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稳定分层水库水质的季节性变化特征及扬水曝气水质改善 总被引：2，自引：0，他引：2
为了解深水型水库水体的热分层结构、水质特征及扬水曝气系统对水质的改善情况,对水温、溶解氧、pH、叶绿素a、营养盐、溶解性有机碳浓度等水质指标进行为期一年的监测,探讨各项指标的季节性变化规律.结果表明,黑河水库水体呈单循环混合模式,在3-10月形成自然热分层,水体的热分层导致相应水库水质明显分层.黑河水库为偏碱性水体,叶绿素a、总磷、总氮、铵态氮和溶解性有机碳浓度平均值分别为2.21 μg/L、0.022 mg/L、1.32 mg/L、0.20 mg/L和2.93 mg/L,表明黑河水库处于中-富营养状态.热分层期底部水体溶解氧浓度在0～7.9 mg/L之间,平均值为2.9 mg/L,氮磷质量比在41～100之间,表明黑河水库是一个底部季节性缺氧、高营养盐型水库.在水库自然热分层末期,应用扬水曝气技术,不仅改善了底部水体的厌氧/缺氧环境,抑制了厌氧/缺氧条件下内源污染物的释放和藻类的增殖,而且还使得水库水体提前混合,实现了强制混合与水体自然混合过程的有机衔接,延长了水质持续改善的作用时效,有效地改善了水环境,保障了安全供水. 相似文献
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稳定分层水库水质的季节性变化特征及扬水曝气水质改善 总被引：1，自引：0，他引：1
为了解深水型水库水体的热分层结构、水质特征及扬水曝气系统对水质的改善情况,对水温、溶解氧、p H、叶绿素a、营养盐、溶解性有机碳浓度等水质指标进行为期一年的监测,探讨各项指标的季节性变化规律.结果表明,黑河水库水体呈单循环混合模式,在3-10月形成自然热分层,水体的热分层导致相应水库水质明显分层.黑河水库为偏碱性水体,叶绿素a、总磷、总氮、铵态氮和溶解性有机碳浓度平均值分别为2.21μg/L、0.022 mg/L、1.32 mg/L、0.20 mg/L和2.93 mg/L,表明黑河水库处于中-富营养状态.热分层期底部水体溶解氧浓度在0~7.9 mg/L之间,平均值为2.9 mg/L,氮磷质量比在41~100之间,表明黑河水库是一个底部季节性缺氧、高营养盐型水库.在水库自然热分层末期,应用扬水曝气技术,不仅改善了底部水体的厌氧/缺氧环境,抑制了厌氧/缺氧条件下内源污染物的释放和藻类的增殖,而且还使得水库水体提前混合,实现了强制混合与水体自然混合过程的有机衔接,延长了水质持续改善的作用时效,有效地改善了水环境,保障了安全供水. 相似文献
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三峡水库典型支流上游区和回水区营养状态分析 总被引：10，自引：3，他引：7
2006年3、5、8月,对三峡水库成库后5条支流的上游区和回水区水质参数及营养因子分布进行了初步研究.研究结果表明,支流高锰酸盐指数范围在1.00-2.50mg/L、COD范围为6.00-26.5mg/L,上游区与回水区有机物含量差异不大,支流目前未受到有机物污染影响.NH_4~+-N范围为0.039-0.367mg/L,各支流含量均为丰水期最大.TN范围在0.58-1.67mg/L,TP范围在0.005-0.133mg/L,支流回水区TN和TP含量均远高于水体发生富营养化的最低限制值,水体存在发生富营养化的风险.大多支流N/P比值处于适宜藻类生长范围.Chl.a浓度范围为0.94-28.9mg/m~3,各支流回水区Chl.a浓度均为5月最大河流回水区Chl.a浓度高于上游区,上游区、回水区Chl.a含量有显著差异.选用修正的Carlson营养状态指数(Trophic State Index)TSI_M法,评价了支流水体营养状态,TSI_M指数范围在36.0-64.2,上游区除龙河、澎溪河5月达到富营养水平外,其余支流均为贫-中营养水平.回水区各支流均达到中-富营养水平.支流回水区营养状态指数均高于上游区,但各支流增加幅度不同.支流回水区水体营养状态明显受三峡水库蓄水水体流速减缓的影响.Chl.a与COD(n=15,P0.01)呈极显著正相关,与其它营养因子无明显相关关系.三峡水库完工后,支流回水区水体流速减缓,富营养化趋势可能加重. 相似文献
