藻类在水体污染监测中的运用

利用藻类进行水体污染监测在水生生物监测中占有重要的地位。各种不同的水体污染对藻类的种类,数量,结构等产生相应的影响,在一定程度上表明了水质的某种变化。     

中国南方地区12个城市水源水的水质特征

对中国南方地区具有代表性的武汉、长沙、成都等12个城市饮用水水源的水质状况进行了调查、监测与分析，结果显示，南方地区的水源普遍存在着低浊、高藻、微污染的特征．据统计，78．6％的水源浊度平均值处于50NTU以下，63．6％的水源藻类污染严重，57．1％的水源微污染状况正逐渐加剧。     

牛粪发酵过程中抗生素耐药基因及相关菌群组成变化规律

随着规模化奶牛养殖迅速发展,牛粪带来的环境污染问题日益严重。实验探究牛粪及其堆肥过程中养分变化、抗生素耐药基因消减情况以及细菌群落演替规律,探讨细菌菌群与养分、抗生素耐药基因之间的相关性。采集牛粪及其堆肥过程样品,测定样品中养分、检测抗生素耐药基因相对丰度,采用16S r RNA高通量测序技术研究牛粪堆肥过程细菌群落变化。结果表明,从新鲜牛粪(组FM)到发酵牛粪(组C),样品中有机质含量下降,全氮和全磷含量有不同程度增加,全钾(TK)显著升高(P<0.05)。堆肥发酵后,抗生素耐药基因erm B、tet M、bla CTX-M和aac(6')-Ib-cr的相对丰度呈现不同程度的下降,而基因sul1相对丰度增加。高通量测序结果表明,在门水平,各组均以Firmicutes、Proteobacteria和Bacteroidetes这3个菌门为主,在属水平,各组具有不同的优势物种,其中发现Bacteroides、Paeniclostridium和Pseudomonas等7个潜在病原菌属的相对丰度在堆肥后有效降低。通过相关性分析发现,潜在病原菌属与基因tet M和sul1呈显著正相关(P<0.05),此外,大部分优势菌属与养分TK有显著相关性(P<0.05)。研究结果表明,牛粪经堆肥发酵后,病原菌相对丰度有效降低,抗生素耐药基因相对丰度的下降与细菌菌群结构变化存在相关关系。     

长春市南湖大气降尘长期演变规律

本文统计分析了１９８４－１９９３年长春市南湖大气降尘数据，探讨了冬季与夏季的代表月份以及１０年间的代表年份大气降尘长期演变规律。１０年间冬季降法量呈波浪式递减趋势；从统计来看，冬季１月份降尘最是夏季７朋份降尘量的２．３倍左右；同年度内冬季、春季大风时段的除尘量一般高于夏、秋季；冬季煤烟型大气污染已逐年在所改善，一些自然因素对大气除尘的影响逐渐突出。     

改性活性炭吸附净化黄磷尾气中的PH3

通过钢瓶配气模拟和气相色谱GC-14C测定的方法，研究了改性活性炭吸附净化黄磷尾气中PH₃的相关问题。得到了吸附反应的最佳吸附温度、氧含量、气体流量、改性液浓度、活性炭粒径和焙烧温度。再生方法可行，可通过再生液回收磷酸。热重差热分析和孔径分布初步证明吸附质为磷和磷氧化物。     

Organohalogenated compounds in pine needles from Beijing city, China

Pine needles collected from 22 sites of six areas in Beijing city, China, were analyzed by instrumental neutron activation analysis (INAA) combined with organic extraction for extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX). The concentrations of EOX (EOX = ECl + EOBr + EOI) were in the order of EOCl > EOBr > EOI. About 1.6-34% of EOCl remained as extractable persistent organochlorine (EPOCl) after treatment with concentrated sulfuric acid, which suggested that major fractions of EOCl in pine needles were an acid-liable or acid-soluble fraction. The fact that pine needle contained higher EOCl contents in chemical industrial and traffic hub areas indicated that chemical industries and exhaust emission from vehicle were the main sources of organochlorines in the Beijing's air. The relative proportions of the known organochlorines (such as HCHs, DDTs, chlordanes, HCB and PCBs) to total EOCl and EPOCl were 0.32-0.76% and 2.5-11.4%, respectively, which implied that a major portion of the EOCl and EPOCl measured in pine needles was unknown. The organochlorinated pesticides (OCPs) and PCBs concentrations in six areas were as follows: sigma HCH (sigma HCH = alpha- + beta- + gamma- + delta-HCH), 11.7-20.8 ng/g; sigma DDT (p,p'-DDT + p,p'-DDE + p,p'-DDD), 12.5-113.3 ng/g; hexachlorobenzene (HCB), 1.1-5.3 ng/g; sigma chlordane (cis-chlordane + trans-chlordane + heptachlor), 1.7-9.5 ng/g, sigma PCB, 41.8-270.5 ng/g, on dry weight basis. The samples from chemical industrial area and residential area nearby chemical industries contained the highest concentrations of sigma DDT, HCB, sigma chlordane and sigma PCB, while the contamination levels of most OCPs and PCBs in iron-steel industrial area were the lowest. The ratios of alpha/gamma-HCH (ranged from 0.9-1.5) and p,p'-DDT/DDTs (ranged from 72.1% to 91.0%) revealed the presence of the recent use of lindane and DDTs or impure dicofol in Beijing.     

