Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China

The natural isotopic compositions and C/N elemental ratios of sedimentary organic matter were determined in the intertidal flat of the Yangtze Estuary. The results showed that the ratios of carbon and nitrogen stable isotopes were respectively −29.8‰ to − 26.0‰ and 1.6‰–5.5‰ in the flood season (July), while they were −27.3‰ to − 25.6‰ and 1.7‰–7.8‰ in the dry season (February), respectively. The δ¹³C signatures were remarkably higher in July than in February, and gradually increased from the freshwater areas to the brackish areas. In contrast, there were relatively complex seasonal and spatial changes in stable nitrogen isotopes. It was also reflected that δ¹⁵N and C/N compositions had been obviously modified by organic matter diagenesis and biological processing, and could not be used to trace the sources of organic matter at the study area. In addition, it was considered that the mixing inputs of terrigenous and marine materials generally dominated sedimentary organic matter in the intertidal flat. The contribution of terrigenous inputs to sedimentary organic matter was roughly estimated according to the mixing balance model of stable carbon isotopes.     

A field experimental study on recolonization and succession of subtidal macrobenthic community in sediment contaminated with industrial wastes

A field experiment was carried out in Hong Kong to study the patterns of recolonization and succession of subtidal macrobenthos in defaunated sediment contaminated with industrial wastes and to determine the time required for benthic recovery in the industrial-contaminated sediment. A total of 50 species was found with an average of 172 animals/tray and 24 species/tray recorded one month after deployment. Initial colonizers were predominantly polychaetes (96 animals/tray, accounting for 55.7%) and gastropods (47 animals/tray, accounting for 27.2%). Abundance of macrobenthos increased quickly to a peak (505 animals/tray) after four months, declined afterwards, and increased again till the end of the experiment. Species number peaked (57 species/tray) in the same month as abundance did, and gradually declined thereafter. Abundance, species number and diversity were significantly lower in the industrial-contaminated sediment as compared to the controls during the early successional stages, indicating the harmful effects of industrial wastes on recolonization and succession of macrobenthos. Although no significant differences in community parameters between the industrial-contaminated and the control sediments were found after eleven months, significant difference in species composition still existed after fourteen months, showing a relatively long-term impact of industrial wastes on macrobenthic community structure.     

The effect of wave-induced turbulence on intertidal mudflats: Impact of boat traffic and wind

Semi-diurnal and fortnightly surveys were carried out to quantify the effects of wind- and navigation-induced high-energy events on bed sediments above intertidal mudflats. The mudflats are located in the upper fluvial part (Oissel mudflat) and at the mouth (Vasière Nord mudflat) of the macrotidal Seine estuary. Instantaneous flow velocities and mudflat bed elevation were measured at a high frequency and high resolution with an acoustic doppler velocimeter (ADV) and an ALTUS altimeter, respectively. Suspended particulate matter concentrations were estimated by calibrating the ADV acoustic backscattered intensity with bed sediments collected at the study sites. Turbulent bed shear stress values were estimated by the turbulent kinetic energy method, using velocity variances filtered from the wave contribution. Wave shear stress and maximum wave–current shear stress values were calculated with the wave–current interaction (WCI) model, which is based on the bed roughness length, wave orbital velocities and the wave period (T_S). In the fluvial part of the estuary, boat passages occurred unevenly during the surveys and were characterized by long waves (T_S>50 s) induced by the drawdown effect and by short boat-waves (T_S<10 s). Boat waves generated large bottom shear stress values of 0.5 N m⁻² for 2–5 min periods and, in burst of several seconds, larger bottom shear stress values up to 1 N m⁻². At the mouth of the estuary, west south-west wind events generated short waves (T_S<10 s) of H_S values ranging from 0.1 to 0.3 m. In shallow-water environment (water depth <1.5 m), these waves produced bottom shear stress values between 1 and 2 N m⁻². Wave–current shear stress values are one order of magnitude larger than the current-induced shear stress and indicate that navigation and wind are the dominant hydrodynamic forcing parameters above the two mudflats. Bed elevation and SPM concentration time series showed that these high energy events induced erosion processes of up to several centimetres. Critical erosion shear stress (τ_ce) values were determined from the SPM concentration and bed elevation measurements. Rough τ_ce values were found above 0.2 N m⁻² for the Oissel mudflat and about 1 N m⁻² for the Vasière Nord mudflat.     

