世界汞矿地区汞污染研究进展

汞是一种人体非必需的有毒重金属元素。近年来,随着全球环境的不断恶化以及人们对汞的毒性的深入认识,世界上不同国家和地区的大型汞矿陆续停产、闭坑。但是,长期的汞矿山开采和冶炼活动,改变和破坏了矿区地表生态系统,对矿区的生态环境造成了严重的汞污染。本文综述了世界范围的汞矿分布和开采冶炼历史以及汞矿开采冶炼的环境影响,主要表现为固体废弃物的排放、水体汞污染、大气汞污染及汞矿活动的大气汞排放、土壤汞污染和食物汞污染。     

贵州省务川汞矿区土法炼汞过程中汞释放量的估算

通过对酸性水溶液、含Fe³⁺水溶液、含Fe²⁺水溶液、细菌菌液和细菌培养基水溶液脱除二氧化硫的实验,探讨了微生物液相氧化二氧化硫的途径.以液相中SO₄^2-浓度考察了Fe³⁺浓度、Fe²⁺浓度、进口SO₂浓度以及温度对脱硫成酸的影响.微生物脱硫有2种机制:一是直接氧化作用,即氧化亚铁硫杆菌(Thiobacillus ferrooxidans)将S(IV)氧化成S(VI);二是间接催化氧化,氧化亚铁硫杆菌在酸性条件下具有快速氧化Fe²⁺成Fe³⁺,增强Fe³⁺对SO₂的液相催化氧化能力,研究表明微生物脱硫以间接催化氧化为主.在浓度0～1.2g/L之间,Fe³⁺和Fe²⁺浓度越高,脱硫效果越好,氧化亚铁硫杆菌表现出对Fe³⁺/Fe²⁺体系氧化SO₂的强化效果.入口SO₂浓度越高,细菌脱硫效率越低,但液相中SO₄^2-浓度随进口SO₂浓度增加变化不大.温度对微生物脱硫影响较大,最佳脱硫温度为30～40℃.     

原子荧光冷汞法测定地表水中的汞

建立原子荧光冷汞法测定地表水中的汞,通过实验及查阅相关资料对部分实验条件,如仪器的负高压和灯电流、屏蔽气和载气的流量、硼氢化钾和氢氧化钠的浓度、酸及其浓度等进行了优化。在最佳实验条件下汞的检出限为0.019μg/L,相关系数r>0.999,加标回收率为93.7%～106.4%,相对标准偏差0.79%～3.59%。实验结果表明:原子荧光冷汞法测定地表水中的汞具有简便、快速、清洁、高效、安全等优点,灵敏度高、精确度和准确度好、检出限低,是测定地表水中汞含量的有效方法。     

丹寨汞矿冶炼厂土壤汞污染的初步研究

汞冶炼主要通过废气污染周围土壤环境。通过调查取样，化学分析及地面风的统计、地形和分布距离等分析，采用分布关系曲线和土壤污染等值线图说明丹寨汞矿冶炼厂土壤汞污染分布特征。     

铜仁汞矿区土壤汞污染现状调查研究

为了进一步对废弃汞矿污染区的生态环境进行跟踪调查及科学的评价,2015年通过对铜仁市废弃汞矿区周围的稻田、旱田及菜地土壤汞污染现状调查分析。采用S型随机抽样方式,并使用原子荧光光度法对研究对象进行分析。结果表明:万山镇、云场萍及路腊村汞矿区稻田土壤总汞(THg)含量平均值分别为123.75、79.33、21.89 mg/kg;其旱田土壤THg含量平均值分别为:117.20、73.34、19.90 mg/kg;其菜地土壤THg含量平均值分别为129.40、81.78、26.50 mg/kg;且,万山汞矿区甲基汞(Me Hg)含量平均值分别为6.48(稻田)、4.80(旱田)、6.40μg/kg(菜地);云场萍汞矿区Me Hg含量平均值分别为3.73(稻田)、2.47(旱田)、6.40μg/kg(菜地);路腊村汞矿区Me Hg含量平均值分别为1.92(稻田)、0.87(旱田)、2.47μg/kg(菜地)。以上结果说明万山废弃汞矿区的污染程度高于云场萍废弃汞矿区及路腊村废弃汞矿区。     

