pH对鲤鳃部微环境铜形态的影响

利用Playle等设计的装置研究了不同pH条件及不同的铜暴露水平下鲤鳃部微环境pH值和粘液分泌量的变化,在此基础上用化学平衡计算方法探讨鱼鳃微环境中铜形态的变化。结果表明,在特定的pH和铜浓度范围内,鱼鳃微环境平衡pH略低于7,鱼鳃粘液分泌量随铜暴露水平提高而增加,与此同时,虽然CO2分泌量有所增加,没有观察到微环境pH随铜暴露量的变化。pH的升高,导致水相优势的游离态铜让位给羟基络合铜,粘液络合态铜的分额逐渭降低,但不会改变其络合当量与条件稳定络合常数。由于鱼鳃微环境对pH改变的调节作用,铜的形态分布变化幅度低于外部环境。     

鲤鱼鳃部微环境的pH特征及其对吸附态铜的解吸影响

研究了不同pH条件下鲤鱼（Cyprinus carpio)鳃部微环境pH及CO2的变化情况以及鳃部微环境出水对水铝矿吸附态铜的淋洗效率,结果表明,鱼鳃微环境的平衡pH为8.0,出外环境pH低于或高于该值时,鱼鳃生理作用可以起到缓冲作用,造成鳃部微环境于外环境之间高达0.4个pH单位的差别,CO2含量也表现出相似的变化规律,在碱性条件下,鱼鳃微环境出水对吸附态铜的洗脱效应显著高于pH值相对较高的外环境水。     

鱼体(去鳃)和鱼鳃对不同形态铜的积累特征

在实验室条件下研究实验鱼Ｐａｒａｃｈｅｉｒｏｄｏｎ对人工河水中不同形态的积累特征,对比了鱼体（去鳃）和鱼鳃对铜吸收量的差异,并探讨了鱼对铜的吸收机理。研究结果表明,实验鱼鳃部和体内铜积累量均随水相游离铜浓度增高,暴露时间增长而增加,但鳃部积累浓度较鱼体其余部分高一个数量级,其从水相富集铜的速率显著高于鱼体。     

光强和硝态氮水平对铜藻(Sargassum horneri)生长和光合生理特性的影响

以金潮种铜藻(Sargassum horneri)为对象,探讨了不同硝态氮水平下光照强度对其生长和光合生理特性的影响,以期为金潮暴发机制的研究提供一定的参考。实验设置了高(100μmol·L-1)、低(自然海水,50μmol·L-1) 2个硝态氮浓度和高(150μmol photons·m-2·s-1)、中(60μmol photons·m-2·s-1)、低(10μmol photons·m-2·s-1)三个光照水平,检测了藻体在不同硝态氮浓度和光照条件下适应培养7 d后生长、色素含量、可溶性糖含量、可溶性蛋白含量、氮吸收速率及最大光合放氧速率(Pmax)等生理指标的变化。结果表明:氮浓度相同时,铜藻的生长速率、可溶性糖含量、可溶性蛋白含量、氮吸收速率、Pmax均随光照强度的增加而增加,而色素含量随着光照强度的增加而降低;低氮条件下,除类胡萝卜素外,以上指标在高光处理下均显著高于低光处理(P0.05);高氮条件下,除可溶性糖外,以上指标在高光条件下也均显著高于低光处理(P0.05);同一光照强度下,色素及可溶性蛋白含量、氮吸收速率及Pmax随氮浓度的增加而增加;可溶性糖含量随着硝态氮浓度的增加而减少;且在3个光照条件下,高氮处理下藻体的Pmax均显著高于低氮处理。总之,不同光照和氮浓度处理7 d后,高光、高氮适应后的藻体表现出较高的生长和光合作用潜能。铜藻断裂后漂浮于海面极易获得较高光强条件,而富营养海水中的高氮条件会刺激铜藻的光合潜能而使其加速生长,进而加剧铜藻金潮的暴发。     

金鱼(Carassius auratus)鳃对颗粒吸附态铅的吸收

研究了金鱼（Ｃａｒａｓｓｉｕｓ ａｕｒａｔｕｓ）鳃在悬浮水铝矿吸附态Ｐｂ暴露实验中对Ｐｂ吸收过程,结果表明,在保持水中游离态Ｐｂ浓度不变（０．１ｍｇ．Ｌ＾－１）、吸附态Ｐｂ浓度增加的条件下,鳃中Ｐｂ,Ａｌ浓度均随暴露浓度增加而增加,血液中Ｐｂ浓度随鳃中Ｐｂ浓度的增加率（直线斜率０．１７１）低于溶解态Ｐｂ、暴露实验的增加率（直线斜率０．３４３）,附着鳃上的部分Ｐｂ未移转至血液中,鳃中Ｐｂ／Ａｌ比较水     