Degradation of crude oil in a contaminated tidal flat area and the resilience of bacterial community

Crude oil spills, Hebei Spirit in South Korea, is considered as one of the worst environmental disasters of the region. Our understanding on activation of oil-degrading bacteria and resilience of microbial community in oil contaminated sites are limited due to scarcity of such event. In the present study, tidal flat sediment contaminated by the oil spill were investigated for duration of 13 months to identify temporal change in microbial community and functional genes responsible for PAH-degradation. The results showed predominance of previously known oil-degrading genera, such as Cycloclasticus, Alcanivorax, and Thalassolituus, displaying significant increase within first four months of the accident. The disturbance caused by the oil spill altered the microbial community and its functional structures, but they were almost restored to the original state after 13 months. Present study demonstrated high detoxification capacity of indigenous bacterial populations in the tidal flat sediments and its resilience of microbial community.     

黄河尾闾段一维耦合水沙数学模型研究及其应用

小浪底水库于1999年运用以后,该河道经历了长时间持续冲刷过程.为掌握小浪底水库运用后黄河尾闾段洪水演进特点及河床冲淤规律,采用一维水沙数学模型研究是一条重要的途径.本研究首先采用浑水控制方程,建立了一维耦合水沙数学模型,并利用2003年利津-西河口段汛期实测水沙及汛前断面地形资料对该模型进行率定,计算的流量、水位及含沙量等过程与实测值吻合较好;然后采用2015年利津—汊3段汛期实测资料对该模型进行验证,结果显示水位与冲淤量计算值与实测值较为符合;最后基于2015年实测洪水过程,计算了若干组不同断面间距下的洪水演进及冲淤过程,分析了不同断面间距对沿程水位及河段冲淤量等计算结果的影响,结果表明:采用不同断面间距对水位计算结果影响较小,而对冲淤量计算结果会产生一定影响;在河段水沙及冲淤特性复杂的情况下,采用一维数学水沙模型计算时应考虑断面间距的选择.     

长江徐六泾河段渔业群落结构(2005-2006年)及多样性初探

根据2005-2006年间徐六泾河段进行的渔业资源调查,初步研究了徐六泾河段渔业群落结构和多样性.调查到鱼类48种、虾类3种、蟹类2种,分别隶属于12目20科44属,其中江湖半洄游性渔业生物(青鱼、草鱼等)6种、江海洄游性渔业生物(刀鲚、鳗鲡等)7种、近海河口类渔业生物(斑尾复鰕虎、六带鲹等)9种,淡水定居性渔业生物31种.相对重要指数(IRI)大于1000的种类定为优势种,共有3种:日本沼虾、斑尾复鰕虎、鳊.多样性特征值为:Wilhm改进指数(H″)为3,Margalef指数(R″)为4.66,Pilou指数(E″)为0.76,McNaughton指数(D″)为0.22.利用生态类型、个体生物学特征、多样性指数、相对重要指数等分析了徐六泾河段的渔业群落结构及多样性现状,表明徐六泾河段渔业群落属于河口渔业群落与淡水渔业群落交叉的类型,相比长江其他江段,多样性处于中等水平,但群落结构不稳定,有小型化趋势.     

长江中游湖泊沿岸带的底栖藻类群落结构特征

测定和分析湖北省21个浅水湖泊沿岸带底柄藻类的现存量,底柄硅藻的种类组成、细胞密度、多样性指数及其群落结构特征,并结合理化指标对水质状况进行评价.结果表明:调查期间,不同湖泊底柄藻类的现存量和底柄硅藻细胞密度分别介于1.01-40.82μg/cm2和0.09×106-14.20×106cells/cm2之间,它们在所研...     

Preliminary results on a high east–west gradient in the macrozoobenthic community structure of the macrotidal Mont Saint-Michel bay

Environmental conditions in terms of river inputs, salt marsh development, shellfish cultures, hydrodynamics and sediment characteristics are very different from the western and the eastern part of the Mont Saint-Michel bay. A large scale study on the spatial structure of the intertidal macrozoobenthic community was then performed at the bay scale in order to determinate how these various conditions may modify the community composition and species density. In terms of density, the community was globally dominated by suspension/deposit filter-feeding bivalves, as well as amphipods in the eastern high levels of the intertidal zone. Several biocoenotic assemblage of the Macoma balthica community were described and large differences in the species composition and density were observed between the eastern and the western sectors of the bay. Total density for all species and recruitment were much higher in the eastern sector than in the west. We discussed about these east–west variations in terms of hydrodynamics, sedimentation processes and trophic conditions. Indeed, the large salt marsh extension and river inputs, as well as the lack of shellfish cultures in the east, may favour high food availability for benthic invertebrates of the area whereas the low river inputs and salt marsh development, the high sedimentation process and the intensification of mussel and oyster cultures in the west may create less favourable environments.     

