Environmental threats to the Three Gorges Reservoir Region:Are mutagenic and genotoxic substances important?

<正>The Three Gorges Dam project(TGDP),with a total static investment of 95.46 billion RMB(US$10.97 billion)based on the 1993 price level,commenced in 1994 and was completed in 2012.The creation of the Three Gorges Reservoir following the completion of the TGDP had brought about significant changes to the Three Gorges Reservoir Region(TGRR),stretching from the town of Sandouping in Hubei Province to the Jiangjin District of Chongqing Municipality.The TGDP has led to progressive urbanization and industrialization of the TGRR,accompanied by increased shipping activities,greater     

Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air vapor pressure deficits

C₄ plants possess better drought tolerance than C₃ plants. However, Hedysarum scoparium, a C₃ species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C₄ species, regarding the interactive effects of drought stress and different leaf–air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C₄ photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO₂ assimilation rate (A_n) was enhanced as vapor pressure deficits increased. A close relationship between A_n and stomatal conductance (g_s) suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C₄ enzymes were higher, including those of phosphoenolpyruvate carboxylase (PEPC) and nicotinamide adenine dinucleotide phosphate-malate enzyme (NADP-ME), whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme (NAD-ME) was higher. Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C₄ biochemical pathways were present in H. scoparium to respond to environmental challenges.     

Rice: Reducing arsenic content by controlling water irrigation

<正>Arsenic has long been recognized as a poison.Arsenic in water supplies that are used for both drinking and crop irrigation can expose many people chronically to elevated levels of arsenic.The main health concern for chronic exposure to arsenic is the development of cancer.Although the World Health Organization(WHO)recommends that total arsenic in drinking water should be under 10μg/L(or 10 ppb),(WHO,2011),some regions     

Forecasting of dissolved oxygen in the Guanting reservoir using an optimized NGBM (1,1) model

An optimized nonlinear grey Bernoulli model was proposed by using a particle swarm optimization algorithm to solve the parameter optimization problem. In addition, each item in the first-order accumulated generating sequence was set in turn as an initial condition to determine which alternative would yield the highest forecasting accuracy. To test the forecasting performance, the optimized models with different initial conditions were then used to simulate dissolved oxygen concentrations in the Guanting reservoir inlet and outlet (China). The empirical results show that the optimized model can remarkably improve forecasting accuracy, and the particle swarm optimization technique is a good tool to solve parameter optimization problems. What's more, the optimized model with an initial condition that performs well in in-sample simulation may not do as well as in out-of-sample forecasting.     

Forecasting of dissolved oxygen in the Guanting reservoir using an optimized NGBM (1,1) model

An optimized nonlinear grey Bernoulli model was proposed by using a particle swarm optimization algorithm to solve the parameter optimization problem. In addition, each item in the first-order accumulated generating sequence was set in turn as an initial condition to determine which alternative would yield the highest forecasting accuracy. To test the forecasting performance, the optimized models with different initial conditions were then used to simulate dissolved oxygen concentrations in the Guanting reservoir inlet and outlet (China). The empirical results show that the optimized model can remarkably improve forecasting accuracy, and the particle swarm optimization technique is a good tool to solve parameter optimization problems. What's more, the optimized model with an initial condition that performs well in in-sample simulation may not do as well as in out-of-sample forecasting.     

饮用水中溴酸盐控制方法和去除技术研究进展

溴酸盐是一种潜在致癌物,通常产生于含溴离子水源水的臭氧消毒过程中,我国和世界卫生组织饮用水标准中规定溴酸盐的最高浓度为10μg/L。重点综述了近7年来溴酸盐生成的控制方法(如优化臭氧投加量、降低溶液pH值、加氨等)以及溴酸盐离子去除技术(如吸附法、还原法、离子交换法、生物法等)的研究进展,并对各种技术的优缺点进行了评述。     

沈阳辉山水库水质污染现状分析及评价

根据《地表水环境质量评价办法》中规定的方法,对沈阳辉山水库进行了水质和富营养化状态评价,并对污染源和水质污染特性进行了分析。结果显示:水库水质类别为劣Ⅴ类,水质状况为重度污染。富营养化综合营养状态指数为34.44,辉山水库水质为中营养化水平,水库没有藻类水华的产生。水库主要污染指标为总磷、总氮和悬浮物,分别超出国家地表水Ⅲ类标准的14.2倍、5.85倍和2.72倍。整个库区水质变化不均匀,水质变化受库区沿岸污染物排放影响较大,辉山明渠上游和某工厂暗渠排污口输入是水库主要污染源,库区周围动迁后的荒地和蚯蚓养殖,是辉山水库地面径流和农业污染污染源。     

酚类内分泌干扰物的污染现状及处理研究进展

为了更好的治理水体中pEDCs的污染,针对pEDCs的代表物质双酚A和烷基酚,综述了世界范围内污染源水中pEDCs的污染现状,并介绍了吸附法、膜处理法、生物降解法、化学氧化法及高级氧化法等主要处理方法。同时,展望了今后pEDCs处理的主要研究方向及现存处理方法的应用前景。两种或两种以上方法的联用将是未来研究的一个重要方向。     

江湖关系演变对洞庭湖水质变化影响研究

利用长江中下游地区监测站点1950~2009年逐日水文监测数据及1995~2010年水质分析资料,结合Spearman相关分析和综合污染指数评价法,分析了长江中下游江湖关系演变对洞庭湖水质变化影响,并面向洞庭湖水环境安全提出一系列调控措施,旨在为洞庭湖地区水质改善提供理论基础与技术支持。     

水污染源解析技术与应用研究进展

阐述了水污染源解析的概念,将水污染源解析方法归纳总结为基于污染负荷估算的方法、基于污染潜力指数的方法及基于源受体污染物特征的方法 3种类型,并分别概述了各种方法的特点,综述了国内外水污染源解析研究的类型与应用进展。最后指出了我国水污染源解析研究在基础资料、研究对象及方法上存在的问题,提出了未来的研究重点。