汞污染地区人群发汞含量调查

报道了对贵州某有机化工厂在采用汞触媒生产醋酸工艺停止前后，该地区人群发样进行测试的结果。结果表明：汞触媒生产工艺停止前，污染区人群发汞平均含量为1．54μg／g，明显高于对照区。汞触媒生产工艺停止后，人群发汞含量明显降低。     

RA-915^＋型汞分析仪测定海水中的总汞

采用RA-915^＋型汞分析仪对海水中的总汞进行了测试。进行了线性关系、检出限、准确度、精密度、回收率等实验。实验结果表明,本方法检出限0．00002mg／L,在0—40000Pg范围内线性良好。本方法操作简单,灵敏度高,结果准确。     

汞的形态分析进展

汞的测定方法由总汞测定深入到汞的形态分析，综述近几年来汞的形态分析方法的发展，包括原子光谱法、气相色谱法、液相色谱法，毛细管电泳法和电化学分析法。     

某地燃煤电厂汞排放与国内外汞脱除技术分析

通过对某地区4个有代表性的燃煤电厂汞排放的数据分析,研究了国内燃煤电厂汞排放的一些特征,并同发达国家燃煤电厂汞排放和汞脱除的情况作了比较,分析了我国燃煤电厂在汞排放和汞脱除领域所存在的差距.在介绍了国内外燃煤电厂的主要汞脱除技术后,提出我国今后应加大对燃煤电厂汞脱除技术投入和研究的建议.     

Absorption characteristics of elemental mercury in mercury chloride solutions

Elemental mercury （Hg^0） in flue gases can be efficiently captured by mercury chloride （HgCl2） solution. However, the absorption behaviors and the influencing effects are still poorly understood. The mechanism of Hg^0 absorption by HgCl2 and the factors that control the removal were studied in this paper. It was found that when the mole ratio of Cl^- to HgCl2 is 10：1, the Hg^0 removal efficiency is the highest. Among the main mercury chloride species, HgCl3^- is the most efficient ion for Hg^0 removal in the HgCl2 absorption system when moderate concentrations of chloride ions exist. The Hg^0 absorption reactions in the aqueous phase were investigated computationaIIy using Moller-Plesset perturbation theory. The calculated Gibbs free energies and energy barriers are in excellent agreement with the results obtained from experiments. In the presence of SO3^2- and SO2, Hg^2＋ reduction occurred and Hg^0 removal efficiency decreased. The reduced Hg^0 removal can be controlled through increased chloride concentration to some degree. Low pH value in HgCla solution enhanced the Hg^0 removal efficiency, and the effect was more significant in dilute HgCl2 solutions. The presence of SO4^2- and NO3^- did not affect Hg^0 removal by HgCl2.     

沿海城市降水中总汞及汞同位素特征研究

大气汞沉降是汞从排放源进入地表系统最主要的迁移途径,利用汞同位素追踪汞在大气中的迁移转化规律及潜在来源对研究汞的生物地球化学循环具有重要意义.本研究于2012—2013年对厦门市小坪、坂头、鼓浪屿和洪文站点降水中总汞(THg)浓度和汞同位素的变化特征进行了研究.结果表明,厦门降水中THg浓度为1.0～59.4 ng·L~(-1),大气THg湿沉降量为13.1μg·m~(-2)·a~(-1).厦门冷、暖季降水中THg浓度相当,但由于暖季丰沛的降水量,导致暖季THg的湿沉降量约为冷季的2.5倍.降水样品中均表现出负的偶数汞同位素质量分馏(δ~(202)Hg,-2.2‰～-1.5‰)、正的奇数汞同位素非质量分馏(Δ~(199)Hg,0.08‰～0.22‰),以及轻微偏正的偶数汞同位素非质量分馏(Δ~(200)Hg,0.01‰～0.07‰).厦门降水中奇数汞同位素非质量分馏是大气汞液相光致还原反应的结果.偶数汞同位素非质量分馏不明显与其处于较低的纬度有关.厦门降水中δ~(202)Hg接近于厦门当地及贵州燃煤烟气中的δ~(202)Hg值,表明厦门降水中汞可能受到本地或传输过来的燃煤排放的影响.     

