Spatial variations of aluminum species in drinking water supplies in Xi’an studied applying geographic information system

This article aimed to investigate the variation of aluminum species and the effects of coagulant type and water quality on aluminum speciation in drinking water.Statistical analysis showed that the concentration of total aluminum(AlT) of drinking water in Xi'an ranged from 0.051 to 0.417 mg/L and the concentration of AlT in about 24.7% studied samples was higher than the currently recommended value(0.2 mg/L).The areas fed by surface water plants had a larger portion(39.4%) of samples over the recommended value.In drinking water treated by alum coagulant,the average concentration of monomeric aluminum(Ala) was higher than that in water treated by poly aluminum chlorine(PACl) and poly aluminum ferric chloride(PAFC).The average concentrations of polynuclear aluminum(Alb) and colloidal/suspended aluminum(Alc) in the drinking water treated by alum were lower than those in water treated by PACl and PAFC.There was a notable decrease in AlT along with the delivery pipeline away from the plants,with an average decline of about 36 μg/(L·km).Besides coagulant type,water quality also could afflect aluminum speciation.In drinking water without orthophosphate,the concentrations of Ala and AlT were positively correlated with pH;while,in drinking water with orthophosphate,the concentrations of Ala and AlT were negatively correlated with pH.The addition of orthophosphate salts in the drinking water treatment process would be an effective method for aluminum control in pH range 6.5-8.2.     

濒危物种的保护

截止到2009年底,我国共建立大熊猫自然保护区62处,总面积近320万公顷,使70％的野生大熊猫个体得到有效保护,野生大熊猫种群数量发展到近1600只,野生大熊猫濒危状况得到有效缓解。而白鳍豚同样作为我国的独有物种,1980年代初有400多头,1990年调查时有200来头,至1995年不足100头,进入2000年的时候,据估计白鳍豚大概仅剩二三十头,被列为世界级的濒危动物,而目前的濒危等级为功能性灭绝。     

防治海水入侵的地下水人工调蓄研究——以辽宁六股河地段为例

随着城市的发展,大量抽取地下水,海水入侵灾害已成为制约沿海地区社会经济可持续发展的突出因素.论文以六股河地段为例,针对海水入侵灾害现状,建立了地下水流数值模拟模型,探讨通过地下水人工调蓄来防治海水入侵灾害的途径.     

云南省环境监测中心站网络安全对策及应用

根据近年国内网络领域的新技术,结合本单位网络建设的需求及工作经验,从防火墙、入侵检测、防病毒、漏洞扫描、访问控制等几个方面作了阐述,对如何建设一个安全的网络提出了自己的见解。     

入侵植物互花米草水浸液对莴苣的化感效应

选用互花米草根、茎、叶5个浓度梯度(0.065、0.130、0.195、0.260、0.325 g·mL-1)的水浸液为处理液,研究其对莴苣种子萌发及幼苗生长的影响.结果表明:互花米草根水浸液在浓度大于0.260 g·mL-1时会显著抑制莴苣种子的萌发,而茎、叶水浸液产生显著抑制作用的起始浓度分别为0.130 g·mL-1和0.195 g·mL-1;互花米草根、茎、叶水浸液对莴苣种子萌发的抑制,不仅表现为降低种子的最终萌发率,还表现为延长种子的平均萌发周期;茎、叶水授液对幼苗生长的影响比较显著.而根水浸液浓度低于0.195g·mL-1时对幼苗胚轴的生长产生促进作用(敏感指数RI>0).不同构件水浸液化感效应强度由大到小依次为:茎>叶>根.并且化感效应强度随水浸液浓度的增加而增强.     

互花米草对持续淹水胁迫的生理响应

对互花米草进行了40cm水深的持续淹水胁迫,研究了其生理指标的响应.结果显示,淹水胁迫下,互花米草叶片中可溶性糖含量和叶绿索含量在初期均显著低于对照,随后逐渐积累并高于对照.丙二醛含量在初期显著高于对照,随后与对照组的差异逐渐减小,至生长季末与对照水平相当.过氧化物酶活性在淹水后63d内均高于对照,至生长季末则低于对照,而超氧化物歧化酶活性则始终高于对照.至生长季末,持续淹水胁迫条件下的互花米草生物量低于对照,其形态学上表现为植株矮小、根系变短、节长变短、地下部分所占生物量比重降低.研究结果表明,持续淹水胁迫对互花米草的生理指标产生影响,但互花米草可以通过生理和形态学的响应来适应这种胁迫,因此,必须进一步结合其它物理控制措施进行综合治理.     

