Chronic exposure effects of copper on growth,metamorphosis and thyroid gland,liver health in Chinese toad,Bufo gargarizans tadpoles

The impact of copper exposure on Chinese toad (Bufo gargarizans) tadpoles was investigated in this study. First, the 96h LC50 value of copper was 8.697 μM, by means of a 4 d acute toxicity test. Second, we studied the chronic effects of copper on B. gargarizans tadpoles at control, 0.025, 0.1 and 1.0 μM concentration. Survival, body length, body weight, developmental stage, incidence of metamorphic climax, and size at metamorphic climax were determined. In tadpoles developed to metamorphic climax (stage G42), liver and thyroid gland were assessed histologically. Copper at 0.1 and 1.0 μM could inhibit tadpole growth and prolong tadpole metamorphic progress relative to controls. Tadpole size (total length and weight) at stage G42 is also affected in the 0.1 and 1.0 μM treatments. In addition, histological examinations have revealed that 1.0 μM copper could cause significant pathological changes and hepatocytes degeneration in liver. Furthermore, histomorphological measurements indicated that copper at 0.1 and 1.0 μM reduced thyroid gland size, diameter and number of follicle. In conclusion, our study suggests that Cu could damage the liver and thyroid gland, so growth and metamorphosis of B. gargarizans tadpoles were inhibited resulted of disrupting liver metabolism and THs homeostasis.     

生活垃圾填埋场填埋气中汞的分布特征

利用Tekran 2537A和Lumex RA-915汞分析仪分别对生活垃圾填埋场排气筒、填埋场内部的气态总汞变化规律进行了分析,结果表明,填埋场排气筒中气态总汞含量呈现明显的昼夜变化规律,白天高于夜间,并于午间达到峰值。气象条件对汞的释放过程有重要影响,光照强度与排气筒中气态总汞含量的相关性明显。受填埋场内部物理、化学、生物作用的影响,填埋场内部填埋气的汞浓度明显高于排气筒中填埋气的汞浓度。填埋场内部气态总汞变化规律为:植被覆盖区域明显低于无植被覆盖区域,表明有效的绿化措施对于控制填埋场汞污染具有重要意义。     

Control strategies of atmospheric mercury emissions from coal-fired power plants in China

Atmospheric mercury (Hg) emission from coal is one of the primary sources of anthropogenic discharge and pollution. China is one of the few countries in the world whose coal consumption constitutes about 70% of total primary energy, and over half of coals are burned directly for electricity generation. Atmospheric emissions of Hg and its speciation from coal-fired power plants are of great concern owing to their negative impacts on regional human health and ecosystem risks, as well as long-distance transport. In this paper, recent trends of atmospheric Hg emissions and its species split from coal-fired power plants in China during the period of 2000-2007 are evaluated, by integrating each plant's coal consumption and emission factors, which are classified by different subcategories of boilers, particulate matter (PM) and sulfur dioxide (SO2) control devices. Our results show that the total Hg emissions from coal-fired power plants have begun to decrease from the peak value of 139.19 t in 2005 to 134.55 t in 2007, though coal consumption growing steadily from 1213.8 to 1532.4 Mt, which can be mainly attributed to the co-benefit Hg reduction by electrostatic precipitators/fabric filters (ESPs/FFs) and wet flue gas desulfurization (WFGD), especially the sharp growth in installation of WFGD both in the new and existing power plants since 2005. In the coming 12th five-year-plan, more and more plants will be mandated to install De-NO(x) (nitrogen oxides) systems (mainly selective catalytic reduction [SCR] and selective noncatalytic reduction [SNCR]) for minimizing NO(x) emission, thus the specific Hg emission rate per ton of coal will decline further owing to the much higher co-benefit removal efficiency by the combination of SCR + ESPs/FFs + WFGD systems. Consequently, SCR + ESPs/FFs + WFGD configuration will be the main path to abate Hg discharge from coal-fired power plants in China in the near future. However advanced specific Hg removal technologies are necessary for further reduction of elemental Hg discharge in the long-term.     

Preface

正Air pollution as well as climate change and their possible effects on the environment,ecosystems and human health,are pressing challenges.Nowadays,it is clear that sustainable societal development cannot remain solely wealth-oriented,but must take into account the present and future environmental issues.However,this approach is possible only if scientifically sound knowledge in all environmental areas becomes available to our societies and decision makers,which requires a firm     

Pedological characteristics of Mn mine tailings and metal accumulation by native plants

In southern China revegetation and ecological restoration of many abandoned Mn tailings has become a major concern. To determine the major constraints for plant establishment and evaluate the feasibility of remediation, a comparative study was conducted on Mn tailings and rhizosphere soils at the boundary of the tailings pond. Both tailings and rhizosphere soils had neutral to slightly alkaline pH and normal electrical conductivity. They were both enriched with organic matter (6.8-9.2%), total N (1.77-5.94 g kg(-1)), available P (41.78-73.83 mg kg(-1)) and K (146.7-906.9 mg kg(-1)), suggesting the tailings were a nutrient rich substrate for revegetation. Mn tailings were clay textured, while rhizosphere soils were silty loam or clay loam. The compaction and anoxic nature of Mn tailings were considered to be the major constraints for plant establishment. Total Mn (31903 mg kg(-1)), Cd (119 mg kg(-1)), Cu (126 mg kg(-1)) and Zn (2490 mg kg(-1)) in tailings were all at phytotoxic levels, but did not differ significantly from those in rhizosphere soils. In both tailings and rhizosphere soils, percentages of water- and DTPA-extractable metals were less than 1% and 2% of the total metal pools, respectively. Sequential extraction revealed that the majority of Mn, Cu and Zn were associated with the residual fraction, while the majority of Cd occurred as Fe-Mn oxides. The natural succession of plants around Mn tailings formed a distinctive metal-tolerant plant community, mainly comprising nine species such as Cynodon dactylon and Humulus scandens and so on. All species studied could be good candidates for revegetation of Mn tailings.     

