Temporal and Spatial Variation of Methylmercury in Sediments in the Second Songhua River,China

The methylmercury (MeHg) content in the Second Songhua River was investigated in this study. Compared with the former data, the following trends in temporal variation were observed. The MeHg content decreased in relation to the distance from the pollution source in 1977; it showed a decline in 1983 after the pollution source had been shut off for one year and continued to decline from 1983 to 1991 when the Second Songhua River was in a cleansing period. The MeHg content in most segments investigated in this study was higher than in 1991. Along the river, sediment samples were collected from the Baishan Segment to the Sifangtai Segment, and from the surface to the underlying layer to check the vertical trend. The MeHg content was high in the segments upstream due to the gold mines existing, with highest content in the Toudaogou Segment (10.0 ng/g). The MeHg content declined from the Jiapigou Segment (6.2 ng/g) to the Hongshi Segment (0.69 ng/g), and it gradually increased from the Hongshi Segment (0.69 ng/g) to the Hadawan Segment (1.8 ng/g). It was still lower than upstream. The MeHg content gradually decreased from the Hadawan Segment to the Zhaoyuan Segment. However, there was no clear trend from the Zhaoyuan Segment to the Sifangtai Segment, where the order of the MeHg content was the Sanzhan Segment > the Sifangtai Segment > the Zhaoyuan Segment > the Laozhou Segment. The vertical variation in sediments showed that the MeHg content in the surface layer was higher than in the underlying layer in all segments with the exception of the Hongshi Segment and the Zhaoyuan Segment. The pollution index of MeHg content in the Second Songhua River was also discussed.     

Geospatial Estimation of Mercury Contamination in Buffalo River Sediments

The Buffalo River Area of Concern (AOC) is associated with heavy metal pollution. This research utilized sediment core data to model the geographic distribution of mercury within surface and subsurface sediments of a section of the AOC. Using ordinary kriging, a geostatistical interpolation technique, mercury concentration prediction maps were created. Standard maps were created by interpolating a prediction surface for the entire study area. In addition, spliced maps were created by interpolating prediction surfaces for three sections of the study area and merging these together to generate a quasi-continuous surface. The latter type of map was needed in order to account for the pronounced meandering nature of the river and to explore the potential existence of regional and local mercury sedimentation patterns. The surface level results show an increased level of mercury contamination from east to west (the direction of river flow), with peak values found in the mid-region of the study area. Additionally, surface sediments were less polluted with mercury than subsurface sediments. Finally, this study highlighted several mercury contamination hotspots, which could be targeted for future sediment restoration endeavors in the AOC.     

第二松花江下游稻田土壤重金属含量特征及来源分析

于2008年秋季,在长期引用第二松花江（二松）江水进行灌溉的前郭灌区,采集了具有不同灌溉历史的稻田耕层土壤样品65个,测定了土壤中7种重金属含量,分析重金属在表层土壤中的累积特征,探讨发生累积的重金属的输入途径和来源.结果表明：稻田土壤中Cu、Pb、Zn、Cd、Ni、As、Hg的含量分别为14.1～28.4、37.6～57.4、53.3～84.4、0.044～0.367、18.4～37.0、3.25～12.11、0.031～0.155 mg·kg^-1.Pb、Hg、Cd表现出明显的累积趋势,其含量超过基线值的比例分别为100.0%、38.7%和66.1%,其余重金属元素未出现累积现象.随着灌溉历史的增长,稻田土壤中Pb含量呈逐渐降低趋势,Hg含量呈逐渐升高趋势.Cd含量与灌溉历史的关系不明显.稻田土壤中累积的Pb主要与过去使用含Pb汽油产生的废气沉降有关;Hg主要来源于曾受污染的二松江水,随引水灌溉输入;Cd主要来源于化肥、农药等农用化学品的施用.尽管本区稻田土壤中Pb、Hg、Cd出现明显累积现象,但其生态风险水平很低,不会对当地农业生产及粮食安全构成威胁.     

