共查询到19条相似文献，搜索用时 281 毫秒
1.
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
2.
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
3.
氮是影响和控制水体富营养化的重要因素,不同形态的氮对水体富营养化贡献不同.使用连续提取法对东苕溪干流悬浮物、表层沉积物样品中各形态氮含量进行测定,探讨各形态氮的分布特征及其影响因素.结果表明,东苕溪水体氮污染严重,总氮浓度均值为4.48 mg/L.悬浮物中各形态氮含量均高于沉积物,其中悬浮物中铁锰氧化态氮(IMOF-N)含量所占比例最大,均值为1506.94 mg/kg;沉积物中有机硫化物结合态氮(OSF-N)含量最高,均值为625.31 mg/kg.IMOFN、OSF-N含量受阳离子交换量、粒径影响显著,均与总氮浓度显著相关.相关性分析表明水体的性质对IMOF-N及OSF-N含量影响较显著,并且总体上对悬浮物的影响强于沉积物.另外,悬浮物有助于水体中的氮发生硝化反应向硝态氮转化,沉积物则有助于水体的氮发生还原作用向氨氮转化.在一定程度上,水体中的悬浮物对藻类具有抑制作用. 相似文献
4.
我国南方桉树(Eucalyptus)人工林区水库突发性泛黑形成机理初探 总被引：2，自引：0，他引：2
桉树(Eucalyptus)在我国南方大规模种植,最快两三年成材,经济价值高,但近来却被认为是"抽水机"、"绿色沙漠",甚至传言"有毒".特别是近年来桉树人工林区水库出现的"泛黑"现象——水体呈现黑褐色并伴有涩味,给种植地附近居民造成了很大的恐慌.并且其黑水形成机理、物质来源及触发条件等尚不清楚.基于此,本文选取我国南方桉树人工林区典型水库,开展了水体"泛黑"现象成因研究:于2015年8月2016年4月对广西南宁市那降水库、天雹水库、百合水库分别进行了4次水体垂直分层采样,测定其理化指标,并结合当地水库管理站提供的水文数据进行综合分析.结果表明,桉树人工林区水库泛黑与特定季节及特殊气候条件有关,水体温度分层结构失稳是黑水物质运移的主要动力因素;夏季水库水温分层结构稳定,限制了底层致黑物质向上迁移,溶解氧等水质指标分层明显,秋冬季节分层消失,水体发生垂直交换,给底层致黑物质提供了上翻的作用力,导致"泛黑"现象发生.硫化物、单宁酸、铁、锰等物质季节性及空间分异特征与水温季节性分层特性密切相关.桉树林区水库水体铁和锰浓度最高可达2.93和3.46 mg/L,桉树茎、叶在水体中浸出大量单宁酸,在硫化物、单宁酸、铁、锰同时存在的条件下,发生铁、锰与硫化物,硫化物与单宁酸,铁、锰与单宁酸等一系列反应,生成黑色络合物,导致水库泛黑.研究结果可为保障桉树人工林区饮用水源地安全提供指导,并为桉树人工林区水库黑水深入研究奠定基础,引领更多学者进行深入研究. 相似文献
5.
为了探究我国南方地区水库季节性热分层消亡前后沉积物铁和磷的迁移规律,于2019年11月2020年1月对天雹水库多点位(浅水区和深水区)水体理化指标进行原位监测,并利用薄膜扩散梯度技术(DGT)高分辨率获取沉积物有效态铁和磷的浓度分布.结果表明:(1)天雹水库沉积物有效态Fe和P浓度分别为4.67～18.72和0.003～0.073 mg/L,其中有效态Fe浓度较太湖、鄱阳湖和洞庭湖高出一个数量级,且浅水区沉积物中有效态Fe浓度较深水区高;(2)热分层消亡过程,沉积物有效态Fe和P浓度的时空差异大,浅水区有效态Fe浓度表现为Day14Day1Day32Day54,有效态P浓度表现为Day1Day14Day32Day54,而深水区有效态Fe和P浓度变幅较小甚至呈增长趋势,归因于浅水区热分层结构对气象因子扰动的响应速率快,水体垂向混合加剧了沉积物中Fe和P的释放;(3)沉积物水界面处有效态Fe和P的交换通量分别为6.58～31.59和0.008～0.086 mg/(m2·d),均自沉积物向上覆水中不断迁移,由于浅水区的热分层消亡时间早于深水区,浅水区内源Fe2+和PO34-的释放对冬季水质恶化的贡献较大,应密切关注水库浅水区沉积物内源释放对整个库区水质的影响. 相似文献
6.
