淠河流域不同强度等级降水变化研究

淠河流域降水时空变率大,深入分析不同强度等级降水的特征和变化,对于全面揭示研究区气候变化、合理有效利用水资源、防治洪旱灾害具有十分重要的意义。基于淠河流域12个气象站1958~2012年逐日降水资料,分析年、季不同级别降水量(频次)的变化特点,以及主汛期(5~9月)连续3d最大降水量的概率分布。结果表明,淠河流域小雨量(频次)四季分布比较均匀,级别越高,降水频次越少,分布越集中,夏季暴雨多发。淠河流域年总降水量增加趋势不显著,总降水频次则显著减少。夏季各级别降水量(频次)均呈增加趋势,其中暴雨增加最显著,冬季总降水频次无明显趋势变化,小雨、中雨量增加显著,春、秋季总降水频次和小雨频次的减少趋势极其显著。淠河流域暴雨量、暴雨频次均在1968年发生增多突变,小雨频次在1975年有极显著减少突变,年总降水量有增多突变,总降水频次则有减少突变。自20世纪70年代后期以来,研究区主汛期连续3d极端强降水出现概率加大,不同重现期极值增大,洪涝灾害风险加剧。     

基于SWAT模型的淠河流域土地利用变化的水文响应模拟

以淮河南岸最大支流——淠河流域为研究区域,采用嵌套入ArcGIS软件的SWAT分布式机理性水文模型定量评估土地利用变化对降水-径流关系的影响.结果表明,1996-2010年淠河流域的土地利用变化主要表现为水田、旱地向建设用地转化以及林地向园地转化.相较于1996年的土地利用情景,2010年土地利用情景下的多年平均径流增加5.87％,年径流的增加主要表现为汛期径流增加,非汛期径流则呈减少趋势,径流量年内变幅加大.对于不同水文年份而言,平水年对土地利用变化的水文响应最明显,变幅最大,枯水年则略大于丰水年,淠河流域的水源涵养能力呈现减退趋势.     

Oral administration of potassium bromate, a major water disinfection by-product, induces oxidative stress and impairs the antioxidant power of rat blood

Potassium bromate (KBrO₃) is a widely used food additive, a water disinfection by-product and a known nephrotoxic agent. The effect of KBrO₃ on rat blood, especially on the anti-oxidant defense system, was studied in this work. Animals were given a single oral dose of KBrO₃ (100 mg/kg body weight) and sacrificed 12, 24, 48, 96 and 168 h after this treatment. Blood was collected from the animals and separated into plasma and erythrocytes. KBrO₃ administration resulted in increased lipid peroxidation, protein oxidation, hydrogen peroxide levels and decreased the reduced glutathione content indicating the induction of oxidative stress in blood. Methemoglobin levels and methemoglobin reductase activity were significantly increased while the total anti-oxidant power was greatly reduced upon KBrO₃ treatment. Nitric oxide levels were enhanced while vitamin C concentration decreased in KBrO₃ treated animals. The activities of major anti-oxidant enzymes were also altered upon KBrO₃ treatment. The maximum changes in all these parameters were 48 h after the administration of KBrO₃ and then recovery took place. These results show for the first time that KBrO₃ induces oxidative stress in blood and impairs the anti-oxidant defense system. Thus impairment in the anti-oxidant power and alterations in the activities of major anti-oxidant enzymes may play an important role in mediating the toxic effects of KBrO₃ in the rat blood. The study of such biochemical events in blood will help elucidate the molecular mechanism of action of KBrO₃ and also for devising methods to overcome its toxic effects.     

北京市地下水中高危害污染物筛选

地下水污染物对用水安全和人民健康造成了巨大的威胁.为开展地下水中高危害污染物筛选,改进了传统的危害评价方法,构建了涵盖毒理学优先指数法（Tox Pi）,吸收、分布、代谢、排泄（ADME）性质评估法和二模网络分析法的污染物危害评估-筛选-表征综合体系,针对北京市地下水中非靶检测到的234种疏水性有机污染物（HOCs）开展危害评估和毒害污染物筛选.利用Tox Pi方法筛选出危害潜力排名前20的污染物,在此基础上耦合其ADME性质进一步识别出17种高优先级HOCs,并通过二模网络分析,系统表征了这17种高优先级HOCs作用的基因分子靶点,通过关联性和加权平均度分析最终得到10种高危害的HOCs,并揭示其毒作用类型多集中于内分泌干扰效应、致癌效应以及遗传毒性.研究结果可为我国区域地下水污染物的防治提供技术支撑.     

Alterations in serum electrolyte levels after dimethoate exposure and recovery in the freshwater air-breathing catfish,Heteropneustes fossilis (Bloch)

Dimethoate, a moderately toxic insecticide, has a wide range of agricultural and domestic applications. Like other organophosphates, dimethoate has anticholinesterase activity. Fish are non-target organisms, inadvertently exposed to pesticides and their metabolic products. The present study includes short-term (96 h) and long-term (36 d) effects of dimethoate exposure on some serum electrolytes Ca²⁺, Mg²⁺, and Pi in the freshwater air-breathing catfish Heteropneustes fossilis. The concentration of dimethoate for short-term exposure was 2.24 mg L^?1 (75% of 96 h LC₅₀) and for long-term exposure 0.75 mg L^?1 (25% of 96 h LC₅₀). The study includes the recovery pattern in serum electrolytes after placing the fish in pesticide-free water. Fish show hypocalcemia, hypermagnesemia, and hyperphosphatemia after short-term and long-term exposure to dimethoate. When placed in pesticide-free water, these electrolytes exhibit recovery towards normalization, indicating significant (p < 0.05) recovery.     

灌区上游水源区生态价值评估方法及实例研究

灌区上游水源区所产生的巨大生态效益对灌区的经济社会发展有着举足轻重的作用。基于对灌区上游水源区生态价值要素的识别,构建了包含4个层次、18项评估指标的灌区上游水源区生态价值评估指标体系,较为全面地反映了区域生态价值的整体构成。并以淠史杭灌区的上游水源区为例,用影子工程法、市场价值法等定量的方法,分别从物质产品价值和生态服务价值两方面评估了其生态价值。结果表明：淠史杭灌区上游水源区的生态价值总量为425．17亿元,充分体现了上游水源区对下游乃至全社会做出的巨大生态服务贡献。