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.     

Spatiotemporal Variation of Karst Ecosystem Service Values and Its Correlation with Environmental Factors in Northwest Guangxi,China

In this investigation we analyzed the spatiotemporal variation of ecosystem service values (ESVs) and its correlation with numerous environmental factors (EFs) for the karst region of Northwest Guangxi, China, from 1985 to 2005 using remote sensing, geographic information systems (GIS) and statistical techniques. The results indicate that historically ESVs for this karst region decreased from 1985 (109.652 billion Yuan) to 1990 (88.789 billion Yuan) and then increased at the turn of the twenty-first century. However, the ESVs in both 2000 (103.384 billion Yuan) and 2005 (106.257 billion Yuan) never achieved the level recorded in 1985. The total of nutrient cycling, organic production and gas regulation combined were 72.69, 64.57, 70.18 and 72.10% of ESVs in 1985, 1990, 2000 and 2005, respectively. In contrast, the ESVs of water conservation, soil reservation, recreation and culture were determined to be relatively low contributing only 17.44, 23.82, 19.26 and 24.76% of total ESVs, respectively, during these four years. With regards to the spatial distribution of ESVs, larger values were recorded in the west and smaller ones recorded in the east. The most significant factors that were deemed to influence ESVs are annual rainfall, per capita cropland, slope and vegetation coverage. Annual rainfall and slope exert a negative force, whereas per capita cropland and vegetation coverage exert a positive force on ESVs. The results of the study would suggest that ecosystem conditions of this important karst region have been improved as the result of the implementation of rocky desertification control policies.     

中国湿地与湿地自然保护区管理

<正>湿地是地球自然生态系统的重要组成部分,与森林和海洋相比,湿地生态系统更加脆弱,与人类的发展关系更为紧密,是人类社会生存和发展的重要自然资源。加强湿地保护对社会经济的可持续发展具有重要作用。中国是湿地大国,天然湿地总面     

Influence of the sewage irrigation on the agricultural soil properties in Tongliao City, China

Increasing shortages of fresh water has led to greater use of treated wastewater for irrigation of crops. This study evaluates the spatial variability of soil properties after irrigation with wastewater and freshwater. Geostatistical techniques were used to identify the variability of soil properties at the different sites. A set of physical and chemical soil properties were measured including total nitrogen (TN), total phosphorus (TP), organic matter (OM) and soil moisture. The TN concentration levels varied from 567 to 700 mg·kg^-1, while OC levels ranged from 7.3 to 16.3 mg·kg^-1 in wastewater-irrigated zones. The concentration levels of TP were between 371.53 and 402.88 mg·kg^-1 for the wastewater-irrigated sites. Wastewater irrigation resulted in higher TN, TP and OM concentrations by 18.4%, 8% and 25%, respectively. The highest TN and OM occurred along the wastewater trunk. It was also observed that nitrogen concentrations correlate with the soil's organic matter. The increase of salinity may be associated with the increase of pH, which might suggest that a reduction of pH will be beneficial for plant growth due to the decrease of salinity. The average concentrations of nitrogen in topsoil were higher than those in subsurface soils in irrigated areas. Such differences of the N profile might be due to variations in organic matter content and microbial populations. Consistent with TN and OM, soil C:N decreased significantly with an increase of depth. This phenomenon possibly reflects a greater degree of breakdown and the older age of humus stored in the deeper soil layers. The analysis of pH levels at different depths for the three sites showed that pH values for wastewater irrigation were slightly lower than the controlled sites at the same depths.     

桂西北喀斯特区原生林与次生林凋落物及养分归还特征比较

森林凋落物是森林生态系统的重要组成成分,其养分归还量在一定程度上决定着土壤养分有效性的高低。在土层浅薄且土被很不连续的我国喀斯特区域进行凋落物生物量及养分归还研究对我们更深刻地了解该区养分循环具有至关重要的意义。本文比较分析了桂西北喀斯特区3种原生林与3种次生林的全年凋落物量、组成、月凋落物量动态及养分归还量与动态。结果表明,圆果化香（Platycarya longipes Wu）、大叶蚊母树（Distylium Sieb．e tZucc．）与青檀（Pteroceltis tatarinowii Maxim．）3种原生林的年凋落物总量分别为2342．16,4057．99和1834．36k·hm～,而圆叶乌桕（Sapium romndifolium Hemsl．）、八角枫似langium chinense（Lour．）Harms）和黄荆（Vitex negundoL．）3种次生林的年凋落物总量分别为3192．82,3284．26,2469．90kg.hm-2,除大叶蚊母树外,次生林年凋落物总量大于原生林。凋落物的组成中,叶凋落生物量均占总凋落物量的80％左右,甚至更高,而圆叶乌桕、八角枫和黄荆3种次生林群落的叶凋落物量占总凋落物量的百分比大于圆果化香、大叶蚊母树以及青檀3种原生林。凋落物的养分归还量的月动态与凋落物量的月动态一致,原生林呈“u”形曲线,而次生林则呈“w”形曲线。原生林和次生林凋落物的年养分归还量均为C〉N〉K〉P,且次生林的c、N、P养分的归还量大于原生林。     

生物质炭对溶液中Cd~(2+)的吸附

以玉米秸秆、稻壳在350~500℃制成的生物质炭作为吸附剂,研究其对溶液中Cd2+的吸附特性。通过模拟实验,考察了初始p H、生物质炭用量、吸附时间和Cd2+的起始浓度对吸附的影响。结果表明,2种生物质炭对Cd2+的吸附反应适应p H范围较宽(4.0~7.0);玉米秸秆炭和稻壳炭对Cd2+的吸附速度较快,分别在10和20 min时达到吸附平衡;玉米秸秆炭对溶液中Cd2+的吸附遵循Langmuir等温线模型,而稻壳炭对Cd2+的吸附遵循Freundlich等温线模型。在实验设定的条件下,玉米秸秆炭对溶液中Cd2+的吸附能力强于稻壳炭。     

Inter-annual and intra-annual variations in water quality and its response to water-level fluctuations in a river-connected lake,Dongting Lake,China

Environmental Science and Pollution Research - The hydrological conditions of river-connected lakes are complex primarily owing to their considerable water-level fluctuations (WLFs). Water quality...     

稻壳活性炭对活性艳蓝KN-R的脱色研究

将稻壳在微波条件下制备成活性炭吸附剂,研究其对活性艳蓝KN-R的吸附特性。通过静态实验,考察了pH值、温度、时间、溶液起始浓度和吸附剂用量对吸附过程的影响。结果表明,当pH为2和12时吸附效果较好,最大吸附量分别为303.03、384.62 mg/g;随着温度的升高,达到吸附平衡的时间缩短;等温吸附过程可以用Langmuir方程来描述;动力学实验表明,吸附过程更符合拟二级动力学模型;热力学数据分析发现,吸附过程是自发进行的吸热过程。     

当前环境管理体系下环保NGO角色定位及生存环境探讨

环保NGO的明确的角色定位有利于提高其行为效率。对中国环保NGO的行为过程进行研究后指出其应以合作者、监督者、环保决策的参与者和环保理念的宣传者的角色规范自己以提高自己的行为能力。同时从经济、法规政策和国际环境三个方面对其生存环境进行了分析,指出改善其生存环境的重要手段就是不断完善相关的法律法规和政策。