Speciation,bioaccumulation and transportation of mercury in sediments of mangrove wetlands of China

为了认识红树林表层沉积物中Hg的生物地球化学行为,采用改进的TESSIEr连续浸取法,对我国主要红树林沉积物中Hg的形态特征进行了研究,并讨论了Hg的生物可利用性和迁移性。结果表明:(1)我国红树林沉积物中的Hg绝大部分以易挥发态为主,具有较高的生物可利用性,易挥发态Hg向大气Hg的转化是红树林湿地中汞迁移的主要方式。只有深圳红树林沉积物中的Hg以残渣态为主,次为可交换离子态和碳酸盐结合态,沉积物中Hg主要通过不可溶的固体颗粒物形式迁移,其生物可利用性较低。(2)总Hg与易挥发态Hg呈极显著正相关(r=0.967,P<0.01),碳酸盐结合态Hg与铁锰氧化物结合态Hg之间存在极显著正相关(r=0.871,P<0.01),有机结合态Hg分别与碳酸盐结合态Hg、铁锰氧化物结合态Hg存在极显著相关(r1=0.618,P1<0.01;r2=0.686,P2<0.01);有机质与总Hg存在显著正相关(r=0.526,P<0.05)。In order to understanding biogeochemical behavior,speciation of mercury in the mangrove sediments from 9 main mangrove wetlands of China were determined with modified Tiesser's method.It shown:(1) Two situations were found.One is that mercury exists mainly in volatile form in most mangrove wetlands.That volatile mercury turns into atmospheric mercury is the main transport form for most mangrove wetlands.The mangrove wetlands are the source of global mercury pollution.The mercury in sediments of mangrove wetlands can be bio-accumulated easily.Another situation is that mercury exists mainly in the form of residue which is hard to bio-accumulate,typically in Shenzhen mangrove wetlands.The mercury transports in the form of insoluble particle.(2) Significant positive correlation was found between volatile Hg and total Hg(r=0.967,p<0.01).Carbonate-bound Hg is strongly correlated with Fe-Mn oxide-bound Hg(r=0.871,p<0.01),and organic matter is significantly correlated with total Hg(r=0.526,p<0.05).Organic-bound Hg is significant correlated with carbonates-bound Hg and Fe-Mn oxide bound mercury(r1=0.618,p1<0.01;r2=0.686,p2<0.01).国家自然科学基金项目(40676064;30530150);东华理工大学核资源与环境教育部重点实验室开放基金(070717

Y型聚乙二醇干扰素琢-2b注射液治疗HCV基因2/3型慢性丙型肝炎患者疗效和安全性的多中心随机对照试验研究

目的以标准剂量的聚乙二醇干扰素(Peg IFN)α-2a联合利巴韦林作为阳性对照,评价新型试验药物Y型Peg IFNα-2b注射液联合利巴韦林治疗2型/3型慢性丙型肝炎(CHC)患者的疗效和安全性。方法采用多中心、随机开放、阳性药对照的Ⅲ期临床试验,筛选符合要求的2型/3型CHC患者,按照2:1的比例随机分配到Y型Peg IFNα-2b组和Peg IFNα-2a组,同时口服利巴韦林,疗程24 w,停药随访24 w。采用Abbott Real Time HCV Genotype II检测HCV基因型,采用Cobas Taq Man实时定量PCR法检测血清HCV RNA水平。详细记录不良事件。主要疗效指标为持续病毒学应答(SVR),并进行非劣效检验。结果本试验实际入组2型/3型CHC患者255例,实际治疗241例。全分析集(FAS)数据显示,158例试验组和83例对照组患者SVR分别为85.4%(95%CI 79.94%~90.94%)和79.5%(95%CI 70.84%~88.20%,P=0.2402);对符合方案分析集(PPS)人群分析显示,试验组和对照组患者SVR分别为87.9%(95%CI 82.45%~93.27%)和85.9%(95%CI 77.82%~94.01%,P=0.7060),率差的95%可置信区间均符合非劣效标准;对PPS人群分析显示,85.8%受试者获得了早期病毒学应答(RVR),RVR的阳性预测值为90.1%;试验组和对照组不良事件发生率相似,分别为95.6%和95.2%,严重不良事件发生率分别为3.8%和3.6%。结论应用Peg IFNα联合利巴韦林治疗2型/3型CHC患者,新型试验药物Y型Peg IFNα-2b具有与对照药物Peg IFNα-2a相似的疗效和安全性。国家科技部“十二五”重大专项(编号:2012ZX10002-003)；“重大新药创制”十二五科技重大专项(编号:2012ZX09303019)

