Methylmercury and total mercury distribution in the sediments of Baihua Reservoir, Guizhou Province, China

Mercury is an important pollutant in lakes. Methylmercury （MeHg）, the most toxic mercury species, which can be formed from inorganic mercury in lakes, can be bioaccumulated into high concentration in food chain and result in a potential threat to human beings. Sediments play an important role for the Hg biogeochemistry in the aquatic systems： Mercury methylation has been shown to be fastest in the surfacial sediments, where the microbial activity is highest. The formation of MeHg in lakes suggests that sediments and/or near-shore wetlands can be the sources of MeHg in aquatic environments. The Baihua Reservoir, located in the suburb of Guiyang, was impounded in 1966. From the 1970s to the 1990s, Guizhou Organic Chemical Plant which used inorganic mercury as catalyst to produce acetic acid, was responsible for the discharge of waste water with high mercury content.     

Spatial and temporal distributions of mercury species and controlling factors in Hongfeng Reservoir, Guizhou, China

The Hongfeng Reservoir was built in 1960 and is an alkaline, hyper-eutrophic and seasonal anoxic reservoir due to the contamination from domestic and industrial wastewaters. The water samples at deferent depths from two sampling sites were collected from November 2003 to September 2004 using metal clean protocols. Total Hg （THg）, reactive Hg （RHg）, dissolved total Hg （DHg）, dissolved gaseous mercury （DGM） were measured by gold trap pre-concentration and CVAFS detection. Methyl mercury was measured by distillation followed by aqueous phase ethylation, precollection on a Tenax, isothermal gas chromatography and cold vapor atomic fluorescence detection. There was no discernible seasonal trend （about 8 ng/L） in THg concentration based on the average information developed during the four cruises except for high concentrations at bottom and water-sediment interface in May and September 2004. On the other hand, particulate mercury （PHg） and methyl mercury have discernible seasonal variability. Proportion of PHg increased from 29% in February 2004 to 50% in May 2004. In November 2003, February and May 2004 methyl mercury concentrations were relative low and increased with depth （from 0.13 to 0.40 ng/L）. In September 2004, methyl mercury concentrations increased from 0.14 ng/L in the epilimnion to 0.99 ng/L in the hypolimnion. DGM concentrations varied from 0.024 to 0.11 ng/L and decreased with depth.     

Damming effect on the distribution of mercury in Wujiang River

Seasonal changes in total mercury concentrations in surface water were observed for the Wujiang River, with higher values at the time of greater flow. The total mercury in this river was mostly associated with suspended particles, particulate mercury accounting for 84% of the total mercury flux on average during the high flow period, and 52% of the total mercury flux on average in the low flow period. Significant losses of Hg from the water were observed in the downstreams of the reservoir. In addition, the concentrations of particulate mercury in the downstreams of reservoir appeared to have been enhanced by sediment re-suspension and shoreline erosion caused by flood discharge, while the filtered portion decreased. These observations suggested that reservoirs played an important role in controlling the transport and fate of mercury in the Wujiang River.     

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.     

贵州省普定水库水体及沉积物孔隙水中汞的含量和形态分布初步研究

为了弄清楚普定水库汞的地球化学循环特征,用金汞齐-冷原子荧光光谱法(CVAFS)和气相色谱技术(GC), 研究了乌江流域上游普定水库水体剖面和沉积物间隙水剖面汞的赋存形态(总汞 THg)、溶解态汞(DHg)、活性汞(RHg)、颗粒态汞(PHg)、总甲基汞(TMeHg)、溶解态甲基汞(DMeHg)和颗粒态甲基汞(PMeHg)的分布特征.结果显示,普定水库水体总汞浓度为1.29～3.18 ng/L, 活性汞浓度为0.09～0.43 ng/L, 总甲基汞浓度为0.06～0.18 ng/L.沉积物间隙水中溶解态汞浓度为2.65 ～11.47 ng/L, 溶解态甲基汞浓度为0.06 ～1.16 ng/L.实验数据表明,普定水库水体中溶解态汞和颗粒态含量相当,其中颗粒态汞占总汞的比例为46%,并与总汞存在极显著相关性(R=0.929,n=20,P＜0.01),溶解态汞与总汞相关性不明显(R=-0.067,n=20);冬季普定水库甲基汞以溶解态甲基汞为主,溶解态甲基汞占总甲基汞的比例为63%,溶解态甲基汞与总甲基汞无明显相关关系(R=0.292,n=20),颗粒态甲基汞与总甲基汞存在极显著的相关性(R=0.815,n=20,P＜0.01).试验数据表明沉积物孔隙水溶解态汞与溶解态甲基汞浓度明显高于上覆水体, 是普定水库水体中汞的一个重要来源.     

