Characterisation of Selected Lentic Habitats of Dharwad, Haveri and Uttar Kannada Districts of Karnataka State, India

Water quality survey was undertaken to study the current status of water quality of some lentic habitats of Dharwad, Haveri and Uttar Kannada districts, to provide a baseline data, comprising study of their main physical and chemical characteristics and also to evaluate the recent limnological changes those have occurred over a time period in some lentic habitats. Trophic status was also analysed. Present study reveals that Unkal lake, and B.K. Shigigatti tank of Dharwad district, Timmapur, Hosalli, and Krishnapur tanks of Haveri district are fast progressing towards hypereutrophication. Of the other tanks, Galgi tank of Dharwad district, Gudgur, Hanamapur, Medleri, and Kadkol tanks of Haveri district have reached the eutrophic stage. The anthropogenic activities, sewage and fertilizers used in agricultural fields appear to be the major causes of the eutrophication in these tanks. If the habitats have to be preserved for their intended use, sustainable and holistic management measures for the remediation of the tanks are an immediate necessity.     

Leaching behaviour of different scrap materials at recovery and recycling companies: Full-, pilot- and lab-scale investigation

Scrap material recovery and recycling companies are confronted with waste water that has a highly fluctuating flow rate and composition. Common pollutants, such as COD, nutrients and suspended solids, potentially toxic metals, polyaromatic hydrocarbons and poly chlorinated biphenyls can exceed the discharge limits. An analysis of the leaching behaviour of different scrap materials and scrap yard sweepings was performed at full-scale, pilot-scale and lab-scale in order to find possible preventive solutions for this waste water problem. The results of these leaching tests (with concentrations that frequently exceeded the Flemish discharge limits) showed the importance of regular sweeping campaigns at the company, leak proof or covered storage of specific scrap materials and oil/water separation on particular leachates. The particulate versus dissolved fraction was also studied for the pollutants. For example, up to 98% of the polyaromatic hydrocarbons, poly chlorinated biphenyls and some metals were in the particulate form. This confirms the (potential) applicability of sedimentation and filtration techniques for the treatment of the majority of the leachates, and as such the rainwater run-off as a whole.     

城区地表径流面源污染和河道水环境治理的研究

河流为人类提供了多样的生态服务功能,然而城市化对河流生态系统健康状况造成严重的影响。随着点源污染的有效管理控制,非点源污染降雨径流己成为造成城市地表水环境污染的主要原因。为了改善河道水质,引调清水激活城市内河水体,提高河道的水环境自净能力,有效改善城市水环境。文章以南京河西水系为例,利用Saint-Venant方程组对水系建立一维水动力模型,并通过汇流结点水位法对方程组进行数值求解;对WASP5水质模型进行二次开发用于水质模拟;建立水质模型和一维河网水动力模型的耦合模型,将水动力模型计算所得到的水动力参数耦合到WSAP5水质模型中,模拟降雨过程以及引调清水过程的河网各河段的水质变量浓度,得出降雨径流对河流的污染程度以及引清冲污措施对河流水质改善的效果并优化调水过程。     

薄膜覆盖减少化肥养分流失研究

我国化肥的利用率低,使用量又不断增长,增加了农业面源污染问题的严重性.本研究针对化肥流失主要通过水带走的特性,进行大田试验种植玉米,利用薄膜覆盖所施用的化肥,实现"肥与水隔离",以减少化肥流失.试验一方面观察了不同施肥处理二季甜玉米的生长和产量,另一方面测定了作物对肥料的利用率以及地表径流养分含量.结果表明,在本土壤条件下甜玉米只需施用常规施肥量的70%即可达到高产.甜玉米收获后土壤中碱解氮、有效磷、有效钾的含量比不经薄膜覆盖的显著提高,其顺序为100%施肥量+覆膜70%施肥量+覆膜100%施肥量、70%施肥量不施肥.氮、磷、钾肥料的表观利用率分别为42%~87%、0%~3%和5%~15%,覆膜处理一般高于不覆膜处理,特别是在高施肥量情况下更为明显.通过8次径流水的收集测定,无薄膜覆盖的施肥处理的地表径流N、P和K平均浓度分别为27.72、2.70和7.07 mg.L-1,薄膜覆盖技术处理降低N、P、K浓度的效果分别达到了39.54%、28.05%、43.74%,对于减少农业面源污染和水体富营养化可起到明显效果.     

