载银活性炭法处理含汞废气

对工业生产作业车间中的含汞废气，采用气相导流－纤维体过滤－载银活性炭吸汞净化工艺，可使车间操作空间的含汞浓度０．１０～０．７０ｍｇ／ｍ＾３，降低到＜０．０７ｍｇ／ｍ＾３，治理效率＞９５％，经处理后的空气中含汞浓度低于国家标准允许排放的浓度值。     

塞曼原子吸收光谱法测定固定污染源废气中的汞

用PMS 30B型汞采样器采集固定污染源废气,再用塞曼原子吸收汞分析仪测定样品中的汞,高、低浓度汞标准样品测定结果均在标准范围内,相对误差分别为0和4.3%。汞吸收管对高、低浓度含汞废气的穿透效率表明,当废气汞质量浓度达到mg/m3级别时,穿透率仅为1.3%。用该方法测定稳定工况固定污染源废气中的汞,6次测定结果的RSD为5.9%,方法检出限为1.04 ng,当采样体积为20 L时,检出限为0.05μg/m3。实际监测表明,钢铁企业、燃煤电厂、垃圾焚烧厂废气中汞为0.07μg/m3~1 031μg/m3。     

贵州省赫章县土法炼锌过程中汞的释放量初步研究

对赫章县铅锌矿石、冶炼矿渣、煤、煤渣中汞含量进行了测定．结果表明,矿石中汞含量与锌含量存在显的正相关关系．基于上述测定结果并运用质量平衡法则,计算出不同类型矿石原料在冶炼过程中向大气的释汞因子：硫化矿为每生产It的Zn向大气释放155g的Hg;氧化矿为每生产It的Zn向大气释放79g的Hg．结合上述释放因子,对赫章土法炼锌过程中汞释放量进行了估算。     

Mercury concentrations in the surface sediments of the intertidal area along the west coast of Peninsular Malaysia

Total mercury (Hg) levels in the intertidal surface sediments along the west coast of Peninsular Malaysia were analysed by using heat vaporization method. Total Hg levels in these sediments ranged from 3.00 to 201?µg?kg^?1 dry weight with a mean concentration of 60.0?µg?kg^?1 dry weight. More than 90% of the samples studied have the total Hg concentrations less than 150?µg?kg^?1 dry weight. Compare with the regional data and sediment quality guidelines, the Hg contamination in the intertidal area along the west coast of Peninsular Malaysia was not serious, except for a few sites that might have received anthropogenic Hg in the samples collected between 1999 and 2000. It is suggested that a similar study of heavy metals in the sediments of the west coast of Peninsular Malaysia be conducted regularly.     

Total mercury content found in edible tissues of top predator fish from the Gulf of California,Mexico

Fish at the top of the food chain bioaccumulate and biomagnify toxic metals including mercury (Hg), at a higher rate than nonpredatory fish. However, although some top predator fish species are important in the human diet, the risks for consumers in Mexico are difficult to evaluate due to the scarce baseline information available. In the present article, data on the total mercury (THg) concentrations found in edible tissues of different species of sharks, rays, large pelagic fishes and groupers from the Gulf of California are presented and compared with national and international health guidelines. During 2003 and 2004, 73 shark dorsal tissue samples, 52 ray samples, 66 large pelagic fish samples and 16 grouper samples were collected at different sites along the Gulf of California. Samples were digested in a microwave system and analyzed by cold vapor atomic absorption spectrophotometry. Thirty samples (14%) showed concentrations of Hg above the national statutory limit of 1?mg?kg^?1, from which 25 samples were sharks and 3 were large pelagic fishes. A positive correlation was found between the natural log of THg [ln(THg)] and total length (TL cm) in species of sharks, rays and groupers. The Teacapán estuary in Sinaloa was detected as a possible source of Hg into the Gulf of California due to historic mining in the watershed. Mean Hg concentrations exceeded the regulatory limit of 1?mg?kg^?1 in the following highly commercial shark species: smooth hammerhead, pelagic thrasher, pacific sharpnose shark, dusky shark, scalloped hammerhead, and whitenose shark, in that order. It is recommended that preventive food advisories be issued with respect to these species until further investigations are conducted.     