Volcanic mercury in Pinus canariensis

Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 μg kg^?1) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 μg kg^?1). Thus, mercury emissions originating from the eruption remained only as a mark—in pyroclastic wounds—and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 μg kg^?1) and bark (6.0 μg kg^?1) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.     

总汞、甲基汞和硒在汞暴露大鼠脑、肝、肾中的分布

利用自动汞分析仪、GC-ECD和原子荧光分析了汞污染暴露1,3,7,20,30,90d后,大鼠脑、肝、肾中的总汞、甲基汞和硒的含量.结果表明,总汞、甲基汞含量随暴露时间的延长而显著增加;各组织对总汞和甲基汞蓄积量的顺序是肾>肝>脑;从甲基汞和总汞的比率分析发现,甲基汞很容易透过血脑屏障,并且在脑中有较高的蓄积;硒能够拮抗汞在脑、肝、肾中的蓄积水平.     

我国煤中汞含量水平及洗选过程汞流向分析

介绍了我国煤中汞含量与分布特征、煤中汞的赋存形态,分析了汞释放对环境的影响以及汞的脱除与控制技术。结果表明:我国(华南)晚三叠世(T3)煤中汞含量最高,平均含量为0.26μg/g;贫煤和无烟煤中汞含量最高,平均含量都超过0.20μg/g。含汞较高的晚三叠世、晚二叠世煤田主要分布于华南各地;多数煤中汞含量在0.300μg/g以下,但华南的江西、广西、贵州等地煤中汞含量总体水平较高;汞的赋存形态可分为有机结合态和无机结合态,煤中汞的控制方法可分为利用前脱汞、利用(燃烧)后脱汞和过程中汞形态转化。提出了煤炭洗选过程汞分布、脱除率和汞平衡等计算公式,指出了煤炭洗选过程中汞迁移行为的主要影响因素。     

Environmental analysis of mercury in China

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Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment

Mercury(Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations(PNECs) for Hg(Ⅱ) and methyl mercury(Me Hg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5 × 10-3μg/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms,and their potential ecological risk should be respectively evaluated on the basis of mercury species.     

不同腐殖酸物质对土壤中汞的固定作用及植物吸收的影响

通过盆栽试验研究了不同腐殖酸物质对土壤有机结合态汞、全汞含量及土壤汞生物有效性的影响.结果表明,不同供试腐殖酸物质可以显著增加土壤中有机结合态汞和残留在土壤中汞的含量,降低土壤中汞的挥发量,从而有效降低土壤汞的生物有效性.与加入HgCl2但不施加腐殖酸物质的对照CK2相比,添加腐殖酸钠、提纯后的煤基腐殖酸、土壤腐殖酸、氨化风化煤、风化煤、褐煤、泥炭的处理中油菜对土壤中汞的吸收量分别降低了73.62%、71.11%、63.39%、40.05%、33.61%、22.26%、5.66%.     

Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment

Mercury (Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations (PNECs) for Hg(II) and methyl mercury (MeHg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5 × 10^-3 μg/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms, and their potential ecological risk should be respectively evaluated on the basis of mercury species.     

Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment

Mercury (Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations (PNECs) for Hg(II) and methyl mercury (MeHg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5 × 10^− 3 μg/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms, and their potential ecological risk should be respectively evaluated on the basis of mercury species.