土著细菌对江汉平原浅层含水层沉积物中砷迁移的影响

对江汉平原水文地质调查发现,该地区地下水砷含量已远超国家饮用水标准。以沉积物培养的土著细菌混合液为生物材料,以江汉平原高砷含水层沉积物为研究对象,在实验室内模拟地下水系统,研究厌氧环境条件下,不同生物量土著细菌和pH值对沉积物中砷迁移转化的影响,以及土著细菌活动下砷在不同沉积物中的迁移转化。结果表明,不同生物量菌悬液都能促进沉积物中As的释放,增加总As和As(III)的浓度,但150mL处理组,在研究后期,总As和As(III)的浓度呈现减缓趋势;在初始生物量一定的条件下,沉积物中As含量越高,细菌活动下总As相对释出量就越低,而且As(III)占所释出总As的比值就越高,但两个高砷含量沉积物组的差异较小;在初始pH值为5、7和9的培养条件下,细菌都能加速砷的迁移,但pH值为5的处理组(简称pH5处理组)最弱,在前8天,pH9处理组较pH7处理组的低,随后超过pH7处理组。研究表明,土著细菌悬液能加速As从沉积物中释出,并且释出的As以As(III)为主;在耐受的弱碱性环境条件下,细菌对砷的迁移和转化随环境的pH值增加而增强。     

上海浦东东滩与九段沙生态环境的比较

上海浦东国际机场建设占用了部分的滩涂，此部分滩涂是鸟类栖息迁徒的活动区域之一。研究和比较了长江口浦东东滩和相邻九段沙的生态环境特点，评述了九段沙作为鸟类栖息迁徒重要“驿站”可能性的重要依据，并提出了相应的建议。     

安徽沿江地下水资源的开发与保护

本文对安徽沿江地下水资源的开发利用与保护进行了论述;把地下水分为地下热水、饮用矿泉水和一般地下水.该文进一步展示了开发利用地下水有利于开发性农业的发展,同时提出了保护地下水资源的对策.     

Optimum nitrogen use and reduced nitrogen loss for production of rice and wheat in the Yangtse Delta region

A long-term field and lysimeter experiment under different amount of fertilizer-N application was conducted to explore the optimal N application rates for a high productive rice-wheat system and less N leaching loss in the Yangtse Delta region. In this region excessive applications of N fertilizer for the rice-wheat production has resulted in reduced N recovery rates and environment pollution. Initial results of the field experiments showed that the optimal N application rate increased with the yield. On the two major paddy soils (Hydromorphic paddy soil and Gleyed paddy soil) of the region, the optimal N application rate was 225-270 kg N hm(-2) for rice and 180-225 kg N hm(-2) for wheat, separately. This has resulted in the highest number of effective ears and Spikelets per unit area, and hence high yield. Nitrogen leaching in the form of NO(3-)-N occurs mainly in the wheat-growing season and in the ponding and seedling periods of the paddy field. Its concentration in the leachate increased with the N application rate in the lysimeter experiment. When the application rate reached 225 kg N hm(-2), the concentration rose to 5.4-21.3 mgN l(-1) in the leachate during the wheat-growing season. About 60% of the leachate samples determined contained NO(3-)-N beyond the criterion (NO(3-)-N 10 mg l(-1)) for N pollution. In the field experiment, when the N application rate was in the range of 270-315 kg hm(-2), the NO(3-)-N concentration in the leachate during the wheat-growing season ranged from 1.9 to 11.0 mg l(-1). About 20% of the leachate samples reached close to, and 10% exceeded, the criterion for N pollution. Long-term accumulation of NO(3-)-N from leaching will no doubt constitute a potential risk of N contamination of the groundwater in the Yangtse Delta Region.     

Bioaccumulation and elimination of avermectin B1a in the earthworms (Eisenia fetida)

The acute toxicity, bioaccumulation, and elimination of avermectin B1a (AVM B1a) in earthworm (Eisenia fetida) were investigated in different exposure systems. The LC50 of AVM B1a on earthworms were 24.1 mg/kg and 17.1 mg/kg, respectively, for 7 and 14 days in artificial soil. The LC50 tested by the filter paper for 2 days was 4.63 microg/cm2. The earthworms were cultivated in artificial soil containing 0.6 mg/kg and 3.0 mg/kg AVM B1a, respectively for bioaccumulation experiments. The AVM B1a residues in earthworms were determined with HPLC-fluorescence method. The results showed that AVM B1a was taken up from the concentrated artificial soil by the earthworms and the steady-state levels were reached after 9-18 days of exposure. On the 18th day, the final concentrations of AVM B1a in the earthworms treated with two different dosages were 107 ng/g and 165 ng/g, respectively; there were not significantly accumulation. About 80.0% and 94.8% of the accumulated AVM B1a were eliminated respectively in two groups within 1 day after they were exposed to AVM B1a-free soil, but a trace amount of AVM B1a was found for a relative long time in earthworms.     

