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1.
The quantitative significance of organic matter degradation in bringing about the early diagenetic mobility of anthropogenic trace metals (Cu, Zn, Pb) is assessed specifically in relation to the use of estuarine sediments as historical records of pollution. A 1,500 mm salt-marsh sediment depth profile from Tites Point, Severn Estuary, England, was sampled at 10-mm intervals. Organic carbon determinations were carried out by a wet oxidation technique, and ‘organic fraction’ metals were separated by sequential leaching. Results demonstrated that organic phase metals are quantitatively significant in Severn Estuary sediments, particularly Cu and Zn (Cu>Zn), and that metals are probably released from this fraction during early diagenesis. The degree of release, and the apparent loss of the released trace metals from the sediment, would suggest that the use of estuarine sediments as historical records of pollution requires qualification.  相似文献   

2.
The present study investigates the anthropogenic metal input into the lake system, the toxic metal pollution in the sediments of Kodaikanal Lake. Surface sediment samples were collected at seven locations to represent its spatial variability within the lake. Samples were subjected to analyze for Fe, Co, Cr, Mn, Ni, Zn, Cd, Cu, Ag, Pb, Hg, and As by energy dispersive X-ray fluorescence (EDXRF) and their concentrations in lake sediments range from 102,000–109,000, 561–2699, 292–544, 211–482, 79–163, 57–265, 57–74, 37–92, 46–59, 20–97, 19–30, to 13–24 mg/kg, respectively. The sources of pollution were inferred through spatial and statistical analyses. Most of the toxic metal contents in the sediments are found to exceed the background concentration in all locations. The enrichment factor (EF) and index of geoaccumulation (I geo) of Hg, Co, Cd, and Ag showed that sediments of Kodaikanal Lake exhibit the probability of anthropogenic influence. The significant Pearson’s correlation coefficient is also suggesting that they probably originated from the same source of occurrence. The contamination factor and degree of contamination of the Kodaikanal Lake sediments are strongly polluted in terms of most of the examined metals. The study also provides environmentally significant information about anthropogenic influence on the lake sediments.  相似文献   

3.
Comparative assessment of pollution by metals (Pb, Cu, Cd, Fe, and As) was performed for the first time for the bays and inlets of the Murmansk coast of the Barents Sea; the international Metal Pollution Index (MPI) was applied for the fucoids. The background pollution was assessed for each studied element by MPI in the fucoids taking into account the seawater salinity. It was found that the MPI index calculated for fucoids might be recommended for the qualitative assessment of the metal pollution level with regard to the water salinity for both the studied sampling sites and the natural environment. The comparative monitoring of Pb, Cu, Cd, Fe, and As concentrations in the bays and inlets of the Murmansk coast of the Barents Sea using MPI evidenced that Pechenga Inlet was the most polluted area; Korabel’naya Inlet was the least polluted, which reflected the existing level of the anthropogenic load.  相似文献   

4.
Five sediment cores were collected in July 2008 from Buckingham Canal, Ennore, India, a water body that is influenced by domestic and industrial effluents. Downcore variations in trace metal concentrations—Ni, Pb, Mn and Zn at every 2.5 cm increment was determined through acid extraction (hydro fluoric acid, nitric acid and sulphuric acid) and analysed by atomic emission spectrophotometer. The sandy clay environment is composed mostly of medium sized grains. Among the four trace metals studied in five cores, Mn and Ni are the highest and the least occurring metals respectively. Quantitative indices such as geoaccumalation index, anthropogenic factor, enrichment factor, contamination factor and degree and pollution load indices were computed. All these analyses classify Ennore as uncontaminated or moderately contaminated. Zn has the highest anthropogenic factor (2.29) indicating the increasing concentration of Zn in the recent times. Zn enrichment is observed only at surface sediments (top 7.5 cm) C4.  相似文献   