五里河沉积物汞的时空变化规律

研究了历史上受纳氯碱污染的辽宁省葫芦岛市五里河沉积物中总汞、甲基汞25年中的时空变化规律.结果表明,经过25年的变化,在人工治理和自然净化作用下,五里河不同地点沉积物总汞和甲基汞含量总体上呈现明显下降的趋势,甲基汞下降尤为显著;但沉积物中汞含量依然处于较高水平,总汞含量为0.491～26.395 mg·kg-1,平均13.766 mg·kg-1,超过辽宁省土壤汞背景值(0.037 mg·kg-1)371倍,甲基汞含量为0.253～12.079 μg·kg-1,污染严重的断面是污染源附近的化工桥以及下游河口附近的茨山北桥.     

Mercury dynamics in Tivoli South Bay, a freshwater tidal mudflat wetland in the Hudson River

The accumulation of total mercury (Hg_T) andmethylmercury (MeHg) was evaluated in sediments ofTivoli South Bay, a freshwater tidal mudflat wetlandin the Hudson River National Estuarine ResearchReserve system. Hg_T concentrations in sedimentcores were measured to evaluate the spatialvariability of Hg_T deposition, and to establisha chronology of Hg_T accumulation. Cores takenfrom the northern, middle, and southern sections ofthe bay had similar distribution patterns andconcentrations of Hg_T, suggesting a common sourceof Hg_T throughout the bay. Sedimentconcentrations ranged from 190 to 1040 ng Hg g^–1,2 to 10 times greater than concentrations expected insediments from non-anthropogenic sources. Hg_Tdeposition rates were similar in different regions ofthe bay, and increased from 200 ng Hg cm^–2yr^–1in the 1930s to a maximum of 300 ngHg cm^–2 yr^–1 in the 1960s. Deposition rateshave steadily declined since the 1970s and arecurrently at 80 ng Hg cm^–2 yr^–1. Transportof Hg_T by tidal waters from the Hudson River islikely the main source of Hg_T in the bay.Distribution patterns and absolute concentrations ofMeHg in sediment cores were similar throughout thebay, with concentrations ranging from 0.43 to 2.95ng g^–1. Maxima in MeHg concentration profilesoccurred just below the sediment-water interface andat a depth of 30 cm. The maximum at 30 cm wascoincident with maximum Hg_T concentrations. MeHgconcentrations in suspended particulate matter (SPM)from the Hudson River suggest that MeHg in the baycould be derived from riverine SPM rather than formedin situ.     

Genotoxic activity of organic contamination of the Songhua River in the north-eastern region of the People's Republic of China

The Songhua River is one of the biggest rivers in China and is the major freshwater source for industry and agriculture, as well as the source of the drinking water for millions of residents living along it. Heavy contamination of the Songhua River is due to domestic sewage and industrial wastewater. Thus, we set out to determine the carcinogenic potential of water samples taken from drinking water source of Harbin city in the Songhua River. Short-term genotoxic bioassays using Ames, SCE, and cell transformation assays were employed to examine the genotoxic activity of the ether extracts of water samples taken from the Songhua River. The results of the Ames test indicated that there were frame shift mutagens in the water samples, which were both direct and indirect. A dose–response relationship for the SCE assay was obtained, and the SCE cumulative frequency moved obviously to the right with increasing doses of water samples. Typical transformed foci were formed in NIH3T3 cells induced by ether extracts of water samples and the transformation frequency showed a dose–response relationship. The transformed cells showed the characteristics of malignant cells. All of the results indicated that the ether extracts of water samples taken from the Songhua River showed genotoxic activity.     

