不同污染区土壤汞的分布特征及变化规律

为揭示不同污染区重金属汞在土壤中的存在形态及分布特征,选取万山汞矿区、大龙燃煤电厂区为研究区域,以无污染区花溪区为对照,选择优化的Tessier连续化学浸提法进行汞的形态分析。结果表明:万山汞矿区与大龙燃煤电厂的土壤总汞平均值分别为22.7 mg/kg和0.648 mg/kg,均超过我国土壤环境质量二级标准(0.5 mg/kg),无污染对照区土壤总汞平均为0.179 mg/kg。在水平方向上,万山汞矿区靠近污染源的土壤汞含量相对较高,随着距离的增加而下降;大龙燃煤电厂区土壤汞在距燃煤电厂2.5 km范围内呈现先减小后增大的趋势。汞矿区土壤汞主要以残渣态(66.6%)为主,其次为有机结合态(30.0%);燃煤电厂则主要以有机结合态(75.7%)为主,其次为残渣态(17.46%);无污染区主要以残渣态(59.1%)为主,其次为有机结合态(28.9%)。内梅罗污染综合指数显示,万山汞矿区的土壤污染指数为107,为重度污染,这与污染源强度大有关,2004—2017年,总汞含量呈下降趋势;大龙燃煤电厂土壤污染指数为1.57,为轻度污染,同时土壤汞以有机结合态为主,潜在生物有效性相对较高,有一定的环境生态风险。     

Global Mercury Pollution and its Expected Decrease after a Mercury Trade Ban

The high toxicity of methyl mercury (MeHg) is well known, as is the existence of transformations between metallic Hg and MeHg. As a consequence the industrialised countries have adopted Hg-free products and processes, because a continued use of Hg would result in diffuse emissions even if used Hg isrecycled. However, Western Europe exports about 100 tons of Hg to Brazil each year, where it is emitted over the Amazon. The export from Europe began during the 1980s, when a gold mining boom spread like wildfire in the Amazon. Mercury agglutinates gold grains by forming an amalgam. Later on the gold is purified from the Hg by heating. The Hg evaporatesinto the air and is subsequently deposited onto land and in surface waters. Another important Hg polluter is China, whichhas increased its burning of coal without appropriate smoke cleaning devices and is also importing considerable amounts of Hg for industrial use and for use in gold mining. RegionalHg emissions contribute to global Hg pollution due to the mobility of Hg. A ban on the Hg trade in Europe and North America would significantly diminish global Hg pollution. A ban would also result in the closing of the state-owned Hg mine (MAYASA) in Almadén, Spain, the world's most important anthropogenic Hg source.     

硒农作物与汞污染防治

该项研究以对农作物喷施一定浓度的硒盐和腐植酸混合硒肥生产富硒农作物，通过动物实验证明硒农作物可用于汞污染的防治。     

Distinct regional profiles of trace element content in muscle of Japanese eel Anguilla japonica from Japan, Taiwan, and China

Trace element distribution patterns were examined in Japanese eel from five Asian regions for the purpose of identifying the elements and patterns that could be used to determine provenance. Distinctive patterns were found in eels from the Japanese prefectures of Miyazaki, Kagawa, and Shizuoka, and from Taiwan and China. The levels of six trace elements, selenium, mercury, copper, manganese, zinc, and arsenic, in muscle tissue varied among eels of different origins, and factorial analysis of the elemental patterns showed that Factor 1 was attributable to selenium and mercury levels and Factor 2 to zinc and copper levels. Multivariate analysis showed that the patterns of elemental composition in fish muscle were mainly differentiated by these two factors.     