5.
《Chemical Geology》2002,182(2-4):377-394
Bulk heavy metal (Fe, Mn, Zn, Cu, Pb, Cd), Al, organic carbon and carbonate concentrations, grain sizes, and δC13 of the organic carbon distributions were studied in sediments collected throughout the East China Sea continental shelf and the Yangtze River Delta. The results demonstrated that terrigenous sediments from the Yangtze River is a dominating factor controlling the spatial variations of heavy metals and organic carbon concentrations on the East China Sea continental shelf. In addition, grain size and recent anthropogenic influences are also major factors modifying the spatial and vertical variations of heavy metals.Large spatial variations with a band type distribution of heavy metals, grain size, organic carbon and carbonate were observed. Higher concentrations of heavy metal and light δC13 of the organic carbon were found primarily in the Deltaic and inner shelf sediments. The band type distribution generally followed the coastline with little variations in the north–south direction. Away from the Delta and inner shelf (west–east direction), most heavy metal concentrations decreased rapidly with the exception of Cd where high concentrations of Cd were also found in the carbonate-rich shelf break sediments. Coarse-grained relict sediments and biogenic carbonate are two primary diluting agents for the fine-grained aluminosilicate sediments from the Yangtze River with high concentrations of heavy metals.Unusually high concentrations of Cu, Pb, and Cd showed both spatially and vertically that more pollution prevention measures are needed in the Yangtze River drainage basin in order to prevent further heavy metal pollution of the East China Sea inner continental shelf.  相似文献   

6.
Industrialization coupled with urbanizaton has led to stress in the Buckingham Canal which runs parallel to Bay of Bengal at a distance of around 1 km from the coastline. 4 sediment cores were collected along Ennore — Pulicat stretch to determine acid leachable trace metal concentration. Core samples were collected using gravity corer. The cores were sliced horizontally at 2.5 cm to determine the grain size, sediment composition, pH, organic matter, calcium carbonate, acid leachable trace metals; cadmium, chromium, copper, lead, zinc. The trace metals were extracted using acid mixture containing hydro fluoric acid, nitric acid and sulphuric acid and analysed by atomic emission spectrophotometer. In an attempt to infer anthropogenic input from geogenic input, several approaches including comparison with sediment quality guidelines — ecotoxicological sense of heavy metal contamination and classification by quantitative indexes such as geoaccumalation index, anthropogenic factor, enrichment factor, contamination factor and degree and pollution load index was attempted. Grain size analysis and sediment composition of core samples shows Ennore is sandy in nature having a neutral pH. Organic matter enrichment is observed to a higher extent in core 3. Core 2 at a depth of 5 cm shows organic matter of 9.4 %. calcium carbonate is totally absent at the surface sediments in core 2. Cores collected within the canal showed a higher heavy metal concentration than the cores collected from Pulicat lagoon and 2 km into the Ennore Sea. The trace metal concentration for cadmium, lead and zinc in Ennore does not pose a threat to the sediment dwelling fauna whereas chromium and copper are likely to pose a threat. Quantitative indexes place Ennore under moderately polluted. Ennore is likely to face a serious threat of metal pollution with the present deposition rates unless stringent pollution control norms are adopted.  相似文献   

7.
Mangrove forests are one of the most productive and biodiverse wetlands on earth. Yet, these unique coastal tropical forests are among the most threatened habitats in the world. Muthupet mangroves situated in the southeastern coast of India, has a reverse “L” shaped structure. Four cores were collected in 2008, sliced and subsampled at 2.5 cm length. The heavy metals (Mn, Cu, Zn, Ni, Pb, Cr, Cd) and other associated geochemical parameters were evaluated to determine pollution history of Muthupet. An evaluation of the status of heavy metal pollution through the index analysis approach was attempted by computing geoaccumulation index, anthropogenic factor, enrichment factor, contamination factor and degree of contamination, pollution load index and metal pollution index. To compensate for the natural variability of heavy metals in the core sediments, normalization using Al was carried out so that, any anthropogenic metal contributions may be detected and quantified. Results of the study reveal that significant metal contamination exists, and all the metals are found to be higher than continental crustal values. The fine sediments of Muthupet vary between uncontaminated and moderately contaminated with almost no enrichment (EF < 1) to severe enrichment (EF > 10). On comparison, the core collected close to aquafarms and dense mangrove forest (C3) is the most polluted core and the core retrieved where minor rivers drain (C2) is the least polluted.  相似文献   