煤矿粉尘沉积模型的研究

推导了落尘的沉积模型,提出了落尘聚集体、落尘凝结体的概念。通过对落尘颗粒间四种主要内聚力以及气流浮力的量级分析,指出矿井条件下抑制落尘颗粒二次飞扬的前提是使尘粒得到充分的湿润,并进行了两种集合体的二次飞扬试验     

汞、镉对水螅细胞重聚体的毒性及其分析

应用HgCl_2、CdCl_2对水螅细胞重聚体进行了毒性作用的研究。结果表明,Hg~(2+)、Cd~(2+)使其重聚体细胞解离的起始浓度为0.2ppm、5ppm。重聚体解离的时间与Hg~(2+)、Cd~(2+)的浓度密切相关。因此,有可能根据水螅细胞重聚体的变化应用于水生毒理学的检测和评估。     

Assessing the factors impacting the bioaccessibility of mercury (Hg) in rice consumption by an in-vitro method

Mercury (Hg) in rice is drawing mounting concern since methylmercury (MeHg) was found capable of accumulating in rice. In-vitro bioaccessibility is a feasible and reliable method to assess the health effects of Hg in rice and has been utilized in a number of studies. This study was done to investigate the impact of cultivar, planting location, and cooking on the total mercury (THg) and MeHg bioaccessibility of rice, for which multiple statistical analysis methods were used to analyze the significance of their effects. The THg concentrations of rice samples taken from non-Hg contaminated areas of China were all below 15 ng/g and their MeHg concentrations were below 2 ng/g. Cooking could significantly reduce the MeHg bioaccessibility of rice because the MeHg was mainly combined with protein and the protein will be denatured during the cooking process, and then the denatured MeHg is difficult to be dissolved into the liquid phase. Indica- and japonica-type rice cultivars did not show significant differentiation in either the concentration of Hg or its bioaccessibility. However, the glutinous rice type differed significantly from the above rice types, and it showed greater bioaccessibility of THg and MeHg due to its distinct protein contents and starch properties. Planting location can affect the Hg concentration in rice and THg bioaccessibility but has a limited impact on MeHg bioaccessibility. Based on these results, two macro factors (rice cultivar, planting location) are presumed to impact Hg bioaccessibility by how they affect micro factors (i.e., Hg forms).     

Food alert patterns for metal contamination analyses in seafoods: Longitudinal and geographical perspectives

The aims of this study are to explore metal contamination in food with respect to variations in: i) the levels found over a period of eleven months and/or ii) by food types; and iii) to report patterns in reporting between countries. The frequencies of reported cases of metal ion contamination were ≤ 25% of total food alerts with notable increases between June and October. The alerted food products were dominated by seafood, where the majority were due to Mercury contamination and were made by EU member states with Italy making 57 of the 102 reports. The contaminated seafoods originate in thirty two countries with only Spain producing over 10 contaminated seafood products with a total of 47. In conclusion, this analysis highlights the main detector and transgressor nations along with the seafood and metal types that lead to alerts owing to high levels of contamination.     

Formation of sulfur oxide groups by SO2 and their roles in mercury adsorption on carbon-based materials

The presence of SO₂ display significant effect on the mercury (Hg) adsorption ability of carbon-based sorbent. Yet the adsorption and oxidation of SO₂ on carbon with oxygen group, as well as the roles of different sulfur oxide groups in Hg adsorption have heretofore been unclear. The formation of sulfur oxide groups by SO₂ and their effects on Hg adsorption on carbon was detailed examined by the density functional theory. The results show that SO₂ can be oxidized into SO₃ by oxygen group on carbon surface. Both C-SO₂ and C-SO₃ can improve Hg adsorption on carbon site, while the promotive effect of C-SO₂ is stronger than C-SO₃. Electron density difference analyses reveal that sulfur oxide groups enhance the charge transfer ability of surface unsaturated carbon atom, thereby improving Hg adsorption. The experimental results confirm that surface active groups formed by SO₂ adsorption is more active for Hg adsorption than the groups generated by SO₃.