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931.
932.
Indraprastha Power Station (IPP Stn) and Rajghat Power House (RPH), owned by Delhi Electric Supply Undertaking, are both coal-fired power stations located on Ring Road in New Delhi. Ash content of the coal used ranges between 38–47%. The ash is collected in electrostatic precipitators which have an efficiency of 99.3% (IPP station), and 99.7% (RPH). There are instances of major dust pollution around the power stations from fly ash dispersal. The main method of disposal of fly ash from the power stations is by mixing with water, the resultant slurry is pumped through pipes to ash disposal ponds. The supernatant from these ponds is discharged into River Yamuna. Field studies have revealed large quantities of fly ash being deposited into the river. Local populations of Eichhornia crassipes have reduced dramatically between 1987–1995, with a marked reduction in the year 1994–1995. Field studies, conducted in January, 1995 have investigated the impact of fly ash dispersal in the Delhi region with particular reference to metal contamination. Elemental concentrations for a range of elements are determined by ICP-AES in fly ash and top soils along four transects from the power stations up to a distance of 8 km. The effects of fly ash leachates from the ash settling ponds on the river are determined by analyzing river overbank soils and vegetation for their elemental contents. It is concluded that fly ash dispersal from the stacks are a source of alkali, alkaline-earth and to some extent heavy metals in soils in the vicinity of the power stations, and enrichment of elements in river overbank soils are a result of discharge of fly ash leachates from ash disposal ponds. However, the impact from both these sources of metal contamination is not large enough to give cause for concern. Marked reduction in populations of Eichhornia crassipes downstream of the river where it receives leachates from the ash disposal ponds are attributed to turbidity of the ash pond leachates and metal toxicity. Elemental enrichment in the floodplain soils, as a result of fly ash particle deposition during monsoons, may enhance the horticultural value of these soils as is shown by a healthy cultivated crop of Brassica juncea. 相似文献
933.
《环境科学学报(英文版)》2023,35(7):1-15
Due to the combined effect of sluices and sea tide, the sluice-controlled coastal plain river would be characterized by both trophic state and salinity gradients, affecting the spatiotemporal optical properties of dissolved organic matter (DOM). In this study, we investigated the spatiotemporal variation of water quality parameters and optical properties of DOM in the Haihe River, a representative sluice-controlled coastal plain river in Tianjin, China. A significant salinity gradient and four trophic states were observed in the water body of the Haihe River. Two humic- and one protein-like substances were identified from the DOM by the three-dimensional fluorescence spectra combined with the parallel factor (PARAFAC) analysis. Pearson's correlation analysis and redundancy analysis (RDA) showed that the salinity significantly affected the abundance of chromophoric DOM (CDOM) but did not cause significant changes in the fluorescence optical characteristics. In addition, the effect of Trophic state index (TSI) on the CDOM abundance was greater than that on the fluorescence intensity of fluorescent dissolved organic matter (FDOM). In the water body with both salinity and trophic state gradients, TSI posed a greater influence than salinity on the CDOM abundance. Our results fill the research gap in spatiotemporal DOM characteristics and water quality variation in water bodies with both salinity and trophic state gradients. These results are beneficial for clarifying the joint influence of saline intrusion and sluices on the DOM characteristics and water quality in sluice-controlled coastal plain rivers. 相似文献
934.
介绍了沈阳市地下水水源地分布状况、浑河沿岸水文地质条件与河水的渗漏、浑河污染对地下水源的影响及2 0 0 2~ 2 0 0 3年浑河治臭工程对地下水环境的影响 相似文献
935.
长江流域治理开发是长江治理、开发、保护和管理的总称,包括流域治理、水资源开发利用、水资源保护、水土保持生态建设以及流域管理等内容,经过建国以来半个多世纪的发展和努力,长江流域治理开发取得了巨大的成就。在可持续发展战略和和谐社会思想的指导下,流域治理开发与生态环境建设息息相关,正确评价长江流域治理开发对生态与环境的改善和保护作用,对于促进治江事业的健康发展,充分发挥其生态环境效益具有十分重要的意义。通过对长江流域近五十多年来治理开发的总结归纳,分别从治理、开发、保护和管理等角度分析和总结了其对生态环境的保护和改善作用,认为长江流域治理开发总体上对生态、环境保护发挥了充分和积极的作用。 相似文献
936.
