bloom. By comparing the
interpolated maps of chlorophyll a and inorganic variables, obvious consumptions of Si and DIN were found when the bloom status was serious. However, no obvious
depletion of PO4P was found. Spatial regression analysis could explained most variation of Chl-a except at the begin of the first and second bloom. The result indicated that Si was the factor limiting Chl-a in space before achieved the max area of hypertrophic in the first and second bloom period. When Si was obviously exhausted,
DIN became the factor limiting the Chl-a in space.
Daily and bidaily monitoring of Site A and B, representing for high DIN: PO4P ratio and low DIN:PO4P ratio, indicated that the concentration of Si was decreased with times at both site A and B, and the dramatically drop of
DIN was found in the end monitoring at site B. Multiple stepwise regression analysis indicated that Si was the most important
factor affect the development of spring bloom both at site A and B in time series. 相似文献
884.
The effect of local-scale physical heterogeneity and nonlinear,rate-limited sorption/desorption on contaminant transport in porous media 总被引:1,自引:0,他引:1
Nonideal transport of contaminants in porous media has often been observed in laboratory characterization studies. It has long been recognized that multiple processes associated with both physical and chemical factors can contribute to this nonideal transport behavior. To fully understand system behavior, it is important to determine the relative contributions of these multiple factors when conducting contaminant transport and fate studies. In this study, the relative contribution of physical-heterogeneity-related processes versus those of nonlinear, rate-limited sorption/desorption to the observed nonideal transport of trichloroethene in an undisturbed aquifer core was determined through a series of miscible-displacement experiments. The results of experiments conducted using the undisturbed core, collected from a Superfund site in Tucson, AZ, were compared to those obtained from experiments conducted using the same aquifer material packed homogeneously. The results indicate that both physical and chemical factors, specifically preferential flow and associated rate-limited diffusive mass-transfer and rate-limited sorption/desorption, respectively, contributed to the nonideal behavior observed for trichloroethene transport in the undisturbed core. A successful prediction of trichloroethene transport in the undisturbed core was made employing a mathematical model incorporating multiple sources of nonideal transport, using independently determined model parameters to account for the multiple factors contributing to the nonideal transport behavior. The simulation results indicate that local-scale physical heterogeneity controlled the nonideal transport behavior of trichloroethene in the undisturbed core, and that nonlinear, rate-limited sorption/desorption were of secondary importance. 相似文献
885.
采用投加预处理烟束曲霉(Aspergillus fumisynnematus)死菌体的方法去除含铬废水中的Cr(Ⅵ).考察了不同溶液初始pH值、Cr(Ⅵ)初始浓度、死菌体投加量及温度条件下,CTAB预处理烟束曲霉死菌体对Cr(Ⅵ)还原速率和总Cr的平衡吸附率的影响,并根据红外光谱分析初步探讨了CTAB预处理烟束曲霉死菌体与Cr的相互作用机理.结果表明:CTAB预处理烟束曲霉死菌体对总Cr有良好的吸附效果,在30℃.150 r·min-1,pH 2.0的条件下,在100mL浓度20gg·L-1的Cr(Ⅵ)溶液中投加0.5 g CTAB预处理烟束曲霉死菌体,2h内总Cr最大吸附率达到了72%,约为原死菌体总Cr吸附率的2倍,但反应达到平衡后的总Cr吸附率下降到30%左右.吸附平衡后的解吸实验结果表明Cr(Ⅵ)几乎全部被还原为Cr(Ⅲ).在实验pH值范围内,pH值越低、Cr(Ⅵ)初始浓度越小、预处理死菌体投加量越大以及温度越高,越有利于Cr(Ⅵ)的还原;pH值越高、Cr(Ⅵ)初始浓度越小、预处理死菌体投加量越大以及温度越低,对总Cr的平衡吸附率越大.预处理死菌体与Cr的相互作用主要是氨基和羧基与不同形态Cr的吸附作用以及菌体对Cr(Ⅵ)的还原作用. 相似文献
886.
Zhaobo Wang Chen Kang Shuqin Zhang Xiaoqin Zhang Zhiqun Deng 《Journal of environmental science and health. Part. B》2020,55(8):704-711
AbstractIn order to solve the problem of heavy metal-organic compound soil pollution, in this paper, we developed a highly efficient electro kinetic-laccase combined remediation (EKLCR) system. The results showed that the EKLCR system had an obvious migration effect on heavy metals (copper and cadmium) and good migration-degradation effect on phenanthrene. The migration rates of copper and cadmium were 48.3% and 40.3%, respectively. Especially, with the presence of laccase, the removal rate of phenanthrene on Cu2+-contaminated soil was higher than that of Cd2+-contaminated soil due to the significant effect of heavy metals on the enzymatic activity of laccase. The average migration-degradation rate of phenanthrene by EKLCR system was 45.4%. Finally, gas chromatography-mass spectrometry (GC/MS) was used to analyze the degradation intermediates of phenanthrene in the soil, which included 9,10-Phenanthrenequinone, phthalic acid, and 2,2-Biphenyldicarboxylic Acid. In addition, we give the possible degradation pathways of phenanthrene, 2,2-Biphenyldicarboxylic Acid is further degraded to produce phthalic acid. The products of the phthalic acid metabolic pathway are protocatechuic acid, pyruvic acid or succinic acid, the final products of these organic acids are carbon dioxide and water. 相似文献
887.
Paudyal Rukumesh Kang Shichang Guo Junming Tripathee Lekhendra Sharma Chhatra Mani Huang Jie Li Yang Yan Fangping Wang Kun Chen Jizu Qin Xiang Sillanpaa Mika 《Environmental science and pollution research international》2021,28(37):51530-51543
Environmental Science and Pollution Research - In this work, samples of surface snow, surface ice, snow pit and meltwater from the Laohugou Glacier No. 12 on the northern edge of Tibetan Plateau... 相似文献
888.
Sun Ya-qiao Xiao Kang Wang Xiao-dong Lv Zi-hao Mao Ming 《Environmental science and pollution research international》2021,28(15):18604-18615
Environmental Science and Pollution Research - The heavy metals, which derived from accumulated coal gangue, are important source of environmental pollution. In this study, coal gangue dumps,... 相似文献
889.
Dai Liang Zhao Weifan Wei Bigui Zhang Kang Han Tao 《Journal of Material Cycles and Waste Management》2021,23(3):1037-1047
Journal of Material Cycles and Waste Management - This study used excess sludge from a sewage treatment plant as raw material to extract humic acid (HA) and explore the ability of HA to adsorb Pb2+... 相似文献
890.
Qureshi Tahira Memon Najma Memon Saima Q. Yavuz Handan Lachgar Abdesadek Denizli Adil 《Environmental science and pollution research international》2019,26(10):9796-9804
Environmental Science and Pollution Research - Pharmaceutically active compounds like diclofenac (DFS), ibuprofen (IBP), and other drugs that persist in the environment are listed as emerging... 相似文献