我国南方地区桉树种植区周边水库冬季水体泛黑现象频发,桉树砍伐残体(尤其是叶)浸出液中富含的溶解性有机碳(DOC)、单宁酸与铁、锰、硫化物等一系列反应是其主要致黑原因,然而目前致黑物质对水库泛黑的贡献程度和途径仍不清楚.为了模拟桉树叶浸泡对水库黑水形成的影响机制,研究选取夏季水体未泛黑期(水体热分层稳定)进行室内浸泡实验,测定每6 h上覆水体溶解氧(DO)、氧化还原电位(Eh)、透光度等理化指标,分析DGT有效态铁、锰、硫和DOC、单宁酸浓度分布规律及迁移转化特征,计算沉积物-水界面处Fe2+、Mn2+、S2-表观扩散通量.结果表明:桉树叶浸泡明显消耗水体中的DO,且显著影响水体Eh与透光度.此外,透光度与DO浓度呈显著正相关(相关系数为0.618~0.978).桉树叶浸泡释放大量DOC和单宁酸,其中单宁酸浓度远超有氧马尾松组,其上覆水中浓度分别达到23.9、26.0和34.0 mg/L,说明桉树浸泡为黑水形成提供了重要的DOC和单宁酸来源.桉树叶浸泡后上覆水和表层沉积物中DGT有效态Fe浓度均明显增加,深层沉积物间隙水中DGT有效态Fe浓度明显下降,且其表观扩散通量均为正值,说明深层沉积物中Fe向沉积物-水界面迁移,为黑水形成提供了重要的Fe来源.研究结果可为解决我国南方地区桉树人工林区水库水体突发性泛黑问题提供科学依据. 相似文献
7.
通过对贵州省红枫湖水库中各种汞形态的空间分布及季节变化的研究,探讨了富营养化对各种汞形态分布特征的影响.红枫湖湖水总汞浓度在2.5-13.9ng/L之间,平均值为6.9ng/L.红枫湖水库中汞浓度的空间分布和季节变化均严重受到人为汞污染源的干扰.水体中汞在颗粒态和溶解态之间的分配,主要受内源有机质以及氧化还原条件的影响.由于水华现象,春季后五采样点大量繁殖的藻类吸附了大量的汞,从而改变了汞在水库中的分配和迁移.藻类的生长对水体中溶解气态汞浓度分布也有显著的影响.在夏季,总甲基汞和溶解态甲基汞在水体中的垂直分布表明:在富营养化较严重的后五采样点,水体中升高的甲基汞主要是由于水体中汞的甲基化过程;而在富营养化特征不明显的大坝,水体中升高的甲基汞主要来自沉积物甲基汞的释放.红枫湖水体中各种汞形态的分布特征表明,富营养化对汞的迁移转化影响显著,尤其是汞的甲基化过程.水体富营养化为汞的甲基化提供了有利条件,给水生生态环境及人体健康带来了潜在的威胁. 相似文献
8.
洪水事件能够在短时间内对生态系统的物理与生物过程产生重大影响,从而导致浮游植物群落结构的快速演替.2010年9月,广东省大型水库——高州水库发生特大洪水.为了解洪水的生态效应,于2010年1月-2011年12月对高州水库湖沼学变量和浮游植物进行了调查研究.特大洪水期间,高州水库流域内大量泥沙等颗粒物进入水体,将原有有机物相对较多的沉积物覆盖,有助于减少营养盐的底泥释放,洪水后次年春季枯水期水体营养盐浓度明显降低(尤其是磷,总磷浓度低于0.01 mg/L).洪水过后水体中悬浮物的组成改变,在接下来的水体混合期间无机颗粒物的再悬浮导致水体透明度显著降低,但次年水库整体的透明度升高,浮游植物生物量降低.洪水事件导致的水体理化环境的改变使水库浮游植物群落结构改变,由洪水前以群体蓝藻和大个体绿藻(H1和N A功能类群)为优势类群的群落转变为洪水后以中心纲浮游硅藻和甲藻(A、B和LO功能类群)为优势类群的群落,而以往枯水期常有发生的粘质鱼腥藻等蓝藻水华在洪水后春季枯水期没有出现. 相似文献
9.
