基于自动监测网络的湘江流域衡阳段铊污染原因分析

运用自动监测网络与实验室验证相结合的手段,通过测定湘江流域衡阳段干流与支流铊浓度,分析铊浓度与溶解氧含量、氨氮浓度及叶绿素a浓度等水质指标的关系,进而对湘江流域衡阳段铊污染进行原因分析。结果表明,2021年8月上旬,湘江流域衡阳段干流铊污染的来源主要为多支流污染汇入。其中,松木下游断面铊污染极有可能来源于支流上游企业排放,江东水厂断面铊浓度异常的原因主要为溶解氧降低、死藻富集。该案例可为我国铊污染应急监测及污染原因分析提供借鉴。     

淮河干流河南段水质预测模型试验研究

淮河干流在河南省境内总长417 km,随着区域经济的发展和人口的增长,淮河干流水环境质量形势不容乐观。根据水体扩散理论,建立了淮河干流水质预测相关模型,并进行了科学验证。对淮河干流河南段氨氮、化学需氧量衰减系数及富氧和耗氧系数4个项目开展现场试验及科学分析,为水资源保护规划中计算水体纳污能力、预测污染物浓度、制定污染物控制方案等提供坚实基础和技术支持。     

关于河流纳污混合水质概率稀释模型及其应用研究

本文以淮河干流上游息县和维滨两个城关纳污河段为例，根据扩散理论和概率学理论，尝试建立了河流纳污混合水质浓度概率稀释模型。并研究确定了概率稀释模型在河流污染控制中的应用方法和技术路线。与实测结果比较，概率稀释模型方法计算更具有准确性和科学合理性．对水质评价和规划河流污染治理方案具有重要指导意义，对实现淮河水质返清目标有积极贡献。     

汉江襄阳城区段水质变化规律及特征分析

为全面掌握汉江襄阳城区段沿程水质变化情况,合理制定相应保护措施,基于2018—2022年汉江襄阳城区段出入境断面及支流水质监测数据,对汉江襄阳城区段水环境质量、变化趋势和相关特征开展综合分析评价。结果表明,2018—2022年汉江襄阳城区段入境与出境断面水质状况总体为优,但出境断面氨氮、总磷、总氮的质量浓度较入境断面均有明显增高,主要支流唐白河、清河及南渠的汇入对出境断面水质影响较大。2018—2021年汉江襄阳城区段出入境断面主要监测指标质量浓度分布表现为丰水期＞枯水期,2022年表现为枯水期＞丰水期。汉江襄阳城区段水质氮污染贡献明显高于磷污染,仍以氮污染为主,水质中氮主要以游离氨和铵盐以外的形式存在。相关性分析结果表明,入境断面与出境断面中氨氮、总氮与各指标相关性差别较大,总磷、溶解氧与各参数间的相关性基本一致。研究结果可为制定汉江水环境改善及污染防治措施提供科学依据。     

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。     

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。     

辽河水体主要污染指标时空异质性分析

利用1987～2009年辽河干流8个常规监测断面的历年监测数据,通过统计分析确定辽河水质的主要污染指标为化学需氧量(COD)和氨氮,2007年前辽河水质首要污染指标是COD,2008年和2009年氨氮超过COD成为辽河水质污染首要污染指标;分析干流两项指标的时间、水期、空间分布规律,明确给出水质污染重点治理时段和河段.     