水溶液中嗪草酮的光化学行为研究

以氙灯为光源模拟太阳光,研究了农药嗪草酮(MT)在水溶液中的光降解;探讨了pH值以及天然水体中广泛存在的光敏荆腐殖酸、硝酸根和Fe3+等对嗪草酮间接光解的影响;测量了嗪草酮量子产率及其与活性氧类物种(ROS)·OH和1O2的反应速率常数.结果表明,在pH值3.5-9.5范围内,嗪草酮直接光降解速率随pH值升高而降低.pH=7时,腐殖酸具有光屏蔽作用而抑制嗪草酮光降解,硝酸根和Fe3+对嗪草酮间接光降解基本没有作用.嗪草酮与1O2反应速率常数为0 mol-1·L·s-1,与·OH反应速率常数为5.7×109mol-1Ls-1.在天然水体中嗪草酮与·OH反应最小半衰期为68 h,远远大于北纬40.(40°N)下直接光解半衰期.以上研究结果表明,嗪草酮直接光解占主导作用,其量子产率为0.01.预测在40°N春、夏、秋、冬时嗪草酮直接光解半衰期分别为1.44、1.08、2.58和5.10h,室外太阳光照实验结果显示,在40°N秋季嗪草酮的半衰期为2.98 h,与理论预测值接近.     

应用物种敏感性分布评估DDT和林丹对淡水生物的生态风险

介绍了利用物种敏感性分布（SSD）进行生态风险评价的原理与步骤,构建了淡水生物对DDT和林丹的物种敏感性分布.在此基础上,计算了DDT和林丹对不同类别生物的HC5(Hazardous Concentration for 5% the species)阈值,预测了不同浓度DDT和林丹对生物可能造成的危害,并比较了不同类别生物对DDT和林丹的敏感性,以及DDT和林丹对淡水生物的生态风险.结果表明,DDT和林丹对淡水生物的HC5值分别为1.70μg·L-1和5.96μg·L-1 ,DDT对生态系统的危害大于林丹.当DDT或林丹的浓度为5μg·L-1时,对生态系统仅有轻微影响,而当DDT或林丹的浓度为500μg·L-1时,将有81.5%的物种受到DDT的危害,或有68.1%的物种受到林丹的危害.不同类别生物对DDT的敏感性从甲壳类、昆虫和蜘蛛类到鱼类依次降低,对林丹的敏感性大小依次为昆虫和蜘蛛类、甲壳类、鱼类.与林丹相比,DDT对淡水脊椎动物与无脊椎动物以及甲壳类和鱼类的生态风险较大,而对昆虫和蜘蛛类,林丹与DDT的生态风险差别不大.     

Methane dehydroaromatization over Mo-modified H-MFI for gas to liquid catalysts

For direct gas to liquid (GTL),a novel process producing energy sources for methane dehydroaromatization is needed.Supporting MoO3 on H-MFI zeolite shows the high catalytic capacity and a selective activity for dehydroaromatization of methane to benzene at 973 K in a fixed bed reactor.On the other hand,deactivation by coke on the active sites in all the catalysts is formed during the reaction.H2 co-feed suppressed the deactivation,which is probably due to the decrease in coking amount.Mo K-edge X-ray absorption fine structure (XAFS) results showed the formation of dispersed Mo2C species with low crystallinity after dehydroaromatization.Mo L-edge XANES (X-ray absorption near-edge structure) indicated the formation of active Mo species including Mo2C and Mo-oxycarbide (MoOxCy),where the red-ox state should be independent in the absence/presence of H2.It is concluded that Mo-oxycarbide species act as highly active species,and their stability affected the durable activity in the presence of H2.     

辽宁省主要自然保护区外来入侵植物的调查分析

通过野外实地调查,对辽宁省的4个国家级自然保护区外来入侵植物的种类数量和分布现状进行了调查分析。结果表明,老铁山、鸭绿江口、医巫闾山、九龙川4个自然保护区内的外来入侵植物分别为27,10,7和6种,总计16科36种。依据保护区内外来入侵植物的特点和生态影响,提出了一些有效的管理措施和防治建议。