8.
The urbanized coastal zones are frequently faced to various pollutant discharges mainly in the shoreline. The quantification of the pollution level was mainly based on sea-water analysis. However, in this environment, the sediment characterization, using quality indicators, may constitute an accurate approach. The latter can be particularly appropriate to define heavy metals pollution degree. Chemical analyses of Cd, Cu, Zn, and Fe were undertaken for a total of 45 surface marine sediment samples of Gabes city coast. There is a significant extension of pollution, strongly influenced by the dominant longshore current. The studied sediments were found usually enriched with Cu, Cd, and Zn. These anthropogenic heavy metals have identical behavior and similar distribution. These metals did not show any correlations with Fe chosen as natural tracer. The multi-element indices used permitted to conclude that 70% of sampling sites are highly affected by heavy metal contamination and associated with very high ecological risk. These indices use a simple contamination factor, which, however, would not take account of the sedimentary inputs and the complex sediment behavior. Consequently, modified indices, employing enrichment factor, were used and demonstrated better to assess pollution and ecological risk.  相似文献   

9.
The spatial distribution and geoaccumulation indices of four heavy metals were investigated in very shallow marine sediments of southwestern Spain. Surface sediments were collected from 43 sites with water depth ranging from 3 to 20 m. High to very high pollution levels (I geo > 4 for zinc, lead and copper) were detected near the end of the Huelva bank, whereas chromium shows a more hazardous distribution in the southwestern Spanish littoral. Low to moderate heavy metal contents (mainly zinc and lead) were also observed in other two areas at different water depths (Isla Cristina-Piedras River: 10–18 m water depth; Mazagón–Matalascañas: <10 m water depth), whereas unpolluted to moderately polluted sediments were detected in the very shallow zones (<8 m water depth) located between the mouths of the Guadiana and the Piedras Rivers. A regional scenario indicates a strong pollution of the adjacent marine areas by polluted inputs derived from the Tinto–Odiel rivers, with a partial transport of heavy metals by W–E littoral currents even 40 km eastward. The Guadiana River is an additional source of zinc–lead contamination near the Spanish–Portuguese border, mainly at water depths up to 10 m. All these rivers are affected by acid mine drainage processes, derived from millennial mining activities. This pollution affects the sediment quality even 40 km eastward.  相似文献   

10.
鸭绿江河口及近岸地区沉积物中重金属分布的影响因素分析   总被引:15,自引:1,他引:14  
对鸭绿江河口不同地区沉积物中重金属分布特征和埋藏通量的垂向变化进行了分析;探讨了其独特的动力环境等因素对重金属分布的影响;评价了鸭绿江河口地区重金属污染状况及潜在生态风险程度.结果显示,自1920年代到2000年以来,除了Cu的含量和埋藏通量逐年减小之外,Cr、Ni、Zn、Cd、Pb、As和Hg的浓度和埋藏通量具有逐渐增加的趋势;鸭绿江河口地区重金属总体污染程度为重到严重,其中西水道沉积物的重金属总体污染程度和总潜在生态风险程度均最高,重金属污染已经对鸭绿江河口地区的生态环境构成了严重的危害;粒度控制效应不是鸭绿江河口地区重金属分布的最主要影响因素;Cu和其他几种重金属有着不同的来源;最大浑浊带独特的动力机制是造成中水道重金属(除Cu外)的高值分布区和最大浑浊带内的高悬沙浓度分布区相对应的最主要原因.  相似文献   

11.
The heavy metal burden of Akkulam–Veli Lake, a shallow lake in southern part of India, is investigated through the analysis of surface sediments. The average concentrations of heavy metals such as lead, chromium, nickel, copper, zinc, cobalt, iron, and manganese were determined at selected stations. The degree of contamination of selected stations was evaluated using indices such as enrichment factor, contamination factor, and pollution load index and compared with sediment quality guidelines. Statistical analysis is carried out by correlation analysis and hierarchical clustering analysis to identify relatively homogeneous groups of cases. The results of this study indicate severe contamination at most of the stations selected. The degree of contamination of the lake could be rated as ‘moderate’ to ‘strong’. The average pollution load index shows progressive deterioration of sediment quality indicating ‘risk’ on the aquatic environment and ecosystems of the lake.  相似文献   

