首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
The island city of Bombay is surrounded by Thane Creek in the east and the Ulhas River to the north. These two aquatic regimes act as receptacles of industrial and sewerage discharges from the city and also lithogenic fluxes from the adjacent basaltic terrain.

Two consecutive sets of pre-monsoon and post-monsoon samples of water, suspended solids and sediments were collected from nineteen stations along the intertidal zone of Thane Creek and from eleven stations along the Ulhas River course. Toxic heavy metals such as Fe, Mn, Ni, Co, Pb, Zn, Cu, Cr, Hg and Cd have been analysed in the samples and the degree of metal contamination has been brought out by comparison with local background as well as global standards. Thane Creek is relatively stagnant and dominated by a marine environment, while the Ulhas River is more dynamic and fluvio-estuarine in nature. The two environmental settings have been recognised in discriminant analysis of the heavy metal data.  相似文献   


2.
The island city of Bombay is surrounded by Thane creek in the east and Ulhas river on the north. These two aquatic regimes act as receptacles of industrial waste and sewage discharges from the city and also lithogenic fluxes from the adjacent basaltic terrain.

Two consecutive sets of pre-monsoon and post-monsoon samples of water, suspended solids and sediments were collected from the intertidal zone of Thane Creek and along the Ulhas River. These were analysed for toxic heavy metals such as Fe. Mn, Ni, Co, Pb, Zn, Cu, Cr, Hg and Cd and the degree of metal contamination was determined. Using this data the pattern and mechanism of distribution of heavy metals in water, suspended solids and sediments were investigated. These are closely related to discharges of industrial effluents and domestic sewage and largely controlled by basic geochemical processes.  相似文献   


3.
The sedimentary basin of Gavkhuni playa lake includes two sedimentary environments of delta and playa lake. These environments consist of mud, sand and salt flats. There are potentials for concentration of heavy metals in the fine-grained sediments (silt and clay) of the playa due to existence of Pb/Zn ore deposits, industrial and agricultural regions in the water catchment of Zayandehrud River terminating to this area. In order to study the concentration of heavy metals and the controlling factors on their distribution in the fine-grained sediments, 13 samples were taken from the muddy facies and concentration of the heavy metals were determined. The results showed that the heavy metal concentrations range in the sediments (in ppm) are Mn (395.5–1,040), Sr (100.4–725.76), Pb (14.66–91.06), Zn (23.59–80.9), Ni (37–73.66), Cu (13.83–29.83), Co (5.73–13.78), Ag (3.03–4.76) and Cd (2.3–5.5) in their order of abundances. The concentration of Ag is noticeable in the sediments relative to the average concentration of this element in mud sediments. The amounts of Pb and Zn are relatively high in all the samples in comparison with the other elements. The concentration of Ni is relatively high in the oxidized samples. The distribution of Pb is directly related to organic matter content of the sediments. The concentrations of Zn, Sr, Cu, Co and Cd in the samples of the playa are lower than those in the delta. The amount of illite is another factor influencing Zn and Pb concentrations. Sr is more concentrated in the sediments with the high content of calcium carbonate. The distribution pattern of Cu, Co, Pb and Mn resembles to that of the clay content of the sediments. The clay content shows positive correlations with Co, Cu and Mn concentrations and negative correlation with Ag. The Sr and Ag concentrations are positively correlated with the amount of CaCO3. The amounts of Co, Cu, Ni and Mn show negative correlations with the calcium carbonate content. Pb and Co are noticeably correlated with Mn.  相似文献   

4.
太平洋北部铁锰结核富集区沉积物的元素地球化学特征   总被引：2，自引：1，他引：2  
鲍根德 《沉积学报》1990,8(1):44-56
本文对太平洋北部铁锰结核富集区沉积物的元素地球化学作了较为详细的研究。因子分析提供的信息表明,元素的分布主要受三个因子控制:（1）粘土及Fe、Mn氧化物水化物胶体的吸附作用;（2）生物化学作用过程有关的自生沉积作用;（3）海底页岩风化及附近海区的火山喷发作用。元素的来源:（1）Fe、Mn、Cu、Co、Ni、Zn、Cr、Cr、Mg、Al、Ti、K共生,主要来自粘土吸附;（2）C有机、N、Sr、Na及Si、Ca、Sr主要来自生物化学过程沉积;（3）Pb主要来源于岩石碎屑（火山喷发碎屑）。  相似文献   

5.
The concentration of metals (Pb, As, Co, Cu, Ni, Zn, Fe and Mn) was investigated in water and sediment samples of E?irdir Lake. The Lake is the second largest fresh water lake of Turkey and it is used as drinking water in the region. The anthropogenic pollutants are primary sources of trace metals which are negatively affected lake water quality. These negative effects were observed in both lake water and bottom sediments. According to obtained data, Pb, Cu, Ni, Fe and Zn have significant enrichment in sediments samples. In addition, the hydrodynamic model of the lake was determined as effectively for Pb, Co, Cu, Ni, Zn, Fe and Mn accumulations. Also, the effect of anthropogenic pollutants was found to be more dominant than geogenic effect in metal accumulation of the lake bottom sediments. Therefore, anthropogenic pollutants within the lake basin should be consistently controlled for the sustainable usage of the lake.  相似文献   

