秋夏季黄河三角洲湿地土壤汞和甲基汞的变化

汞在湿地中的行为对湿地水生生物健康具有重要影响.于2011年和2012年分别采集干(夏初)湿(秋季)季节黄河三角洲湿地土壤样品,分析不同季节汞与甲基汞的含量差异和垂直变化.秋季总汞平均含量为0.064 mg·kg-1;夏季为0.027 mg·kg-1,总汞含量平均减少57%,湿地由积水到干旱过程中导致汞的释放.秋季各点位0~10 cm深甲基汞平均含量为0.28μg·kg-1,夏季甲基汞平均含量为0.066μg·kg-1,各点位含量平均减少76%.在秋季受湿地淹水影响,利于甲基汞的形成,水分减少和湿地干旱导致土壤中的甲基汞减少.在垂直方向上,夏季与秋季相比总汞在0~10 cm深度都有减少,土壤中的汞发生释放,因此,湿地在秋季表现为汇,而在春夏季为大气汞的源.硫酸盐还原细菌的含量秋季远高于夏季,在夏季硫酸盐还原菌与甲基汞和甲基化率均显著相关,硫酸盐还原菌、淹水环境、有机物质都会影响甲基汞产生和分布.     

达里诺尔湖近2400年以来Hg元素含量变化及环境意义

汞（Hg）元素作为一种全球性循环元素,对环境的影响正逐渐成为人们关注的焦点之一.为揭示寒旱区达里诺尔湖沉积物的Hg污染历史及人类活动对湖泊沉积物中Hg污染的影响,通过采集湖泊沉积物岩芯（编号DL1）,在建立DL1岩芯沉积地层年代框架的基础上,结合沉积物粒度特征、总有机质（TOC）含量等指标参数的变化,对DL1岩芯记录的地质历史上的Hg含量变化特征及环境意义进行了综合分析.结果显示,沉积物记录的Hg元素污染具有明显的阶段性变化特征：2400~1400 cal.a BP,Hg含量呈逐渐降低趋势,期间降水量呈逐步减少趋势,区域气候显著干旱;1400~200 cal.a BP,Hg含量相对稳定,呈小幅度波动变化,对应了区域气候的干-湿交替;近200 cal.a BP以来,Hg含量明显增加,这可能是受人类活动影响的结果.整体上,地质历史上DL1沉积物中Hg含量变化受气候干冷-暖湿交替周期性变化影响较大.而近200 cal.a BP来Hg与TOC等指标间显著正相关,则显示了沉积物中有机质可能吸附了大量的Hg元素,使其呈顶端富集趋势,进而对湖泊水生态环境造成影响.     

Inorganic and methyl-mercury speciation in sediments of the Swarzędzkie Lake

Sediment samples were analysed for mercury and methylmercury content in different parts of the bottom sediment of Swarz ?dzkie Lake, which were influenced by different external pollution sources. The results of determination with two methods of mineralization using two separate media (HNO₃/H₂O₂ and HF) were compared. The accuracy of the studied methods was analysed using certified reference material IAEA 405 of river sediment. The recovery of mercury was satisfactory and ranged from 97.5 to 98.8%. Methylmercury compounds in the studied sediments were found in limited concentrations. Their concentrations ranged from 0.26 to 58.1 μg kg^?1, i.e. 1.0–7.4% of the total mercury content. The depth profile displayed high values of both total and methylmercury content at a depth of 10–20 cm, related to the heavy pollution of the lake in the 1980s. Canonical analysis displayed the relationship of both total mercury and methylmercury concentrations with organic matter and phosphorus content in bottom sediments.     

Differential fitness of allelic isozymes in the marine gastropodsLittorina punctata andLittorina neritoides,exposed to the environmental stress of the combined effects of cadmium and mercury pollution

The present study tested the separate and the interactive pollution effects of cadmium and mercury on the electrophoretically detected allelic isozyme frequencies of the enzyme phosphoglucose isomerase for two species of littoral marine gastropods —Littorina punctata andL. neritoides — and the enzyme amino peptidase forL. neritoides. Our results indicate differential survivorship of allelic isozyme genotypes specific for each type of pollutant and for their interaction, as well as trends common to all pollutants. Theoretically the results reflect the adaptive nature of at least some allozymic genotypes in these marine gastropods and seem inconsistent with the neutral theory of allozyme polymorphisms. Practically, the results reinforce earlier conclusions that changes in the frequency of allelic isozymes may be used as a genetic monitor of pollution.     