河流岸坡净化径流中氨氮的实验室研究

利用实验室内建立的河流岸坡展开对地表径流中氨氮在模型内部沿程净化效果的实验研究。结果显示,河流岸坡对氨氮的去除率在90%以上;沿程氨氮浓度在缓坡模型的第二断面、第三断面的浓度及净化效率较为稳定,而在陡坡模型中的第三断面浓度及净化效率均出现较大波动;此外,合理的进水负荷使两种河流岸坡对氨氮的去除率稳定在96%左右;相比较而言,缓坡模型沿程对氨氮的净化效率要比陡坡模型稳定。     

贵州红枫湖大冲小流域农业面源污染负荷特征研究

为揭示红枫湖汇水区农业面源污染物氮、磷、有机物输出的一般规律,以典型农业小流域为研究对象,自2010年1~12月,对流域降雨、流域出口的径流、TN、TP、CODcr浓度进行同步监测,并对流域内各个不同土地利用类型的产污负荷进行监测分析。结果表明,流域除TP外,其他指标严重超标;监测期间小流域径流量为414×105 m3,TN、TP、CODcr入湖总量分别为2 5467、856、10 8832 kg,其日均单位排放负荷分别为577、019 、1451 kg/(km2·d);在降雨丰富、农业生产活动频繁的6~10月,TN、TP、CODcr的含量都明显高于其他月份,分别占各自总量的94.8%、73.3%、94.3%;坡耕地、天然林、疏林地产生的TN、TP、CODcr污染负荷量分别为流域入湖污染总负荷的13.38%、13.29%、13.54%,稻田、蔬菜地径流中TN、TP、CODcr含量分别为0.84~10.32、0.07~0.18、20.50~68.00;2.16~7.54、0.01~0.04、4.50~22.40 mg/L。居民生活污水中TN、TP、CODcr含量分别为13.84~50.11、3.20~5.10、35.7~207.0 mg/L,蔬菜、水稻种植、居民生活污水及禽畜养殖对流域面源污染贡献大;大冲小流域面源污染负荷与径流间存在极强的相关性     

Determination of Cs in the water system of a pre-Alpine lake

The aim of this study was to measure the ¹³⁷Cs activity derived from the Chernobyl accident in the water system of Lake Wallersee, a pre-Alpine lake in Austria within an area highly contaminated by the Chernobyl fallout.     

Comparison of a Subjective and a Physical Approach for Identification of Priority Areas for Soil and Water Management in a Watershed – A Case Study of Nagwan Watershed in Hazaribagh District of Jharkhand, India

The present investigation was an attempt to compare the within-watershed prioritization capabilities of a physical model based SDSS with the SYI and RPI model based subjective-SDSS, conventionally devised for between-watershed prioritizations, by All India Soil Survey and Land Use Planning Division of Ministry of Agriculture, Government of India. Application of these two approaches on a test watershed situated in Damodar-Barakar catchment in India, the second most seriously eroded area in the world, demonstrated that the proposed physical model based SDSS was capable of realistically and logically mimicking the sub-watershed-scaled water and soil losses thereby suggesting its immense application potential for priority area identification within the test watershed. In contrast to the proposed physical method, the subjective approaches, which assigned totally reverse priorities to about 67–93% of the test-sub-watersheds, were observed to be incapable of realistically assessing the impact of topography and varied land use and soil types in the test watershed on their sub-watershed scaled run-off and soil loss generating potential. Besides, the physical approach could be used for assessing the annual dynamics of the total water and sediment yields, under prevailing resource management systems in the test watershed with good to moderately good correlation coefficients of 0.83 and 0.65; model efficiency coefficients of 0.54 and 0.70; mean relative errors of –4.28% and –17.97% and root mean square prediction errors of 71.8 mm and 9.63 t/ha, respectively.     

水动力作用对潮滩表层沉积物重金属时空分布的影响

选取上海滨岸滩具有代表性的4个采样断面，分析了重金属在潮滩表层沉积物中的季节含性量变化。结果表明，在水动力作用较弱的地貌部位，表层沉积物中重金属元素明显趋于富集。在崇明东旺沙、白龙港排污口附近和奉新边滩表层沉积物中，Cu、Pb、Fe、Mn、Zn的最低值出现于夏季，而在东海农场表层沉积物中，这几中重金属元素的最低值出现于秋季，夏季值反而较高。Cd与此不同。这说明在长江冲淡水作用下，重金属污染物能沿岸发生迁移与扩散，Cd受长江冲淡水影响较小。     

Occurrence and behavior of emerging contaminants in surface water and a restored wetland

Pollution mitigation is an important target for restored wetlands, and although there is much information in relation to nutrient removal, little attention has been paid to emerging contaminants. This paper reports on the occurrence and attenuation capacity of 17 emerging contaminants in a restored wetland and two rivers in North-East Denmark. The compounds belong to the groups of pharmaceuticals, fragrances, antiseptics, fire retardants, pesticides, and plasticizers. Concentrations in surface waters ranged from 2 to 1476 ng L⁻¹. The compounds with the highest concentrations were diclofenac, 2-methyl-4-chlorophenoxyacetic acid (MCPA), caffeine, and tris(2-chloroethyl) phosphate (TCEP). The herbicide concentrations increased after a rain-fall event, demonstrating the agricultural run-off origin of these compounds, whereas the concentration of the other emerging contaminants was rather conservative. The mitigation capacity of the restored wetland for the compounds ranged from no attenuation to 84% attenuation (19% on average). Hence, restored wetlands may be considered as a feasible alternative for mitigating emerging contaminants from river waters.