中国汞的地球化学空间分布特征

20世纪80年代以来中国积累了岩石、土壤和水系沉积物中的大量可靠的汞分析数据和图件,为分析汞的地球化学空间分布特征提供了依据.从空间分布上看,从中国北部到南部,从西部到东部,土壤和水系沉积物中汞的含量背景值逐渐增高,汞在以干旱荒漠区、半干旱荒漠区、黄土地区和高寒山区为主的西部和北部呈低背景,在东部的森林沼泽区和半湿润低山丘陵区为中等背景,在南部的湿润低山丘陵区、热带雨林区和高山峡谷区为高背景,尤其在以云南东南部、贵州、广西西部、湖南西部岩溶区为中心的低温成矿域内,无论岩石、土壤还是水系沉积物,汞含量背景值达到最高.一般情况下,岩石、土壤和水系沉积物之间的汞含量具有继承性,在地理空间分布上呈明显的对栽应关系,并且土壤和水系沉积物之间的汞含量具有相近性,土壤和水系沉积物较岩石更为富集汞.     

Seasonal distribution of total mercury and methylmercury in sediments of the Wujiangdu Reservoir, Guizhou, China

The concentrations of total mercury and methylmercury in sediments were determined at the dam of the Wujiangdu Reservoir in different seasons. Total mercury (HgT) levels in the whole sediment profile were 254.2±47.0 ng/g in winter, 254.2±31.6 ng/g in spring, and 256.7±60.8 ng/g in summer, without significant variations in different seasons or at different depths. In contrast, the methylmercury (MeHg) compounds were most abundant at the sediment-water interface and decreased progressively with depth. MeHg contents of the sediments during different seasons are highly dependent on microbial activity, and seem to be higher when Hg (II)-methylating microorganisms are active. Thus, MeHg levels tend to rise in the loci where nutrient supplies and biological productivity are favorable. The percentage of HgT that is present as MeHg in the sediments increased gradually from December 2003 to April 2004 and to July 2004.     

水库汞生物地球化学循环研究进展

对近年来国内外有关水库汞生物地球化学循环的研究现状进行了综述,主要从基质释汞行为、汞释放对水体的影响、汞在水库水生食物链中的迁移富集和水库对河流汞输送的影响等四个方面进行了探讨,并指出该领域研究工作的薄弱环节及发展方向.     

Distribution and speciation of mercury in the Hongfeng Reservoir,Guizhou Province,China

The water, pore water, sediment, and fish samples were collected from the Hongfeng Reservoir in November 2003 and February 2004 in accordance with trace metal protocols. The average concentrations of total mercury （THg）, dissolved mercury （DHg）, reactive mercury, dissolved gaseous mercury, total methylmercury, and dissolved methylmercury in the water columns were 8.00, 5.70, 0.63, 0.05, 0.16, and 0.07 ng/L, respectively. THg and DHg in the water columns, THg in pore water and THg in lake sediments of the Hongfeng Reservoir showed the level of mercury in the Hongfeng Reservoir was higher than in other natural waters in the world due to the loading of a lot of waste water with relatively high concentrations of mercury, whereas methylmercury concentrations in fish （wet weight） varied from 1.73-51.00 ng/g, much lower than in most remote lakes and reservoirs reported in northern Europe and North America. Methylmercury distributions in pore water and sediments showed methylation occurred mainly in the upper several centimeters of sediment cores in the Hongfeng Reservoir. The concentrations of dissolved organic carbon, total suspended particles, total Hg, and methylmercury were higher at Houwu than those at Daba in November 2003. It is suggested that other pollutants such as N and P from fishing farm and other waste water at Houwu, which resulted in deterioration of water quality, affected the concentrations and distributions of mercury species in the reservoir.     

淮南采煤沉陷区土壤中汞的时空分布特征

以淮南采煤沉陷区土壤为研究对象,测试分析了样品中汞的含量,结合土壤pH值、有机质含量特征,探讨了采煤沉陷区土壤中汞的时空分布特征。结果表明：与未沉陷区土壤相比,沉陷区土壤有机质破坏严重,最高下降了46%;采煤沉陷区土壤中汞的含量为0.013~0.050 mg/kg,平均值为0.027 mg/kg,69.7%的采样点超过了淮南市土壤背景值;沉陷8 a后土壤汞含量最高,为0.033 mg/kg,是未沉陷土壤汞含量的1.74倍,且随着沉陷时间的增加,土壤中汞存在富集趋势;水稻土壤汞富集能力最高,高于玉米和大豆土壤;在垂直剖面上,汞含量由表层向下依次降低;且汞与pH值表现出显著负相关,有机质与汞显著正相关。     

