美国NIST元素汞发生器的基准溯源传递方法

综述了美国NIST元素汞发生器的基准溯源传递方法,通过在输出的汞标准气体中混合加入已知高纯度的201Hg0气体（201Hg2＋标准溶液还原雾化）,并采用同位素稀释电感耦合等离子体/质谱法（IDICP/MS）测量加标后201Hg/202Hg同位素丰度比例,计算出待溯源元素汞发生器输出的Hg0 质量浓度.该过程实现了从元素汞一级标准物质SRM 3133到201Hg2＋标准溶液,再到元素汞发生器输出标准气体的溯源传递,完成了从NIST元素汞基准到仪器供应商生产基准的一级溯源传递,为建立符合我国需求的元素汞溯源传递方法和形成元素汞发生器溯源传递能力提供借鉴.     

基于吸附原理的双路独立汞采样方法

参照美国EPA 30B方法,基于吸附原理,研制了用于燃煤燃烧源排放烟气中总气态汞的双路独立采样系统,结合热解析分析技术,现场测试结果符合30B方法的质控指标要求。建议加大国产吸附管的研制力度,开发适用于中国工况的汞采样器。     

半自动超痕量汞测定装置及环境水中ppt级超痕量汞的测定

汞是一种毒性很强的重金属元素,一般环境水中汞的含量很低,在ppt级水平。目前,国内外商品化的测汞仪器其实际检测能力均在ppm到亚ppb级水平。水中ppt级汞绝大部分均采用预富集处理,然后用冷原子吸收,冷原子荧光或其他方法进行测定。能够直接、简便快速准确地测定环境水中ppt级汞的仪器和方法尚未见报导。我们研制了一套采用冷原子荧光原理进行工作的半自动超痕量汞测定装置。该装置采用了全封闭小型汞蒸气发生器,还原剂自动定量加入器,双层多通道进样控制阀等技术,具有灵敏度     

汞质控样品的保存试验

中国环境监测总结制备的汞质控样是以３％ＨＮＯ３为固定剂，经过试验发现，用它稀释的汞质控样其衰减速度相当则用５％ＨＮＯ３＋０．０５％Ｋ２Ｃｒ２Ｏ７为固定剂，则保证了汞质控样的稳定性。     

燃煤电厂排放总气态汞连续自动监测技术的选择

介绍了汞连续排放监测系统和汞吸附管采样系统的主要特点,比较了不同仪器的测定原理、样品处理技术、检出限和测定汞的形态,报道了美国环境保护署认证中心关于两个系统的认证结果.建议将汞连续排放监测系统与汞吸附管监测系统两种技术联合用于我国燃煤电厂排放总气态汞的自动监测.     

东平湖不同粒径底泥沉积物中汞的形态分布

对东平湖底泥沉积物中重金属汞的总量和形态及沉积物形貌进行了研究.从粒径分布与沿程分布分析了汞元素的形态分布特征.结果表明,东平湖底泥沉积物的主要粒径<63μm,且沉积物颗粒粒径越小,其表面的吸附物越多.不同粒级沉积物中汞的存在均以可氧化提取态形式为主,汞的形态分布与沉积物粒径的相关性可能受到原生矿物及因粒度效应产生吸附差异的综合影响.汞形态的沿程分布特征表明,湖南采样点受污染严重,潜在危害较大.     

中国和美国冷原子吸收分光光度法测汞的比较

我国已加入WTO，国际间的合作日益加强。环境监测部门不仅要了解本国本行业的规范，还应了解世界，了解国外的标准分析方法。对中国和美国的4种冷原子吸收分光光度法测定汞作了比较；提出用冷原子吸收分光光度法测定汞时，应按照不同的样品及不同的要求，选择合适的方法以实现质量控制的要求。     