Impact of Different Land Use Modes on Nutrients of Sediments from Mangrove Wetlands of China

以广西、广东、海南等地代表性红树林湿地为对象,研究红树林湿地利用方式的改变对沉积物有机碳、总硫、总氮和总磷等营养元素的含量变化和影响,结果表明:1)广东和海南红树林区总氮和总磷变化相似,均为:沉积物>农田>鱼塘>光滩,广西大冠沙稍有不同,光滩的氮磷含量最低;有机碳和总硫含量各地稍有差异,但是红树林沉积物中的有机碳,总硫含量普遍高于当地光滩、鱼塘和农田土壤,并且以光滩的土壤营养元素含量最低。2)根据广东、广西、海南主要红树林区推算全国红树林区土地利用方式的改变后土壤有机碳、总硫、总氮、总磷的损失量分别为3.05x1012 g、2.68x1011 g、2.94x1012 g和0.377x1011 g。说明土地利用与土地覆被的变化加剧了土壤有机碳、硫、氮磷的流失,导致原红树林区土壤逐渐贫瘠。This study aims at evaluating impacts of mangrove wetland-use on the levels of organic carbon,total surfer,total nitrogen and total phosphorus in sediments from major mangrove wetland ecosystems in Guangxi Autonomous Region,Guangdong and Hainan Island,China.Our results show that: 1) both Guangdong and Hainan displayed the same pattern for total nitrogen and total phosphorus,decreasing in the order of sediment> farmland> pond> mudflat;within a slightly different order,the lowest levels for total nitrogen and total phosphorus were also observed in the mudflat of Guangxi Daguansha mangrove wetland.As to the concentrations of organic carbon and total surfer,although a slight difference was detected,all the three districts exhibited greater values in mangrove sediments,with the levels of mudflat being the lowest;2) based on loss amounts from Guangdong,Guangxi and Hainan,we further calculated the nationwide loss amounts of organic carbon,total sulfur,nitrogen and phosphorus(3.05×1012 g,2.68×1011 g,2.94×1012 g and 0.377×1011 g,respectively) and it can be concluded that changes in land use mode escalated the loss of organic carbon,surfer,nitrogen and phosphorus in soils,thus leading to gradual soil erosion in mangrove wetlands.国家自然科学基金项目(41176090;40676064);海洋公益性行业科研专项经费项目(200805063-3);东华理工大学核资源与环境教育部重点实验室(101102)联合资

cuoznoceo2zro2催化剂上甲醇水蒸气重整制氢反应机理研究

利用原位傅里叶变换红外光谱技术对CuO/ZnO/CeO_2/ZrO_2催化剂上的甲醇水蒸气重整制氢反应机理进行了研究。结果表明:甲醇水蒸气重整制氢反应主要由甲醇脱氢解离、甲酸甲酯转化和逆水气变换三个过程组成。副产物CO主要是由CO_2和H2经逆水气变换反应而生成的,这是造成甲醇水蒸气重整后的CO含量总是低于热力学平衡浓度的原因

cuoznoceo2zro2催化剂上甲醇水蒸气重整制氢反应机理研究

利用原位傅里叶变换红外光谱技术对CuO/ZnO/CeO_2/ZrO_2催化剂上的甲醇水蒸气重整制氢反应机理进行了研究。结果表明:甲醇水蒸气重整制氢反应主要由甲醇脱氢解离、甲酸甲酯转化和逆水气变换三个过程组成。副产物CO主要是由CO_2和H2经逆水气变换反应而生成的,这是造成甲醇水蒸气重整后的CO含量总是低于热力学平衡浓度的原因

绿洲农田土壤粒径分布特征及其影响因素分析——以策勒绿洲为例/Characterizing Soil Particle-size Distribution and Its Variation in Farmland of Oasis——A Case Study of Cele Oasis[J]

以塔里木盆地南缘策勒绿洲为例,重点探讨了绿洲农田土壤粒径分布特征及其主要影响因素。基于2008年9月对策勒绿洲范围内农田表层土壤粒度测定数据,首先通过土壤粒径分布体积分形维数分析,表明绿洲农田土壤粒径分布差异性显著,并根据分析结果提出假设,认为农田利用年限及空间位置的不同是土壤粒径分布产生差异性的主要因素;其次利用排序方法对影响因素的贡献率进行定量分析,并与分维值结果进行相互验证。研究结果表明在影响土壤粒径分布差异性方面,利用年限为主导因素,其相对贡献率达67％。因此,保证农田长期合理的耕作管理方式将有助于土壤粒径分布属性的稳定及改善