12.
The present study was carried out to investigate the impact of anthropogenic influences on Cuddalore coast, Southeast coast of India, with regard to physicochemical parameters and heavy metal concentration in the surface water and sediment samples of the study area. The samples were collected in different seasons of the year (January–December 2010) and analysed for physicochemical parameters (Temperature, pH, salinity, nitrate, nitrite, ammonia, phosphate and silicate) and heavy metals (Cd, Cu, Pb and Zn) using standard methods. Results showed that physicochemical characteristics and heavy metals concentration in the samples of the study area were varied seasonally and spatially. The concentrations of heavy metals in water and sediment samples of the study area were higher in the monsoon season compared with those of other seasons. The heavy metal concentration in collected samples was found to be above WHO standards. The order of heavy metals in water and sediment samples was Pb > Cu > Cd > Zn. The heavy metal data were analysed through widely using multivariate statistical methods including principle component analysis (PCA) and cluster analysis (CA). CA classified the sampling sites into three clusters based on contamination sources and season. The PCA revealed that the season has a huge impact on the levels, types and distribution of metals found in water and sediment samples. The study also shows the main basis of heavy metals pollution at Cuddalore coast is land based anthropogenic inputs as a result of discharging of waste from industries, municipal, agricultural activities and sewage into estuarine regions, which carries the wastes into coastal area during tidal action. Statistical analyses and experimental data revealed that the Cuddalore coast may cause health risk to the recreational users and fisher folk, ultimately warrants environmental quality management to control heavy metal contamination.  相似文献   

13.
During recent years, the basins of the Kara Sea (Kamennomysskaya, Obskaya, and Chugor’yakhinskaya structures) in the Russian Federation have been considered as promising regions for oil and gas exploration and, simultaneously, as possible paths of relatively cheap pipeline and tanker transportation of hydrocarbons projected for recovery. On the other hand, exploration operations, recovery, and transportation of gas pose a considerable risk of accidents and environmental pollution, which causes a justified concern about the future state of the ecological system of the Gulf of Ob and the adjoining parts of the Kara Sea. Therefore, regular combined environmental investigations (monitoring) are the most important factor for estimating the current state and forecasting the dynamics of the development of estuary systems. The program of investigations (schedule, station network, and measured parameters) is standardized in accordance with the international practice of such work and accounts for the experience of monitoring studies of Russian and foreign researchers. Two measurement sessions were performed during ecological investigations in the region of exploration drilling: at the beginning at final stage of drilling operations and borehole testing; in addition, natural parameters were determined in various parts of the Ob estuary before the beginning of investigations. Hydrophysical and hydrochemical characteristics of the water medium were determined and bottom sediments and water were analyzed for various pollutants (petroleum products, heavy metals, and radionuclides). The forms of heavy-metal occurrence in river and sea waters were determined by the method of continuous multistep filtration, which is based on water component fractionation on membrane filters of various pore sizes. These investigations revealed environmental pollution by chemical substances during the initial stage of drilling operations, when remains of fuels, oils, and solutions could be spilled, and part of the chemical pollutants could enter the environment. Owing to horizontal and vertical turbulent diffusion, wave mixing, and the effect of the general direction of currents in the Ob estuary from south to north, areas are formed with elevated concentrations of the analyzed elements and compounds. However, the concentration levels of chemical pollutants are practically no higher than the maximum admissible concentrations, and their substantial dissipation to the average regional background contents can be expected in the near future. Our investigations allowed us to determine in detail the parameters of anthropogenic pollution in the regions affected by hydrocarbon exploration drilling in the Obskii and Kamennomysskii prospects in the Gulf of Ob and estimate their influence on the ecological state of the basin of the Ob River and the Kara Sea on the whole.  相似文献   

14.
Within the last century, water pollution has become a major problem throughout the world. Aquatic systems are endangered by many different types of pollution but one of the most threatening is contamination by heavy metals, for example, Cd, etc. The presence of these metals is mainly due to industrial wastes or mining wastes being improperly treated and dumped into the water supply. The contamination may damage marine organisms or create changes in the aquatic environment. For these reasons, monitoring the concentrations of trace elements in rivers, coastal waters and open seawater is very important for environmental conservation. Like many countries in the world, China is facing the serious problem of water pollution in its aquatic system. Areas like the Yangtze River have been industrialized very quickly, and without proper waste control practices the pollution levels have increased with the economic growth. The Yangtze River covers thousands of square kilometers and crosses more than half of China before reaching the East China Sea.  相似文献   