2017—2022年雅砻江甘孜以下干流及部分支流鱼类种类组成及群落结构

基于2017—2022年在雅砻江甘孜以下干流及部分支流的鱼类监测数据,采用多样性指数和多元统计方法分析了该流域的鱼类群落结构。通过在雅砻江干流和6条支流21个采样点的监测及相关文献调研共获得鱼类98种,包括9种国家二级重点保护鱼类和28种长江上游特有鱼类。除干流下游Margalef丰富度指数外,其他区域多样性指数值相差不大;干流上、中、下游和6条支流间鱼类生物多样性不存在显著差异。Cluster分析和NMDS分析表明鱼类群落可以分成6组,ANOSIM检验表明6组间存在显著性差异,6组在海拔和河流等级上存在极显著和显著性差异。分别计算6个聚类组的优势种和常见种,并从栖息类型、食性和产卵类型上进行分析,结果显示6组在栖息类型和产卵类型上差异显著。二滩库区和鳡鱼河静缓流河段优势种为翘嘴鲌(Culter alburnus)、尼罗罗非鱼(Oreochromis niloticus)等,建议加强对下游流域外来物种的监测,避免发生大规模生物入侵现象。自1980s以来,雅砻江下游流域鱼类种类组成发生了明显变化,推测与梯级电站修建运行等造成生境改变有关。     

Potential effect of sedimentary iron-phosphorus accumulation on frequent algal bloom in the Pearl River Estuary

Based on laboratory culture of harmful alga on iron and phosphorus uptake, and the study of accu-mulation of iron-phosphorus in cores and release of iron and phosphorus from surficial sediments collected in the Pearl River Estuary, the reasons of the high frequency of phytoplankton bloom therein are discussed. The results show that Fe starvation can make algal growth rate slow down and the peak of cell number decrease. Fe and P contents in algal cell bear a significant correlation and the molar ratio of P:Fe is ~356:1, suggesting that algal uptake of Fe and P is synergistic. Total Fe and total P in sediments are positively correlated and Fe-P is the main species of inorganic sedimentary P. Through continuous leaching with agitation, 34.26%―80.21% of exchangeable P and 4.04%―22.52% of ex-changeable Fe are released from surficial sediments, implying that the accumulation of Fe-P in sedi-ments is available for providing nutrients (P and essential Fe) for the demand of phytoplankton bloom. These factors might be responsible for a higher frequency of red tides than other marine regions.     

Distribution and Fate of Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments and Fluffy Layer Material from the Odra River Estuary

The distribution and fate of polycyclic aromatic hydrocarbons (PAHs) were investigated in surface sediments (0...2 cm) and fluffy layer material of the internal and external coastal waters of the Odra river estuary (north-eastern Germany). The area includes the Odra Lagoon (Oderhaff), the Greifswalder Bodden, the Pomeranian Bight, and the Arkona Basin. Elevated concentrations were observed in the surface sediments of the internal coastal waters with highest concentrations in the Odra Lagoon. This indicates a significant contribution of river discharge to the contamination of sediments with PAHs. During the exceptional Odra flood in the summer of 1997 significantly higher concentrations of PAHs were found in the fluffy layer material of the Odra Estuary. The distribution of the individual PAH compounds varies widely depending on their structure and molecular weight. A concentration gradient of the lower molecular weight PAHs was found from the Odra Lagoon to the open sea areas. The concentrations decreased rapidly from the Oder Haff to the Arkona Basin. These results were found in both sediments and fluffy layer material. This is attributed to the degradation of the lower molecular weight PAHs during transport from the urban regions to the sedimentation basins. A decrease of this magnitude was not found for the higher molecular weight PAHs (i.e. benzo(a)pyrene) due to their higher persistence. An enrichment of these compounds was measured in the Arkona Basin.     

