Distribution and Controlling Factors of Dissolved Gaseous Mercury and Reactive Mercury in Seawater Near Yangtze River Estuary

Complex hydrocultural conditions in the estuary affect the migration and transformation of mercury.Using two voyages in July and October 2018,Dissolved Gaseous Mercury(DGM)and Reactive Mercury(RHg)were determined to explore the source,transformation and influence of DGM content in the adjacent waters of Yangtze River Estuary in summer and autumn.The results showed the contents of DGM and RHg in summer were higher than those in autumn,and both of them were higher than those in open sea.In summer and autumn,the Yangtze River brought a higher concentration of DGM,and different flow direction and runoff resulted in differences in the high value region of the surface.The emergence of low-oxygen zones in summer was conducive to the production of DGM.In autumn,windy weather allowed seawater disturbances to promote the release of mercury from the underlying sediments,especially in shallow sea in northwest.RHg showed a higher concentration in the offshore than in the open sea in summer,but there was no such trend in autumn,reflecting the influence of less runoff input.DGM is the main product of RHg reduction,and there was a significant positive correlation between DGM and RHg in summer(r=0.356,P<0.05),while the correlation between DGM and RHg was not significant in autumn due to the influence of light intensity,wind speed and nutrients.The exchange flux of mercury in the adjacent waters of the Yangtze River Estuary was higher than that in the open sea.There was no significant difference of the release flux of mercury in summer and autumn.This article highlighted that the input of mercury from the Yangtze River runoff promotes the release of mercury in seawater,and the hypoxic zone caused by eutrophication is conducive to the production of DGM.

Effect of dissolved organic matter on adsorption and desorption of mercury by soils

Effects of dissolved organic matter (DOM) on adsorption and desorption of Hg were investigated in two kinds of soils, Xanthi-Udic Ferralosols (XUF) and Typic Purpli-Udic Cambosols (TPUC). The DOM was obtained from humus soil (DOMH), rice straw (DOMR), and pig manure (DOMP). The presence of DOM obviously reduced Hg maximum adsorption capacity with up to 40% decreases over the control, being an order of DOMH (250.00 mg/kg)< DOMR (303.03 mg/kg) < DOMP (322.58 mg/kg) < CK (control 416.67 mg/kg) for the...

Spatial Differences and Influencing Factors of Dissolved Gaseous Mercury in the Yellow Sea and Bohai Sea in Spring

From 28 March to 17 April, 2018, different forms of mercury(Hg) in the Yellow Sea and Bohai Sea were measured to study the influencing factors on the distribution and transformation of Hg in spring using a shared cruise. The mean concentration of dissolved gaseous mercury(DGM) in the surface water of the Yellow and Bohai Seas was(44.3 ± 43.9) pg/L, which was close to that in mid-latitude oceans and deep seas. The ratio of DGM to THg(total mercury) was lower than in the oceans and in the Yellow and Bohai Seas in summer or fall. DGM concentrations in surface water were highest in the central part of the South Yellow Sea and were higher than those in the Bohai Sea, and their spatial distributions were consistent with RHg(reactive mercury). DGM and RHg correlated positively with water temperature in surface seawater(r = 0.506, P < 0.01;r = 0.278, P < 0.05). The concentrations of both DGM and RHg in surface water were controlled by solar radiation and water temperature. Foggy weather did not benefit the production of DGM and RHg. DGM in the bottom seawater was mainly affected by Dissolved Oxygen and water temperature(r =-0.366, P < 0.01;r = 0.331, P < 0.01), produced mainly by anaerobic reactions of the bottom seawater and sediment microorganisms. The bottom DGM concentrations in the Yellow and Bohai Seas were the highest, and DGM produced in bottom seawater and sediment plays a more important role than the surface water in spring. The concentrations of DGM and RHg in the surface and bottom water in the South Yellow Sea were all higher than those in the middle layer. Vertical variations in the North Yellow Sea and the Bohai Sea were small. The production and distribution of DGM and RHg were influenced by differences of latitude and by the Yellow Sea warm current in spring.

