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811.
812.
813.
Structural and functional parameters of protozoan communities colonizing on PFU (polyurethane foam unit) artificial substrate were assessed as indicators of water quality in the Chaohu Lake, a large, shallow and highly polluted freshwater lake in China. Protozoan communities were sampled 1, 3, 6, 9 and 14 days after exposure of PFU artificial substrate in the lake during October 2003. Four study stations with the different water quality gradient changes along the lake were distinguishable in terms of differences in the community's structural (species richness, individual abundance, etc.) and functional parameters (protozoan colonization rates on PFU). The concentrations of TP, TN, COD and BOD as the main chemical indicators of pollution at the four sampling sites were also obtained each year during 2002-2003 for comparison with biological parameters. The results showed that the species richness and PFU colonization rate decreased as pollution intensity increased and that the Margalef diversity index values calculated at four sampling sites also related to water quality. The three functional parameters based on the PFU colonization process, that is, S(eq), G and T90%, were strongly related to the pollution status of the water. The number of protozoan species colonizing on PFU after exposure of 1 to 3 days was found to give a clear comparative indication of the water quality at the four sampling stations. The research provides further evidence that the protozoan community may be utilized effectively in the assessment of water quality and that the PFU method furnishes rapid, cost-effective and reliable information that may be useful for measuring responses to pollution stress in aquatic ecosystems. 相似文献
814.
以钛酸四丁酯为钛源、膨胀石墨(EG)为载体,通过溶胶凝胶-浸渍法制备了Ag_6P_2W_(18)O_(62)/TiO_2/EG复合光催化剂。采用SEM,EDS,XRD,FTIR,UV-vis等技术对其进行表征,研究了该催化剂在紫外光及可见光下对甲基橙的降解性能。表征结果显示:Ag_6P_2W_(18)O_(62)被成功负载到TiO_2上且保持Dawson结构;经Ag_6P_2W_(18)O_(62)表面修饰后的复合光催化剂可见光吸收性能增强;EG提供的丰富孔道有利于有机污染物吸附去除。实验结果表明:在甲基橙质量浓度为20 mg/L、催化剂加入量为1.0 g/L、反应温度为25℃的条件下,n(Ag)∶n(Ti)=1∶16时的复合光催化剂(ATE-2)的紫外光、可见光催化活性最佳;紫外光下反应70 min时甲基橙去除率为96.5%,可见光下反应40 h时甲基橙去除率为83.5%;ATE-2使用5次后,反应70 min时,其甲基橙去除率仍为92.5%。 相似文献
815.
选取淮河流域临沂市4个出境监测断面2014年1~11月,每月上下旬各一次化学需氧量和高锰酸盐指数浓度的分析,利用每个监测断面21对化学需氧量和高锰酸盐指数浓度的监测结果,分析了临沂境内4个出境断面两个水质参数的相关关系,给出各断面二者的一元线性回归方程及相关系数并 F检验,得出不同断面二者的相关性及因水质不同相关性的差异。通过分析同一样品的二者的监测结果的相关性,相互佐证,从多角度进行质量控制和质量保证。提出二者相关性分析结果在实际使用的建议,以期引起从事水环境监测分析、监测评价和监测管理等相关人员重视。 相似文献
816.
Liu Xinji Zhang Jingjing Sang Yanru Liu Kaiyong Zhu Yitian Yang Linsheng Wang Sufang Sheng Jie Wang Qunan Zhang Dongmei Cao Hongjuan Tao Fangbiao 《Environmental science and pollution research international》2021,28(21):26794-26806
Environmental Science and Pollution Research - To examine the associations between urinary antibiotics from various sources and depression in the elderly using the biomonitoring method. In the... 相似文献
817.
818.
The tree species that contribute to decomposed leaf litter can have important effects on soil properties and thus nutrient cycling and interactions between tree species. We examined ground leaf litter and soil mixtures consisting of leaves from Ulmus pumila (Up) combined individually with leaves from one of six other species: Betula platyphylla (Bp), Quercus liaotungensis (Ql), Salix matsudana (Sm), Hippophae rhamnoides (Hr), Caragana microphylla (Cm), and Amorpha fruticosa (Af). The soil–litter mixtures were incubated for 120 days to analyse the effects of their decomposition on soil properties and to determine the interactions between the different types of litter within each mixture. The decomposed litter mixtures were composed of Up combined with Sm- or Hr-improved soil fertility relative to the pure Up mixture, but the decomposed litter mixtures were composed of Up combined with Cm-, Af-, or Ql-diminished soil properties. Three leaf mixture treatments, namely Up?×?Bp, Up?×?Sm, and Up?×?Hr, exhibited synergistic effects on soil properties (i.e. soil properties exceeding the predicted values); however, three other treatments, namely Up?×?Ql, Up?×?Cm, and Up?×?Af, exhibited antagonistic effects (i.e. properties below the predicted values). Therefore, litter from Bp, Sm, or Hr should be mixed with Up to improve soil fertility and production in plantations. 相似文献
819.
填料在净化污水过程中渗透性能变化趋势的研究 总被引:3,自引:1,他引:2
选取腐殖垃圾和砂以及两者质量比分别为4:1、3:2、2:3的混合物共5种填料,在1.0 m/d的水力负荷下,进行人工快速渗滤系统净化生活污水的试验,研究填料在进水过程中渗透性能的变化趋势.结果表明,腐殖垃圾的初始饱和水力渗透系数(K)最大,为3.32×10-2cm/s,而砂的初始K只有5.14×10-3cm/s,腐殖垃圾含量越大的混合物其仞始K也越大.在净化污水的过程中,5种填料的K逐渐减小,腐殖垃圾含量越大的混合物其K降幅也越大.随着进水时间的延长,各个填料柱填料层50~250 mm处的水头损失占总水头损失(填料层50~450mm处)的比例均逐渐增加,最终各个填料柱均发生堵塞,堵塞均发生在填料层50mm以上范围内. 相似文献
820.
The populations of many North American landbirds are showing signs of declining. Gathering information on breeding productivity
allows critical assessment of population performance and helps identify good habitat-management practices. He (Biometrics
(2003) 59 962–973) proposed a Bayesian model to estimate the age-specific nest survival rates. The model allows irregular
visiting schedule under the assumption that the observed nests have homogeneous nest survival. Because nest survival studies
are often conducted in different sites and time periods, it is not realistic to assume homogeneous nest survival. In this
paper, we extend He’s model by incorporating these factors as categorical covariates. The simulation results show that the
Bayesian hierarchical model can produce satisfactory estimates on nest survival and capture different factor effects. Finally
the model is applied to a Missouri red-winged blackbird data set. 相似文献