Impact of the Phaeocystis globosa spring bloom on the intertidal benthic compartment in the eastern English Channel: a synthesis

From 1999 to 2005, studies carried out in the frame of regional and national French programs aimed to determine whether the Phaeocystisglobosa bloom affected the intertidal benthic communities of the French coast of the eastern English Channel in terms of composition and/or functioning. Study sites were chosen to cover most of the typical shore types encountered on this coast (a rocky shore, an exposed sandy beach and a small estuary). Both the presence of active Phaeocystis cells and their degradation product (foam) did have a significant impact on the studied shores. The primary production and growth rates of the kelp Saccharina latissima decreased during the bloom because of a shortage of light and nutrient for the macroalgae. On sandy sediments, the benthic metabolism (community respiration and community primary production), as well as the nitrification rate, were enhanced during foam deposits, in relation with the presence of bacteria and active pelagic cells within the decaying colonies. In estuarine sediments, the most impressive impact was the formation of a crust at the sediment surface due to drying foam. This led to anoxic conditions in the surface sediment and resulted in a high mortality among the benthic community. Some organisms also tended to migrate upward and were then directly accessible to the higher trophic level represented by birds. Phaeocystis then created a shortcut in the estuarine trophic network. Most of these modifications lasted shortly and all the systems considered came back to their regular properties and activities a few weeks after the end of the bloom, except for the most impacted estuarine area.     

澜沧江下游补远江大型底栖动物群落结构的时空分布及其影响因素

自然流淌的支流在维持建坝河流水生生物多样性中起着重要作用。补远江是澜沧江下游的重要一级支流,保持了较为天然的河流状态,人类活动干扰相对较少,是流域土著鱼类保护区和水生生物重要栖息地。在澜沧江流域水电开发的背景下,掌握补远江大型底栖动物群落结构的时空分布及其影响因素,对澜沧江乃至西南河流的水生生物多样性保护和恢复具有重要参考意义。于2019年4月(旱季)和2019年10月(雨季)对补远江的大型底栖动物进行了详细调查,共检出大型底栖动物150个分类单元,隶属于5门7纲68科,其中水生昆虫121种,软体动物20种,蛭类3种,寡毛类2种,甲壳类2种,涡虫、线虫各1种。毛翅目和蜉蝣目为全流域优势类群。补远江底栖动物密度和生物量在旱季和雨季均表现为上游大于中下游,物种丰富度和Shannon-Wiener多样性指数在雨季显著高于旱季。功能摄食类群中,滤食者(41.09%)和收集者(31.81%)占绝对优势,其次为刮食者(11.00%)、捕食者(11.21%),撕食者(4.89%)较少。Mantel检验分析表明,河宽(RW)、硝态氮(NO₃^--N)、化学需氧量(COD_Mn)是影响补远江大型底栖动物群落结构的主要环境因子;不同功能摄食类群所受到的环境影响因素不同。生物指数(BI)和生物监测工作组记分(BMWP)系统评价显示,补远江大部分样点处于良好及以上水平,少数样点处于中等及以下水平,总体水生态状况良好。     

黑河张掖段浮游植物群落结构及其与环境因子的关系

为探究黑河张掖段浮游植物群落季节动态及其与环境因子的相互关系,于2017年对黑河张掖段10个断面进行4个季度的采样调查,共计检出浮游植物8门80属316种,其中蓝藻门、绿藻门和硅藻门种类分别占总种类数的10.75%、15.22%和68.35%.水环境因子中,温度、电导率、盐度、溶解氧和叶绿素a浓度时空变化显著,总氮、总磷浓度则随着海拔降低而呈现显著升高的趋势.调查期间,黑河张掖段浮游植物密度在0.92×10⁴~116.67×10⁴ cells/L之间,从上游到下游呈现明显的递增趋势.优势种主要集中在硅藻门,包括扇形藻（Meridion sp.）、弧形峨眉藻（Ceratoneis arcus）、极小曲壳藻（Achnanthes minutissimum）、延长等片藻细弱变种（Diatoma elongatum var.tenuis）、尖针杆藻（Synedra acus）、简单舟形藻（Navicula simplex）、谷皮菱形藻（Nitzschia palea）、变异直链藻（Melosira varians）、普通等片藻（Diatoma vulgaris）、肘状针杆藻（Synedra ulna）等,此外,在河段优势种中,中下游出现蓝藻门的微囊藻（Microcystis sp.）（优势度为0.025）、绿藻门的四尾栅藻（Scenedesmus quadricauda）（优势度为0.020）、隐藻门的尖尾蓝隐藻（Chroomonas acuta）和卵形隐藻（Cryptomonas ovata）（优势度为分别为0.045和0.032）种类.4个季度Shannon-Wiener多样性指数（H''）均值分别为2.65、2.76、2.89和2.44,Pielou均匀度指数（E）均值为0.93、0.90、0.91和0.87,Margalef丰富度指数（d）均值为1.73、1.77、2.00和1.31.随着海拔的降低,浮游植物H''和d显著升高,而E变化范围相对平稳.结合水体营养盐指标、浮游植物及多样性指数等指标对水质评价,黑河张掖段水质总体呈无污染或轻度污染到轻中度污染状态,且中游污染程度加剧.RDA与Pearson相关性分析结果表明,水体氮磷营养盐、温度、海拔是影响黑河张掖段浮游植物群落结构及动态的关键因素,而在河段下游,电导率、盐度也是影响浮游植物群落结构的主要环境因子.     