天然砂与修饰砂对病毒的吸附与去除

分别在不同pH、含有不同金属阳离子及腐殖酸的脱氯自来水与蒸馏水中,研究了砂与金属氢氧化物修饰砂吸附与去除Polivirus 1(PV1)和Bacteroides fragilis phage(B．fp)的不同效果。结果显示,天然砂吸附病毒效率随水体pH的降低而增加,但当砂表面经氧氧化铝、氢氧化铁沉积修饰后,却在中性pH具有较高的吸附率。金属阳离子可促进天然砂吸附病毒,并随其浓度和价态的增加而增加,但对修饰砂作用不明显。腐殖酸对砂及修饰砂吸附病毒的影响也不同,修饰砂吸附病毒不受腐殖酸的存在及其浓度影响,而天然砂会因腐殖酸的存在及其浓度的提高而降低吸附病毒效率。在任一实验条件下,砂与修饰砂在自来水中的吸附病毒效率高于在蒸馏水中的吸附效率,扫描电镜观察显示砂与修饰砂具有明显不同的表面结构特征,这是两者具有不同吸附效率的基础。从砂与修饰砂吸附PV1的效率高于B．fp的现象说明B．fp是一个更为合适的病毒去除指示生物。本实验结果表明了金属氢氧化物修饰砂可为传统的净水工艺提供高效的病毒去除过滤介质与途径。     

天然砂与修饰砂对病毒的吸附与去除

分别在不同pH、含有不同金属阳离子及腐殖酸的脱氯自来水与蒸馏水中,研究了砂与金属氢氧化物修饰砂吸附与去除Polivirus 1(PV1)和Bacteroides fragilis phage(B.fp)的不同效果.结果显示,天然砂吸附病毒效率随水体pH的降低而增加,但当砂表面经氢氧化铝、氢氧化铁沉积修饰后,却在中性pH具有较高的吸附率.金属阳离子可促进天然砂吸附病毒,并随其浓度和价态的增加而增加,但对修饰砂作用不明显.腐殖酸对砂及修饰砂吸附病毒的影响也不同,修饰砂吸附病毒不受腐殖酸的存在及其浓度影响,而天然砂会因腐殖酸的存在及其浓度的提高而降低吸附病毒效率.在任一实验条件下,砂与修饰砂在自来水中的吸附病毒效率高于在蒸馏水中的吸附效率,扫描电镜观察显示砂与修饰砂具有明显不同的表面结构特征,这是两者具有不同吸附效率的基础.从砂与修饰砂吸附PV1的效率高于B.fp的现象说明B.fp是一个更为合适的病毒去除指示生物.本实验结果表明了金属氢氧化物修饰砂可为传统的净水工艺提供高效的病毒去除过滤介质与途径.     

BSA与α-MnO2及δ-MnO2间的界面吸附作用

比较研究了牛血清白蛋白(BSA)与α-MnO2和δ-MnO2的界面吸附作用及其影响因素。结果表明,BSA在两种MnO2颗粒物表面有明显的吸附,且δ-MnO2比α-MnO2对BSA的吸附能力略强。pH3.8~8.0范围内,BSA在α-MnO2和δ-MnO2上的吸附率随pH的升高而减小,pH3.8条件下,α-MnO2上的吸附率为88.2%,δ-MnO2上的吸附率为94.0%。BSA在α-MnO2和δ-MnO2上的吸附量均随BSA浓度的增加而增大,吸附率随NaCl浓度的增加而减小。BSA在α-MnO2上的吸附具有很高的不可逆性,δ-MnO2上的吸附完全不可逆。吸附过程中BSA发生解螺旋作用,引起结构熵增大。     