松花江流域大型底栖动物群落结构与水质评价

【目的】松花江流域是中国最早的工业基地之一,其水生态环境遭到严重破坏,环境保护工作面临巨大挑战。开展松花江流域水质评价及典型生物类群多样性状况调查,可为松花江流域生态系统的保护和修复提供依据。【方法】于2016年7月调查整个松花江流域近岸的大型底栖动物群落组成和测定水质理化指标,开展其水质理化特征评价和生物指数评价,并探讨底栖动物群落分布与水环境因子间的关系。【结果】理化指标评价结果显示,南源松花江水质状况最差,处于中度污染;北源松花江处于轻度污染;梧桐河水质最好,处于良好状态。松花江流域3个河段的底栖动物群落结构存在空间差异性。另外,梧桐河的物种多样性最高,北源松花江次之,南源松花江最低。溶解氧和营养元素K的浓度是驱动底栖动物群落组成发生显著性差异的主要环境因子。生物指数评价结果显示,3个河段水质均处于轻度污染状态。【结论】松花江流域水质处于轻度到中度污染状态。有机污染是松花江流域面临的主要水质环境问题,对松花江流域底栖动物群落结构产生了显著影响。因此,控制有机质的输入是维持松花江流域水生态系统平衡的重要举措之一。     

Change of bacterial communities in sediments along Songhua River in Northeastern China after a nitrobenzene pollution event

More than 100 tons of nitrobenzene and related compounds were released into Songhua River due to the explosion of an aniline production factory in November, 2005. Sediment samples were taken from the heavily polluted drainage canal, one upstream and three downstream river sites. The change of bacterial community structures along the river was studied by denaturing gradient gel electrophoresis (DGGE) and cloning and sequencing of 16S rRNA genes with five clone libraries constructed and 101 sequences acquired representing 172 clones. Both DGGE profiles and sequences of 16S rRNA genes from clone libraries demonstrated that the contaminated drainage canal and three downstream river sites were similar in that all had Betaproteobacteria , mainly grouped into Comamonadaceae , as the dominant group of bacteria, and all had Firmicutes , primarily as Clostridium spp. These results suggest that these latter two groups of bacteria may play potential roles in degradation and detoxification of nitrobenzene in the present contaminated river environments.     

Applying a Watershed-Level,Risk-Based Approach to Addressing Legacy Mercury Contamination in the South River,Virginia: Planning and Problem Formulation

In 2001, the DuPont Company and various Virginia regulatory agencies (Virginia) established the South River Science Team (SRST) as a multi-stakeholder and collaborative program to address legacy Hg contamination of the South River, Virginia. Specifically, the SRST began to apply a watershed-level risk-based assessment process to evaluate the potential impact of a former DuPont facility adjacent to the South River. Mercury had been found in facility soils in 1976 spawning numerous chemical and biological studies. However, prior to 1999, with the exception of a structured, long-term fish monitoring plan developed by Virginia, these studies were conducted by diverse, independent organizations resulting in limited scientific oversight and implementation, or interaction with the public. This article focuses on some key findings (e.g., defining/refining the issues, setting up the team, the role of the different stakeholders in making the process work) from the problem formulation and planning phase of this multi-stakeholder effort. The SRST effort draws heavily on the concepts of problem formulation (PF) and planning (as described by the U.S. Environmental Protection Agency) to guide the overall risk-based approach. PF is one of the most important steps in the process and, if done correctly can lead to a well-conceived and implemented assessment.     

利用细胞计数手段和DGGE技术分析松花江干流部分地区的细菌种群多样性

松花江是我国东北地区的重要河流之一,为加强对其水环境微生物状况的了解,对松花江干流部分地区的微生物数量和多样性进行了分析。应用传统平板培养法和流式细胞技术测定水样中的细菌数;直接提取样品中的总DNA,以巢式PCR(Polymerase Chain Reaction)扩增细菌16SrDNA片段,应用聚丙烯酰胺凝胶电泳(Denaturing Gradient Gel Electrophoresis,DGGE)技术对扩增片段进行分离,研究水样和底泥样品细菌的种群多样性。实验结果显示,pH值为影响水环境中微生物总细胞数量的主要因素。水样中细菌群落多样性主要根据上下游分区,分区点在哈尔滨段附近,而底泥中细菌群落多样性的影响因素呈多样化,没有显示出较为明确的分区特征。     