Total mercury and methylmercury levels in commercially important fishes in Japan

ABSTRACT:   The distribution of mercury in the muscle and other tissues was determined in 23 species of fishes and invertebrates. This study reveals species-specific patterns of mercury accumulation in the muscle of tuna and alfonsino. Consistently high levels of total mercury were found in Beryx splendens (0.78 ± 0.56 µg/g), Atlantic Thunnus thynnus (0.42 ± 0.06 µg/g), Pacific T. thynnus (0.59 ± 0.34 µg/g), Thunnus obesus (0.98 ± 0.34 µg/g), Makaira nigricans (0.56 ± 0.05 µg/g), Tetraptrus audax (0.51 ± 0.08 µg/g), and Xiphias gladius (0.47 ± 0.24 µg/g). Other fish species had lower levels of total mercury or methylmercury in muscle than the maximum permitted level of mercury in fish in Japan (0.4 µg/g). Total mercury and methylmercury levels in the muscles of T. thynnus , T. obesus, and B. splendens were closely correlated with body weight.     

微波消解—原子荧光光谱法测定黑米中汞的研究

采用微波消解—原子荧光光谱法,探寻一种检测黑米中汞的简便、准确的方法,优化了仪器的最佳工作条件,最佳载流浓度和还原剂浓度。结果表明:测定汞的检出限为0.001 8 ng/mL,加标回收率为90.2%～110.8%。该方法简单、省时、灵敏度高,适合于黑米中汞含量的测定。     

(微)塑料污染对土壤生态系统的影响:进展与思考

近年来土壤重金属污染已经成为全球性的环境问题。而汞作为五大毒性重金属元素之一,其在土壤中的迁移转化不仅会影响作物的正常生长,还会对农产品质量和安全造成严重威胁。土壤pH是影响汞迁移转化的重要因素之一,对其作用机理的不断探索已经成为近年来的研究热点。本文在前人的研究基础上,概述了土壤中汞的来源、危害及存在形态,并从汞的生物有效性及迁移转化过程两个方面详细阐述了土壤pH对汞迁移转化的影响机制。研究表明,酸性条件可能会使土壤中有效态汞的含量增加,进而导致其生物有效性提高,迁移能力增强;土壤pH对汞迁移转化过程中吸附-解吸的影响较大;土壤pH对汞迁移转化过程中络合-螯合、氧化-还原及甲基化反应的影响机理分别体现在离子竞争吸附、价态变化及甲基化促使因子的合成等方面。最后对今后的研究方向作出展望,旨在为汞污染土壤的修复与治理及汞污染扩散模型的建立提供参考依据。     

点源汞对环境的污染效应研究

对体温计厂附近大气,水体,土壤及植物等遭受汞污染危害的调查表明,汞污染的水平范围为１０００ｍ以内,垂直范围土壤８０ｃｍ以内。园林土壤的含汞量为农业土壤的６倍,园林植物吸持汞量是农业植物的６５倍。     

Oxidation capability of modified fly ash based adsorbent for mercury in coal-fired flue gas

Fly ash based adsorbent is dipping modified by NaCl or NaBr solution and the purpose is to improve their oxidation capability. Adsorption experiments of vapor-phase elemental mercury are performed in a laboratory-scale fixed-bed reactor. Physical properties of the adsorbent before and after modification are measured and the influences of the solution concentration and flue gas temperature on mercury oxidation rate are studied. The results show that when NaBr solution concentration is 5%, the mercury oxidation rate can reach 79.43%. The saturation adsorption quantity of absorbent 5%-NaBr is 1 700 ng/g and the service life is about 480 hours. Flue gas temperature played an important role in mercury oxidation and the best temperature ranged from 100 to 200 ℃.     

快速检测痕量汞的光电型传感方法的建立

为建立一种检测痕量汞的光电型传感方法,利用汞抑制葡萄糖氧化酶体系(即葡萄糖氧化酶—辣根过氧化物酶-葡萄糖-邻联甲苯胺—偶联反应体系)生成蓝色产物的原理,将Glu与OT固定化制成试纸条,插入自制的便携式光电型传感器,绘制出汞离子溶液浓度与对应的反射光强度值的标准曲线。实验结果表明,当汞溶液的浓度范围分别处于0.010～0.050mmoL/L时,光反射强度值与汞浓度皆呈现良好线性关系。经优化检测条件,汞溶液与双酶孵育的最佳时间为1h。该方法测定汞的检出限为1.0×10-4 mmol/L,检测时间分别为5min。由此可知,此方法检测汞快速、简便,有望实现对样品中汞含量的现场检测。