香溪河库湾氮的时空分布及影响因子分析

为研究解决香溪河库湾水体富营养化问题，需探明库湾水体氮的时空分布及影响因子。2010年12月—2011年11月对香溪河与水库干流交界处至香溪河库湾尾部共12个采样点进行连续监测，分析香溪河库湾氮的时空分布，结果表明，香溪河库湾氮存在明显的时空分布规律。空间上，回水末端处TN和NO₃^--N浓度低，河口处浓度高，随着与回水末端距离的增加，浓度逐渐升高。在时间上，香溪河库湾TN和NO₃^--N浓度的变异系数随着与河口距离的增加总体上逐渐增大，研究时间内的变化程度逐渐变大；且香溪河库湾TN和NO₃^--N浓度在三峡水库不同运行阶段的时间变化规律不同。     

2013—2020年泸沽湖溶解氧随时间变化规律及主要影响因素分析

泸沽湖坐落于川滇交界处,是中国典型高原淡水湖泊。对泸沽湖水质的客观评价对于其规划保护及保护成效评估极为重要。鉴于溶解氧常常成为决定泸沽湖水质类别的唯一关键指标,在综合分析泸沽湖2013—2020年连续8年水环境主要指标变化的基础上,着重分析了溶解氧随季节、年际等的变化情况及其主要影响因素。结果表明,溶解氧浓度及饱和率存在明显的季节和年际波动。其中:溶解氧浓度一般是在春季升至全年最高,夏季末降低,并在秋冬季维持低位;溶解氧饱和率则是夏秋季节最高,冬季最低。溶解氧浓度的季节变化与水温显著负相关,而溶解氧饱和率的季节变化和水温、pH显著正相关;溶解氧浓度及饱和率的年际变化与水质主要指标均不存在显著相关关系。受高海拔低气压影响,虽然采取了大气压和温度补偿校准,但泸沽湖溶解氧浓度仍不易达到Ⅰ类水质标准限值(7.5 mg/L);而优良的水质加之茂盛的水生植被使得其溶解氧饱和率长期处于较高水平,可以达到Ⅰ类标准限值(90%)。因此,在自然环境特征类似于泸沽湖的水质优良高原湖泊,优先以饱和率作为溶解氧的评价指标更为合理。     

长江江苏段抗生素的空间分布特征及典型污染来源分析

利用超高效液相色谱-三重四极杆质谱法,于2021年4月对江苏省长江干流12个监控断面、入江支流116个监控断面表层水中7大类42种抗生素的分布特征和浓度水平进行研究,并开展典型污染来源分析。结果表明,平水期长江干流42种抗生素总质量浓度范围为47.3～92.8 ng/L,处于较低水平;各入江支流抗生素总质量浓度范围为16.2～3 052 ng/L,干支流水体中检出品种以磺胺类、氯霉素类、林可酰胺类及大环内酯类为主;通过差异性比较发现,C市存在磺胺类抗生素污染的典型区域;典型污染溯源分析结果表明,工业废水可能是该地区环境水体中抗生素污染的来源之一。长江江苏段及地表水中各类抗生素普遍检出,虽然抗生素总量水平不高,但由制药废水、畜禽养殖、污水处理厂等污染源引入而引起的长期积累仍是隐患。研究结果为江苏省长江流域水环境抗生素污染控制和管理提供基础数据。     

太湖流域断头河道微循环水质效应与生物响应

针对太湖流域断头河道微循环过程中水质效应和生物响应不清楚的问题,笔者通过水槽模拟实验,分析了氮磷和有机物等水质指标随水体微循环时间、频率的变化关系;通过常州武进洛阳镇徐家头浜实际河道微循环实验,探讨了微循环运行过程中实际河道水质的稳定性,微循环过程中实际河道的生物响应,及浊度、溶解氧、pH等环境因素的影响。结果表明：水槽模拟实验条件下微循环对水体氨氮去除的影响最为明显（去除率达62.91%）,COD去除率变化幅度受微循环频率的影响最大（可达50%）;微循环设置后实际河道COD浓度下降趋势明显（降幅约30%）;微循环过程中河道水体浮游动物和浮游植物数量均呈上升趋势,而河道边坡和底泥中Proteobacteria、Bacteroidetes、Actinobacteria、Acidobacteria等优势微生物菌群的丰度却有不同程度的变化。同时,浊度对总磷和COD的影响程度相当,溶解氧和pH对水体氨氮浓度的影响均最显著。该研究为改善断头河道水质提供新方向,为微循环技术的实际应用提供数据参考。     