重金属在根际中的化学行为——Ⅱ.土壤中吸附态铜解吸的根际效应

用第四纪红壤性水稻土(QP)、淀浆白土(WP)、第四纪红土(QR)和赤红壤(LR)研究了土壤中吸附态铜的解吸的根际效应。结果表明,吸附态铜可分为0.1M KNO_3解吸的易解吸态铜和0.1MHCl解吸的难解吸态铜。随吸附量增加,易解吸态铜百分数增加,而难解吸态铜百分数下降。易解吸态铜在根际土中的量小于非根际土中的量,各土壤的根际效应依次为:QP>WP>LR>QR;其平均解吸百分数则为:QR>LR>WP>QP。难解吸态铜的量为根际土大于非根际土,各土壤的根际效应为:WP>LR>QP>QR,其平均解吸百分数依次为QP>WP>LR>QR。根际中铜吸附的增加主要是因为难解吸态铜的增加。     

木瓜微粉及其对胆酸钠和重金属吸附特性研究

研究了吸附时间对木瓜微粉吸附胆酸钠的影响,并分别对金属混合液浓度、模拟人体胃肠环境的pH条件、木瓜粉的粒径对木瓜微粉吸附混合液中Cu2+、pb2+、Cd2+、Hg2+的能力进行分析,以明确木瓜微粉及其体外对胆酸钠、Cu2+、Pb2+、Cd2+、Hg2+的吸附特性.结果显示:(1)随粉碎时间的延长,微粉所占的比例增大,粒径分布更加均匀,粉碎过程中存在粉碎一团聚一再粉碎的动态变化.(2)木瓜微粉对胆酸钠的吸附随吸附时间的延长,吸附量显著增加,粗粉和粉碎10、60 min得到的微粉A、C在30 min内对胆酸钠(0.2%)吸附达到了平衡,粉碎30 min得到的微粉B在吸附60 min时对胆酸钠仍有显著的吸附能力.(3)在试验范围内,木瓜微粉B对Cu2+、Pb2+、Cd2+、Hg2+的最适吸附浓度分别为3.00、3.00、1.00、0.01 μg/mL.(4)在pH为7时对Cu2+、Pb2+、Cd2+、Hg2+的吸附率分别比pH为2时高出40.85%、21.07%、27.33%、66.38%.(5)不同粒径的木瓜粉对Cu2+的吸附率随粒径的减小而降低,对Hg2+的吸附率则增加,但对Pb2+和Cd2+的吸附率没有显著差异.研究表明,木瓜微粉在体外具有良好的吸附胆酸钠、Cu2+、Pb2+、Cd2+、Hg2+作用,可广泛用于食品和药品中.     

Kinetics of the binding of immunoglobulins, antibodies and virus haemagglutination inhibitors to kaolin

Kaolin is widely used in diagnostic virology, mainly to remove serum lipoproteins that may interfere with antibody assaying. The binding kinetics of antibody to kaolin at different pH values and with varying amounts of kaolin indicated a uniform and characteristic binding pattern for IgG with maximum adsorption at pH 5 and no adsorption at pH above 9. To avoid loss of IgG antibody adsorption with kaolin should therefore be performed at pH greater than or equal to 9. The amount adsorbed increased with the amount of kaolin used. The IgM pattern was less uniform with maximum adsorption of total IgM at about 7.0, the amount adsorbed being highly dependent on kaolin concentration. Serum lipoproteins were rapidly and strongly adsorbed independent of pH from 7 to 11 and independent of the lipoprotein content of the serum. The amount of kaolin used was, however, critical.     

Heterogeneity in the reactivity of various groups of IgM antibodies with kaolin.

Kaolin strongly adsorbed rheumatoid factor (RF) and mono-nucleosis antibodies, while cold agglutinins and some antimicrobial IgM antibodies were poorly adsorbed. Maximum adsorption took place at a pH of about 7. The degree of adsorption also depended on the amount of kaolin. Rheumatoid factor could be eluted from kaolin at pH 11 after adsorption at pH 7. The reported heterogeneity with regard to reactivity with kaolin is suggested to be due to hydrophobic interactions.     

Effect of copper on liver key enzymes of anaerobic glucose metabolism from freshwater tropical fish Prochilodus lineatus

We investigated the effect of copper on liver key enzymes of the anaerobic glucose metabolism (hexokinase, HK; phosphofructokinase, PFK; pyruvate kinase, PK; lactate dehydrogenase, LDH) as well as of the pentose pathway (glycose-6-phosphate dehydrogenase, G6PDH) from the fish Prochilodus lineatus. The fish were acclimated at either 20 degrees C or 30 degrees C at pH 7.0, transferred to water at pH 4.5 or 8.0, and exposed to 96 h-CL(50) copper concentrations. Copper accumulation in liver was higher in fish acclimated at 20 degrees C and maintained in water pH 8.0. Three-way analysis of variance revealed a significant effect of temperature on all enzymes, a significant effect of pH on all enzymes except for PK, and a significant effect of copper on only PFK, and LDH in pH 4.5 at 20 degrees C and, at 30 degrees C, on PFK and PK at pH 4.5 and 8.0, HK at pH 4.5 and G6PDH at pH 8.0. There were significant interactions between treatments for many enzymes. These changes suggest that the activity of enzymes in question is modified by a change in ambient water. At least at 30 degrees C, the overall reduction in the glycolytic enzyme activities of copper-exposed fish seems to reduce energy availability via glucose metabolism, thereby contributing to enhance copper toxic effects.     