15.
A good understanding of roadside soil contamination and the location of pollution sources is important for addressing many environmental problems. The results are reported here of an analysis of the content of metals in roadside dust samples of four major highways in the Greater Toronto area (GTA) in Ontario, Canada. The metals analyzed are Pb, Zn, Cd, Ni, Cr, Cu, Mn, and Fe. Multivariate geostatistical analysis [correlation analysis (CA), principal component analysis (PCA), and hierarchical cluster analysis (HCA)] were used to estimate soil chemical content variability. The correlation coefficient shows a positive correlation between Cr–Cd, Mn–Fe, and Fe–Cu, while negatively between Zn–Cd, Mn–Cd, Zn-Cr, Pb–Zn, and Ni–Zn. PCA shows that the three eigenvalues are less than one, and suggests that the contamination sources are processing industries and traffic. HCA classifies heavy metals in two major groups. The cluster has two larger subgroups: the first contains only the variables Fe, Mn, Cu, Cr, Ni, and Pb, and the second includes Cd and Zn. The geostatistical analysis allows geological and anthropogenic causes of variations in the contents of roadside dust heavy metals to be separated and common pollution sources to be identified. The study shows that the high concentration of traffic flows, the parent material mineralogical and chemical composition, and land use are the main sources for the heavy metal concentration in the analyzed samples.  相似文献   

16.
Concentrations and sources of polycyclic aromatic hydrocarbons (PAHs) were investigated in surface sediments of the Yellow River Estuary (YRE). The isobath-parallel tidal and residual currents play important roles in the variation of PAH distribution, such that the contamination level of PAHs in fine-grained sediments is significantly higher than in the relatively coarse grain size sediments. Both diagnostic ratios and principal component analysis (PCA) with multivariate linear regression (MLR) were used to apportion sources of PAHs. The results revealed that pyrogenic sources are important sources of PAHs. Further analysis indicated that the contributions of coal combustion, traffic-related pollution and mixed sources (spills of oil products and vegetation combustion) were 35, 29 and 36 %, respectively, using PCA/MLR. Pyrogenic sources (coal combustion and traffic-related pollution) contribute 64 % of anthropogenic PAHs in sediments, which indicates that energy consumption could be a predominant factor in PAH pollution of YRE. Acenaphthylene and acenaphthene are the two main species of PAHs with more ecotoxicological concern in YRE.  相似文献   

17.
Trace metal concentrations were investigated in a recent sediment core collected from the Rehri Creek area of the Karachi coast,Sindh-Pakistan.The core was sliced horizontally at 2.5-cm intervals to determine grain size,sediment composition,pH,organic matter,and acid-leachable trace metals:cadmium,chromium,copper,lead,and zinc.The trace metals were analyzed by ICP.To separate anthropogenic from geogenic input,several approaches were made,including comparison with sediment quality guidelines—ecotoxicological sense of heavy metal contamination and classification by quantitative indexes.Grain-size analysis and sediment composition of core sample show a sandy nature with neutral pH.Elemental sequence(ES)of the trace metals is in the order of Zn(19.2-109.56 ppm)>Si(66.46-101.71 ppm)>Ba(12.05-26.86 ppm)>As(8.18-17.36 ppm)>Ni(4.2-14.69 ppm)>Cr(3.02-9.62 ppm)>Pb(2.79-6.83 ppm)>Cu(2.2-5.29 ppm)>Co(0.9-2.05 ppm).Thus it is likely that the area may face a serious threat of metal pollution with the present deposition rates unless stringent pollution control norms are adopted.The Sediment Geo-accumulation Index shows that there is no Cr,Cu,Ni,Pb,Zn,or Fe pollution;however,the former index and the Pollution Load Index indicate arsenic pollution in the sediments.  相似文献   