风浪扰动下湖滨带悬浮物和营养盐响应特征 总被引：1，自引：0，他引：1
为研究风浪扰动下沉积物起悬过程中悬浮物浓度的分布特征和水体营养盐时空分布状况,以太湖西北湖滨带为例,选择代表4种不同生境的6个点位进行了连续12 d的野外观测.利用高精度分层同步采样装置,采用重量法计算悬浮量,并对悬浮过程中总磷(TP)、总氮(TN)、铵态氮(NH_4~+-N)和硝态氮(NO_3~--N)浓度进行分析.结果表明:风速是引起太湖西北湖滨带水体悬浮物增加的主要因素,沉积物悬浮的临界风速为3.6 m/s.各点位悬浮物浓度的均值差异明显,表现为:无植被区植被区河口区湖心区.太湖西北湖滨带水体氮、磷浓度日变化幅度较大,TN浓度为1.82~4.96 mg/L,TP浓度为0.10~1.47 mg/L.NH_4~+-N和NO_3~--N浓度分别在0.09~2.83和1.05~3.69 mg/L之间波动.近岸无植被区水柱的总悬浮量与风速的相关性最好,相关系数达到0.722;而远岸湖心区与风速的相关系数仅为0.039.悬浮物浓度除了受风情(风向和风速)的影响外,同样受水深、地形特征和水生植被的影响. 相似文献
10.
大型深水水库溶解氧层化结构演化机制 总被引：2，自引：0，他引：2
深水水库溶解氧(DO)的演化成因目前尚不完全清楚,研究其演变机制对制定水库水质保护和管理策略十分重要.本文以我国京津冀地区重要的大型深水水源水库潘家口水库为例,系统分析了水库水温和DO浓度的时空分布特征、演化成因,以及水库的水质响应情况.结果表明:4月中旬-11月底该水库存在显著的季节性热分层,水库热分层为DO层化结构的形成提供了垂向分异性物理环境;与热分层类似,DO层化表现为3层结构,本文从上至下将其分别定义为混合层、氧跃层和氧亏层.垂向各层不同生化过程的作用为DO浓度空间差异性演变提供了驱动力,其中混合层受浮游藻类过量生长的影响,DO往往处于过饱和状态;氧跃层受大量生物的呼吸及有机物分解等耗氧的影响,DO浓度急剧下降,7-8月一般处于缺氧状态(DO2 mg/L);氧亏层受重污染沉积物耗氧的影响,DO浓度持续下降,热分层末期水库底部可能出现缺氧.热分层末期DO浓度降低的同时,沉积物中会发生Mn的还原、Mn-P解吸释放等现象,但沉积物中含量较高的Fe没有发生还原以及Fe-P的解吸释放现象.潘家口水库目前正在逼近缺氧、内源污染大量释放的临界点,其水环境治理应予以高度重视. 相似文献
11.
Seasonal variation of the turbidity (suspended substance) has been investigated in Lake Biwa. During the last five years, vertical and horizontal distributions of water temperature, turbidity, electric conductivity and chlorophyll-a have been obtained both in the south basin and the southern part of the north basin of Lake Biwa. The benthic nepheloid layer (BNL) developed in the seasons of thermal stratification, and is not detectable in the non-stratification period (winter). The BNL is mainly maintained by the organic matter such as phytoplankton under decomposition. However, the turbidity in the nepheloid layer was much affected by the turbid water from rivers after heavy rainfall. In this case, the major component of the suspended substance (SS) in the nepheloid layer was inorganic soil. The particulate P concentration, which is originated from phytoplankton, also increased after a rain fall. This suggests that phytoplankton in the surface layer sinks with clay and silt coming through rivers. From summer to the end of the stratification period, another kind of turbidity appeared in the bottom layer. This is caused by the chemical reaction of manganese under the anoxic condition. The resuspension of bottom sediment by strong currents also occurred, but it is not a major process for maintaining the BNL. 相似文献
12.
The space and time regularities in the distribution, migration, and turnover of dissolved and suspended manganese forms in Novosibirsk Reservoir water are considered. The flux of dissolved manganese forms (Mn2+) from bottom sediments into the water mass is shown to reach its maximum in the under-ice period (since the late February to the mid-April), as well as in the period of maximal abundance of biota (August–early September), when reduction conditions form everywhere in reservoir bottom sediments. In this period, bottom sediments are the main source of manganese input into the reservoir water, their contribution reaching 250–400% relative to the inflowing river water; manganese vertical distribution in water is opposite to that of dissolved oxygen, and its concentration is in excess of the hygienic standards. The maximal flux of dissolved manganese forms (Mn4+) from water into bottom sediments is recorded in August–September (on the average, 0.17 g/(m2 day)); it drops to 0.06 g/(m2 day) during spring flood, and practically vanishes in the under-ice period. 相似文献
13.