937.
938.
珠江流域河流碳输出通量及变化特征 总被引:6,自引:10,他引:6
研究河流碳运移对于研究全球碳循环以及探讨河流对全球气候变化的响应机制具有重要意义.2012年4月和7月选取珠江主流及支流11个代表性断面,分析悬浮颗粒物和碳组分的空间分布和季节变化,同时选取博罗、石角和高要这3个主控断面,对珠江流域的碳通量和侵蚀模数进行了估算.结果表明,珠江流域悬浮颗粒物(TSS)、颗粒有机碳(POC)以及溶解有机碳(DOC)随雨季的到来而质量浓度升高,西江上游TSS和POC的质量浓度增加显著;珠江流域河流碳的4种组分中,溶解无机碳(DIC)的所占质量分数最高,且西江、北江的DIC质量浓度明显高于东江;西江、北江和东江河流中外源POC分别占78%、72%和26%,三大支流的POC均受上游C3植物的影响;珠江流域的TSS、总碳(TC)、POC、颗粒无机碳(PIC)、DOC、DIC、以及颗粒碳(TPC)、总有机碳(TOC)的入海通量分别为134×1012、12.69×1012、2.50×1012、1.01×1012、1.13×1012、8.05×1012、3.51×1012和3.65×1012g·a-1,对应的侵蚀模数分别为:309×106、28.98×106、5.75×106、2.27×106、2.56×106、18.4×106、8.02×106和8.31×106g·(km2.a)-1.与全球主要河流碳侵蚀模数相比,珠江流域河流DOC、POC和TOC的侵蚀模数均高于全球平均值. 相似文献
939.
6+ ), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), zinc (Zn), and polychlorinated biphenyls (PCBs). Water-column,
bed-sediment, and fish-tissue (fillets) data collected by five government agencies comprised the ambient data set; effluent
data from five registered facilities comprised the compliance data set. The nonparametric Mann-Kendall trend test indicated
that 33% of temporal trends in all data were statistically significant (P < 0.05). Possible reasons for this were low sample sizes, and a high percentage of samples below the analytical detection
limit. Trends in compliance data were more distinct; most trace elements decreased significantly, probably due to improvements
in wastewater treatment. Seven trace elements (Cr, Cd, Cu, Pb, Hg, Ni, and Zn) had statistically significant decreases in
wastewater and portions of either or both ambient water and bed sediment. No trends were found in fish tissue. Inconsistency
in trends between ambient and compliance data were often found for individual constituents, making overall similarity between
the data sets difficult to determine. Logistical differences in monitoring programs, such as varying field and laboratory
methods among agencies, made it difficult to assess ambient temporal trends. 相似文献
940.
渭河浮游细菌群落结构特征及其关键驱动因子 总被引:6,自引:0,他引:6
基于T-rflp技术和高通量测序技术,分析了渭河在平水期、枯水期和丰水期的浮游细菌群落变化特征,并采用冗余分析和典范对应分析识别了不同水文时期影响细菌群落的关键环境因子.结果表明,渭河水体浮游细菌群落空间和季节差异明显,且季节性差异比空间差异更加显著.平水期、枯水期和丰水期渭河(陕西段)干流浮游细菌群落Shannon多样性指数分别在2.13~2.82、2.05~2.84和2.61~2.91之间.平水期浮游细菌多样性指数空间差异最大(RSD=16.75%),样点间群落结构相似度最低(26.8%),流域优势T-RF片段数最多(23种);丰水期浮游细菌Shannon指数空间差异最小(RSD=9.27%),样点间群落相似度最高(62.6%),且检出的优势片段数最少(12种).咸阳-西安段是浮游细菌群落多样性最低、优势菌群结构最单一的河段.河流水体细菌群落在不同时期的关键环境驱动因子不同,而其中悬浮颗粒物(TSS)浓度是不同水文时期都不可忽视的关键影响因子.高通量分析结果表明,丰水期渭河水体浮游细菌物种涉及21个已知细菌门类和26个候选门类,其中,变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)共同的相对丰度占比达到75%以上,是最主要的细菌类群.汛期渭河干流各样点浮游细菌群落特征趋于一致,物种结构与泾河相似而与黑河存在明显差异. 相似文献