Photodegradation of Dyes in Aqueous Solutions containing Fe(III) -hydroxy Complex II. Solar Photodegradation Kinetics

The solar photodegradation of five dyes, C.I. reactive red 2, C.I. reactive blue 4, C.I. reactive black 8, C.I. basic red 13, and C.I. basic yellow 2, were studied in a sunlight/Fe(III)-hydroxy system. It was observed that the photodegradation of these five dyes were pseudo-first order reactions, which has a little difference with the photodegradation kinetics of the dyes with UV-light as the irradiation source. The comparison between the two studies is also conducted.     

Effects of redox potential and pH value on the release of rare earth elements from soil

Equilibrium release experiments were conducted under three different pH values of 3.5, 5.5 and 7.5 as well as three redox potentials of 400, 0 and -100 Mv to investigate the influence of redox potential and pH value on the La, Ce, Gd and Y release of from the simulated-REEs-accumulation (SRA) soil. Oxygen and nitrogen were allowed to flow into soil suspension to adjust redox potential to a preset value, and 1 mol/l HCl or 1 mol/l NaOH solutions were added into the soil suspension to keep pH at a preset value. Results indicated that La, Ce, Gd and Y release increased gradually with the decrease of pH value or Eh, and the influence of redox potential on Ce was more remarkable than on La, Gd and Y. At the same time. It was observed that La, Ce, Gd and Y releases were positively correlated with the release of Fe and Mn, indicating that La, Ce, Gd and Y releases might originate from dissolution of Fe-Mn oxyhydroxides under reduction and low pH conditions. Moreover, it was found that alteration of pH value and redox potential might affect the change of La, Ce, Gd and Y species in the soil. The contents of La, Ce, Gd and Y in exchangeable fraction and Fe-Mn oxide fraction in the solid phase from soil suspension separation decreased with the decline of pH value and redox potential. Multiple stepwise regression analysis showed that exchangeable fraction and Fe-Mn oxide fraction predominately contributed to the La, Ce, Gd and Y release. Low pH value and redox potential were more favorable to La, Ce, Gd and Y releases following the change of their species. The La, Ce, Gd and Y contents in exchangeable fraction and Fe-Mn oxide fraction are the main contributors to their release.     

Evaluation of mercury emissions to the atmosphere from coal combustion,China

Mercury emissions from the coal smoke is the main source of anthropogenic discharge and mercury pollution in atmosphere. The calculated total amount of mercury emissions of China in 1995 is approximately 213.8 tonnes, which accounts for c. 5% of estimated total global discharge of 4000 tonnes in the same period. From 1978 to 1995, total coal consumption increased fourfold. Based on these data it is estimated that the mercury emissions will increase at a rate of 5% a year, and the predicted emissions will be 273 tonnes in China in 2000. Controlling and solving mercury emissions from coal combustion are among the most important environmental tasks facing China.     

Photocatalytic degradation of p-nitrophenol on nanometer size titanium dioxide surface modified with 5-sulfosalicylic acid

The surface of nanometer size TiO(2) was simply and fast modified by chemical adsorption in saturated solution of 5-sulfosalicylic acid. After surface modification, a stable, yellow surface complex was formed quickly, the wavelength response range of TiO(2) was expanded, it has obvious absorption in the region from 320 to 450 nm; the adsorption efficiency of p-nitrophenol (PNP) by TiO(2) was enhanced from 42% to 84%. The photocatalytic activity was tested on the degradation of PNP. The influences of catalyst and its dosage, pH value, and PNP concentration on the degradation were investigated. On optimal photodegradation conditions, including initial pH 4.0, PNP 5 mg l(-1), catalyst 100 mg, irradiation time 120 min with 160 W high-pressure mercury lamp, the degradation efficiency of PNP was increased from 40% to 88% after surface modification. Surface modification led not only to an increase in the light utilization, but also improved the surface coverage of PNP in comparison with the pure TiO(2). Both of these factors are crucial for the photocatalytic activity of heterogeneous photocatalysis, especially for photodegradation of benzenoid pollutants.