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异尾轮虫是热带亚热带地区轮虫的重要优势类群.为了解其在水库中的分布模式和潜在影响因素,于2013-2014年对广东流溪河水库河流区、过渡区及湖泊区的异尾轮虫群落及环境因子进行逐月调查.2年共采集到异尾轮虫11种,其中对棘异尾轮虫(Trichocerca similis)、圆筒异尾轮虫(T.cylindrica)、暗小异尾轮虫(T.pusilla)和刺盖异尾轮虫(T.capucina)为优势种,主要出现在丰水期,具有明显的季节分布模式.2013-2014年河流区、过渡区和湖泊区异尾轮虫丰度平均值分别为142.9、102.5和53.6 ind./L,3个水域的异尾轮虫总丰度在夏季(5-9月)较高.从水库上游到下游,异尾轮属的物种丰富度和Simpson多样性指数呈现递减趋势,体现了群落对环境的分区和稳定性变化的响应.群落丰度组成的主成分分析表明,主要优势种的丰度全年分布差异较大,而多数种类全年分布差异小.冗余分析表明,叶绿素a浓度、晶囊轮虫丰度、水温+磷酸盐浓度分别为影响河流区、过渡区和湖泊区异尾轮虫群落结构的关键变量,而降雨则是影响整个库区异尾轮虫群落结构的潜在变量. 相似文献
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2017年5月—2019年10月,对"南水北调"中线水源水库——丹江口水库库区水体7个监测位点、0～20 m间4个水层的垂向叶绿素a (Chl.a)浓度与水质因子进行了季度性调查,以期了解不同位点、不同水层Chl.a分布的主要驱动因子.结果表明,丹江口水库各位点营养状态指数(TSI)均为中营养化状态.水体Chl.a浓度具有逐年增加的趋势,且极高值有逐渐增加的趋势.营养盐和Chl.a浓度均存在较大的空间异质性,入库区具有较高的总磷和氨氮浓度,汉江库区具有最高的Chl.a浓度,源头污染源控制和监测仍然是丹江口水库管理的重中之重.不同位点Chl.a浓度的驱动因子存在较大差异,汉江入库和大坝区Chl.a浓度分别受到硝态氮和p H的影响,而出水口大坝位点主要受到了水深、水温和氨氮的影响.丹江入库区Chl.a浓度受到了水深、氨氮、总磷和水温的影响,但丹江库区表现出了与其他生态区较大的区别,其Chl.a浓度主要受到水深和有机质输入的影响.因此,对丹江口水库各位点的管理,应该分不同生态区采取针对性的管理措施.本研究旨在为南水北调中线工程可持续的生态调度提供基础生态数据支持,为完善水库水源地的有效管理提供理论支撑. 相似文献
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基于1990—2018年于桥水库流域入库河流与水库的逐月总氮(TN)和总磷(TP)监测数据,整理并分析了1990-2002、2003—2014和2015—2018年3个时段TN、TP浓度和氮磷比(TN/TP)的时空变化特征,探究流域内点面源污染削减、调水、氮磷滞留等对营养盐浓度变化的影响。结果表明,1990—2018年于桥水库TN浓度年均值在1.14～3.74 mg/L之间,水库TP浓度年均值在0.025～0.131 mg/L之间,多年TN/TP平均值为45,远高于淡水磷限氮磷比,是磷限水库。于桥水库流域5个测点中,沙河TN浓度最高,黎河TP浓度最高,入库TN、TP浓度大于库区,水库TP滞留率略大于TN。水库TN、TP浓度在2000s中后期下降,之后出现反弹。原因是2003年水源保护工程实施后,入库营养物浓度降低;2014年底南水北调中线一期工程通水后,于桥水库的引滦水量减少,TN的稀释效应弱化,上游来水TP浓度上升与水库内夏秋两季浮游植物的增殖,导致第三时段水库内TP浓度上升。基于月尺度水质分析,夏季水库TN浓度最低,TP浓度达到峰值,主成分分析表明,历年6—10月的水库Chl.a浓... 相似文献
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南亚热带典型调水型水库——广东大镜山水库的富营养化特征分析 总被引：2，自引：0，他引：2
