MERCURY EMISSION INVENTORY IN ONTARIO

Mercury is released to the environment from various anthropogenic and natural sources. This work is a compilation of mercury emissions from anthropogenic sources in Ontario, Canada. The goal of our study was to identify all sources of mercury, and develop an emission inventory of anthropogenic mercury in Ontario. The result of our investigation revealed that combustion of fossil fuels and emissions from landfill sites are two primary sources of mercury to the atmosphere. Other sources of significance are emissions from waste incinerators, various industrial activities, and cement production. Total mercury emission in Ontario is estimated as 4100 kg per year.     

Using Wet-FGD systems for mercury removal

A plan to control mercury emissions to the atmosphere and to establish mercury emission limits has recently been elaborated by the European Commission, making it necessary to devise an efficient and cost effective mercury removal technology. Towards this end wet flue gas desulfurization units appear as a promising option for multi-pollutant control. However, more investigation on mercury removal and a greater mercury removal efficiency are required to achieve this objective. In the present work scrubber chemistry and the application of various solid additives to enhance mercury removal in wet scrubbers is evaluated. The results obtained show a significant correlation between mercury removal efficiency and the pH of the scrubber slurry and SO2 concentration. A weaker correlation was observed between oxygen or slurry concentration and removal efficiency. Finally several solid oxides were found to be effective additives for enhancing mercury capture in wet scrubbers.     

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.     

典型钢铁企业汞排放水平及排放特征研究

以某典型钢铁企业为研究对象,测定企业废气、废水、固废汞排放水平,并分析汞排放特征。研究表明,球团、烧结、高炉工艺废气排口烟尘中汞排放浓度和排放速率明显低于烟气;汞主要以气态形式排放,烧结工艺排口废气汞最高浓度分别是其他2个排口的7倍和3倍。球团、烧结、高炉、电炉四工艺环节中,烧结汞排放速率占四工艺汞排放速率总和的87%。半干法脱硫、氨法脱硫、石灰石石膏脱硫对废气中汞的去除效率分别为90.0%、78.7%和29.9%。企业废水排放未检出汞,脱硫产生固废汞含量明显高于除尘产生固废汞含量,脱硫灰汞含量是脱硫石膏的15倍。     

南京燃煤电厂烟气中汞的排放调查

对南京市8家国控污染源13台（套）燃煤锅炉进行监测,结果表明,燃煤电厂烟气中汞主要以气相部分汞形态存在,其排放值均达标,为0．16～15．9μg／m3,均远低于标准限值;煤质中汞含量与电厂烟气中汞浓度变化曲线的趋势是大致相似,相关系数为0．91;燃煤电厂机组容量、发电负荷越大,汞平均排放因子呈变小趋势;静电除尘器、湿法脱硫和选择性催化还原法的净化配置对汞的脱除效率最高,达到95．4％。     

复合式吸收器采样还原一体化冷原子吸收法测定大气中的汞

目的研制一种高效率采集大气中汞的吸收器.方法利用一种集大泡式与玻砂板式吸收器为一体的复合式吸收器采样,并使采样还原一体化冷原子吸收法测定大气中汞.结果平均吸收率为96%,变异系数在4%～12%之间.结论复合式吸收器采样吸收效率高,适合于大气中微量汞的测定.     

Rapid,ultra-sensitive detection of gas phase elemental mercury under atmospheric conditions using sequential two-photon laser induced fluorescence

