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The Distrbution of Various Mercury Species in Soil

According to the mercury species with different solubilities,the analytical procedure involving sequential chemical extraction has been applied to partitioning the mercury species in soils into seven fractions.Soil samples collected from five localities in different areas (the high-mercury ares.the man-made mercury-polluted area and the reference area)were an alyzed for the seven mercury species.It is found that high mercury contents of soils can be attributed to both man-made pollution and geological processes,but the two kinds of solis show obvious differences in the distribution of their mercury species.     

Mercury speciation and distribution in Aha Reservoir which was contaminated by coal mining activities in Guiyang, Guizhou, China

Two sampling campaigns were carried out in March and August 2005 representing dry and wet seasons, respectively, to investigate the distribution patterns of Hg species in the water column and sediment profiles at two sampling stations in Aha Reservoir located in Guiyang, Southwestern China. Aha Reservoir has been contaminated by Hg due to small scale coal mining activities. Mercury concentrations in both water and sediment were elevated. A clearly seasonal variation of dissolved Hg (DHg), particulate Hg (PHg) and total Hg (THg) concentrations in the water column was observed. The concentrations of these Hg species in the wet season were significantly higher than in the dry season. Runoff input and diffusion of Hg from sediments could be the reasons for elevated concentrations of these Hg species in the wet season. The contaminated sediment is acting as a secondary contamination source for both inorganic Hg (IHg) and methylmercury (MeHg) to the overlying water. The cycling of Mn in the sediment governs the diffusion process of IHg to the water column. In the dry season (winter and spring), Mn occurs as MnO₂ because the uppermost part of sediment is in an oxic condition and Hg ions are absorbed by MnO₂. In the wet season (summer and fall), the uppermost part of the sediment profile is in a reduced condition because of stratification of the water column and MnO₂ is reduced to Mn²⁺, which results in transformation of Hg²⁺ into porewater as Mn²⁺ became soluble. This causes a higher diffusive flux of IHg from sediment to overlying water in the wet season. Both sampling stations showed a consistent trend that THg concentrations decreased in the uppermost part of sediment cores. This demonstrated that the measures taken to reduce ADM contamination to Aha Reservoir also reduced Hg input to the reservoir. Methyl Hg diffusive fluxes from sediment to overlying water were higher in the wet season than the dry season demonstrating that high temperatures favor Hg methylation processes in sediment.     

2008—2022年上海大莲湖湿地营养盐时空分布特征、水质评价及来源解析

为了解大莲湖湿地区域水体营养盐的时空分布特征及污染来源,本文系统汇整了2008—2022年大莲湖湿地的水质数据,于2021—2022年丰水期和枯水期针对6种不同土地利用类型进行水样采集分析,也于2021年平水期进行各指标的24 h昼夜监测分析。年际研究结果表明,2008—2022年期间大莲湖湖区总氮(TN)浓度基本处于《地表水环境质量标准》(GB3838—2002)Ⅳ～Ⅴ类水质标准,在2009年枯水期达到最大值(2.97 mg/L);湖区氨氮浓度近年来满足Ⅲ类水质标准;总磷浓度在2021年的丰水期达到最大值0.79 mg/L,超过Ⅴ类水标准限值0.4 mg/L。湖区水质较生态修复之前有所好转,但营养盐浓度依旧处于较高水平。整体趋势与淀山湖的营养盐浓度基本一致,说明上游淀山湖入湖来水可能是造成大莲湖营养盐增高的原因之一。季节性研究结果显示,水体各类指标存在一定季节性差异,枯水期略劣于丰水期。不排除入湖河流带来的污染对大莲湖湿地区域产生影响,丰枯水期鱼塘和荷花塘水体营养盐和有机物质超标现象突出,尤其是鱼塘点位TN浓度是Ⅴ类水标准限值2.0 mg/L的2～4倍。24 h昼夜监测结果发现,大部...     

