南京市地表水溶解氧分布特征及低氧成因初探——以外秦淮河七桥瓮为例

于2018—2021年对南京市及国考断面七桥瓮进行水质调查,分析其溶解氧变化特征,采用水质水量联合评价及皮尔逊相关分析法,并结合水文气象等相关信息,对南京市地表水溶解氧分布特征及国考七桥瓮断面低氧成因进行研究分析。结果表明,南京市地表水溶解氧浓度夏季最低,中心主城区及附近区域溶解氧浓度均相对较低。七桥瓮断面溶解氧浓度在2.25~11.07 mg/L,其中5—9月溶解氧易出现超标波动。溶解氧浓度昼间高于夜间,与pH值呈正相关关系,与水温、高锰酸盐指数、氨氮、总磷均呈负相关关系。水温和上游来水带入的耗氧污染物是七桥瓮断面溶解氧偏低的主要成因,其中,溶解氧浓度与水温相关性最为显著。研究结论可为七桥瓮断面稳定达标提供基础支撑,为秦淮河流域精准治污提供技术依据,为南京市水环境多源同治提供治理思路。     

基于在线自动监测的钦州湾海域水质参数周年时空变化特征

通过分析位于钦州湾的2个海水水质自动监测站2009-2010年的自动监测数据,发现钦州湾水温、盐度、溶解氧季节变化明显,海水表层水温变化是引起钦州湾溶解氧含量变动的主要原因;钦州湾海水表层盐度及pH值主要受钦江、茅岭江径流及潮汐涨落的影响;处于河口区域,受大陆径流影响显著的海域使用海水水质标准来评价有欠妥当。     

釜溪河自贡城区段季节性低氧成因研究

釜溪河为沱江一级支流,在自贡城区段设有国考碳研所断面。收集碳研所断面近10年来水质自动站数据,分析溶解氧(DO)变化特征,采样调查釜溪河自贡城区段水质及河道底泥污染状况,采用相关性分析、数值模拟等,研究分析釜溪河自贡城区段溶解氧分布特征及碳研所断面季节性低氧成因。研究结果表明,碳研所断面的溶解氧质量浓度变化特征呈现春末夏初最低,白天高晚上低的特征。釜溪河碳研所断面河水耗氧类污染物质量浓度较沱江流域内其他断面高,耗氧强度较大,溶解氧质量浓度较沱江流域其他断面偏低;其次,研究河段中釜溪河污水厂以下河段受污水厂低氧水排入和金子凼堰底层低氧水下泄影响,其溶解氧水平整体较污水厂以上河段低;最后,河段底泥有机质含量较高,春夏季气温升高将导致微生物分解活性增强大量消耗溶解氧,同时,闸坝和外来水体排入的水文扰动造成污水厂以下河段水温梯度弱,表层溶解氧易受底层低氧水影响,促使断面形成季节性低氧现象。溶解氧预测模型结果也进一步证实了温度变化和垂向温度梯度弱是碳研所断面溶解氧质量浓度季节性偏低的主要因素。     

云南水环境放射性水平监测结果分析

根据2013—2020年云南省河流、湖泊、饮用水和地下水省控点、国控点的水中放射性水平监测结果,分析了水中总α、总β、U、Th、²²⁶Ra、⁴⁰K、¹³⁷Cs、⁹⁰Sr的监测浓度。结果表明:六大水系监测断面水中总α、总β均小于0.5、1.0 Bq/L;九大高原湖泊水中放射性水平相对较高的是Ⅴ类水体杞麓湖、异龙湖,放射性水平相对较低的是Ⅰ类水体抚仙湖、泸沽湖,滇池内海水中U、Th浓度优于滇池外海;饮用水源地水中放射性总α、总β均显著低于《生活饮用水卫生标准》(GB 5749—2022)规定限值。     

太湖微囊藻毒素与湖泊物理因素之间的关系

应用酶联免疫吸附法(ELISA)监测了太湖2001年的微囊藻毒素的周年变化,探讨了微囊藻毒素浓度(Microcystin-LR,MCLR)和水温、光照、悬浮质、溶解氧、风浪等湖泊物理因素之间的关系,显示微囊藻毒素在夏秋季节较高,但各采样点微囊藻毒素浓度的最高值及其变化趋势与各采样点所处地理位置,水动力学变化及样点周围水域藻类生长情况等有密切关系,从湖泊物理因素来看,微囊藻毒素浓度受风浪和水温的影响较大。     

黄河兰州段氨氮含量变化特征分析

于2007年对黄河兰州市区段上的新城桥断面和雁儿湾断面逐月取样,测定了其中氨氮、溶解氧、温度、pH值等指标。经分析认为,两断面氨氮含量最高值出现在枯水期、最低值均出现在枯水期,两断面均有水温低时氨氮含量升高、水温高时氨氮含量降低的现象,氨氮与溶解氧变化关系不明显。     

2000—2019年阳澄湖水质变化趋势分析

根据阳澄湖2000—2019年的水质监测数据,分析了总磷、总氮对水质的影响,以及水质富营养状况的年际变化趋势.结果显示,与2000年相比,阳澄湖水质明显好转,主要超Ⅲ类指标总磷、总氮浓度总体呈波动下降趋势,但近几年水质稳定在Ⅳ类,改善不明显;2011年以来,总氮月度变化特征呈明显波浪型周期变化,阳澄西湖水质较差,东湖较...     