18.
 Contaminated ground forms a problem in all of the industrialized countries of the world. Contaminated ground may give rise to hazards and that implies a degree of risk which also involves a problem of definition. The investigation of a site which is suspected of being contaminated differs somewhat from a routine site investigation. Sampling of soil, groundwater and gas-producing material may be required. Various precautions may be necessary to do this and personnel may have to wear protective clothing. The first case history considered involves a site investigation for a relief sewer in Glasgow. As the site investigation progressed it ran into made-ground which contained chemical waste. The presence of this waste meant that the nature of the investigation changed and much more stringent safety precautions had to be taken. It also meant that the initial location of the sewer tunnel had to be repositioned at greater depth in uncontaminated sandstone rather than in the superficial deposits above. The other case history considers the contamination of sediments in the Forth Estuary. When trace metals are released into the water column they can be transferred rapidly to the sediment phase by adsorption onto suspended particulate matter, followed by sedimentation. Intertidal flats may be considered as important trace metal sinks since they accumulate large amounts of suspended matter. Hence, in polluted estuaries the deposition of suspended particles on intertidal flats may thus cause severe contamination. The Forth Estuary has unique contamination for British estuaries; it is experiencing significant Hg pollution. In addition, due to the presence of a nuclear submarine base in the Forth Estuary, 60Co is detectable in the intertidal sediments. Temporal and spatial contamination patterns were analysed in relation to historical and present pollution point sources. The effect of fluvial and marine sediment mixing on trace metals and other processes controlling contaminant levels is reviewed. Preliminary results on quantifying sediment accretion rates using Caesium levels are discussed. Received: 9 August 1996 · Accepted: 17 December 1996  相似文献   

19.
Surface sediments collected at the Tirumalairajan river estuary and their surrounding coastal areas were analyzed for the bulk metal concentration. The sediments were collected from post- and premonsoon seasons. Dominances of heavy metals are in the following order: Fe > Mn > Zn > Pb > Cu in both seasons from estuary and coastal area. The results reveal that Fe, Mn, Cu, Pb, and Zn demonstrated an increased pattern from the estuary when compared to the coastal area. The heavy metal pattern of the sediments of the Tirumalairajan river estuary and its surrounding coastal area offered strong evidence that the coastal area was a major source of heavy metals to the estuarine region. For various metals, the contamination factor and geoaccumulation index (I geo) have been calculated to assess the degree of pollution in sediments. The contamination factor and geoaccumulation index show that Zn, Pb, and Cu unpolluted to moderately pollute the sediments in estuarine part. This study shows the major sources of metal contamination in catchment and anthropogenic ones, such as agriculture runoff, discharge of industrial wastewater, and municipal sewage through the estuary and adjoining coastal area.  相似文献   

20.
The study was taken up to establish the distributions of metals as well as to assess the extent of anthropogenic inputs into the Subarnarekha River. Bed sediments were collected; analyzed for metals; and assessed with the index of geo-accumulation (I geo), enrichment factor (EF) value, concentration factor (CF) and pollution load index (PLI). Metals in the sediment were variable in the river and there are major pollution problems at certain locations. The average concentrations of Fe, Cu, Cr, Pb, Mn, Ni, Zn, Co and Ba in mg/kg was found to be 30,802 ± 11,563, 69 ± 57, 111 ± 74, 75 ± 61, 842 ± 335, 42 ± 22, 100 ± 39, 15 ± 4 and 698 ± 435, respectively. The I geo, EF, CF and PLI indices showed that the contamination of Pb and Cu was more serious than that of Ni, Zn, Co and Ba, whereas the presence of Fe, Mn and Cr might be primarily from natural sources. The contamination of the sediments with metals at few locations is attributed to mining, industries and other anthropogenic causes. Principal component analysis was employed to better comprehend the controlling factors of sediment quality. The statistical analysis of inter-metallic relationship revealed the high degree of correlation among the metals indicated their identical behaviour during transport. PCA outcome of three factors together explained 83.8 % of the variance with >1 initial eigenvalue indicated both innate and anthropogenic activities are contributing factors as source of metal profusion in Subarnarekha River basin.The overall study reveals moderately serious pollution in the river basin principally in some locations under the anthropogenic influences.  相似文献   

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