秦巴山区重晶石与毒重石矿床成矿特征研究

秦巴山区按地质成矿特征可划分大巴山、平利、南秦岭三个区。重晶石与毒重石矿床分三条成矿带 :南带为毒重石矿带、北带与中带为重晶石矿带 ,成矿具有多期作用 ,含火山喷发、大陆边缘沉积、裂谷与脉体成矿叠加。本区找矿前景是乐观的。     

近百年北半球陆面降水资料的插补及初步分析

采用ＥＯＦｓ展开方法插补延长了一个北半球陆面月降水资料,并讨论了该资料插补工作的合理性。利用该资料初步分析了近百年北半球陆面降水的基本特点。     

华东沿海ASCAT反演风速的检验和订正

基于2010—2014年ASCAT反演风速、华东沿海14个浮标站和浙江沿海249个自动气象站资料,对华东沿海ASCAT反演风速进行检验和订正。研究表明:站点ASCAT风速误差不仅与离岸距离相关,而且与站点周围地形有关,误差较大的5个浮标站均位于舟山群岛附近海区,平均偏大4.79 m·s-1,其他海区浮标站的ASCAT反演风速平均偏差仅为0.46 m·s-1。ASCAT反演风速与浮标站风速的线性回归可有效减小反演风速误差,订正后误差大幅减小,误差越大的站点订正效果越好。相距160 km内的浮标站点间风速误差呈正相关,且站点间距越小,误差正相关越明显。考虑带影响半径的反距离权重,采用邻站方程订正法和邻站误差订正法分别对华东沿海ASCAT反演风速进行订正,均能明显减小平均偏差和均方根误差,两种方法订正效果接近,即两种方法均有较好的订正效果,可用于实际业务。     

我国东北地区冬季气温变化的东亚冬季风背景

利用中国气象局国家气象信息中心1961—2011年我国东北地区72个气象站月平均气温资料及NCEP/NCAR月平均海平面气压、500 hPa高度场及200 hPa与850 hPa风场再分析资料,对东亚冬季风强度与我国东北地区冬季气温序列经去除线性趋势处理后的变化特征进行对比分析。结果表明:去除线性趋势后,东亚冬季风强度与我国东北地区冬季气温序列的相关系数为-0.69,较原始序列更为显著;两者变化的阶段性较为同步,我国东北地区冬季气温于2004年已转入低温阶段,这与东亚冬季风同时转为偏强阶段关系密切;两者均存在20年左右的长周期,同样存在相近的阶段性短周期;我国东北地区冬季气温的增温变化趋势在1986年前后的增暖性气候突变中起重要作用。东亚冬季风强度与我国东北地区冬季气温年代际信号的相关系数达-0.86,较原始序列年代际相关更为显著;两者的年代际变化存在21.5年左右的共同准周期。东亚冬季风强度与我国东北地区冬季气温的年际变化序列存在4年左右的共同准周期。我国东北地区冬季气温的年际和年代际异常存在与东亚冬季风相关联的200 hPa东亚急流、500 hPa东亚大槽、乌拉尔高压、850 hPa风场、地面西伯利亚高压等的异常背景。     

秦岭地区煌斑岩特征及其与金矿成矿关系

秦岭地区广泛分布有煌斑岩,其主要赋存于古生界志留系与濯舅系的粉砂质板岩中,大部分含金较高。经不同成矿区煌斑岩与金矿关系的对比研究,认为其具有相似性,并与金成矿关系密切。对煌斑岩出露区的找矿标志以及本区的找矿方向作了分析。     

滨海地区基于避咸蓄淡模式的供水安全临界流量研究——以粤港澳大湾区珠澳供水为例

枯水期咸潮入侵已经严重威胁到了感潮河流区域供水安全.本文通过构建避咸蓄淡供水模型,耦合了咸度预测、河库联合供水调度和供水安全分析模块,为依赖感潮河流为水源地的区域供水安全管理提供了一种整体思路和决策方法.以面向粤港澳大湾区珠海东部及澳门的珠江三角洲磨刀门水道取供水为例,基于潮汐、径流和风等因子及咸度实测数据,较好地拟合了基于BP神经网络的咸度预测模型,及含氯度与超标时间的曲线函数,建立了上游来水和咸度超标时间之间的联系,得到了避咸蓄淡取水时机.咸度预测与当地河库联合供水调度相结合,得到了上游枯水期来水过程的当地区域供需平衡状况.枯水期不考虑水库调蓄的资源性缺水临界需水量为3.22亿m³,水库参与调蓄的工程性缺水临界需水量为3.75亿m³.通过供水安全分析模块,基于设定的风险阈值和临界阈值识别出了不同需水规模的上游来水临界流量特征.对于当地规划的需水规模4.23亿m³,期望上游枯水期临界流量均值约为3372 m³/s.整体上来说,需水规模越大,对上游来水期望的临界流量越大,但同时还与枯水期流量分布有关.