Ultraviolet absorbance titration for the determination of conditional stability constants of Hg(Ⅱ) and dissolved organic matter

Strong interaction between natural dissolved organic matter (DOM) and Hg(Ⅱ) may influence the trans- port, conversion, toxicity and bio-validity of mercury in the environment. In this paper ultraviolet (UV) absorbance titration was employed for the first time for the determination of the conditional stability constants of Hg(Ⅱ) and (DOM). With increasing Hg(Ⅱ) concentrations, the UV absorbance of fulvic acid, humic acid, and DOM in river increases progressively. By linear and non-linear model fitting, the conditional stability constants (lgK) of Hg(Ⅱ) and DOM were worked out to be 3.54?4.93 and 3.64?4.85, respectively. The results are consistent with those acquired by the typical fluorescence quenching titration method, with the maximum relative error of lgK being 2.6% and the average relative error being 0.2%. The UV absorbance titration method has the advantages of rapid determination, simple performance, and it will probably become a new approach to studying interactions between DOM and trace metallic ions.

渔业养殖区藻源溶解性有机质性质特征对汞甲基化影响

溶解性有机质(dissolved organic matter,DOM)是水生生态系统中的重要成分,能够显著影响汞的甲基化等形态变化过程.以近岸渔业养殖区藻源DOM为研究对象,运用傅里叶变换红外光谱和三维荧光光谱技术,对其结构特征进行表征;并选取总有机碳浓度TOC_(DOM)=10 mg·L^(-1)(DOM_(10))和TOC_(DOM)=50 mg·L^(-1)(DOM_(50))两种水平藻源DOM提取液,分析其在不同汞浓度条件下对汞甲基化过程的影响.结果表明,藻源DOM主要由类蛋白和类腐殖质组分组成,其中前者含量较高,疏水及芳香组分含量较低;红外光谱显示藻源DOM中含有—OH、—CH3、—CH2、芳香性C=C等官能团.甲基化实验表明,在溶液中DOM含量相对较少时(DOM:Hg浓度比≤15625),DOM表现出抑制汞甲基化的趋势,而当溶液中DOM含量逐渐升高(DOM:Hg浓度比>15625),DOM可以显著促进水体中汞向甲基汞的转化.藻源DOM既能作为碳氮来源提高微生物活性,为汞的甲基化提供甲基供体,又可以与溶液中Hg^(2+)发生络合,从而影响汞甲基化过程.在汞溶液浓度相对较低时,DOM对汞甲基化过程的影响主要表现为提供大量的甲基供体,同时作为微生物利用的底物,促进无机汞向甲基汞的转化,甲基汞转化率最高可达0.257%;但在高汞浓度条件下,DOM对汞的络合作用降低了无机汞的微生物可利用性,水体中甲基汞下降,表现出抑制作用.

稻田满江红溶解性有机质光谱特征及其对汞甲基化影响

满江红作为稻田重要的有机质输入来源,研究其溶解性有机质(DOM)对稻田土壤中汞形态及转化机理具有重要意义.以稻田满江红DOM为研究对象,运用紫外吸收光谱(UV-Vis)和三维荧光光谱(3D-EEM)技术对不同腐解时间满江红DOM进行表征;此外,通过树脂串联技术分离得到疏水酸性物(HOA)、疏水碱性物(HOB)、疏水中性物(HON)、亲水酸性物(HIA)、亲水碱性物(HIB)、亲水中性物(HIN)等6种DOM亚组分,将不同腐解时间提取的满江红DOM及其亚组分与Hg^(2+)溶液混合培养,分析其对汞甲基化过程的影响,以期为提高汞污染农田生产安全性提供理论依据.结果表明,腐解初始时满江红DOM的芳香性最大,随腐解进行呈骤降缓升趋势.腐解中期小分子量DOM较多.类蛋白质组分始终占据主导地位,腐解后期含量缓慢减少,类腐殖质组分含量则呈现先低后高的趋势.甲基化实验表明,不同腐解时间满江红DOM对汞的甲基化反应均具有促进作用,当DOM芳香性较高,分子量较小时,其促进汞甲基化能力增强,腐解初始时DOM促进汞甲基化作用最强,随腐解时间呈现先降低后升高逐渐平稳的趋势.疏水性组分对汞甲基化促进作用显著高于亲水性组分,其中HOB促汞甲基化能力最强.腐解后期HIA、HIN对汞甲基化无促进作用.