We have examined the sensitivity of sequential two photon laser induced fluorescence (LIF) detection of elemental mercury, Hg(0) in the gas phase. The most sensitive approach involves an initial laser excitation of the 6(3)P1-6(1)S0 transition at 253.7 nm, followed by excitation with a second laser to the 7(1)S0 level. Blue shifted fluorescence is observed on the 6(1)P1-6(1)S0 transition at 184.9 nm. The excitation scheme, involving sequential excitation of two atomic transitions, followed by detection of the emission from a third is extremely specific and precludes detection of anything other than atomic mercury. Using our 10 Hz laser system we have achieved a detection sensitivity of 0.1 ng m(-3) at a sampling rate of 0.1 Hz, i.e. averaging 100 laser shots at a pressure of one atmosphere in air. At low concentrations we sampled simultaneously with an automated mercury analyzer (Tekran 2537A), to ensure accuracy. We have examined the linearity of the technique, generating flows containing mercury concentrations between 1 and 10,000 ng m(-3) using a permeation tube and dynamic dilution, but relying on the concentrations given by the Tekran at low levels and the concentration calculated from dilution at high levels. We find that the detection is linear over the five orders of magnitude that we were able to vary the concentration. Our measured detection limits in He and Ar are much lower as these gases are inefficient fluorescence quenchers.     

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。     

基于燃煤电厂超低排放的汞分布特性研究

为掌握超低排放改造后烟气处理装置对汞分布的影响,选择6台有代表性的超低排放火电机组进行现场测试。通过对火电机组入炉煤、炉渣、飞灰、脱硫石膏、末端烟气等样品的测试,得出不同燃烧产物中汞的分布:底渣和湿除出水的汞含量极微;电除尘底灰中的汞所占比重相对较大,平均汞含量占燃烧产物中总汞的比例可达57.97%。依据质量平衡原理,计算出不同超低排放改造工艺路线对汞的协同脱除效率为87.26%~95.60%,并分析了不同污染控制设备对汞排放的影响。     

基于实测的燃煤电厂烟气中汞排放水平浅析

简述汞污染和控制问题成为环境问题的新热点和前沿研究领域,介绍中国燃煤电厂烟气汞监测试点的基本情况。分析江苏省7家燃煤电厂煤中汞及烟气中汞排放水平,提出利用现有的除尘、脱硫、脱硝设施,能满足《火电厂大气污染物排放标准》中汞的排放限值要求。     

Total mercury status in an urban water body,Mithi River,Mumbai and analysis of the relation between total mercury and other pollution parameters

Mercury is a heavy metal which has garnered attention recently in India. Minamata Convention on mercury was established on October 2013 and was joined by India on September 30, 2014. India is seen as a major mercury pollution source after China according to many studies in the past. Various mercury pollution sites that are currently recognized in India are Kodai Lake, Kodaikanal, Tamil Nadu, and Thane Creek, Mumbai. Since 1992, chlor-alkali plants have been regulated to eliminate mercury cell process of manufacturing. Also, medical and health care facilities are discarding mercury-containing equipment and processes. Various anthropogenic sources of mercury to the atmosphere include combustion of fossil fuels, processing and mining of primary metal ores, cement manufacturing units, chlor-alkali plants, and use of mercury in various products like paints, electric switches, and relays. The hazard associated with mercury pollution becomes extremely serious when we consider its ability to be transported over long-range distances. Various atmospheric transport models suggest India and other Asian countries to be a major source of long-range transport of mercury to North America. Considering the hazards of mercury and its widespread presence in our life, a study on mercury pollution in an urban water body is conducted. This study deals with Mithi River located in Mumbai Metropolitan Region (19.0760° N, 72.8777° E) to study the total mercury in water and derive its relationship with other pollution parameters.     

Determination of elemental carbon emission

The studies on elemental carbon content in the atmospheric air, performed at the air monitoring station in Katowice (Poland), have revealed violations of allowable maximum average annual and diurnal concentrations. Elemental carbon is introduced into the atmosphere mainly as soot generated from combustion processes. This work presents the determination of elemental carbon in emission generated from coal combustion processes.     