Estrogenic effects of phenolic compounds on glucose-6-phosphate dehydrogenase in MCF-7 cells and uterine glutathione peroxidase in rats

In this study, we tested phenolic compounds such as bisphenol A (BPA), 4-nonylphenol (NP), 4-octylphenol (OP) and 4-propylphenol (PP) by using glucose-6-phosphate dehydrogenase (G6PD) in estrogen sensitive human breast cancer cells (MCF-7 cells) and glutathione peroxidase (GPx) in female immature Sprague-Dawley (SD) rats. This study was designed to investigate whether phenolic compounds have estrogenic effects in these useful screening methods for endocrine disruptors. We chose 6 h as the incubation period for the G6PD assay through a preliminary experiment using 17beta-estradiol (E2). Above the concentration of 1 x 10(-8) M, BPA significantly increased the G6PD activity in a concentration-dependent manner, relative to the control. NP (over the concentration of 1 x 10(-9) M) also enhanced the G6PD activity by about 1.8 times that of the control. OP produced weaker effects on G6PD than NP, and showed a tendency to increase the G6PD activity. PP did not affect the G6PD activity. These results show that BPA and NP have the effect of enhancing G6PD activities in MCF-7 cells. In the in vivo GPx assay, both BPA and E2 significantly increased the uterus wet weights and dramatically enhanced uterine GPx activities in immature female rats in a dose-dependent manner. Treatment with NP (500 mg/kg/day) increased significantly both the uterine GPx activity and the uterus wet weights in immature female rats. OP (500 mg/kg/day) also caused a significant increase in uterine GPx activity, but had no effect on the uterus wet weights. This finding indicates that the change in uterine GPx activities could be a more sensitive parameter than that of uterus wet weights in immature rats. This study implies that phenolic compounds have a weak estrogenic effects.     

雾化电晕净化烹调油烟技术

对雾化电晕放电极雾化过程、荷电液滴的捕集原理、自清洗作用进行探讨,在相同电压下雾化负电晕放电电流高于干式负电晕放电电流,极间大量荷电液滴具有很高的荷质比,并高速向极板驱进,对烟尘具有静电凝并和动力凝并除尘作用,具有高效净化油烟、自清洗极板的功能,此项净化烹调油烟的新技术,优于传统油烟净化技术,具有很好的应用价值和前景。     

不同pH条件下酵母菌处理高含油废水的研究

在使用混合酵母菌菌株处理高浓度含油废水中,研究了序批式反应器(SBR)内酵母菌在不同起始pH条件下对废水的处理效果.通过与pH中性或碱性条件比较发现,pH 4～5的条件在酵母菌的发泡抑制、菌体生长以及COD/油去除等方面均显示出更好的效果,pH 5是系统运行的最佳条件.长达100d的SBR连续运行试验表明,系统可以在pH=5条件下长期、稳定运行.     

掺杂负载型纳米TiO2降解橙黄G的光催化活性及其动力学研究

采用溶胶-凝胶法和浸渍-焙烧法制备了掺杂Sn(Ⅳ)的TiO2/AC光催化剂,以偶氮染料橙黄G为目标降解物,对光催化反应条件进行了优化.结果表明:利用Sn(Ⅳ)掺杂量为2.5 at.%的TiO2/AC光催化剂,在进水浓度50 mg/L,催化剂的用量12.5 g/L,pH值2.0,H2O21.5 mL/L,主波长为365 nm的300W高压汞灯光照条件下,反应60 min,橙黄G的光催化去除率可达99.1%.该反应符合Langmuir-Hinshelwood动力学方程,其速控步为吸附反应.共存阴离子SO42-和H2PO4-,对橙黄G的光催化降解反应均有一定的抑制作用.     

Enhancement of photocatalytic oxidation of humic acid in TiO2 suspensions by increasing cation strength

This study aimed at improving the photocatalytic (PC) oxidation of humic acids (HA) in TiO2 suspensions by adding cationic ion such as calcium or magnesium. A set of tests was first conducted in the dark to study the adsorption of HA onto TiO2 in suspensions at different pH and calcium concentrations. The experiment demonstrated that the adsorption of HA onto the TiO2 particles was either pH-dependent or calcium strength-dependent due to electrostatic interaction and calcium ion bridging. The photodegradation of HA in the presence of UV irradiation was investigated as a function of pH and the concentration of calcium and magnesium ions. The results showed that the adsorption behavior between HA and TiO2 played a very important role during the PC oxidation process. The PC oxidation could be enhanced at neutral pH by increasing the cation strength. The kinetics of HA PC degradation in TiO2 suspensions with different initial concentrations was also studied using the Langmuir-Hinshelwood model.