Estimation of vegetative mercury emissions in China

Vegetative mercury emissions were estimated within the framework of Biogenic Emission Inventory System (BEIS3 V3.11). In this estimation, the 19 categories of U.S. Geological Survey landcover data were incorporated to generate the vegetation-specific mercury emissions in a 81-km Lambert Conformal model grid covering the total Chinese continent. The surface temperature and cloud-corrected solar radiation from a Mesoscale Meteorological model (MM5) were retrieved and used for calculating the diurnal variation...

Mercury emission and pollution in Chongqing City, China

Investigation showed that mercury emission in Chongqing City, China is about 2.1 t/a, 70% of which came from coal burning.Mercury in many water bodies have been detected, in vegetables and milk had exceeded the food standard value in some places.

Differentiated emission control strategy based on comprehensive evaluation of multi-media pollution:Case of mercury emission control

In order to comprehensively evaluate the environmental impact of multi-media mercury pollution under differentiated emission control strategies in China,a literature review and case studies were carried out.Increased human exposure to methylmercury was assessed through the dietary intake of residents in areas surrounding a typical coal-fired power plant and a zinc(Zn)smelter,located either on acid soil with paddy growth in southern China,or on alkaline soil with wheat growth in northern China.Combined with knowledge on speciated mercury in flue gas and the fate of mercury in the wastewater or solid waste of the typical emitters applying different air pollution control devices,a simplified model was developed by estimating the incremental daily intake of methylmercury from both local and global pollution.Results indicated that air pollution control for coal-fired power plants and Zn smelters can greatly reduce health risks from mercury pollution,mainly through a reduction in global methylmercury exposure,but could unfortunately induce local methylmercury exposure by transferring more mercury from flue gas to wastewater or solid waste,then contaminating surrounding soil,and thus increasing dietary intake via crops.Therefore,tightening air emission control is conducive to reducing the comprehensive health risk,while the environmental equity between local and global pollution control should be fully considered.Rice in the south tends to have higher bioconcentration factors than wheat in the north,implying the great importance of strengthening local pollution control in the south,especially for Zn smelters with higher contribution to local pollution.

Mercury emissions in China:a general review

This paper provides a general review of the research status of mercury emissions in China.Global surveys rank Asia as the region with the largest share of global mercury emissions,accounting for almost half.China contributes about one-third of the world’s mercury emissions,which is 600-800 t per year.And thus,it plays a vital role in reducing global mercury emissions.Data since 2003 has been surveyed.Mercury emissions in China have risen in the beginning and then declined.There are differences in the composition of mercury emissions sources between China and the world,in which coal combustion and non-ferrous metals smelting contribute more than 50%of the emissions in China.Although mercury emission standards in China are close to those of the European Union and the United States,annual mercury emissions in China are four times higher than those of the United States.Mercury emissions in China are concentrated in the central and eastern regions now,but the annual mercury emissions are increasing in the western regions,which may be related to the construction of industrial parks.

Mercury mass flow in iron and steel production process and its implications for mercury emission control

The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%–49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%–36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven,sintering machine and blast furnace were 0.039–0.047 g Hg/ton steel, and for the electric furnace it was 0.021 g Hg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%–73% of total mercury emissions to air.

Mercury in coal and its emission by coal combustion in the Northeast China

This paper reports on the mercury content distribution in coals produced in the Northeast of China, and the east of Inner Mongolia, and transmission of mercury from coals into the burned products. The arithmetic average value of mercury content in coals is 0.158 mg/kg, and the mercury content shows considerable positive correlation with ashes in coals. The mercury content in fly ash is increased as the particle diameter of fly ash decrease. After combustion, 23.1—26.9 percent of mercury in coals enters fly ash,and 56.3—69.7 percent of mercury escapes into atmosphere. We estimated that the amount of mercury in raw coals produced in the Northeast of China and the east Inner Mongolia was 30.9 tons in the whole year and the amount emitted into atmosphere was 20 30 tons in 1990.

Refining mercury emission estimations to the atmosphere from iron and steel production

Due to its long-range transport in the atmosphere,mercury is a pollutant of global concern with health risks to humans and ecosystems worldwide（Li et al.,2012;Lindqvist et al.,1991;Liu et al.,2012a;Tang et al.,2016;Wang et al.,2015;Shao et al.,2016）.Atmospheric mercury,mainly from emission from various natural and anthropogenic sources and re-emission of previously released mercury built up in surface soils and oceans,

A sensitive and compact mercury analyzer by integrating dielectric barrier discharge induced cold vapor generation and optical emission spectrometry

An environmentally friendly,low power consuming,sensitive and compact mercury analyzer was developed for the determination of mercury in water samples by integrating a thin film dielectric barrier discharge induced cold vapor reactor and a dielectric barrier discharge optical emission spectrometer into a small polymethyl methacrylate plate（10.5 cm length×8.0 cm width×1.2 cm height）.Mercury cold vapor was generated when standard or sample solutions with or without formic acid were introduced to the reactor to form thin film liquid and exposed to microplasma irradiation and subsequently separated from the liquid phase for transport to the microplasma and detection of its atomic emission.Limits of detection of 0.20 μg L^-1 and 2.6 μg L^-1 were obtained for the proposed system using or not using formic acid,respectively.Compared to the conventional microplasma optical emission spectrometry used for mercury analysis,this system not only retains the good limit of detection amenable to the determination of mercury in real samples,but also reduces power consumption,eliminates the generation of hydrogen and avoids the use of toxic or unstable reductant.Method validation was demonstrated by analysis of a certified reference material of water sample and three real water samples with good spike recoveries（88-102%）.

Mercury transportation in soil via using gypsum from flue gas desulfurization unit in coal-fired power plant

The mercury flux in soils was investigated, which were amended by gypsums from flue gas desulphurization （FGD） units of coal- fired power plants. Studies have been carried out in confined greenhouses using FGD gypsum treated soils. Major research focus is uptakes of mercury by plants, and emission of mercury into the atmosphere under varying application rates of FGD gypsum, simulating rainfall irrigations, soils, and plants types. Higher FGD gypsum application rates generally led to higher mercury concentrations in the soils, the increased mercury emissions into the atmosphere, and the increased mercury contents in plants （especially in roots and leaves）. Soil properties and plant species can play important roles in mercury transports. Some plants, such as tall fescue, were able to prevent mercury from atmospheric emission and infiltration in the soil. Mercury concentration in the stem of plants was found to be increased and then leveled off upon increasing FGD gypsum application. However, mercury in roots and leaves was generally increased upon increasing FGD gypsum application rates. Some mercury was likely absorbed by leaves of plants from emitted mercury in the atmosphere.

Preparation of Sulfur-doped PANI/TiO2 Nanowires and Its Sensing Properties to Mercury

TiO2 nanowires were successfully prepared via a simple hydrothermal method and a layer of sulfurized polyaniline（PANI） was loaded onto their surface to prepare a sensor of elemental mercury at room temperature. The sulfurized PANI/TiO2 composite sensor has a high sensitivity to mercury in a range of density from 5.57 mg/m3 to 126.18 mg/m3 at room temperature. The response time and recovery time are relatively short. We also investigated the sensitivity and response time to other interfering gases, such as NO2, SO2 and NH3. And the sulfurized PANI/TiO2 composite material shows a good selectivity for element mercury. The microscopic structure of the sensor was inves- tigated via X-ray diffraction（XRD）, scanning electron microscopy（SEM） and energy dispersive X-ray analysis （EDAX）. The sulfurized PANI/TiO2 composite material shows a high sensitive response, and good selectivity to element mercury, which is promising for the application in the detection of element mercury.