望虞河西岸河网区沉积物营养盐和重金属污染时空分布特征

以无锡市望虞河西岸河网区为研究区域,于2018年12月—2019年9月分冬、春、夏、秋4个季节采集了上覆水和沉积物样本,研究氮磷营养因子在沉积物-上覆水界面的释放规律,探究主要水质指标、沉积物氮磷和重金属含量的时空分布特征。结果表明:研究区域内的水质状况不佳,主要是氮含量超标,污染严重的点位集中在人类活动较为密集的市区和工业区;受上覆水氮磷浓度、溶解氧浓度等变化的影响,沉积物营养盐含量季节变化明显,污染状况较为严重,75%的点位属于中度和重度污染;沉积物重金属含量季节变化不显著,部分重金属的空间分布特征相似,污染程度排序为Zn>Cd>Cu>Pb>Ni>Cr>As。     

1982—2012年滇池水质变化及社会经济发展对水质的影响

滇池是中国著名的高原淡水湖泊,是国家"三河三湖"治理重点之一。采用Mann-Kendall和Daniel趋势检验法解析滇池外海在1982—2012年典型污染物指标(CODMn、BOD5、TN、NH3-N和TP)的年际变化特征;对滇池流域人口、人均GDP与滇池CODMn、TN和TP相关性进行研究,阐明流域社会经济发展对滇池水质变化的影响。研究结果表明,滇池各污染物指标年际变化波动较大。在α=0.01的显著水平上TN和NH3-N有显著上升趋势,CODMn和TP有上升趋势但不显著,BOD5基本未发生趋势变化,Mann-Kendall和Daniel趋势检验结果基本一致。滇池TN、CODMn与流域人口、人均GDP密切相关,社会经济发展是TN和CODMn浓度上升的重要原因;随着滇池污染治理工作的不断推进,特别是"十一五"水污染治理规划实施以来,流域社会经济发展对滇池TP、TN影响有所减轻,滇池磷的治理取得初步成效。     

南水北调东线江苏段2005年10月水质状况

2005年10月，14个控制断面中有9个断面达到Ⅲ类水质标准，达标率为64．3％。5个未达标断面中扬州三垛西大桥和徐州沙庄桥断面水质为V类，其余断面水质为Ⅳ类；主要超标污染指标有溶解氧、五日生化需氧量、高锰酸盐指数、石油类和氨氮。与上月相比，南水北调东线江苏段总体水质基本持平，14个断面中，8个断面水质无明显变化，1个断面水质显著好转，1个断面水质好转，3个断面水质恶化，1个断面水质显著恶化。与2004年同期相比，14个断面中，9个断面水质无明显变化，2个断面水质显著好转，1个断面水质好转，2个断面水质恶化。     

右江百色水库下游断面低溶解氧形成原因分析

广西右江东笋断面溶解氧(DO)呈现5—11月浓度较低,12月及1—4月浓度较高的变化规律。从水温、藻类呼吸、沉积物耗氧、有机物耗氧、上游来水等方面分析了东笋断面低DO形成的原因。结果表明,5—11月东笋断面DO浓度较低,主要是受夏季高温和水利工程运行等非污染型因素的影响。右江流域夏秋季水温较高,限制了水体DO浓度的上限。热分层现象导致百色水库中层水体DO浓度较低,而水利枢纽发电时的下泄水正是中层水体,因此,下泄水DO浓度低是导致5—11月东笋断面DO浓度低的主要原因。东笋河段沉积物和有机物耗氧对DO浓度的影响很小,藻类呼吸作用对DO浓度的影响有限。     

Dissolved oxygen content as an index of water quality in San Vicente Bay,Chile (36 degrees 45'S)

The present report describes some effects of industrial and municipal effluents on the waters of San Vicente Bay. Analyses ofthe main substances contained in the fishing industry effluentsuggest rating criteria based on the oxygen saturation of thewater as an assessment of organic pollution. Six cruises were carried out throughout the Bay, from June to December 1996. Watersamples were analyzed for dissolved oxygen, oil and grease content, and sediment samples for organic matter content. Waterparameters (salinity, temperature) were used to characterize theBay's hydrography, and to calculate values for oxygen saturation. The measurements demonstrated a local broad range of oxygen deficit, with a maximum of 45% in the winter to 95% in the spring. In November more than 65% of the Bay's area showed oxygendeficits greater than 40%. Organic matter was unusually high insediments along the northern sector of the Bay. The results suggest that the oxygen depletion was a representative parameterfor establishing a relative scale of water quality in this Bay.     