红枫湖水体中活性汞和溶解气态汞的分布特征及其控制因素

基于二次金汞齐结合冷原子荧光测定法对红枫湖活性汞（RHg）和溶解气态汞（DGM）的时空分布特征及其控制因素进行了研究.红枫湖溶解气态汞含量（ρ（DGM））为0.024-0.110 ng/L,随着水深的增加ρ（DGM）降低,且夏季高,冬季低,这种分布特征表明光在原子态汞的形成中起着重要的作用.红枫湖ρ（DGM）除受光强影响外,还受到春季后五大量生长的藻类影响,但与溶解性有机碳含量（ρ（DOC））及温度的相关性不大.活性汞含量（ρ（RHg））为0.14-2.70 ng/L,其主要受Hg^2＋的光致还原过程,Hg^2＋的甲基化过程以及人为源的释放等因素的控制.

季节性缺氧水库甲基汞的产生及其对下游水体的影响

本文采用蒸馏-乙基化结合GC-CVAFS法对贵州红枫湖水库及其各入库和出库河流中的甲基汞时空分布和控制因素进行了研究.在春、秋、冬季节总甲基汞浓度和分布无明显时空变化,在0．053-0．333 ng／L之间.春季河流是水库甲基汞一个重要的输入源．夏季水库下层甲基汞显著升高,缺氧层最高值达0．923 ng／L.同时发现．缺氧层升高的甲基汞主要来自于水体自己产生或上层水体甲基汞的沉降,而不是来自于沉积物的释放．各季节湖水和河流样品的总甲基汞和溶解氧存在显著的负相关关系,Personal相关系数r为-0．81(n=78).在春、秋、冬季节溶解态甲基汞比例略低于颗粒态甲基汞,但在夏季,特别是缺氧层,甲基汞主要以溶解态存在．夏季河流入水经水库蓄水后,到再流出时已经富含甲基汞,出库河流中总甲基汞浓度已达到各入湖河流总甲基汞平均值的5.5倍,很明显在复季红枫湖已成为下游水体甲基汞的输入源,必将会对下游生态系统产生一定影响．

三峡水库蓄水至135m后坝前及香溪河水域溶解无机汞分布特征研究

根据2004年8月在长江三峡水库坝前及香溪河水域对溶解无机汞浓度观测结果,分析了三峡水库蓄水至135 m（135-139 m）1 a后溶解无机汞的变化,初步探讨了影响溶解无机汞变化的因素,估算了蓄水对河流输送汞的影响.结果表明,三峡库区干流河段平均浓度为22.7 ng·L^-1,范围为未检出至82.6 ng·L^-1.较高浓度区主要集中在20 m以浅的水体;香溪河溶解无机汞浓度与干流基本相当,平均浓度为18.0 ng·L^-1,浓度范围为未检出至61.4 ng·L^-1.蓄水后,溶解无机汞浓度显著升高,数量可观的汞将随着泥沙的沉降而滞留库区,值得关注和进一步深入研究.