High precision Fe isotope measurement and applications in aquatic environmental studies

In aquatic environment, iron redox reaction may occur through a） microbial activity and b） photo-chemistry. Iron chemistry plays a significant role in the health of aquatic ecosystems. For example, Fe^2＋ is more mobile than Fe^3＋. Iron can be bound to dissolved organic carbon （DOC）, and when Fe^2＋ is oxidized to Fe^3＋ （biotically or abiotically）, Fe is precipitated and induce co-precipitation of the DOC. Furthermore, iron is a major nutrient to aquatic organisms. Because Fe^2＋ is more bioavailable than Fe^3＋, iron redox chemistry can be a controlling factor in biological production, such as algae bloom which can be a public health concern. Experiments have shown that Fe redox reactions, biotically or abiotically, can generate significant Fe isotope fraction among different Fe species. Accordingly, analysis of Fe isotope composition of phytoplanktons can be a valuable tool in studying Fe dynamics in ecosystems. Precise measurement of Fe isotope, however, presents some challenges. Recent advances in mass spectrometry, specifically high resolution MC-ICP-MS, allow measurement of Fe isotopes free of interferences.     

Distribution of mercury species in water and sediments in Caohai Lake, Guizhou Province

Caohai Lake which is situated in Guizhou Province, has suffered drain project many times since 1958.The main mercury contamination includes industry waste water, litter and waste residue from refine zinc furnace and so on. The water and sediment samples which were collected from Caohai Lake in different seasons using metal clean protocols. Study sites were selected at the upper and down reaches and the tributaries of this lake, respectively. Total mercury （THg）, reactive mercury （RHg） and dissolved mercury （DHg） concentrations were measured by trap pre-concentration and CVAFS detection methods, and the concentrations of particulate mercury （PHg） are equal to difference of THg and DHg. Total methylmercury （MeH） and dissolved methylmercury （DMeHg） concentrations were measured by GC-CVAFS detection method. Mercury in sediment was measured by AAS method. The results in autumn were obtained as follows： the average concentrations of total mercury, reactive mercury,     

北极阿拉斯加春季积雪中汞的时空分布及其来源分析

开展北极雪冰中汞分布特征及其来源的探究,不仅可以丰富冰冻圈汞生物地球化学循环的认识,而且对评估北极环境中汞的潜在暴露风险具有现实意义。在2017年4月至5月对美国阿拉斯加的积雪进行大范围样品采集,探讨了该区域积雪中汞的空间分布特征及其成因、汞的沉降后过程以及潜在来源分析。研究表明:积雪中汞的空间分布受大气汞亏损事件(AMDEs)及人为源的共同影响,毗邻北冰洋海岸(如巴罗)积雪中总汞(THg)浓度较高,接近人为源的山地表层雪中THg浓度较高。巴罗雪坑中THg浓度随深度增加呈下降趋势。积雪中主要阴阳离子与THg的相关性分析表明,阿拉斯加积雪中THg的空间分布可能主要受北冰洋海盐气溶胶以及人类活动的影响。     

淮南矿区采煤塌陷积水区水生态环境研究

采煤塌陷积水体已成为淮南市一种特殊的地表水体。本文概要地评价了淮南煤矿区塌陷积水区水生态环境状况,以及这些水体目前能支持的功能用途,说明该积水体水生态环境已受到一定程度的污染,必须加强该区的生态环境监管。     

漓江水系汞的分布和污染研究

对漓江水系干流、支流、连体湖泊、较大的孤立湖塘和近岸水井设置40个采样点。水样采样周期为2个水文年,分枯水季和丰水季两次采样,现场测定水温、电导率、pH值等理化参数。系统采集水样112件、底泥样40件、水草样40件、近岸土壤样40件。底泥样用逐步浸提法进行不同形态汞分析。研究结果显示,干流河水、底泥和水草中汞的平均含量分别为0．12μg／L、0．20μg／g和0．032μg／g;主要支流河水、底泥和水草中汞的平均含量高于干流,分别为0．15—0．23μg／L、0．38～1．7μg／g和0．028—0．044μg／g。底泥中汞含量均高于近岸土壤汞含量。无论是干流还是支流,河水汞含量与底泥、水草汞含量有明显的相关关系。由上游至下游,漓江水系干流、主要支流河水样汞含量均不断增高,可高出源头河水汞含量的1．5—5倍。相应地指示重金属离子污染的参考指标——电导率值不断增高,河水的pH值亦逐渐增高。丰水期（5月至6月）河水中的汞含量（0．12—0．28μg／L）明显高于枯水期（9月至11月）河水中的汞含量（0．091—0．28μg／L）。不同断面河水汞含量均高于相应近岸井水汞含量。不同水体底泥中汞的形态分布一般顺序为：残渣态〉难氧化降解有机质结合态〉腐殖酸结合态〉碳酸盐和铁锰氧化物吸附态〉交换态〉易氧化降解有机质结合态〉水溶态。综合各项资料分析,认为漓江干流是桂林城市汞污染最大的汇。根据地表水环境质量标准（GB3838--2002）,仅汞而言,漓江水系均达到Ⅳ类水质标准（河水中汞含量≤1μg／L）。漓江支流汞污染高于干流,对干流存在较大的污染风险。     