Suitability for developing riverside groundwater sources along Songhua River,Northeast China

Riverbank filtration is a natural water treatment technology that consists of extracting water from rivers by pumping wells located in the adjacent alluvial aquifer. It is vital to choose the most appropriate from multiple potential candidate sites, which is a complex procedure and seldom paid attention to. In this study, a method system including multicriteria evaluation indexes was developed with which the suitability of bank filtration along the Songhua River of China for developing riverside groundwater sources was assessed. The system was comprised of main suitability indexes for water quantity, water quality, interaction intensity between surface water and groundwater, and the exploitation condition of aquifer condition, weights of which were determined by specialist marking methods. Based on this assessment system, the suitability of the study area was divided into five grades. Results show that riversides along Lalin River, Hulan River, and the middle part of Songhua River are suitable for developing riverside groundwater sources.     

Fractionation and ecological risk assessment of trace metals in surface sediment from the Huaihe River,Anhui, China

Abstract

The Huaihe River has suffered increasing pressure from pollutants including metals from anthropogenic activities. In this study, enrichment and fractionation behavior of trace metals were analyzed in sediment samples obtained from fish spawning area of the Huaihe River (Anhui Section) to evaluate the potential ecological risk of trace metals to aquatic organisms. Geochemical indices including enrichment factor and geo-accumulation index as well as mean probable effect concentration quotient and risk assessment code were adopted to assess the contamination degree and potential ecological toxicity. Results showed that the total contents of Cu, Pb, Zn, Cr, Cd, As, and Hg in sediment were 23.1?±?6.4, 32.3?±?11.1, 76.8?±?14.2, 84.6?±?17.2, 0.2?±?0.1, 9.0?±?3.0, and 0.031?±?0.010?mg/kg, respectively. The indexes EF and I_geo revealed slight accumulation for Pb, Zn, Cr, Cd, and As in some sampling sites. The result of Q_m-PEC demonstrated that trace metals in sediment were not toxic to aquatic organisms. Most trace metals appeared to mainly associate with the residual form suggesting lower mobility whereas Cd presented a relative higher exchangeable fraction indicating a great degree of bioavailability. The result of risk assessment code (RAC) evaluation revealed that Cd poses a medium ecological risk for aquatic organisms whereas most of the other trace metals pose low risks.     

松花江哈尔滨段浮游植物群落格局及其与环境因子的相关性

松花江是黑龙江在我国境内的最大支流,流经吉林、黑龙江两省。松花江哈尔滨段是哈尔滨市工农业生产与生活用水的重要水资源,近年来由于人类活动的频繁影响,水体质量有所下降。鉴于此,于2018年春、夏、秋三季(4月、8月和10月),在松花江哈尔滨段设置14个采样点,对电导率、总氮和总磷等理化指标进行测定,同时对其浮游植物群落结构及环境因子相关性进行研究。利用群落相似性分析(ANOSIM)探讨浮游植物群落时空分布差异;通过SIMPER分析筛选出影响群落时空格局的关键物种。基于优势种和10项理化指标的冗余分析(RDA)揭示了浮游植物群落生态分布特征并对关键影响因子进行识别。研究结果表明,调查期间共鉴定浮游植物136种,其中优势种15种,群落结构主要以硅藻门和绿藻门的物种构成。松花江哈尔滨段浮游植物群落结构与过去10余年间相比较为稳定。ANOSIM和SIMPER分析表明,季节变化和人为活动干扰对浮游植物群落时空格局具有一定驱动作用,蓝藻门物种的空间分布活动干扰影响明显。RDA分析表明,浮游植物分布特征与水环境时空异质性关系密切,驱动松花江哈尔滨段浮游植物群落时空分布的主要水环境因子为电导率、总磷、浊度和pH。     

Assessment of Anthropogenic Influence on Heavy Metals Contamination in the Aquatic Ecosystem Components: Water,Sediment, and Fish