三维荧光光谱研究垃圾渗滤液水溶性有机物与汞相互作用

为了研究垃圾填埋过程中渗滤液水溶性有机物(DOM)对重金属配位能力的影响,采用三维荧光光谱、共振瑞利散射、荧光猝灭滴定技术及非线性回归拟合分析,研究了不同填埋年限渗滤液DOM与Hg(Ⅱ)的相互作用过程。结果表明:Hg(Ⅱ)与DOM中不同荧光基团配位比接近1∶1,配位过程中没有生成沉淀;不同填埋年限渗滤液DOM中类蛋白物质和类富里酸物质与Hg(Ⅱ)配位的条件稳定常数分别为4.30～5.70和4.35～4.98;参与配位的荧光基团分别为54.1%～92.3%和35.8%～60.1%。随着填埋年限的增加,类富里酸物质对Hg(Ⅱ)的配位能力降低,但参与配位的荧光基团的比例增加。渗滤液DOM-Hg(Ⅱ)配位过程受介质pH值的影响,在酸性和碱性范围内尤为明显。

溶解性有机质对土壤中汞吸附迁移及生物有效性影响的研究进展

汞是一种全球性的污染物,在环境中具有不可降解和生物累积的特性,可通过食物链进入人体,对人体健康产生危害。而溶解性有机质(DOM)作为陆地生态系统和水生生态系统中一种很活跃的重要化学组分,是环境中重要的天然有机配体和迁移载体。因此,DOM作为重金属的有机配体,是控制陆地和水环境中汞浓度的主要影响因素之一。综述了DOM对土壤中汞的吸附迁移、甲基化及生物毒性影响的研究成果,并阐述了DOM影响汞吸附迁移的作用机制。

乌江流域水库水体中溶解性气态汞季节变化特征

选取乌江流域上两个典型的水库(乌江渡水库和东风水库)作为研究对象,对不同季节水库水体中溶解性气态汞进行研究。结果显示:两个水库溶解性气态汞均明显表现为上层水体﹥下层水体,夏季﹥春季、冬季。水库中溶解性气态汞的含量受太阳辐射和水体中溶解性有机碳两个因素共同控制。

桑沟湾溶解态汞的生物地球化学行为

作为一种毒性极强的重金属元素,汞在海洋中可以通过海洋生物的呼吸、摄食和吸附等过程被利用,并在沿食物链传递的过程中不断富集,最终危害人类的健康.利用冷原子荧光光度法（CV-AFS）对2011年4月、8月、10月和2012年1月桑沟湾溶解态无机汞（DIHg）和溶解态有机汞（DOHg）的含量进行了测定.结果表明,桑沟湾四个季节DIHg的浓度范围分别为52～865、131～359、31～134和22～119 pmol·L^-1,DOHg的浓度范围分别为37～214、52～635、21～98和未检出～51 pmol·L^-1.桑沟湾DIHg和DOHg具有相似的分布特征,均呈现出从近岸向外海逐渐降低的趋势,有明显的季节变化.桑沟湾DIHg和DOHg的周日变化与潮汐呈现出较好的负相关关系,且存在明显的昼夜差异.影响桑沟湾DIHg和DOHg分布的主要因素包括河流和地下水的输入、大气的干湿沉降、与黄海的交换、活性气态汞（Hg0）在海-气界面的交换、表层水体发生的光化学还原反应以及养殖生物的清除等.通过初步计算,桑沟湾溶解态汞（TDHg）的存留时间约为（127±0.53）年,远远低于大洋.根据美国国家环境保护局汞的质量标准和我国地表水环境质量标准,桑沟湾没有明显的汞污染.但海产品体内富集的汞可能会带来潜在的生态危机和食品安全问题,需要相关部门加以重视,确保桑沟湾养殖产业的平衡发展.