调水型水库是一种以抽水入库为主要来水水源的水体,是沿海地区重要的供水水源地.为了解这类水库的富营养化特点,于2005年全年每月2次对地处我国南亚热带地区(广东珠海市)的大镜山水库进行采样和监测.监测和测定指标主要包括氮、磷营养盐浓度、水温、透明度及叶绿素a浓度等,结合水库水文数据对水库富营养化特征和主要的影响因素进行分析.结果表明,2005年,大镜山水库的富营养化状态TSI_M指数在45-53之间,水库处于中富营养状态,多数时间处于富营养状态.水体富营养化主要参数表现出明显的季节变化,即叶绿素a浓度和富营养化状态指数在早春和晚秋出现两个峰值,明显地与温带富营养化水体在夏季出现单个峰值的特征不同.调水入库增加了水库营养盐负荷的同时,也在很大程度上影响了水库水动力学过程,与夏季的集中强降雨一起成为影响该水库富营养化的关键因素,这些因素改变了浮游植物群落对营养盐的直接响应,导致叶绿素a浓度与总磷、总氮浓度之间呈弱相关关系,降水和调水量在时间上相对配置重要性决定了叶绿素a浓度与营养盐浓度的关系. 相似文献
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舌状叶镖水蚤(Phyllodiaptomus tunguidus)是我国特有的大型哲水蚤,主要分布在我国华南地区.根据2000年对广东省19座典型大中型水库的2次采样和2002年对流溪河水库和新丰江水库的5次采样,重点测定了流溪河水库、新丰江水库和鹤地水库等3座大型水库中舌状叶镖水蚤个体体长及形态参数,分析了广东省大中型水库中舌状叶镖水蚤的种群与个体大小的分布特征.在对19座水库的2次采样中,11座水库发现该种成体,其中5座水库在丰水期没有出现该种的成体,6座水库在丰水期和枯水期都有该种类成体的出现.丰水期与枯水期舌状叶镖水蚤的平均丰度分别为0.465ind./L和0.996ind./L.舌状叶镖水蚤主要出现在大型水库中,特别是贫营养的大型水库,其丰度主要由食物数量、质量与捕食压力所决定.2002年,流溪河水库丰度和新丰江水库舌状叶镖水蚤全年的平均值为1.308ind./L和0.294ind./L,丰水期高于枯水期.在个体大小和形态特征上,2座贫营养水体——流溪河水库、新丰江水库的舌状叶镖水蚤的体长与第一触角长度均大于中营养水体——鹤地水库,这种形态上的差异是由鱼类捕食方式(滤食或选择性捕食)所决定. 相似文献
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喀斯特地区梯级水库建造对水化学分布的影响 总被引：1，自引：0，他引：1
为深入了解河流梯级筑坝对喀斯特地区河流水化学分布的影响,于2017年1、4、7和10月别对乌江干流洪家渡水库(多年调节)、乌江渡水库(季调节)和索风营水库(日调节) 3个具有不同滞留时间的水库进行水样采集,分析入库水、坝前剖面水和下泄水的水化学特征,探讨河流梯级筑坝对水化学分布及风化速率估算的影响.研究结果表明:3个水库深层水比表层水HCO3-浓度分别高12.9%、5.5%和8.0%,Ca~(2+)浓度分别高15.9%、2.4%和8.5%.河流梯级筑坝一定程度上改变了水体水化学组成,从而影响碳酸盐岩风化速率估算.整体上,洪家渡水库、索风营水库和乌江渡水库的全年风化速率变化范围分别为:-1.7%～15.4%、-5.6%～1.1%和-0.3%～3.4%.河流筑坝作用对风化速率估算及主量离子浓度的影响:HCO_3~-与Ca~(2+)浓度分布均为:洪家水库乌江渡水库索风营水库,这与水体滞留时间长短规律一致,表明水体滞留时间影响着水化学的组成分布.同时水体离子浓度表现出明显的季节性差异,丰水期各水库变化率明显大于枯水期.上述结论表明喀斯特地区河流连续筑坝后水化学组成及分布特征发生了一定程度改变,影响流域化学风化速率的估算,且影响程度随水体滞留时间延长而增大,并受气温影响.因此,今后在估算流域风化速率及探究水化学空间变化时应对筑坝作用加以考虑,以便更加准确地评估喀斯特流域岩石风化在全球碳循环中的作用. 相似文献
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《中国科学:地球科学(英文版)》2014,(12)
正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in both basic and applied research. 相似文献
12.