北疆积雪中溶解性砷和汞的空间分布特征及来源分析

为了解北疆积雪中砷(As)和汞(Hg)的空间分布特征及来源,基于2018年1月在北疆地区58个采样点采集的积雪样品,采用原子荧光光谱法测定积雪中溶解性砷和汞的含量,用反距离加权插值法分析空间分布特征,并利用后向轨迹模型探讨了其来源.结果表明:积雪中溶解性砷和汞的浓度分别在0.21～2.69μg?L-1和5.32～64....     

Distribution and speciation of mercury in surface water in Wanshan Hg-mined areas, Guizhou Province, China

Mercury as a toxic element poses environmental concerns, especially in historically Hg-mined districts. The Wanshan Hg mine located in the eastern part of Guizhou Province, southwestern China, ranks the largest Hg-producing district in China. Mining at Wanshan was initiated in 221 B.C., but ceased in 2001. Approximately 22000 tons of Hg, 6000 tons of cinnabar and large quantities of mine-wastes had been produced at Wanshan. Significant quantities of calcines, which were piled irregularly near the old mine processing sites and retorts, continue to impact the local environments in the Wanshan area. In this study, a regional contamination of mercury in surface waters collected from the Meizixi, Dashuixi, Huandao and Gaolouping rivers, whose upstreams or branches originate from the hilly karstic area and receive drainage arising from the calcines, was investigated by determining all Hg species in a base-flow and a flood-flow season. Reactive, dissolved, particulate, and total Hg concentrations in surface water varied from 0.60 to 400 ng/L, 11 to 430 ng/L, 1.4 to 9210 ng/L, and 15 to 9260 ng/L, respectively. Total methylmercury in water samples ranges from 0.31 to 25 ng/L. The concentrations of total Hg and particulate Hg in water samples collected during the flood season are higher than those in the base-flow season, whereas, the concentrations of dissolved and reactive Hg are lower with the peak values observed in water samples collected in the base-flow season. A strong positive correlation between total Hg and particulate Hg is noticed in the water samples collected from Hg-mined areas with the proportion higher than 80%.     

水生生态系统中汞-硒相互作用研究进展

甲基汞是汞存在于水生生态系统(水体、沉积物和水生生物)毒性最强的形态,并通过食物链的传递对生物体产生危害,因此有效控制汞的甲基化过程是汞环境化学和毒理学研究的重要课题。生物体内硒对汞的甲基化过程有明显的抑制作用,明确汞和硒在水生生态系统的形态特征以及汞-硒相互作用机制,有助于解决汞污染问题。汞在生物体内的毒性与生物体内硒含量紧密相关,汞与硒相之间的相互作用主要表现在生成不溶的化合物促使汞去甲基化或受生物体内硒相关酶抑制被直接排除于生物体外,从而抑制了汞的毒害作用。本文评述了汞、硒在水生生态系统中的形态特征,指出在水体中合理添加硒化合物可抑制无机汞在生物体内甲基化过程,深入研究生物体内汞和硒相互作用机制及其生理效应是该领域未来发展方向。     

桂林市及近郊土壤汞的分布和污染研究

通过对桂林市区及近郊表层、底层土壤汞的系统取样,测试和编图,阐明了本区土壤汞的分布规律,确定了土壤汞的污染区段和污染程度。在上述工作的基础上,结合基岩汞测量、热释汞方法和重金属元素组合分析,对土壤汞的来源、污染无比汞的赋存状态进行了初步探讨。     

苏州西部土壤汞分布特征及成因

在收集以往自然重砂测量、土壤测量资料的基础上,结合1∶5万土壤地球化学调查,进行苏州西部土壤中汞的分布特征及成因解析。结果表明,研究区土壤中Hg含量变化范围较大,介于0.023～5.012 mg/kg之间,平均值高达0.386 mg/kg,远高于苏州地区表层土壤及太湖水网平原表层土壤Hg含量平均值,土壤汞污染比较严重。区内辰砂矿物与土壤中Hg的空间分布具有较高的耦合性,与区内断裂构造、矿床分布有关,表明区内土壤中的汞、辰砂分布是多金属矿成生作用的产物,人类活动的影响不大。