Wind-induced resuspension of particulate matter was investigated in a shallow coastal region off southwestern Australia, chosen for its isolation from the complexity of other confounding physical processes. The site had negligible river discharge, low nutrient concentrations and was largely devoid of tidal currents. Moorings were deployed in the micro-tidal waters to measure current speed, wave parameters, backscatter, subsurface irradiance and dissolved oxygen concentration. Two contrasting sites were chosen as representative of high and low wave-energy environments. Turbulent kinetic energy, recorded by the instruments, was dominated by the wind-wave signal. During wind events, at the most exposed site, bed shear stress exceeded the critical stress required to lift and resuspend sediments. At the most enclosed site, bed shear stresses only exceeded the critical stress required to suspend less dense material such as benthic fluff. Wind-waves were found to be the dominant mechanism driving the vertical redistribution of particulate matter. Low frequency storm events and high frequency (daily) sea breezes were found to differ significantly in their retention of particulate matter suspended in the water column. Long periods of calm generally followed the passage of a storm, allowing suspended particulate matter to settle out, while consecutive daily sea breezes were more effective in holding particulate matter in suspension. Linear correlations were found between the backscatter (a proxy for suspended particulate matter), light attenuation and dissolved oxygen concentration. Approximately half the variability in dissolved oxygen concentration could be attributed to the variability in light attenuation, with a decline in concentration during wind resuspension events. Variability in dissolved oxygen concentration was interpreted as a possible indicator of the moderation of pelagic phytoplankton productivity during wind events. 相似文献
14.
The distributions of dissolved and of particulate iron in the Dead Sea during the period which preceeded its overturn and thereafter (1977–1980) are reported. During 1977–1978, the vertical profiles of the iron phases revealed facets of the mixing pattern: the progressive deepening of the pycnocline, restricted mixing within the upper water mass and penetration of surface waters into the deepest layer. The inventories of particulate iron suggest resuspension of bottom sediments in November 1978 and after the overturn the gradual disappearance from the water column of iron sulfides and iron oxy-hydroxides. Fluxes of iron from and to the lake in the undisturbed meromictic Dead Sea have been estimated: it appears that diffusion of divalent iron from bottom sediments was the major source for the standing crop of iron in the lower water mass. Low settling velocities of solid particles in the dense and viscous Dead Sea is one of the causes for the relatively large concentrations of particulate iron. The rate constant for oxidation of divalent iron in Dead Sea sediment interstitial waters is larger by two orders of magnitude than in other natural waters. 相似文献
15.
Ramalhosa E Pereira E Vale C Válega M Monterroso P Duarte AC 《Marine pollution bulletin》2005,50(11):1218-1222
Determinations of dissolved reactive and total dissolved mercury, particulate and sedimentary mercury, dissolved organic carbon (DOC), particulate organic carbon (POC) and suspended particulate matter (SPM) have been made in the estuary of river Douro, in northern Portugal. The estuary was stratified by salinity along most of its length, it had low concentrations of SPM, typically <20 mg dm(-3), and concentrations of DOC in the range <1.0-1.8 mg dm(-3). The surface waters had a maximum dissolved concentration of reactive mercury of about 10 ng dm(-3), whereas for the more saline bottom waters it was about 65 ng dm(-3). The surface waters had maximum concentrations of total suspended particulate mercury of approximately 7 microg g(-1) and the bottom waters were always <1 microg g(-1). Concentrations of mercury in sediments was low and in the range from 0.06 to 0.18 microg g(-1). The transport of mercury in surface waters was mainly associated with organic-rich particulate matter, while in bottom waters the dissolved phase transport of mercury is more important. Lower particulate organic matter, formation of chlorocomplexes in more saline waters and eventually the presence of colloids appear to explain the difference of mercury partitioning in Douro estuarine waters. 相似文献
16.
Samples of raw water were collected at regular intevals at two transects in the St. Lawremce River and four of its tributaries
from March to November 1991 and from April to June 1992. Water samples were analyzed for both the dissolved and the particulate
phase for cadmium (Cd), organic carbon, iron and manganese. Mean dissolved Cd concentration was 10±5 ng/L and no spatial variability
was observed. Higher concentrations were found during high flow periods, suggesting an uptake of cadmium by phytoplankton
during summer. In addition, dissolved cadmium did not appear to be associated with either DOC, dissolved Fe or dissolved Mn.