Heavy metals (Pb, Cd, Ni, Cr, Cu, Zn, Mn, and As) concentration was investigated in the industrial effluents, water, sediment, and fish samples collected around the Dhaka Export Processing Zone, Savar, Bangladesh, to evaluate the level of contamination. The metals concentration in the industrial effluents of DEPZ and in the water samples of Dhalaibeel (lowland cum lake) and Bangshi River were significantly higher compared to the guideline values for industrial effluents and for drinking water (WHO and USEPA), respectively. The sedimentary metal concentrations were found to be lower than the respective probable effect concentrations (PECs) following the sediment quality guidelines. Furthermore, in comparison with the fish standards, the studied fish species were not found to be contaminated by heavy metals. Principal component analysis and cluster analysis demonstrated that the wastewater from the numerous industries and the domestic sewages around the DEPZ might have a possible impact on heavy metals contamination in the study area. The Pearson correlation analysis showed significant correlations (p < 0.01 and p < 0.05) between most of the metals in the samples of effluents, water, sediments, and fish muscles. The percentage enrichment factor (EF%) and geo-accumulation index () were followed to evaluate metal contamination in the sediment samples. Dhalaibeel sediment was maximally enriched for Cr (53.55%) and Bangshi River sediment for Zn (54.37%). The geo-accumulation index values for the sediment samples were less than zero, indicating that the sediment samples were free from contamination. This study could be used as a model study to assess the impact of anthropogenic activities on heavy metals contamination in aquatic ecosystems.     

松花江干流大型底栖动物群落结构与水质生物评价

于2010年春季（4-5月）、夏季（7-8月）和秋季（9-11月）,对松花江干流大型底栖动物群落结构进行调查研究,并利用生物指数对松花江干流水质进行评价.共采集到大型底栖动物16目36科116种,其中水生昆虫种类最多,为74种,属6目21科,占总数63.8%,年平均密度为66.80 ind·m^-2、生物量为24.30 g·m^-2.春、夏、秋季的平均密度以春季最高 (90.52 ind·m^-2),秋季(61.26 ind·m^-2)次之,夏季(48.63 ind·m^-2)最低;平均生物量以秋季最高(35.35 g·m^-2),夏季(23.12 g·m^-2)次之,春季(14.41 g·m^-2)最低.Shannon指数、Pielou均匀度指数、Simpson指数均以春季最高,夏季与秋季相近.各断面微生境共有种不多, 物种相似性不高,最大仅为60%;功能摄食群种类数相近,共有撕食者26种,收集者32种,刮食者28种,捕食者30种.采用BI生物指数和FBI生物指数对松花江干流水质的评价结果基本一致,并与化学监测结果基本吻合.松花江干流哈尔滨断面以上水质一般,哈尔滨以下断面水质在不同时期处于污染或严重污染状态.推测大顶子山航电枢纽的修建已对大型底栖动物的物种组成、群落结构造成了较大影响.     

Metal Contamination in Sediment of One of the Upper Reaches of the Yangtze River: Mianyuan River in Longmenshan Region,Southwest of China

Metal contamination in sediment of the Mianyuan River (one of the major upper reaches of the Yangtze River) in Longmenshan Region (China) was investigated in 2012. Means of metal concentrations in sediment (<74μm) were Cr: 59.93 ± 19.8% mg/kg; As: 7.21 ± 50.2% mg/kg; Se: 0.45 ± 66.3% mg/kg; Pb: 19.89 ± 29.3% mg/kg; Zn: 78.98 ± 31.9% mg/kg; Cd: 0.69 ± 28.3% mg/kg; Ba: 0.71 ± 34.0% g/kg; Mn: 0.55 ± 62.2% g/kg. This study suggested: (1) concentrations of Cd, As, Cr, and Pb in Mianyuan River sediment were lower than those of the middle and lower reaches of the Yangtze River; (2) the increase of metals during the period from 2006 to 2009 was probably related to the destruction of tailings piles by the Wen Chun earthquake in 2008; (3) organic materials decided the distribution of Cd, Se, As, Ba, and Mn in the upstream sediment, while the iron and manganese minerals controlled the distribution of Ba, Cr, and Zn in the downstream sediment; (4) sources of Cd, Se, and As were geogenic, while sources of Cr, Zn, Ba, and Mn were anthropogenic; (5) the source of Pb in the upstream sediment was probably automobile exhaust, but that of Pb in the downstream sediment was geogenic.     