Immunological parameters of Javanese carp Puntius gonionotus (Bleeker) exposed to copper and challenged with Aeromonas hydrophila.

This study was to determine the median lethal concentration (LC50) of copper to Javenese carp, Puntius gonionotus (Bleeker), and the immune response after the fish were exposed to sublethal levels of copper and challenged with formalin killed Aeromonas hydrophila. The LC50 of copper on P. gonionotus at 24, 48, 72, 96 and 120 h were estimated as 2.17, 0.91, 0.57, 0.53 and 0.42 mg l(-1), respectively. To determine the effect of copper on the immune system, fish were exposed for 66 days to 0.05, 0.10 and 0.15 mg Cu l(-1). After 56 days of initial exposure to copper, fish were challenged with 0.1 ml of 4.5 x 10(5) cfu ml(-1) formalin killed A. hydrophila and maintained in the same concentration of copper. After the challenge, the immune response was monitored for 2 weeks using haematological and serological assays. During the initial phase of exposure to copper, significant changes were noted in the white blood cell, lysozyme, potential killing activity, total plasma protein, total immunoglobulin and haematocrit levels between the control and treated fish. One week after challenge with A. hydrophila, there was a significant increase in the values of white blood cells, total protein and total immunoglobulin compared to the values before the challenge. However, these values were not significantly different (P>0.05) between the control and the treated fish. In contrast, NBT and lysozyme assays exhibited a significant difference (P<0.05) in fish exposed to 0.10 mg Cu l(-1) (0.525 +/- 0.17; 24.42 +/- 3.35 x 10(2) micromg ml(-1)) and 0.15 mg Cu 1(-1) (0.536 +/- 0.19; 21.78 +/- 1.29 x 10(2) micromg ml(-1)) compared to the control (0.746 +/- 0.31; 30.73 +/- 5.42 x 10(2) micromg ml(-1)) after the bacterial challenge (day 61). There was however no significant difference (P>0.05) in NBT and lysozyme levels in fish exposed to lower level of copper (0.05 mg Cu l(-1)), suggesting the absence of immunosuppressive effects at lower level of exposure.     

Removal of Astrazon Yellow 7GL from aqueous solutions by adsorption onto wheat bran

Adsorption kinetic and equilibrium of a basic dye (Astrazon Yellow 7GL) from aqueous solutions at various initial dye concentration (50-300 mg/l), pH (4-10), adsorbent dosage (2-8 g/l), particle size (354-846 microm) and temperature (30-50 degrees C) on wheat bran were studied in a batch mode operation. The result showed that the amount adsorbed of the dye increased with increasing initial dye concentration and contact time, whereas particle size and pH had no significant affect on the amount of dye adsorbed by the adsorbent. A comparison of kinetic models on the overall adsorption rate showed that dye/adsorbent system was best described by the pseudo second-order rate model. The removal rate was also dependent on both external mass transfer and intra-particle diffusion. The low value of the intraparticle diffusivity, 10(-11) cm2/s, indicated the significant influence of intraparticle diffusion on the kinetic control. The adsorption capacity (Q0) calculated from the Langmuir isotherm was 69.06 mg/g for at pH 5.6, 303 K for the particle size of 354 microm. The experimental data yielded excellent fits with Langmuir and Tempkin isotherm equations. Different thermodynamic parameters showed that the reaction was spontaneous and endothermic in nature.     

