程海沉积物重金属时空变化及人为污染与潜在生态风险

沉积物重金属污染是影响湖泊等水体环境质量与健康的主要因素之一.通过对程海9个沉积短岩芯中10种金属元素含量的分析,在~(210)Pb与~(137)Cs定年的基础上,研究了沉积物中重金属含量与污染的时空变化特征;采用潜在生态风险指数法与沉积物质量基准法、并参考重金属污染水平,评估了表层沉积物重金属的潜在生态风险.结果表明,各岩芯不同年代沉积物中,除了Cd含量变化较大之外(变异系数为0.59),其余各金属元素含量变化均较小(变异系数小于0.20);空间上,各岩芯之间每一种金属的平均含量差异较小,最大值与最小值的比值为1.2~1.8,显示了不同湖区重金属较为相似的富集规律.沉积物中主要污染元素为Cd、Pb和Hg,其中Cd和Pb污染始于20世纪80年代中期;近十年来Cd污染程度稍有下降,但仍呈中等污染水平,而Pb污染程度持续增加,属于弱污染水平;Hg污染始于20世纪90年代末期,呈弱污染水平;而As、Cu和Zn仅在部分近表层沉积物呈现较弱污染.空间上,沉积物中重金属污染水平并未表现出明显的趋势.除了大气沉降(主要为有色金属冶炼释放)输入之外,程海沉积物重金属污染还可能受到农业面源与生活污水排放的影响.表层沉积物中As、Cu、Ni、Pb和Zn具有较低的潜在生态风险,Hg和Cd具有中-高潜在生态风险.     

Lake area changes in the middle Yangtze region of China over the 20th century

The Jianghan Plain and the Dongting lake area, located in the middle reaches of the Yangtze River are famous for their abundant freshwater lakes. The lakes have undergone changes in size and number over thousands of years due to natural causes and human activities. The 20th century particularly, witnessed dramatic changes in the freshwater resources of this region. This paper traces and analyzes lake evolution in the middle reaches of the Yangtze River over the past century. Lakes greater than 0.1 km(2) in size are mapped using Geographic Information System. Data is acquired and integrated from drainage network maps, relief maps, historical maps and remotely sensed images for different time periods. The results indicate that while there has been little change in the number of lakes over the past century, the lake area has experienced a dramatic decrease of 58.06%. The paper also examines the natural processes and human activities that may have contributed to the decrease in lake area. The results show that the decrease in total lake area appears to coincide with periods of rapid land reclamation in the middle reaches of the Yangtze River. Moreover, uncontrolled land reclamation activities can create an increase in sediment deposition in lakes thereby further reducing the lake size. Reduction of the lake area directly affects flood-control and has a negative ecological impact on the environment and on human life and property.     

湖泊水面温度遥感定量反演研究综述

湖泊水面温度与藻类生长密切相关,通过获取水体表层温度信息来监测湖泊水面温度时空动态变化,对于蓝藻水华预警监控具有重要意义。湖泊水面温度遥感定量反演的理论方法与反演地表、海洋表面温度基本相同。本文在介绍遥感反演地表温度原理的基础上,总结了国内外基于热红外波段反演水体表面温度的单窗算法、劈窗算法、多通道算法等几种常用方法,重点分析了各算法的优缺点和反演的主要难点,并对今后在内陆水体藻华预测顸警等方面的应用趋势进行了展望。     

鸭儿湖表层沉积物中有机氯农药残留及其分布特征

鸭儿湖地区在上世纪60—70年代有机氯农药（OCPs）污染严重,为了改善水质1975年鸭儿湖开展了水质污染处理,并于2003年和2004年开展了清淤工作.为了解现阶段鸭儿湖地区有机氯农药污染状况,本文于2009年采集了鸭儿湖5个氧化塘20个表层沉积物,对有机氯农药残留进行了研究.利用气相色谱-质谱联用法（GC-MS）对...     

南四湖流域水污染防治存在的问题及对策

南四湖通过采用"治、用、保"并举的流域污染综合治理措施,把污染治理与水资源循环利用相结合,取得了明显的成效,但仍面临工业结构性污染严重、城市基础设施建设滞后、面源污染突出等问题。根据南四湖实际情况,可从加大资金筹措力度、继续实施流域综合治理、整合现有港口资源、开展生态养殖、加强执法等方面入手,解决流域水污染防治存在的问题。     

Analysis of the trade-off between economic growth and the reduction of nitrogen and phosphorus emissions in the Poyang Lake Watershed, China

Lake eutrophication leading to water pollution is a major global concern. In recent years, rapid economic growth and the increase in the intensity of resource exploitation in China have caused the influx of nitrogen and phosphorus into lakes. This in turn has led to more severe lake eutrophication, more frequent outbreaks of algal blooms, and the degradation of lake ecosystems. An effective plan balancing economic growth with the reduction of nitrogen and phosphorus emissions is greatly needed. The design and implementation of such a plan requires the collection and analysis of pertinent data. In this paper, we use the environmental computable general equilibrium (ECGE) model to identify the most effective way to balance economic growth with the reduction of nitrogen and phosphorus emissions. For the multiregional analysis, we use social accounting matrices (SAMs) and a provincial trade matrix based on the assumptions of the gravity model. We consider the Poyang Lake Watershed as a case study to illustrate the utility of the model. Based on present conditions in the Poyang Lake Watershed, restricting nitrogen and phosphorus emissions from sectors with the highest emissions is more effective for balancing economic growth and the reduction of nitrogen and phosphorus emissions than restricting nitrogen and phosphorus emissions from all sectors.     