基于稳健统计方法对实验室比对中土壤汞的质量控制指标研究

利用稳健四分位间距法和迭代法2种稳健统计方法,通过对全国31个省、自治区、直辖市范围内共334家环境监测单位开展土壤中汞的实验室间比对,对比对测定结果和质控数据进行统计分析,系统性地研究了土壤中汞的质量控制指标。建议实际监测工作中土壤汞的实验室间相对标准偏差范围为7%～19%,相对误差控制指标为±8%,低浓度水平下可适当放宽至±10%,加标回收率控制范围为81%～109%,为日常监测开展土壤汞的质量控制工作提供了评价依据,具有广泛的应用价值和较好的指导作用。     

气体中痕量汞的富集与测定

大气中汞含量通常可直接使用测汞仪进行检测。当要求气体中汞含量低于2微克/米~3时就要预先富集。目前国内多用传统的高锰酸钾——硫酸溶液进行富集。但我们在长期实践中认为用金、银与汞形成汞齐的方法与二氧化锰富集法互相配合使用较为适宜。其特点是环境适应性强、携带方便且取样后可在较长时间内保存。本文用上述两种富集方法以冷原子吸收法和冷原子荧光法进行试验,同时自制一个适于汞分析试验用的“稳恒连续汞蒸气发生器”,效果较好。     

Hg质控样品的保存

Ｈｇ质控样品的保存陈黎军（青海省环境监测中心站，西宁８１０００７）实验表明，无机汞由于微生物的作用转变成有机汞或金属汞而挥发。鉴此，改用固定液（５％硝酸和００５％重铬酸钾）取代３％ＨＮＯ３作为保存微量汞的稳定剂来稀释质控样品，使Ｈｇ２＋在其强氧化剂...     

Biomonitoring with epiphytic lichens as a complementary method for the study of mercury contamination near a cement plant

The study was focused on understanding the mercury contamination caused by a cement plant. Active and passive biomonitoring with epiphytic lichens was combined with other instrumental measurements of mercury emissions, mercury concentrations in raw materials, elemental mercury concentrations in air, quantities of dust deposits, temperatures, precipitation and other measurements from the cement plant's regular monitoring programme. Active biomonitoring with transplanted lichens Pseudevernia furfuracea (L.) Zopf was performed at seven of the most representative sites around the cement plant and one distant reference site for periods of 3, 6 and 12 months. In situ lichens of different species were collected at the beginning of the monitoring period at the same sites. Mercury speciation of the plant exhaust gas showed that the main form of emitted mercury is reactive gaseous mercury Hg2?, which is specific for cement plants. Elemental mercury in air was measured in different meteorological conditions using a portable mercury detector. Concentrations in air were relatively low (on average below 10 ng m?3). In situ lichens showed Hg concentrations comparable to lichens taken from the background area for transplantation, indicating that the local pollution is not severe. Transplanted lichens showed an increase of mercury, especially at one site near the cement plant. A correlation between precipitation and Hg uptake was not found probably due to a rather uniform rainfall in individual periods. Dust deposits did not influence Hg uptake significantly. Lichens vitality was affected over longer biomonitoring periods, probably due to some elements in dust particles, their alkalinity and the influence of other emissions. Mercury uptake measured in vital transplanted lichens was in a good correlation with the working hours (i.e. emitted Hg quantity) of the kiln. The study showed that selected lichens could be used to detect low to moderate Hg emissions from a cement plant and that the biomonitoring procedure could be further standardized and used as part of an environmental monitoring programme.     

Fractions and leaching characteristics of mercury in coal

A huge amount of coal is always stored in open spaces in coal-fired power plants before combustion. Mercury released from coal by rain or flowing water is an environmental risk and can cause contamination of the soil around the storage area. To better understand mercury pollution and to control mercury emission before combustion, it is necessary to determine the mobility and leaching characteristics of mercury from coal. In this study, we collected ten coal samples from one coal-fired power plant and proposed a sequential extraction procedure to get five fractions of mercury for evaluation. Elemental Hg was found as the most dominant fraction, and sulfate Hg was shown to be the second largest fraction. The mercury in the organic and the soluble fractions were not the major fractions, but they should still be considered because of their high mobility.     