东平湖浮游动物对南水北调东线运行的时空响应

东平湖是南水北调东线工程输水线路下游的最后一个调蓄湖泊.为探究调水后的东平湖浮游动物时空响应,于2016—2017年对东平湖浮游动物进行了涵盖春(4月)、夏(7月)、秋(10月)、冬(1月)的4次调查,共检出浮游动物3类72种(属),其中,轮虫51种(70.83％)、枝角类11种(15.28％)、桡足类10种(13.8...     

调水后东平湖浮游植物群落结构及水质生物评价

东平湖是南水北调东线工程的重要调蓄湖泊,在防洪、灌溉、休闲旅游、水产养殖及水资源供应等方面发挥着至关重要的作用.为了解南水北调东线调水后的东平湖浮游植物群落结构及水体健康状态,于2016年4月(春季)、7月(夏季)、10月(秋季)及2017年1月(冬季)对东平湖不同空间区域(根据调水路线划分为进水区、湖中区和出水区)的...     

升钟湖水体叶绿素a动态特征及其影响因子分析

2011—2015年每月监测升钟湖湖区的4个代表性断面的水质指标,分析水体中叶绿素a时空分布特征、变化规律及影响水体水质状况的其他要素。结果表明:升钟湖的叶绿素a具有显著性的年际差异,表现为夏季高、冬季低且呈现逐年下降的变化趋势,总磷、总氮、氨氮、溶解氧、透明度监测指标同样表现为夏季高、冬季低的变化趋势,除溶解氧和透明度的监测指标逐年上升外,其他监测指标均逐年下降。构建了叶绿素a与总氮、总磷的多元回归方程模型,该模型可根据水体营养盐状态准确预测升钟湖叶绿素a的变化趋势。     

淀山湖总氮和总磷的时空模拟分布

为了解氮磷在淀山湖的时空分布特征及变化规律,运用ELCOM-CAEDYM耦合模块分析了2008年淀山湖总氮和总磷浓度的时空变异。研究表明:模型较好地模拟了淀山湖上覆水中的总氮、总磷的时空分布,总氮、总磷质量浓度总体变化趋势与实测值相一致。淀山湖春冬季总氮的质量浓度要明显高于夏秋季,3月份是淀山湖总氮质量浓度最高的时候,千墩港是淀山湖总氮质量浓度最高的区域。淀山湖总磷的分布并未表现出季节上的规律性,空间分布整体呈现北高南低的趋势。     

Phase I of the Kissimmee River restoration project, Florida, USA: Impacts of construction on water quality

Phase I of the Kissimmee River restoration project included backfilling of 12 km of canal and restoring flow through 24 km of continuous river channel. We quantified the effects of construction activities on four water quality parameters (turbidity, total phosphorus flow-weighted concentration, total phosphorus load and dissolved oxygen concentration). Data were collected at stations upstream and downstream of the construction and at four stations within the construction zone to determine if canal backfilling and construction of 2.4 km of new river channel would negatively impact local and downstream water quality. Turbidity levels at the downstream station were elevated for approximately 2 weeks during the one and a half year construction period, but never exceeded the Florida Department of Environmental Protection construction permit criteria. Turbidity levels at stations within the construction zone were high at certain times. Flow-weighted concentration of total phosphorus at the downstream station was slightly higher than the upstream station during construction, but low discharge limited downstream transport of phosphorus. Total phosphorus loads at the upstream and downstream stations were similar and loading to Lake Okeechobee was not significantly affected by construction. Mean water column dissolved oxygen concentrations at all sampling stations were similar during construction.     

Water Quality Assessment and Modeling of an Effluent-Dominated Stream, the Notwane River, Botswana

In an effort to assess current and future water quality of the only perennial river in southeastern Botswana, this study presents water quality monitoring and modeling results for the effluent-dependent Notwane River. The water quality along the Notwane River, pre- and post-implementation of secondary wastewater treatment, was compared and results demonstrated that water quality improved after the new wastewater treatment plant (WWTP) went online. However, stream standards for chemical oxygen demand, total dissolved phosphorous, and fecal coliform were exceeded in most locations and the critical dissolved oxygen (DO) reached concentrations of less than 4 mg L⁻¹. High dissolved P concentrations and intense macrophyte growth at the impounding ponds and at sites within 30 km of the effluent waste stream confluence suggest that eutrophication was a function of P release from the ponds. Results of DO modeling demonstrated that an unpolluted inflow at approximately 10 km downstream of the confluence was responsible for raising DO concentrations by 2.3 mg L⁻¹, while SOD was responsible for a decline in DO concentrations of 1.4 mg L⁻¹ at 6 km downstream of the confluence. Simulations also showed higher DO concentrations during winter months, when water temperatures were lower. Simulations, in which the distributed biochemical oxygen demand (BOD) loading from cattle excrement was decreased, produced nominal increases in DO concentrations. An increase in WWTP BOD loadings to projected 2020 values resulted in a 1.3 mg L⁻¹ decrease in the critical DO concentration. Furthermore, a decrease in treatment plant efficiency, from 94% to 70% BOD removal, produced critical DO concentrations and anoxia along much of the modeled reach. This has significant implications for Gaborone, especially if decreased WWTP efficiency occurs as a result of the expected future increase in pollutant loadings.