Influence of pH and ionic strength on formation and stability of emulsions containing oil droplets coated by beta-lactoglobulin-alginate interfaces

Emulsions of 0.1 wt % corn oil-in-water containing oil droplets coated by beta-lactoglobulin (0.009 wt % beta-Lg, 5 mM phosphate buffer, pH 7.0) were prepared in the absence and presence of sodium alginate (0 or 0.004 wt %). The pH (3-7) and ionic strength (0-250 mM NaCl) of these emulsions were adjusted, and the particle charge, particle size, and creaming stability were measured. Alginate adsorbed to the beta-Lg-coated droplets from pH 3 to 6, which was attributed to electrostatic attraction between the anionic polymer and cationic patches on the droplet surfaces. Droplets coated by beta-Lg-alginate had better stability to flocculation than those coated by beta-Lg alone, especially around the isoelectric point of the adsorbed proteins and at low ionic strengths (< 100 mM NaCl). At pH 5, alginate molecules desorbed from the droplet surfaces at high salt concentrations due to weakening of the electrostatic attraction.     

Influence of food ration, copper exposure and exercise on the energy metabolism of common carp (Cyprinus carpio)

The present study was conducted to extend the understanding of the combined physiological effects of different food rations in combination with sublethal levels of copper in common carp (Cyprinus carpio). Fish acclimated to low (0.5% body weight) and high (5% body weight) food rations were exposed to 1 microM copper for a period of 28 days and kept for a further 14 days in copper free water to examine their recovery. Measurements of oxygen consumption, ammonia excretion and ammonia accumulation in plasma and muscle were done at various time intervals during the experimental period. Overall, oxygen consumption and ammonia excretion rates were significantly affected by food ration in both copper free and copper exposed fish. Additional challenges, such as copper exposure and/or exercise, significantly increased plasma and muscle ammonia in the fish fed a high food ration. Muscle ammonia levels in general responded slower (first increase after 72 h) and recovered within 2 weeks of exposure. There was a significant correlation between plasma ammonia levels, muscle ammonia levels and ammonia excretion rates. Influence of copper in terms of ammonia excretion and plasma ammonia accumulation was observed in high ration fish but low ration fish remained unaffected. This clearly indicates that ammonia metabolism was significantly influenced by copper in this group of fish showing that during unfavourable environmental conditions a high amount of food supply may turn deleterious to fish.     

Anaerobic decolorisation of simulated textile wastewater containing azo dyes

The effects of the addition of powered particles of kaolin to nitrifying activated sludge systems were studied. Kaolin was added to a nitrifying activated sludge reactor, during the operational phase, to observe the effects of this clay on reactor performance. The results were compared to those obtained from a similar unit operated without kaolin. The settling properties of the sludges from both units were similar (sludge volume index (SVI) of 14.5 ml/g VSS; zone settling velocity (ZSV) of 7.5 m/h), but the specific nitrifying activities of ammonia and nitrite oxidizing processes were enhanced up to 75% and 50%, respectively, when kaolin was added. The mechanism of action of kaolin was not clear. Additional ammonia, nitrite and nitrate adsorption tests showed that these compounds were not adsorbed by kaolin. This demonstrated that no beneficial effect was caused by adsorption of either substrates or products. Short-term activity tests also showed that the stimulating effects of kaolin on specific activity were not immediate. The effects of kaolin when nitrifying units were operated under unfavorable conditions were also evaluated: In a second set of experiments, a nitrifying unit was operated with low levels of dissolved oxygen (DO), with and without kaolin. The presence of kaolin exerted practically no effect on ammonia oxidation but nitrite oxidation slightly diminished. In a third set of experiments, a nitrifying unit was subjected to pH shocks (9, 10 and 11) over 3 h with pH then restored to 7.8. A pH shock of 11 caused a decrease of 60% in nitrifying activity for 12 days. When kaolin was added to this unit the efficiency of the system was completely restored in 4 days. Therefore, kaolin might be useful to restore damaged units.     

Interactions of temperature and sublethal environmental copper exposure on the energy metabolism of bluegill, Lepomis macrochirus Rafinesque

Copper (0.21 mgl⁻¹) caused a decrease in whole body oxygen consumption in bluegills exposed for 32 days, but no changes occurred during days 3, 4 or 9 of copper exposure. In vitro oxygen consumption of gill and brain, were not significantly altered, whereas liver Q O₂, was slightly elevated which suggests that copper is acting to decrease oxygen consumption of the whole animal at a higher level of integration than these individual tissues. In fish subjected to an increase in temperature as well as sublethal copper exposure, whole body oxygen consumption was higher than controls 5 days after the temperature was increased, indicating a delay in temperature acclimation in the copper exposed fish. This difference was reflected in higher in vitro oxygen consumption in the liver and gill of these fish suggesting the metal was delaying the process of temperature acclimation by at least in part acting directly on the tissues.