南京某燃煤电厂汞的排放特点及分布特征

选择南京某燃煤电厂330 MW机组，对煤、炉渣、粉煤灰、烟尘、石灰石、石膏和烟气中的汞取样测量，探讨煤中汞在燃烧过程中的变化情况，并进一步分析汞的排放特点及分布特征。指出，煤经燃煤锅炉炉内高温燃烧后，炉渣中的汞对环境影响不明显；粉煤灰、烟尘中的汞存在富集现象，且随着粒径变细，富集程度加剧；燃煤锅炉燃烧后，随石膏排放的汞占比较大，应采取相应的防治措施。     

固定污染源烟气中汞排放连续监测系统

介绍了中美两国法规对汞排放连续监测的要求，分析了烟气中汞排放连续监测的技术难点，指出现有的汞在线监测只能得到气态总汞的浓度。阐述了冷蒸气原子吸收光谱法、塞曼调制原子吸收光谱法、冷蒸气原子荧光法、原子发射光谱法、紫外差分吸收光谱法等气态元素汞的不同分析方法。通过对湿化学法与热转化单元的比较，得出热转化技术更加适合烟气汞的在线监测。分析了造成汞测量误差的相关因素，并提出了减少误差的措施。     

Total mercury loadings in sediment from gold mining and conservation areas in Guyana

The Low Carbon Development Strategy proposed in June 2009 by the government of Guyana in response to the Reducing Emissions from Deforestation and Forest Degradation in Developing Countries program has triggered evaluation of forest-related activities, thereby acting as a catalyst for improvements in Guyana's small- to medium-scale gold mining industry. This has also shed light on areas committed to conservation, something that has also been handled by Non Governmental Organizations. This paper compares water quality and mercury concentrations in sediment from four main areas in Guyana, two that are heavily mined for gold using mercury amalgamation methods (Arakaka and Mahdia) and two that are considered conservation areas (Iwokrama and Konashen). Fifty-three sediment and soil mercury loadings ranged from 29 to 1,200 ng/g and averaged 215 ± 187 ng/g for all sites with similar averages in conservation and mining areas. Sediment loadings are within the range seen in French Guiana and Suriname, but conservation area samples had higher loadings than the corresponding uncontaminated baselines. Type of ore and location in the mining process seemed to influence mercury loadings. Mercury sediment loadings were slightly positively correlated with pH (correlation coefficient = 0.2; p value < 0.001) whereas no significant correlations were found with dissolved oxygen or turbidity.     

Speciation of mercury in mine waste: case study of abandoned and active gold mine sites at the Bibiani–Anwiaso–Bekwai area of South Western Ghana

Speciation determines toxicity, transport pathways and residence time of a metal in different compartments of the environment. This study investigated the speciation of mercury in soils, derived from sites known for dumping of mine wastes in the Bibiani–Anwiaso–Bekwai district, a gold mining community of the Western Region of Ghana. Soil samples were taken from the surface; depths of 20, 40 and 60?cm from mine waste at both abandoned and active mine sites. Each sample was analysed for total mercury, organic mercury and elemental mercury. After sample treatment, digestion and reduction with stannous chloride (SnCl₂), total mercury content was determined using the Inductively Coupled Plasma—Optical Emissions Spectrometer (ICP–OES). Organic mercury content was determined employing a differential technique after disposing of elemental mercury by heating. Total mercury content in samples ranged from 0.067 to 0.876?mg/kg for surface soils. The same soil of depths 20, 40 and 60?cm had total mercury from 0.102 to 1.066, 0.037 to 4.037 and 0.191 to 4.998?mg/kg, respectively. For organic mercury, concentrations range from 0.012 to 0.260?mg/kg for surface soil. Soil depths of 20, 40 and 60?cm had organic mercury concentrations from 0.016 to 0.653, 0.041 to 1.093 and 0.101 to 2.546?mg/kg respectively. Elemental mercury concentrations in surface soils, soils at depths of 20, 40 and 60 cm ranged from 0.043 to 0.780; 0.017 to 0.749; 0.014 to 2.944 and 0.009 to 2.452 mg/kg respectively. Among the sites studied, only galamsey tailings (GM) showed a trend of increasing total mercury level with increasing depth. For the other sites, trends were not defined. There has been no defined trend for elemental mercury with depth at any of the sampling sites. Just as with total mercury, it was only GM that showed an increasing trend of organic mercury concentration with depth.     

