Antioxidant responses to benzo[a]pyrene, tributyltin and their mixture in the spleen of Sebasticus marmoratus

It has been reported that there is an interaction between Benzo[a]pyrene （BaP）, a widespread carcinogenic polycyclic aromatic hydrocarbon, and tributyltin （TBT）, an organometal used as an antifouling biocide. This study was therefore designed to examine the potential in vivo influence of BaP, TBT and their mixture on splenic antioxidant defense systems of Sebastiscus marmoratus. The fish were exposed to water containing environmentally relevant concentrations of BaP, TBT and their mixture. Spleens were collected for biochemical analysis after exposure for 7, 25, 50 d and after recovery for 7, 20 d. Cotreatment with BaP and TBT for 7 d potentiated the induction of glutathione peroxidase （GPx） activity by BaP or TBT alone. The cotreatment for 25 and 50 d resulted in inhibition of GPx activity, which was similar to the effect of TBT. Splenic glutathione S-transferase （GST） activities were significantly elevated in S. marmoratus exposed to BaP starting from 7 d and remained high up to 25 d. However, no further activity change was found with prolonged exposure. Cotreatment of BaP and TBT primarily inhibited the GST activity, which was similar to the effect of TBT. Cotreatment with BaP and TBT for 25 or 50 d potentiated the depletion of GSH （glutathione） by BaP or TBT alone. MDA （malondialdehyde） contents in spleen of S. marmoratus were not significantly altered compared with the control during the test period. Spleen, as an immune organ, is sensitive to exposure of BaP or TBT. It should have an effective mechanism to counteract oxidative damage. Antioxidative defense systems in spleen of S. marmoratus should be considered as potential biomarkers. Short-term exposure of BaP or TBT could result in induction of antioxidant defense system. A significant decrease of these indices, such as GSH, GST, GPx might indicate more severe contamination.     

Thermodynamics and kinetics of cadmium adsorption onto oxidized granular activated carbon

Cadmium sorption behavior of granular activated carbon oxidized with nitric acid was systematically studied by sets of the equilibrium and time-based experiments under various conditions.The cadmium adsorption capacity of oxidized granular activated carbon enlarged with an increase in pH,and reduced with an increase in ionic strength.Experimental data were evaluated to find out kinetic characteristics.Adsorption processes were found to follow pseudo-second order rate equation.Adsorption isotherms correlate well with the Langmuir isotherm model and the maximum sorption capacity of cadmium evaluated is 51.02μmol/g.Thermodynamic parameters were calculated based on Van't Hoff equation.Equilibrium constant Kd was evaluated from Freundlich isotherm model constants,Langmnir isotherm model constants,and isotherms,respectively.The average change of standard adsorption heatΔH~0 was -25.29 kJ/mol.NegativeΔH~0 andΔG~0 values indicate the adsorption process for cadmium onto the studied activated carbon is exothermic and spontaneous.The standard entropyΔS~0 was also negative,which suggests a decrease in the freedom of the system.     

Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

Anaerobic treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor(ATFBR) with a mesoporous granular activated carbon(GAC)as a support material.The experimental protocol was defined to examine the effect of the maximum organic loading rate(OLR),hydraulic retention time(HRT),the efficiency of the reactor and to report on its steady- state performance.The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/(m~3.d).The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m~3/(m~3·d) of the reactor. With the increase of OLR from 83.7 kg COD/(m~3.d),the COD removal efficiency decreased.Also an artificial neural network(ANN) model using multilayer perceptron(MLP)has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data,the experimental values obtained have been used.The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data.The mean square error(MSE)was found to be only 0.0146.     

液液萃取-气相色谱/串联质谱法测定水中五氯酚及其钠盐

采用液液萃取处理水样,用气相色谱-串联质谱法测定样品中五氯酚及其钠盐,通过优化测定条件,使方法在1.00μg/L～500μg/L范围内线性良好.检出限和定量限分别为1.00μg/L和5.00μg/L,空白水样五氯酚钠3个质量浓度水平的加标回收率为89.8％～98.4％,5次平行试验测定结果的RSD为5.5％～10.7％...     

环境-经济系统整合模型的构建研究

环境经济系统整合模型的研究将环境的、经济的、社会的因素整合在可持续发展框架中．模拟、分析经济系统与环境系统之闻的相互作用和反馈关系。本文在分析环境经济系统整合模型构建的背景、理论与方法的基础上．设计了环境经济系统整合模型开发的技术路线．提出了环境经济系统整合模型的主要内容。     

三峡库区坡耕地利用与水土保持种植制

三峡库区耕地资源十分有限,且坡耕地占有相当大的比重,陡坡地多,在不良的耕作方式下肥力低下,水土流失十分严重在分析三峡库区自然条件与坡耕地资源特点的基础上,讨论了坡耕地种植制度与土壤侵蚀的关系,提出通过合理搭配作物种类进行多熟制间套作,一年生农作物与多年生经饲作物间作及农作物与木本植物等高间作等手段来建立坡耕地水土保持种植制,从而达到减轻土 蚀之目的。     