Numerical Modeling on the Effect of Dissolved Oxygen on Nitrogen Transformation and Transport in Unsaturated Porous System

Nitrogen pollution in groundwater resulting from wastewater application to land is a common problem, and it causes a major threat to groundwater-based drinking water supplies. In this study, a numerical model is developed to study the nitrogen species transport and transformation in unsaturated porous media. Further, a new mass transfer module for dissolved oxygen (DO) is incorporated in the one-dimensional numerical model for nitrogen species transport to describe the fate and transport of nitrogen species, dissolved oxygen, dissolved organic carbon (DOC), and biomass. The spatial and temporal variation of dissolved oxygen is incorporated in the model through the mass transfer from gaseous phase to water phase in an unsaturated porous system. The numerical results of the water flow model and single species and multispecies transport model in an unsaturated zone developed for this purpose have been validated with the available analytical/numerical solution. The developed model is applied in clay loam, silt, and sand soils to analyze the transport behavior of nitrogen species under unsaturated condition. The numerical results suggest that the high rate of oxygen mass transfer from the air phase to the water phase positively increases the dissolved oxygen in the applied wastewater and enhances the nitrification process. Because of this high oxygen mass transfer, the nitrate nitrogen concentration significantly increases in the unsaturated zone and the same is transported to a larger depth at higher simulation period. On the other hand, the low rate of oxygen mass transfer implicitly enhances the denitrification process and finally reduces the nitrate nitrogen concentration in the unsaturated zone. The numerical results also show that the nitrate nitrogen transport is rapid in sandy soil when compared with clay loam and silty soils under high oxygen mass transfer rate. In essence, the high oxygen mass transfer rate significantly increases the nitrate nitrogen in the unsaturated zone, especially at a greater depth at larger time levels and eventually affects the groundwater quality.     

Nutrients in the Changjiang River

N, P and SiO3-Si in the Changjiang mainstream and its major tributaries and lakes were investigated in the dry season from November to December, 1997, and in the flood season in August and October, 1998. An even distribution of SiO3-Si was found along the Changjiang River. However, the concentrations of total nitrogen, total dissolved nitrogen, dissolved inorganic nitrogen, nitrate and total phosphorus, total particulate phosphorus increased notably in the upper reaches, which reflected an increasing impact from human activities. Those concentrations in the middle and lower reaches of the Changjiang River were relatively constant. Dissolved N was the major form of N and the particulate P was the major form of P in the Changjiang River. The molar ratio of dissolved N to dissolved P was extremely high (192.5-317.5), while that of the particulate form was low (5.6-37.7). High N/P ratio reflected a significant input of anthropogenic N such as N from precipitation and N lost from water and soil etc. Dissolved N and P was in a quasi-equilibrium state in the process from precipitate to the river. In the turbid river water, light limitation, rather than P limitation, seemed more likely to be a controlling factor for the growth of phytoplankton. A positive linear correlationship between the concentration of dissolved N and the river's runoff was found, mainly in the upper reaches, which was related to the non-point sources of N. Over the past decades, N concentration has greatly increased, but the change of P concentration was not as significant as N. The nutrient fluxes of the Changjiang mainstream and tributaries were estimated, and the result showed that the nutrient fluxes were mainly controlled by the runoff, of which more than a half came from the tributaries. These investigations carried out before water storage of the Three Gorges Dam will supply a scientific base for studying the influences of the Three Gorges Dam on the ecology and environment of the Changjiang River and its estuary.     