Monitoring cyclical air/water elemental mercury exchange

Previous experimental work has demonstrated that elemental mercury evasion from natural water displays a diel cycle; evasion rates during the day can be two to three times evasion rates observed at night. A study with polychlorinated biphenyls (PCBs) found that diurnal PCB air/water exchange rates exceeded nocturnal exchange rates by 32%. Given that the exchange rates of both PCBs and elemental mercury are dominated by the resistance in the aqueous thin film at the air/water interface and that water column elemental mercury concentrations in natural water bodies also display a diel cycle (and water column PCB concentrations do not) the findings here suggest that PCBs can serve as a tracer to assess the relative contribution of diel atmospheric temperature variations on elemental mercury air/water exchange rates. Using previously published data describing water column elemental mercury concentrations and the previously published diel mercury evasion model, four evasion scenarios are examined within the context of monitoring air/water toxicant exchange: constant atmospheric temperatures and constant water column elemental mercury concentrations; variable atmospheric temperatures and constant water column elemental mercury concentrations; constant atmospheric temperatures and variable water column elemental mercury concentrations; and variable atmospheric temperatures and variable water column elemental mercury concentrations. A scenario of monthly elemental mercury air/water exchange also is examined (at constant atmospheric and water column elemental mercury concentrations). Some of the findings include: (1) atmospheric temperature variations do have a significant effect on air/water toxicant exchange; (2) diel atmospheric temperature variations become more significant to overall diel toxicant exchange rates the closer the air/water system is to equilibrium conditions; (3) for refractory toxicants, average diel exchange rates are best estimated by averaging datasets obtained over a 24 h period or, at minimum, by measuring exchange rates at average atmospheric temperature values; (4) for elemental mercury, variable diel water column concentrations are likely to be the dominant contributor to variations in diel evasion rates; (5) diel atmospheric temperature variations amplify the magnitudes of both diel mercury evasion and absorption events and can shift maximum evasion rates to later in the day; (6) variations in monthly elemental mercury air/water exchange rates may exceed diel variations: and (7) 24 h and monthly monitoring efforts will likely be required to accurately describe diel and annual elemental mercury air/water exchange in a given system.     

Emission factor of mercury from coal-fired power stations

Mercury emission from coal-fired power stations, situated in Poland in the Silesian region was investigated. The determination methods for mercury in the consumed coal and in combustion gas, used in this research, are described. The mass of mercury emitted into the air from coal combustion in the power station is in constant relation to the mercury content in the consumed coal during the assumed period. A relationship between mercury emission into the air and the mercury content in the consumed coal in electric power stations is derived.     

Snapping Turtles (Chelydra serpentina) As Monitors for Mercury Contamination of Aquatic Environments

We assessed the distribution of mercury in snapping turtles(Chelydra serpentina) by analyzing front shoulder muscle,back leg muscle, tail muscle, blood, liver, and marginalcarapacial scute (shell) of 26 adult turtles from five smalllakes. Total mercury concentration in muscle ranged from 50 to500 ng g^–1 wet weight and was highly correlated among the threetissue locations. There was no relationship between musclemercury concentration and body size. Mercury concentration inblood was similar to muscle; the correlation with muscle mercuryconcentration was significant but there was some variability. Mercury concentration in shell was much higher than in muscle orblood, ranging from 500 to 3300 ng g^–1, and was highly correlatedwith muscle mercury concentration. Liver mercury concentrationwas similar to shell, but was highly variable and uncorrelatedwith any other tissue. We conclude that snapping turtlesaccumulate mercury from their environment and may be usefulmonitors of mercury contamination.