Cosmic exergy based ecological assessment for a wetland in Beijing

Wetlands research and restoration has become one of the critical concern due to their importance in providing ecosystem services. This study proposes a holistic methodology to assess the wetland ecosystem based on cosmic exergy as a thermodynamic orientor. This new approach is applied to two typical wastewater treatment facilities (an activated sludge system and a cyclic activated sludge system) and to a constructed wetland ecosystem in Beijing for comparison. Results show that the Beijing wetland ecosystem gains positive net present ecological value of 3.08E+14 J_c regarding its total life cycle. Comparison with the activated sludge system and cyclic activated sludge system, shows that the wetland ecosystem has greater dependencies on local resources (22% vs. 0% vs. 0%) and renewable resources (67% vs. 38% vs. 31%) as well as a larger ecological sustainability index (0.64157 vs. 0.00005 vs. 0.00008). This implies that the wetland ecosystem is more environmentally friendly and sustainable method for water treatment.     

A model on the carbon cycling in Lake Taihu, China

A model of the carbon cycling in Lake Taihu was developed based on the previous developed model EcoTaihu Model, which couples the hydrology, the nutrient cycling and a number of biological processes. The carbon cycling model (abbreviated CCM) has in addition to the states variables of the EcoTaihu Model, the carbon in phytoplankton, zooplankton, fish, macroplant, hydrogen carbonate carbon, carbonate carbon, dissolved carbon, abiotic organic carbon in water, organic carbon in sediment, soluble organic carbon in pore water, inorganic carbon in sediments, soluble inorganic carbon in pore water and pH. The calibration and validation of the CCM showed that the model results are in good accordance with the observations (from the period February17 to December. 5, 2003). It implies that the model can be used to assess the variation of the carbon dioxide flux at the water-air interface, and to find the pH value of the lake water as function of time. According to the model, the carbon dioxide flux at the water-air interface has clear, diurnal variations. Eutrophied water is a sink for the atmospheric carbon dioxide due to the phytosynthesis during the summer. Due to the terrestrial input of carbon to the lake, Lake Taihu is, however, a source of atmospheric carbon dioxide. The total annual flux is almost equal to the terrestrial input of carbon to the lake.     

武汉月湖近代沉积物中的硅藻组合与环境关系研究

采集武汉月湖2处近代沉积物,分析了沉积硅藻组合与其环境关系,共发现24属83种硅藻。结果表明：2个柱状沉积物中硅藻优势属为小环藻属、直链藻属、舟形藻属、Cyclostephanos属。Z-1钻孔共有20属61种硅藻,Z-2钻孔共有24属68种硅藻。Z-1钻孔优势种为梅尼小环藻（Cyclotella meneghiniana）、颗粒直链藻（Aulacoseira granulata）、Navicula porifera、Cyclostephanos tholifomis。Z-2钻孔优势种为梅尼小环藻、颗粒直链藻、舟形藻（Navicula sp.）、Cyclostephanos invisitatus。就硅藻密度分布而言,总趋势上层最多,平均7.14×10^5～58.65×10^5 ind.g-1,中层其次,平均0.08×10^5～13.98×10^5 ind.g-1,下层最少,平均0.24×10^5～0.64×10^5 ind.g-1。硅藻种数最少的样品出现在沉积物中层,梅尼小环藻、颗粒直链藻、舟形藻、Navicula porifera、Cyclostephanos tholifomis、Cyclostephanos invisitatus的组合可以指示湖泊水体环境出现富营养化。通过探讨分析影响硅藻分布的环境因素,为恢复月湖近代水环境演化过程提供了依据。     

呼伦湖冰封期污染特征分析及对水处理的意义

以内蒙古呼伦湖为研究对象,对其在冰封过程中总氮、总磷和有机物在冰体和水体中的浓度及分布特征及其在呼伦湖的空间变异性进行分析。结果表明,冰封条件下,呼伦湖水体中总氮、总磷和有机物的含量均大于其在对应冰体中的含量,其含量均值分别是其对应冰体中的3.144倍、2.200倍和3.042倍,即低温冷冻过程对水体中的污染物有一定的浓缩效应;水体中各营养盐和有机物的空间变异性明显小于其在冰体中的;从固-液相平衡理论、结晶学理论和热力学理论三个方面对冷冻浓缩效应做出了合理的解释。研究认为,可以将冷冻浓缩效应运用到给水处理和污水处理领域,这样既可以进行大规模的处理,也可以节约资源、保护环境。