鄂尔多斯盆地东北部上古生界太原组及下石盒子组碎屑岩储集层特征

鄂尔多斯盆地东北部上古生界太原组及下石盒子组是该区天然气的主力储集层。应用偏光显微镜、环境扫描电镜、恒压压汞以及近几年来发展起来的恒速压汞技术,对该地区上古生界太原组及下石盒子组储集层进行了研究。研究区储集层岩性以粗粒、巨—粗粒岩屑石英砂岩为主,石英砂岩、岩屑砂岩为次。由于成岩作用强烈,残余原生粒间孔基本全部丧失。由于煤系地层提供的大量有机酸以及丰富的可溶性组分,太原组形成了以溶孔为主的储集空间类型,下石盒子组则主要以高岭石晶间微孔为主。太原组及下石盒子组储集层孔隙结构差别巨大,太原组储集层孔径大、孔喉比大,而下石盒子组储集层孔径小,孔喉比接近于1:1,属于较差的孔喉配置。

溶解性有机质对水体汞还原反应影响机制研究进展

汞是一种毒性很高的持久性污染物,可通过水生食物链中富集并进入人体.溶解性有机质(DOM)在水体汞(Hg2+)还原反应中起到重要作用.文章综述了近年来DOM对水体汞(Hg2+)还原反应影响的研究成果,主要对目前研究中尚存在争议及不足之处进行了探讨.

电感耦合等离子体质谱法同时测定天王补心丸中可溶性铅、砷、汞的含量

目的:建立电感耦合等离子体质谱法(ICP-MS)同时测定天王补心丸中可溶性铅、砷、汞的含量。方法:模拟人体胃肠道环境,用人工胃液提取天王补心丸中可溶性铅、砷、汞,采用ICP-MS对其进行测定分析。结果:该方法快速、准确、灵敏。测得铅、砷、汞的回收率分别为101.50%、100.08%和102.55%;检出限分别为0.36、0.50和0.30μg/L。结论:该方法可用于天王补心丸中可溶性铅、砷、汞等有害元素的测定评价。

中国北方四条河口的汞——以大辽河、鸭绿江、滦河、东村河为例(英文)

分别于 1989年 ,1992年 ,1991年 8月 ,1991年 5月对大辽河口、鸭绿江口、滦河口、东村河口水体中总汞进行了取样和分析 ,其中又对大辽河口和东村河口进行了溶解态汞的分析。大辽河口和东村河口溶解态汞的含量分别为 85～ 4 60 ng/ L和 180～ 50 0 ng/ L,平均值分别为 2 10和 32 4 ng/ L;总汞含量分别为 95～ 550和 4 0 0～ 10 0 0 ng/ L,平均值分别为 310和 640 ng/ L。大辽河河流段和河口段溶解态汞和颗粒态汞是主要存在形式。河口溶解态汞和颗粒态汞随氯度变化趋势相似。东村河口溶解态汞约占 50 %。鸭绿江口和滦河口总汞含量分别为 30～ 2 50 0和 370 0～ 670 0 ng/ L,平均值分别为 70 0和 570 0 ng/ L。鸭绿江口总汞随氯度变化趋势与随浊度变化趋势一致。而在滦河口总汞含量随两者变化趋势则不同。还讨论了滦河口、东村河口。

可溶性有机物对土壤汞向大气释放的影响

通过模拟试验,研究了浸提自稻草、腐殖土和堆肥的可溶性有机物(DOM)对紫色潮土、紫色土和黄壤三种土壤中汞向大气释放的影响.结果表明,DOM尤其是堆肥DOM能有效地抑制土壤汞向大气的释放,且土壤中DOM添加量越高,土壤汞释放量越少,即DOM对土壤汞释放的抑制作用越强;不同土壤类型,DOM的抑制作用不同,三种土壤汞释放量大小顺序均为:紫色潮土>紫色土>黄壤.

原子吸收分光光度法测定羚羊清肺散中酸可溶性汞

采用原子吸收分光光度法对羚羊清肺散中酸可溶性汞进行检查,并根据实测数据结合安全范围制定合适的限度。光源:汞灯;检测波长:253·7nm;工作电流:10mA。回归方程为Y=0·01219+0·05886X,r=0·9965,回收率为99·1%,RSD=1·6%。本方法简便、快速,结果可靠,重现性好,可用于羚羊清肺散中酸可溶性汞的检查。