上海隧桥工程海域生态系统健康的初步评价

随着上海经济的快速发展,一些大型海洋工程在上海海域纷纷兴建,造成了生境破碎化、生物多样性的破坏等一系列的生态损害。在分析海洋工程可能造成生态损害的同时,以上海长江口隧桥工程为例,选择2007年春季和秋季的2次生态调查数据进行研究。架桥阶段结束后,综合分析了春季与秋季的调查数据,发现各项指标均有偏向于不利的趋势。基于结构功能指标体系评价法,并利用层次分析法研究后得出上海长江口隧桥工程附近海域的综合健康指数分别为2043和2166。根据CHI≤3的情况下判断,该海域的生态健康状况属于不健康接近亚健康状态,表明河口生态系统自然属性发生明显改变,生物多样性及生态系统结构发生了一定程度的变化,主要生态服务功能出现退化或丧失。针对遭遇海洋工程破坏的生境,需要进行更多、更长时间的人工干预,并提出有效的生态保护和修复对策。     

湖泊型水源地管理研究——以苏州市太湖水源地为例

饮用水安全是最大的民生工程,也是自然资源管理研究的热点。基于实地调研、部门访谈和制度条文的梳理与分析,以苏州市太湖水源地为例研究湖泊型水源地管理体制。研究表明：我国水源地管理由国家、省、市、县的法律法规、规章和规范性文件构成相对完善的制度体系,具有水资源和水环境分割管理、流域管理和行政区管理交错的制度特征,初步具备了综合管理的架构;水源保护缺乏流域管治的思维,农村面源污染治理制度支撑不足;在管理手段上以命令控制型手段为主,经济激励与公众参与不足。建立水源地综合管理协调机制,完善经济激励手段,推进公众参与,实施水源地管理共同责任机制将有利于提高水源地管理效率     

人工园林大面积种植区土地利用/覆被变化对生态系统服务价值影响

近10a来由于经济利益的驱动,橡胶、茶园、咖啡和桉树等人工园林在云南省西南部西盟县大规模种植,使土地利用结构和布局发生了较大变化,影响了种植区的生态系统服务价值。以西盟县为研究对象,基于2000年、2005年和2010年的遥感影像解译的土地利用/覆被数据,参照"中国生态系统单位面积生态服务价值当量",修订了西盟县生态系统单位面积服务价值,结合敏感度分析,探讨了土地利用/覆被变化及其对生态系统服务价值的影响。结果表明:(1)2000~2010年西盟县的耕地、园地、水域和乡镇用地面积增加,林地和草地面积减少,西南部的土地利用/覆盖类型相互转化主要表现在林地和耕地转化为园地,而东北部表现在林地转化为耕地;(2)从时间上看,生态系统服务价值呈减少趋势,10 a间净减少106.29×106元,林地的生态系统服务价值始终最高;(3)研究期内,只有食物生产服务有价值量的增加,其余生态系统服务的价值量均为不同程度的减少;(4)从空间上看,西盟县生态系统服务价值东北部和东南部高,西部、中部和东部低。力所乡生态系统服务价值有小幅度增加,其余乡镇均呈减少趋势。西盟县以经济利益为目的的发展模式给生态系统服务和可持续发展带来巨大压力,在一定程度上使区域整体生态效应下降。因此,西盟县的发展应该在保证生态系统稳定的前提下,适当发展园地,同时优化土地利用结构,在生态效益和经济利益之间,找到双赢的平衡点。     

三峡消落带沉积物-大气界面汞交换通量及其影响因素

应用动力通量箱(Dynamic Flux Chamber,DFC)与高时间分辨率的RA-915+自动汞分析仪联用技术,在消落带沉积物出露期,野外现场监测沉积物-大气界面汞交换通量,同时对其影响因素进行了分析。结果表明:三峡库区消落带沉积物-大气界面汞交换通量范围为-6.80±12.35~28.17±36.17 ng/(m2·h)晴天库区消落带沉积物-大气界面汞交换通量表现出相同的变化趋势,即从早晨开始沉积物-大气界面汞的交换通量逐渐增加,到正午左右达到峰值,之后交换通量逐渐减小,但阴天这一趋势不明显。暖季白天沉积物-大气界面汞交换通量都以释放为主,冷季白天则以沉降为主。暖季晴天,沉积物-大气汞交换通量与气温、沉积物温度、光照强度呈显著正相关关系,与相对湿度呈显著负相关关系。无论晴天还是阴天,大气汞浓度都与沉积物-大气汞交换通量呈负相关关系。白天,光照强度和大气汞浓度是影响消落带沉积物/大气界面汞交换通量的主要因素,而在夜间,沉积物温度和大气汞浓度是其主要影响因素。