Mercury contamination-what we have learned since Minamata

Atmospheric cycling of mercury and other pollutants has become a major concern as industrialized countries have eliminated point discharges, sometimes by relocating the industries to underdeveloped and developing countries where point sources have become problems. Such circumventions may be to no avail in the long run as pollution continues to elevate levels of methylmercury in fish in waterways that are remote from direct contamination as well as where the source can be readily identified. Much has been learned about the cycling of mercury in the environment since human disabilities and deaths at Minamata, Japan, initially drew attention to the problem of methylmercury poisoning from the consumption of contaminated seafood in the 1950s. In that instance, methylmercury produced industrially concentrated to toxic levels in fish. As this manufacturing process was not used outside Japan, concern did not become immediate in other developed nations until the 1960s when it was established that mercury was not only biomethylated by microorganisms but also biomagnified through the food chain. Point sources to the waterways may have been eliminated too late to return the levels in fish to background because of the geochemical cycling of mercury through the environment. Despite decreases in domestic, industrial and agricultural point source releases over the last two decades, large quantities from non-point sources such as fossil fuel combustion, smelters, and incinerators are still being released. Much of this mercury is transported from the atmosphere to aquatic ecosystems and stored in sediments until it is again released to the water and atmosphere.     

镀金石英砂吸附-AMA 254测汞仪测定大气中痕量汞的研究

采用镀金石英砂来富集大气中的气态总汞,AMA 254测汞仪测定。结果表明,不同采样时间下的单级吸附管的吸附效率均在90%以上,采样40min时的相对标准偏差为5%左右。与巯基棉吸附和吸收液吸收方法的对比显示,该方法具有吸收效果好、多次采样的精密度高、操作简便并且可以再生重复使用等优点。运用该法,对徐家汇等几个地点的大气总汞进行了测定。     

Mercury emission and dispersion models from soils contaminated by cinnabar mining and metallurgy

The laboratory flux measurement system (LFMS) and dispersion models were used to investigate the kinetics of mercury emission flux (MEF) from contaminated soils. Representative soil samples with respect to total Hg concentration (26-9770 μg g(-1)) surrounding a decommissioned mercury-mining area (Las Cuevas Mine), and a former mercury smelter (Cerco Metalúrgico de Almadenejos), in the Almadén mercury mining district (South Central Spain), were collected. Altogether, 14 samples were analyzed to determine the variation in mercury emission flux (MEF) versus distance from the sources, regulating two major environmental parameters comprising soil temperature and solar radiation. In addition, the fraction of the water-soluble mercury in these samples was determined in order to assess how MEF from soil is related to the mercury in the aqueous soil phase. Measured MEFs ranged from less than 140 to over 10,000 ng m(-2) h(-1), with the highest emissions from contaminated soils adjacent to point sources. A significant decrease of MEF was then observed with increasing distance from these sites. Strong positive effects of both temperature and solar radiation on MEF was observed. Moreover, MEF was found to occur more easily in soils with higher proportions of soluble mercury compared to soils where cinnabar prevails. Based on the calculated Hg emission rates and with the support of geographical information system (GIS) tools and ISC AERMOD software, dispersion models for atmospheric mercury were implemented. In this way, the gaseous mercury plume generated by the soil-originated emissions at different seasons was modeled. Modeling efforts revealed that much higher emissions and larger mercury plumes are generated in dry and warm periods (summer), while the plume is smaller and associated with lower concentrations of atmospheric mercury during colder periods with higher wind activity (fall). Based on the calculated emissions and the model implementation, yearly emissions from the "Cerco Metalúrgico de Almadenejos" decommissioned metallurgical precinct were estimated at 16.4 kg Hg y(-1), with significant differences between seasons.     