三峡水库汞活化效应对鱼汞含量影响的预测

报道了三峡库区长江干流江段鱼体汞元素的含量范围为０．０４￣０．４２ｍｇ／ｋｇ（湿重）,高于长江水系鱼体汞含量水平。分析了三峡库区鱼体汞含量高的原因,指出三峡库区毗邻武陵山高汞背景区,主要受汞矿开发、高汞燃煤及城市废弃物排放的影响。利用水库汞活化指数模型,预测三峡水库蓄水后库区干流及４０条主要支流水域汞的活化效应将增强０．３５￣１．５倍,鱼体汞含量将是现在鱼汞含量的１．４￣２．５倍;并根据不同鱼种汞     

Lowest Effect Levels of Lead and Mercury on Decomposition of Mor Layer Samples in a Long-Term Experiment

Indications of possible negative effects of lead (Pb) and mercury(Hg) on microbial respiration in Southern Swedish forest humus layers led to experiments on dose-response relationships by additions of metal salts in the laboratory. Respiration rates andweight loss due to decomposition of organic material were measured. For relevance to field situations metal doses were low,the time span was long, 550 days including freeze storage, and microbial activity was kept up by plant litter additions. We looked for effects of Pb and Hg at levels moderately elevated above the Southern Swedish reference, as well as combined effectsof Pb + Hg. A reduction in respiration and decomposition of10% was found at about 225–245 g g^-1 of total Pb, i.e. ata Pb level elevated 3.5 times. Although small effects of Hg werefound even at the lowest dose level, 10% inhibition of microbialactivity appeared temporarily at about 2–3 g g^-1 of total Hg, i. e. at 6–8 times the reference level. There were nolong-term additive effects of Pb and Hg on decomposition. Type of anion had a strong influence on the test, chlorides of Pbbeing more toxic than nitrates. Long-term monitoring and maintenance of microbial activity during the experiment were prerequisites for the occurrence of effects at low metal levels.     

AFS-830型双道原子荧光光度计同时测定饮用水中砷、汞

主要探讨应用AFS-830型双道原子荧光光度计，在饮用水监测中同时测定水中砷、汞的方法和技术。此法是在硝酸介质，以硼氢化钠作还原剂，进行原子化，被测元素原子激发出荧光强度值在一定范围内与被测元素的浓度成正比。砷与汞的检出限分别为0．0618和0．0158ug／L。     

烟气脱汞技术现状简述

火力发电厂是我国最主要的烟气排放源, 期间微量元素汞将以不同的形式排放到大气中,对环境造成很大的危害.汞控制技术一般分为燃烧前脱汞,燃烧中脱汞及燃烧后脱汞.燃烧后脱汞是汞控制技术的主要方式,近些年研究异常活跃,主要表现在2个方面:一方面加强了各种吸收剂的研究,另一方面加强利用现有的脱硫装置脱汞的研究.     

两次金汞齐—冷原子吸收光谱法测定大气中的痕量气态总汞

本文作者在已有仪器的基础上进行简单改装，建立了两次金汞齐—冷原子吸收光谱法测定大气中的微量气态总汞的方法。研究表明，这种方法最低检出限为０．０５ｎｇ；１００μｌ饱和汞蒸气连续测定结果表明其相对标准偏差＜１．４１％。在０～２．０ｎｇ汞量范围内标准工作曲线线性关系良好。运用该法，对贵州省万山汞矿、丹寨汞矿、清镇汞污染农田、省农科院和中国科学院地球化学研究所等地大气气态总汞进行了测定。这种分析方法还可以运用到其它环境样品微量汞的测定。     

Thimerosal in childhood vaccines contributes to accumulating mercury toxicity in the kidney

Mercury (Hg) is a hazardous chemical that accumulates in many cells and tissues, thereby producing toxicity. The kidney is a key target organ for Hg accumulation and toxicity. The contributing factors to Hg accumulation in humans include: (1) elemental and inorganic Hg exposure, often occurring by inhalation of Hg vapors; (2) exposure to methyl Hg (meHg), for example, through contaminated seafood; and (3) exposure to ethyl mercury (etHg) via thimerosal-containing vaccines. Systematic investigations on the toxic effects of etHg/thimerosal on the nervous system were carried out, and etHg/thimerosal emerged as a possible risk factor for autism and other neurodevelopmental disorders. There is, however, little known about the mechanisms and molecular interactions underlying toxicity of etHg/thimerosal in the kidney, which is the focus of the current review. Susceptible populations such as infants, pregnant women, and the elderly are exposed to etHg through thimerosal-containing vaccines, and in-depth study of the potential adverse effects on the kidney is needed. In general, toxicity occurring in association with different forms of Hg is related to: intracellular thiol metabolism and oxidative stress reactions; mitochondrial function; intracellular distribution and build-up of calcium; apoptosis; expression of stress proteins; and also interaction with the cytoskeleton. Available evidence for the etHg-induced toxicity in the kidney was examined, and the main mechanisms and molecular interactions of cytotoxicity of etHg/thimerosal exposure in kidney described. Such accumulating knowledge may help to indicate molecular pathways that, if modulated, may better handle Hg-mediated toxicity.