《中国科学:地球科学(英文版)》2014,(9)
正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in 相似文献
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In natural waters arsenic concentrations up to a few milligrams per litre were measured. The natural content of arsenic found in soils varies between 0.01 mg/kg and a few hundred milligrams per kilogram. Anthropogenic sources of arsenic in the environment are the smelting of ores, the burning of coal, and the use of arsenic compounds in many products and production processes in the past. A lot of arsenic compounds are toxic and cause acute and chronic poisoning. In aqueous environment the inorganic arsenic species arsenite (As(III)) and arsenate (As(V)) are the most abundant species. The mobility of these species is influenced by the pH value, the redox potential, and the presence of adsorbents such as oxides and hydroxides of Fe(III), Al(III), Mn(III/IV), humic substances, and clay minerals. 相似文献
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Due to deleterious effects on non-target organisms, the use of organotin compounds on boat hulls of small vessels (<25 m) has been widely prohibited. The International Maritime Organisation (IMO) resolved that the complete prohibition on organotin compounds acting as biocides in antifouling systems should commence in 2008. As a result of restrictions on the use of organotin based paints, other antifouling formulations containing organic biocides have been utilised. This survey was conducted to assess the contamination of replacement biocides in the marine environment following the ban of TBT-based paints. Surface sediments samples were collected in the major ports and marinas along the France Mediterranean coastline (Cote d’Azur) and analysed for organotin compounds, Irgarol 1051, Sea-nine 211TM, Chlorothalonil, Dichlofluanid and Folpet. Every port and marina exhibited high levels of organotin compounds, with concentrations in sediments ranging from 37 ng Sn g−1dry wt in Menton Garavan to over 4000 ng Sn g−1dry wt close to the ship chandler within the port of Villefranche-sur-Mer. TBT degradation indexes suggested that fresh inputs are still made. Among the other antifoulants monitored, only Irgarol 1051 exhibited measurable concentrations in almost every port, with concentrations ranging from 40 ng g−1dry wt (Cannes) to almost 700 ng g−1dry wt (Villefranche-sur-Mer, ship chandler). 相似文献
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Ian R. Falconer 《洁净——土壤、空气、水》2005,33(1):64-71
Microcystins are cyclic heptapeptide toxins produced by a range of cyanobacterial genera. These cyanobacteria occur naturally in drinking water reservoirs subject to eutrophication, and in rivers and natural lakes. Because of the diversity of organisms, the toxins occur, from oligo‐mesotrophic lakes in North Temperate latitudes, to hypertrophic tropical ponds. The toxins are responsible for numerous cases of injury and death of domestic animals, and human poisoning from drinking water. The initial poisoning includes hepatic cell death. This leads to secondary effects from liver deficiency, including jaundice and photosensitisation. The toxic effects are largely due to inhibition of phosphatase enzymes, acting to regulate protein phosphorylation. The consequences include structural damage, apoptosis and, at lower concentrations, cell cycle effects and tumour promotion. As there is no clear evidence for direct carcinogenesis by microcystins, they are classed as non‐carcinogenic toxins in drinking water. Guideline Values for safe drinking water are derived from data for subchronic rodent toxicity, using the No Observed Adverse Effect Level (the highest dose giving no toxicity). To this dose are applied uncertainty factors, to calculate a Tolerable Daily Intake. On the basis of a standard bodyweight and water consumption the Guideline Value is determined for drinking water. For microcystin‐LR the WHO have set a provisional Guideline Value of 1 μg/L for drinking water. 相似文献
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The geomagnetic field and secular variation exhibit asymmetrical spatial features which are possibly originating from an heterogeneous thermal control of the Earth's lower mantle on the core. The identification of this control in magnetic data is subject to several difficulties, some of which can be alleviated by the use of core surface flow models. Using numerical dynamos driven by heterogeneous boundary heat flux, we confirm that within the parameter space accessible to simulations, time average surface flows obey a simple thermal wind equilibrium between the Coriolis and buoyancy forces, the Lorentz, inertial and viscous forces playing only a secondary role, even for Elsasser numbers significantly larger than 1. Furthermore, we average the models over the duration of three vortex turnovers, and correlate them with a longer time average which fully reveals the signature of boundary heterogeneity. This allows us to quantify the possibility of observing mantle control in core surface flows averaged over a short time period. A scaling analysis is performed in order to apply the results to the Earth's core. We find that three vortex turnovers could represent between 100 and 360 years of Earth time, and that the heat flux heterogeneity at the core-mantle boundary could be large enough to yield an observable signature of thermal mantle control in a time average core surface flow within reach of the available geomagnetic data. 相似文献
17.