珠江下游浮游细菌群落结构的时空分布特征

浮游细菌群落对河流变化具有高度响应性,并可能影响河流生境的生物地球化学过程.因此,了解浮游细菌群落的时空特征,阐明其在河流生态系统中的生态功能具有重要科学意义.于2016年6月和12月对珠江下游浮游细菌群落结构的时空特征进行调查研究,并采用16S rRNA高通量测序技术对样品组分进行分析.结果表明细菌群落主要由变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、抗微菌门(Verrucomicrobia)和蓝细菌门(Cyanobacteria)组成.其中变形菌门相对丰度最高,主要包括β-变形菌纲(Betaproteobacteria)、α-变形菌纲(Alphaproteobacteria)和γ-变形菌纲(Gammaproteobacteria).季节上,丰水期Shannon-Wiener和Chao 1多样性指数高于枯水期其中芽孢杆菌纲(Bacilli)和黄杆菌纲(Flavobacteriia)差异显著;空间上,珠江下游可分为西江沿线、珠三角河网中部和广州市周边3个区域.采用RDA分析...     

The Consequences of the Oder Flood in 1997 on the Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in the Oder River Estuary

Changes in the levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) as a consequence of the Oder flood in the summer of 1997 were investigated in surface water samples and fluffy layer material from the Oder Lagoon and the Pomeranian Bight. The measurements of the contaminants were complemented by satellite data to describe the spreading of the Oder flood discharge including the distribution of the particulate material. During the flood elevated levels of PAHs were discussed in the surface water and fluffy layer material of the Oder River Estuary in comparison to the average values in this region. These increased concentrations were attributed to flooding of municipal and industrial waste disposal areas in the drainage area of the Oder River. The meteorological conditions during the sampling period were characterized by predominant easterly winds, which guided the river plume along the German coast into the Arkona Sea, as verified by satellite observations. The highest concentrations of PAHs were observed near the mouth of the Swina and along the main direction of the river plume. Elevated concentrations of PAHs were also found in fluffy layer samples taken from the Oder Lagoon in late August. As derived from satellite data the eastern and the western parts of the lagoon differed in their SPM load during the entire flood period. The eastern part was covered by Oder water, while the western part contained a mixture of Oder Lagoon water. The highest concentrations of PAHs were not observed in the western part with the highest suspended matter values, but in the eastern part where the flood water entered the lagoon. Despite the significantly increased PAH levels measured during the flood, all measured concentrations were below the values that are considered to pose a risk to the ecosystem.     

渭河干流与其秦岭北麓典型支流浮游动物群落结构及影响因素

浮游动物作为食物链中重要的初级消费者,其群落结构特征是水生态系统健康评价的重要指标之一.本研究于2017年秋季和2018年春季对渭河干流及秦岭北麓五条典型支流开展了系统的水环境及浮游动物群落调查.结果表明,渭河干流营养盐浓度整体高于秦岭北麓支流,干流浊度远高于支流.两次调查共鉴定出浮游动物种类数136种(原生动物65种,轮虫44种,枝角类15种,桡足类12种),其中2017年秋季渭河干流浮游动物种类数、密度和生物量分别为14种、9.02 ind./L和0.0051 mg/L,秦岭北麓支流为37种、42.78 ind./L和0.0229 mg/L;2018年春季渭河干流浮游动物种类数、密度和生物量分别为52种、292.89 ind./L和0.1734 mg/L,秦岭北麓支流为68种、70.15 ind./L和0.0508 mg/L.秋季渭河干流下游浮游动物种类数、密度和生物量最低,而春季随上、中、下游三者均依次增大;秋季秦岭支流中罗敷河浮游动物密度和生物量最高,而春季灞河最高.春、秋两季干支流间浮游动物优势种差异较小,但秋季优势种种类数少于春季.秋季渭河干流中游Shannon-Wiene...     