铅职业危害及其防治

通过对某铅冶炼厂职业铅危害情况及防治现状进行调查分析,提出了防治铅中毒、铅吸收的措施。     

中国大气挥发性有机物控制现状及对策研究

大气挥发性有机物(VOCs)不仅本身具有较强毒性,而且是影响中国区域复合大气污染的重要前体物和参与物。近年来,中国不断加大对VOCs的管控力度,从制定政策体系、建立监测标准等角度采取了一系列的措施。但总体来看,中国大气VOCs控制仍存在许多问题。突出地体现在:基础数据匮乏,排放状况不清;法律法规滞后,污染防治与监管体系不健全;排放标准和监测规范不完善,控制技术亟需革新。基于此,本文从完善法律法规、健全制度体系和加强标准控制等方面提出了加强VOCs管控的思路和对策建议。     

根表铁膜的形成和添加硒对水稻吸收转运无机汞和甲基汞的影响

为了研究根表铁膜和硒对水稻吸收、转运不同形态的汞的影响,用Fe2+溶液诱导根表形成铁膜后,将水稻植株分别暴露于无机汞(Hg Cl2)、甲基汞(Me Hg Cl)、无机汞和亚硒酸钠(Hg Cl2+Na2Se O3)混合溶液、甲基汞和亚硒酸钠(Me Hg Cl+Na2Se O3)混合溶液的培养液中继续培养72 h。用DCB(dithionite-citrate-bicarbonate)提取根表铁膜,并用电感耦合等离子体质谱(ICP-MS)测定DCB溶液中Fe、Hg含量及水稻根、茎叶中Hg含量。结果表明:水稻根表铁膜对Me Hg Cl和Hg Cl2均有吸附,对Me Hg Cl的吸附作用高于Hg Cl2。根表铁膜的形成显著降低了汞暴露水稻根、茎叶中汞的含量;铁膜的形成也显著降低了Hg Cl2和Me Hg Cl从水稻根部到茎叶部分的转运效率。硒的存在可增加铁膜对Hg Cl2和Me Hg Cl的吸附,降低水稻对Hg Cl2和Me Hg Cl的吸收和转运。研究结果表明:根表铁膜和硒单独或联合作用能显著抑制水稻对无机汞和甲基汞的吸收和转运,进而可以减少汞在稻米中的蓄积。研究的开展对于提高汞污染区稻米的质量和保证粮食安全具有一定的现实意义。     

有机膨润土吸附对硝基苯酚的性能及其在水处理中的应用初探

分别用溴化十六烷基三甲铵（ＣＴＭＡＢ）和氯化十六烷基吡啶（ＣＰＣ）改性膨润土，研究了制备有机膨润土的适宜条件及其对吸附对对硝基苯酚性能的影响。２５℃时，ＣＴＭＢ－膨润土和ＣＰＣ－膨润土对对硝基苯酚的饱和吸附量分别为４７５ｍｇ／ｇ，远大于原土的饱和吸附量（１２５ｍｇ／ｇ）。ｐＨ〉７时，有机膨润土吸附处理对硝基苯酚的去除率都在８５％以上，比原土的去除率（８．６％）大９倍，通过Ｘ－衍射、红外光谱分析、比     

Leaching of elements from flue dust produced in copper scrap smelting process

To understand the features and leaching characteristics of copper (Cu) scrap smelting dust and its potential risk to environment and humans, three types of smelting dust were sampled and investigated. The dust samples were collected from the dust captured by cyclone collector, panel cooler, and bag house in a typical Cu scrap smelting process of a factory in Guangxi of China. Zinc (Zn), Cu and lead (Pb) were the main elements of the samples of cyclone collector dust (CCD), panel cooler dust (PCD), and bag house dust (BHD). There were less arsenic (As), Pb and Cu in CCD than PCD and BHD, and PCD contained more manganese (Mn), nickel (Ni), and iron (Fe) than BHD. The particle shapes of BHD appeared more regular than CCD and PCD, and energy dispersive X-ray spectroscopy analysis illustrated the compositions of selected surface areas of three samples. The size of particles ranged from 0.011 to 33.11 μm in CCD, from less than 1 μm to several mm in PCD, and from 0.832 to 363.078 μm in BHD. The main elements in leachate were Zn and Mn from CCD, Zn, cadmium (Cd) and Pb from PCD, Zn, Mn and Cd from BHD. The leaching toxicity risk of Cd, Mn, and Zn of PCD and BHD was higher than CCD.