The mean particulate Cd concentration was 1.3±1.1 μg/g, with almost all stations presenting the same concentration except
the Yamaska River, which had a concentration of 0.5±0.2 μg/g. Particulate Cd showed a negative correlation with suspended
particulate matter and a positive correlation with particulate organic carbon and particulare manganese. Fifty-nine percent
of the cadmium was found to be in the particulate phase. Partition coefficients for cadmium (Kd), organic carbon (Kc), iron
(KdFe) and manganese (KdMn) were calculated for each sample. Log Kd varied from 3.9 to 5.9, with an average of 5.0±0.4. Log
Kd decreased with increasing particulate, matter as did Log Kc and Log KdMn. No significant correlation was found between
Log Kd and Log Kc, suggesting that the distribution of cadmium between the dissolved and the particulate phase is not influenced
by the distribution of organic carbon. In contrast, positive correlations were observed between Log Kd, Log KdFe and Log KdMn.
Cadmium distribution appears to be influenced by Fe and Mn distribution. 相似文献
17.
P. Pato M. Otero M. Válega C.B. Lopes M.E. Pereira A.C. Duarte 《Marine pollution bulletin》2010,60(10):1658-1666
After having estimated the patterns of flow to the ocean and found some seasonal and tidal differences, mainly with regard to the relative importance of dissolved and particulate fractions, mercury partitioning at the interface between a contaminated lagoon and the Atlantic Ocean was investigated during four tidal cycles in contrasting season and tidal regimes. Mercury was found to be located predominantely in the particulate fraction throughout the year, contributing to its retention within the system. Seasonal conditions, variations in marine and fluvial signals and processes affecting bed sediment resuspension influenced the character and concentration of suspended particulate matter in the water column. Variation in the nature, levels and partitioning of organic carbon in the particulate fraction affected levels of particulate mercury as well as mercury partitioning. These results highlight the dominant role of suspended particulate matter in the distribution of anthropogenic mercury and reinforce the importance of competitive behavior related to organic carbon in mercury scavenging. 相似文献
18.
Sediment diffusive fluxes of Fe,Mn, and P in a eutrophic lake: Contribution from lateral vs bottom sediments 总被引：3，自引：0，他引：3
Nelson Belzile Jaime Pizarro Montserrat Filella Jacques Buffle 《Aquatic Sciences - Research Across Boundaries》1996,58(4):327-354
Water column data and porewater profiles are used to study the chemical evolution with time and with depth of a eutrophic lake. By using different approaches, diffusion fluxes for dissolved iron, manganese and phosphate are calculated and used to describe the processes occurring at the sediment-water interface as well as in the hypolimnion of the lake. These data are used in the elaboration of a qualitative model to describe the chemical behaviour of the sedimentary interface of an anoxic lake with emphasis on the Fe/P/S system. Acorona model is proposed to explain the evolution with time of the diffusion process by estimating the relative contribution of bottom and lateral sediment surfaces to the total fluxes of dissolved elements diffusing from the sediment to the overlying water. As the hypolimnion becomes more anoxic, it has been observed that lateral sediment surfaces (16 to 10 meters in depth) represents a larger supplier of diffusing dissolved components than the bottom sediment portion (bottom to 18 meters). 相似文献
19.
This investigation showed that urban stormwater runoff provides a significant amount of petrogenic material to receiving waters and sediments. A characteristic hydrocarbon ‘fingerprint’ for sediments and particulate matter in the Hillsborough Reservoir, Hillsborough River and upper Hillsborough Bay was provided. Determination of source material for petroleum contamination in stormwater runoff and river sediment indicated that crankcase oil was a primary contributor to sediment hydrocarbon contamination. A comparison of sediment hydrocarbons with hydrocarbons from stormwater runoff showed that the most probable source of crankcase oil-like petrochemicals found in sediment was the stormwater runoff.A comparison of hydrocarbon composition in suspended particulate matter with that of accumulated bottom sediments in the reservoir, river and bay, during a non-storm period and rising tide showed no resuspension and upriver transport of petroleum contaminated bay sediment. No special influence of the bay upon the lower river was observed relative to hydrocarbon tracers, indicating that most contaminated sediment transport was downriver during storm events. Additional studies should be performed over various tidal cycles and storm events incorporating sediment cores, sediment grain size analysis and hydrocarbon characterization at more closely spaced stations near the river mouth to address adequately the question of specific hydrocarbon pollution sources, rate of petroleum influx and persistence of petrochemical contaminants in the sediment. 相似文献