Improvement of the sediment ecosystem following diversion of an intertidal sewage outfall at the Fraser river estuary,Canada, with emphasis on Corophium salmonis (Amphipoda)

Primary treated sewage effluent from the city of Vancouver, Canada was deposited directly onto the intertidal ecosystem of Sturgeon bank, Fraser river estuary between 1962 and 1988. In response to the degraded sediment conditions an azoic zone developed near the discharge outfall. Effluent discharges into the intertidal zone were almost completely stopped in 1988 with the construction of a submerged outfall. Our studies, conducted between 1994 and 1996, showed considerable improvement in the environment of the mudflat ecosystem, including increased dissolved oxygen, decreased sediment chlorophyll, decreased organic material in the sediment, reduced heavy metals in surficial sediment and increased grain size. The amphipod Corophium salmonis, important in the food web for juvenile salmon and other fish species, recolonized the previously azoic location. At reference stations, C. salmonis density was similar to that observed in previous surveys two decades earlier. Our data strongly suggest that improvement or sediment conditions near the former sewage outfall was a major factor enabling colonization by C. salmonis.     

Riverine export of water,sediment and carbon during flood events in the arid to semi-arid Wuding River on the Chinese Loess Plateau

Floods have become increasingly important in fluvial export of water, sediment and carbon (C). Using high-frequency sampling, the export of water, sediment and C was examined in the Wuding River catchment on the Chinese Loess Plateau. With groundwater as an important contributor to runoff all year round, floods were relatively less important in the export of water. However, large floods were disproportionately important in exporting sediment and inorganic C (DIC) and organic C (DOC and POC). The three largest floods in each year transported 53.6–97.3 and 41.4–77% of the annual sediment and C fluxes, respectively. An extreme flood in 2017 alone contributed 94.6 and 73.1% of the annual sediment and C fluxes, respectively, in just 7 days, which included 20.3, 92.1 and 35.7% of the annual DOC, POC and DIC fluxes, respectively. A stable carbon isotope (δ¹³C) analysis of POC indicated that modern soils and C3 plants were its primary source. Furthermore, floods greatly accelerated CO₂ degassing due to elevated gas transfer velocity, although stream water CO₂ partial pressure (pCO₂) exhibited a decreasing trend with flow discharge. Although these results illustrated that increasing runoff diluted pCO₂, the timing and magnitude of floods were found to be critical in determining the response of pCO₂ to flow dynamics. Low-magnitude floods in the early wet season increased pCO₂ because of enhanced organic matter input, while subsequent large floods caused a lower pCO₂ due to greatly reduced organic matter supply. Finally, continuous monitoring of a complete flood event showed that the CO₂ efflux during the flood (2348 ± 664 mg C m^–2 day^–1) was three times that under low-flow conditions (808 ± 98 mg C m^–2 day^–1). Our study suggests that infrequent, heavy storm events, which are predicted to increase under climate change, will greatly alter the transport regimes of sediment and C. © 2020 John Wiley & Sons, Ltd.     

The Flood in the Odra River 1997 – Impact of Suspended Solids on Water Quality

The flood in the Odra river in 1997 has led to considerable additional pollution of the Stettin Lagoon and the Baltic Sea with contaminated suspended solids. For some priority substances, the pollutant entries via suspended solids during the flood period are estimated to be approximately 1/3 of the usual annual load. Among these priority pollutants there are total organic carbon (TOC), nitrogen, and the heavy metals Cu, Pb and Zn. For the concentrations of the priority pollutants in suspended solids accumulation factors from 2 to 4 in the comparison with normal conditions were observed. On the basis of the analysis of sediments sampled after the flood, main sources of the pollutants should be evaluated. As reference area with an industrial background as well as a typical pollutant pattern the region around Glogow/Legnica is proposed.