Richard McCreary John McGaughey Yves Potvin Dave Ecobichon Marty Hudyma Harald Kanduth Alain Coulombe 《Pure and Applied Geophysics》1992,139(3-4):349-373
Located in northern Québec, the Lac Shortt Mine was a small gold mine consisting of a thin subvertical orebody which was mined in three main phases. High stress and rockbursting conditions were experienced when ore was extracted in the upper zone between the surface and a depth of 500 metres during the first two phases of mining. Severe rockbursts were experienced in late 1989 near the shaft and in the footwall development following a deepening of the mine shaft to a depth of 830 m and partial development of footwall drift access for the third phase of mining (the mining of the lower zone starting at a depth of 830 m moving upward toward a depth of 500 m). A 16-channel Electrolab MP250 microseismic system, with a Queen's University Full-Waveform piggy-back system, was installed underground at the site due to these problems.It was expected that the thinning sill would be subjected to an ever-increasing load as the thickness of the 500 m sill pillar decreased in the face of the mining excavation from below. A monitoring program consisting of the microseismic monitoring system, a range of conventional geomechanics monitoring tools as well as the undertaking of periodic seismic tomography surveys to assess the ongoing state of stress and rock mass condition within the sill was therefore warranted.The anomalously high-magnitude stress field and the brittle rockmass created a situation in which rockmass failure was common and violent. In the creation and thinning of the sill pillar, the location of banded microseismic activity was crucial in tracing rockmass failure and the associated ground control problems. Reliable source-location determination enabled the identification of areas of stress increase. The movement of the rockmass failure front could be followed, and was responsible for stope dilution, footwall and orebody development deterioration, and caving.Source-mechanism analyses gave accurate double-couple solutions for approximately forty percent of these events having at least ten recognizable polarities. Results suggested movement along vertical north-south striking or vertical east-west striking features. Underground observation of damaged access points showed that vertical north-south striking joints were experiencing failure.The microseismic activity, which was consistently concentrated close to the southwest and northeast corners of current production stopes, could be explained by a stress field oriented obliquely to the strike of the orebody, as measured prior to shrinkage of the sill pillar byin situ stress measurements and observed borehole overbreaks. The orientations of theP andT axes for the microseismic activity further confirmed that the stress field oriented obliquely to strike.While an increase in compressional-wave velocity of 2.3 percent, corresponding to a measured stress increase of approximately 10 MPa could be measured by repeated tomographic surveys, it was relatively small and only a factor of two or so above the velocity measured uncertainty. The relative insensitivity of thein situ rock mass modulus to the applied stress is believed to be largely due to the rockmass discontinuities being relatively closed prior to stress increase, as substantiated by the small deformations seen by the extensometer and borehole camera. This situation existed because of the very high pre-mining stress level.The experimental demonstration that the rock could not absorb substantially increased load through the mechanism of discontinuity closure or tightening (which would be reflected in the modulus) may be evidence in itself of potentially burst-prone ground, such as encountered at Lac Shortt. 相似文献
18.