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。     

Comparative assessments of VOC emission rates and associated health risks from wastewater treatment processes

With the growing concern regarding emission of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs), the relationship between the VOC emission rates and the associated public health risks has been rarely discussed. The objective of this study was to examine and compare the VOC emission rates and cancer and non-cancer risks by inhalation intake, using a municipal WWTP in China as an example, with respect to the effects of treatment technologies, VOC species, and seasonal variation. Given the treatment technology considered, the emission rates of VOCs in this study were estimated by means of mass balance or calculated on the molecular level. From the viewpoints of both emission rates and cancer and non-cancer risks, sedimentation was the treatment technology with the highest health risks to the workers. Slightly lower VOC emission rates and health risks than those for sedimentation were observed in anaerobic treatment. Although the aeration significantly enhanced the VOC emission rates in the aerobic treatment process, the associated health risks were limited due to the low VOC concentrations in the gas phase, which were likely attributed to the strong mixing and dilution with fresh air by aeration. Amongst the VOCs investigated, benzene was the VOC with both a relatively high emission rate and health risk, while trichloroethylene possessed a high emission rate but the lowest health risk. Without strong interfacial aeration and turbulence between the water and atmosphere, the effects of treatment technology and seasonal variation on the health risks might be connected to the VOC emission rates, while the effect of VOC species depended considerably on the respective cancer slope factors and reference concentrations; the employment of aeration provided a different conclusion in which the emission rates were enhanced without a significant increase in the related cancer risks. These findings can provide insight into future health risk management and reduction strategies for workers in WWTPs.     

Mercury Vapor Determination in Hospitals

The measurements of metallic mercury vapor were carried out in seven local hospitals, where mercury-containing products are widely used, as well as in one residence to check effectiveness of decontamination after mercury spillage. Hopcalite as a solid sorbent was used in active and passive sampling methods, and mercury was analyzed by CV-AAS technique. Good agreement was found between results of mercury measurements using active samplers (pumped hopcalite adsorption tubes) and passive (diffusion) monitors applied in indoor atmosphere. The results indicated the presence of metallic mercury vaporization sources in the assessed hospital rooms but in the majority of cases mercury levels did not exceed 1 g/m³ i.e. Polish permissible concentration for residence. However, in some of the hospital rooms, elevated concentrations of mercury vapor were found and airborne levels of up to 13.9 g/m³ were recorded. Higher concentrations of mercury vapor were observed in autumn season when compared to summer.     

大气中不同形态汞的采集和分析方法

作为一种环境优先污染物,汞对人体和其它生物毒性很大。大气是全球汞生物地球化学循环的重要场所。不同形态的汞由于理化性质不同,迁移转化过程及其对生态环境的影响也不同,准确测定大气环境中各种形态的汞对于了解其在大气中的行为具有重要意义。1990年以来,大气汞的采集和分析方法技术已经取得了长足进步,一些自动测汞仪、低汞空白和高时间分辨率的采样及分析技术相继出现,使得准确测定大气中不同形态的痕量汞成为可能。文章就国内外近10多年来在这些方面所取得的研究进展进行了回顾和总结,主要介绍了气态总汞、颗粒态汞、活性气态汞、甲基汞等的采集和分析方法。     

Measurements of fractionated gaseous mercury concentrations over northwestern and central Europe, 1995-99

Although it makes up only a few per cent. of total gaseous mercury (TGM) in the atmosphere, the fraction of oxidised (divalent) mercury plays a major role in the biogeochemical cycle of mercury due to its high affinity for water and surfaces. Quantitative knowledge of this fraction present in mixing ratios in the parts-per-10(15) (ppq) range is currently very scarce. This work is based on approximately 220 data for divalent gaseous mercury (DGM) collected during 1995-99 in ambient air. Over the course of the measurements, the sampling and analytical methods were modified and improved. This is described here in detail and includes transition from wet leaching and reduction procedures to thermo-reductive desorption, the use of annular as well as tubular denuders and adoption of an automated sampling system. The concentration of DGM exhibited a strong seasonal behaviour in contrast to atomic gaseous mercury, with low values in winter and maximum values in summer. The DGM/TGM ratios were frequently found to be below the detection limit (< or = 1%) and in the range 1-5%. A trend of diurnal DGM patterns was observed and implies photolytically induced sources. Scavenging of DGM during rain events was also noticed.