Heavy Metals in Sediments of the Gold Mining Impacted Pra River Basin,Ghana, West Africa

Total concentrations of Hg, Al, Fe, As, Pb, Cu, Cr, Ni, Mn, Co, V, and Zn were determined in surface sediments collected from 21 locations within the gold mining impacted Pra River basin in southwestern Ghana. Samples were collected during both the rainy and dry seasons. We hypothesized that in the rural southwestern portion of Ghana, the lack of industrial activities makes artisanal gold mining (AGM) by Hg amalgamation the main source of water resource contamination with heavy metals. Therefore, metals showing concentration trends similar to that of Hg in the studied system are likely impacted by AGM. We found that total-Hg (THg) concentrations in riverine sediments are rather low as compared to other aquatic systems that are impacted by similar mining activities. Measured THg concentrations ranged from 0.018 to 2.917 mg/kg in samples collected in the rainy season and from about 0.01 to 0.043 mg/kg in those collected during the dry season. However, the determination of the enrichment factor (EF) calculated using shale data as reference background values showed signs of severe contamination in most of the sampled sites. In the dry season, THg concentrations correlated positively and significantly to the concentrations of As (r = 0.864, p < 0.01), Cu (r = 0.691, p < 0.05), and Ni (r = 0.579, p < 0.05). Based on our previously stated hypothesis, this could then be an indication of the impact of AGM on ambient levels of these 3 elements. However, the determined concentrations of Cu, and Ni co-varied significantly with Al, suggesting that natural sources do account for the observed levels. Accordingly, both AGM and metal inputs from weathered natural deposits are likely co-responsible for the observed levels of Cu and Ni. In contrast, the lack of correlation between As and Al tends to suggest an impact of AGM on As levels. Overall, our data suggest that besides Hg and to some extent As, the impact of AGM on ambient levels of investigated metals in the gold mining impacted Pra River remains negligible. Finally, the increase in metal concentrations from the dry to the rainy season underlines the impact of changes in hydrologic conditions on levels and fate of metals in this tropical aquatic system.     

An Investigation of Total Mercury in Sediments and Interstitial Water in the North Fork Holston River below Saltville,Virginia, USA

The North Fork Holston River (NFHR) is historically renowned for having one of the most diversity rich unionid populations (Unionidae) worldwide; however, in recent decades, drastic reductions in mussel diversity, abundance, and recruitment have been documented. Unionid declines have been blamed on anthropogenic influences, specifically mercury-contaminated wastewater from a now closed chlorine-alkali plant in Saltville, VA. The objective of this research was to evaluate total mercury (Hg) contamination of sediments and interstitial waters in the NFHR beginning below Saltville and downstream for approximately 50 river miles. Mercury contaminated sediments and interstitial water were found downstream of the closed plant with the highest sediment concentration of 2.82 mg/kg dry weight total Hg found at river mile (rm) 80 and the highest interstitial water value at rm 30.4 with 2.1 μg/l. After 60-d in situ testing, total Hg concentrations in Asian clam (Corbicula fluminea) tissues were found to range from 0.016 to 0.13 mg/kg, while resident clams had Hg concentrations of 0.094 and 0.11 mg/kg wet weight. Although chronic toxicity was not observed, based on Corbicula growth and survival tests, nor in testing with cladocerans, mercury contamination is still a persistent problem at sites in the NFHR below the closed plant with negative correlations between mean clam growth and sediment Hg concentrations.