《水文科学杂志》2013,58(4):704-712
Abstract The upper Niger and Volta rivers exhibit a great and highly contrasting variability of inter-annual runoff. The Bani River, the largest tributary to the Niger River in Mali, shows a dramatic decrease in runoff after the 1970s, with the result that many boreholes in the region have dried up since the drought began. In contrast, the Nakambe River (Upper Volta basin, in Burkina Faso) shows an increase in runoff for the same period, leading to unexpected flood peaks that damaged infrastructures. The contribution that the groundwater and its variability make to surface runoff variability is assessed in this study by comparing the data of the national groundwater monitoring networks of Mali and Burkina Faso to surface runoff. Several variables are compared at the basin scale: the date of the maximum level of the water table, the annual rainfall, discharge, low flows and depletion coefficients. Variability in the low flows of the Bani River is well correlated to a decrease in the water table. Since 1970, the greater decrease in runoff in comparison to the rainfall decrease is due to a reduction in the baseflow, related to the cumulated rainfall deficit. Concerning the Nakambe River, the runoff increase is not supported by a water table increase, but is due to the increase in runoff coefficient related to land degradation. 相似文献
19.
The inability to detect the presence of viable Helicobacter pylori bacteria in environmental waters has hindered the public health community in assessing the role water may play in the transmission of this pathogen. This work describes a cultural enrichment method coupled with an H. pylori‐specific PCR to identify these bacteria in water. While far from perfected at the present time, this represents an exciting new approach to studying the significance of water as a transmission mechanism for H. pylori. Evidence is presented that indicates culturable H. pylori bacteria were found using this enrichment/PCR method in a local groundwater source. 相似文献
20.
Response spectrum predictions for potential near-field and far-field earthquakes affecting Hong Kong: rock sites 总被引：1，自引：0，他引：1
N. T. K. Lam A. M. Chandler J. L. Wilson G. L. Hutchinson 《Soil Dynamics and Earthquake Engineering》2002,22(1)
To realistically assess the seismic risk relating to built infrastructures in Hong Kong and in the neighbouring coastal cities of southern Guangdong province, it is necessary to predict ground shaking induced by different earthquake scenarios with good accuracy. A companion paper has described the modelling of the spatial and temporal distribution of the diffused seismic activities in the region, based on the newly-developed ‘Expanding Circular Disc’ (ECD) method. Representative Magnitude–Distance (M–R) combinations for both near-field and far-field earthquakes (in relation to Hong Kong) have been derived using the ECD method. The present paper describes the modelling of the response spectrum on rock sites associated with the predicted M–R combinations, using the Component Attenuation Model (CAM) that was also developed recently by the authors, based on stochastic simulations of the seismological model. The significant effects of soil resonance on the response spectrum are described in a separate publication.The accuracy of CAM in modelling ground motion properties on rock sites has been tested here by comparisons with (i) strong motions recorded in Taiwan and South China from the 1999 ‘Chi-Chi’ earthquake in Taiwan (M=7.6), (ii) motions recorded in South China from another earthquake occurring in the southern Taiwan Strait in the same year (M=5.1), and (iii) historical seismic intensity data obtained within South China. The overall capability of CAM in modelling both near-field and far-field attenuation has been shown to be unmatched by existing empirical models. Results of the comparison studies confirm the accuracy of CAM, particularly within an epicentral distance of 300–400 km.This study shows that the developed serviceability response spectra (i.e. at short return periods) are controlled mainly by the earthquake recurrence behaviour of major distant seismic sources. In contrast, the ultimate response spectra (i.e. at long return periods) relate to events with magnitudes close to the maximum credible earthquake (MCE) limit, the effect of which may also be represented by the Characteristic Response Spectrum (CRS). Both types of earthquake scenario can be significantly affected by the regional crustal properties. The proposed response spectrum envelopes have been compared with previously developed recommendations, and a critical review has been conducted. The intrinsic advantages of the ECD–CAM modelling approach have been highlighted, emphasising its directness and transparency when compared with the more complex process required to implement traditional Probabilistic Seismic Hazard Assessment (PSHA). 相似文献