Assessing the influence of nutrient reduction on water quality using a three-dimensional model: case study in a tidal estuarine system

A coupled three-dimensional hydrodynamic and water quality model has been developed and applied to the Danshuei River estuarine system and adjacent coastal sea. The water quality model considers various species of nitrogen, phosphorus, organic carbon, and phytoplankton as well as dissolved oxygen and is driven by a three-dimensional hydrodynamic model. The hydrodynamic and water quality models were validated with observations of water surface elevation, velocity, salinity distribution, and water quality parameters. Statistical error analysis shows that predictions of hydrodynamics, salinity, dissolved oxygen, and nutrients from the model simulation quantitatively agreed with the observed data. The validated model was then applied to predict water quality conditions as a result of a reduction in nutrient loadings based on different engineering strategies. The simulated results revealed that the dissolved oxygen concentration would increase significantly and would be higher than 2 mg/L in the main stream and in three tributaries to meet the minimum statutory requirement for dissolved oxygen. Active estuarine management focused on the reduction of anthropogenic nutrient loads is needed for improvement in water quality.     

三峡库区神女溪水华成因初探

通过对神女溪大规模水华进行现场监测和调查,结合当地水文、气象、污染源调查资料,并运用对比、相关分析等方法对神女溪水华原因进行了综合分析,认为叶绿素a与溶解氧、氧化还原电位、总氮、总磷、高锰酸钾指数均存在正相关关系,与pH和电导率呈负相关关系,总磷是此次水华的限制因子.     

Application of physicochemical data for water-quality assessment of watercourses in the Gdansk Municipality (South Baltic coast)

The paper presents water-quality evaluation based on an 8-year monitoring programme in the Gdansk Municipality region, on the Southern coast of the Baltic Sea. The studies were carried out from 2000 to 2007 by surface water analysis at 15 various sites within eight watercourses. Sampling sites included rather urbanized or developed lands, farming fields and non-polluted city recreational areas such as parks and forests. Most of the watercourses were sampled monthly at two locations, one within the upper course of the watercourse and the other near its mouth. In all samples, eight parameters of water quality were determined: total suspended solids, dissolved oxygen, water temperature, oxygen saturation, 5-day biochemical oxygen demand, chemical oxygen demand, total phosphorus and total nitrogen concentration. Interpretation of the obtained results revealed that examination of those basic physicochemical parameters permits to discriminate initially watercourses with respect to level of water contamination. During the research, a large dataset was obtained and it was described by both basic statistical parameters and chemometric method of cluster analysis. The paper presents relations between analysed parameters and influence of land exploitation mode on water quality and describes variation of the results both in space and time.     

Impact of storm water on groundwater quality below retention/detention basins

Groundwater from 33 monitoring of peripheral wells of Karachi, Pakistan were evaluated in terms of pre- and post-monsoon seasons to find out the impact of storm water infiltration, as storm water infiltration by retention basin receives urban runoff water from the nearby areas. This may increase the risk of groundwater contamination for heavy metals, where the soil is sandy and water table is shallow. Concentration of dissolved oxygen is significantly low in groundwater beneath detention basin during pre-monsoon season, which effected the concentration of zinc and iron. The models of trace metals shown in basin groundwater reflect the land use served by the basins, while it differed from background concentration as storm water releases high concentration of certain trace metals such as copper and cadmium. Recharge by storm water infiltration decreases the concentration and detection frequency of iron, lead, and zinc in background groundwater; however, the study does not point a considerable risk for groundwater contamination due to storm water infiltration.     

Water quality in Lis river, Portugal

In the past 30?years, the Lis river basin has been subjected to constant ecological disasters mainly due to piggery untreated wastewater discharges. The aim of this study was to evaluate the effect of existing domestic, agricultural, and industrial activities on the water quality, and to propose a watershed plan to protect and manage surface water resources within the Lis river basin. For this purpose, 16 monitoring stations have been strategically selected along the Lis river stretch and its main tributaries to evaluate the water quality in six different sampling periods (2003–2006). All samples were characterized in terms of organic material, nutrients, chlorophyll, and pathogenic bacteria. Generally, the Lis river presents poor water quality, according to environmental quality standards for surface water, principally in terms of dissolved oxygen, biochemical oxygen demand, total nitrogen, and fecal coliform, which can be associated mainly with the contamination source from pig-breeding farms.