6.
Fourteen ferromanganese nodule–sediment pairs from different sedimentary environments such as siliceous ooze (11), calcareous ooze (two) and red clay (one) from Central Indian Ocean Basin (CIOB) were analysed for major, trace and rare earth elements (REE) to understand the possible elemental relationship between them. Nodules from siliceous and calcareous ooze are diagenetic to early diagenetic whereas, nodule from red clay is of hydrogenetic origin. Si, Al and Ba are enriched in the sediments compared to associated nodules; K and Na are almost in the similar range in nodule–sediment pairs and Mn, Fe, Ti, Mg, P, Ni, Cu, Mo, Zn, Co, Pb, Sr, V, Y, Li and REEs are all enriched in nodules compared to associated sediments (siliceous and calcareous). Major portion of Si, Al and K in both nodules and sediments appear to be of terrigenous nature. The elements which are highly enriched in the nodules compared to associated sediments from both siliceous and calcareous ooze are Mo – (307, 273), Ni – (71, 125), Mn – (64, 87), Cu – (43, 80), Co – (23, 75), Pb – (15, 24), Zn – (9, 11) and V – (8, 19) respectively. These high enrichment ratios of elements could be due to effective diagenetic supply of metals from the underlying sediment to the nodule. Enrichment ratios of transition metals and REEs in the nodule to sediment are higher in CIOB compared to Pacific and Atlantic Ocean. Nodule from red clay, exhibit very small enrichment ratio of four with Mn and Ce while, Al, Fe, Ti, Ca, Na, K, Mg, P, Zn, Co, V, Y and REE are all enriched in red clay compared to associated nodule. This is probably due to presence of abundant smectite, fish teeth, micronodules and phillipsite in the red clay. The strong positive correlation (r ? 0.8) of Mn with Ni, Cu, Zn and Mo and a convex pattern of shale-normalized REE pattern with positive Ce-anomaly of siliceous ooze could be due to presence of abundant manganese micronodules. None of the major trace and REE exhibits any type of inter-elemental relationship between nodule and sediment pairs. Therefore, it may not be appropriate to correlate elemental behaviour between these pairs.  相似文献   

7.
《Applied Geochemistry》1998,13(2):213-233
Porewater concentration profiles were determined for Fe, trace elements (As, Cd, Co, Cu, Mn, Ni, Pb, Zn), sulfide, SO4 and pH in two Canadian Shield lakes (Chevreuil and Clearwater). Profiles of pyrite, sedimentary trace elements associated with pyrite and AVS were also obtained at the same sites. Thermodynamic calculations are used, for the anoxic porewaters where sulfide was measured, to characterize diagenetic processes involving sulfide and trace elements and to illustrate the importance of sulfide, and possibly polysulfides and thiols, in binding trace elements. The ion activity products (IAP) of Fe sulfide agree with the solubility products (Ks) of greigite or mackinawite. For Co, Ni and Zn, IAP values are close to the KS values of their sulfide precipitates; for Cu and Pb, IAP/Ks indicate large oversaturations, which can be explained by the presence of other ligands (not measured) such as polysulfides (Cu) and thiols (Pb). Cobalt, Cu, Ni and Zn porewater profiles generally display a decrease in concentration with increasing ΣH2S, as expected for transition metals, whereas Cd, Pb and Zn show an increase (mobilisation). The results suggest that removal of trace elements from anoxic porewaters occurs by coprecipitation (As and Mn) with FeS(s) and/or adsorption (As and Mn) on FeS(s), and by formation of discrete solid sulfides (Cd, Cu, Ni, Pb, Zn and Co). Reactive Fe is extensively sulfidized (51–65%) in both lakes, mostly as pyrite, but also as AVS. Similarities between As, Co, Cu and Ni to Fe ratios in pyrite and their corresponding mean diffusive flux ratios suggest that pyrite is an important sink at depth for these trace elements. High molar ratios of trace elements to Fe in pyrite from Clearwater Lake correspond chronologically to the onset of smelting activities. AVS can be an important reservoir of reactive As, Cd and Ni and, to a lesser extent, of Co, Cu and Pb. Overall, the trace elements most extensively sulfidized were Ni, Cd and As (maximum of 100%, 81% and 49% of the reactive fraction, respectively), whereas Co, Cu, Mn, Pb and Zn were only moderately sulfidized (11–16%).  相似文献   

8.
Mining activities and resulting wastes can be considered one of the most important sources of toxic metals and metalloids in the environment. To assess environmental risk in the surrounding areas of old abandoned W-Sn and Pb–Zn mines and resulting tailings and rejected materials, 333 samples were collected in stream sediments under the influence of abandoned mines. Samples were prepared and analyzed for Fe, Ba, P, Cu, Cr, Ag, B, Zn, Be, Y, Nb, Pb, Ni, V, Mn, Mo, As, W, Co, Cd, Sn and U. The inexistence of Portuguese legislation concerning parametric values for stream sediments led to the application of a quantitative index for progressive contamination on stream sediments, the Geoaccumulation Index (Igeo), as variables to create risk maps. A first exploratory multivariate statistical analysis, using the Principal Component Analysis (PCA), applied to the obtained Igeos, shows a first factor (F1) explaining the dependence of P and B (positive correlation with the axis) and the inverse correlation of these two elements with the cluster formed by Cr, Ni and V (negative correlation with the axis); the second factor (F2) explains Ni, Fe, Zn and As; Cd and U Igeos are not explained in the new factorial space and, therefore, are characterized individually. The variographic studies showed the existence of spatial structure for the new synthesis variables (F1, F2) as well as for Cd and U Igeos. The experimental point-support data was then interpolated using ordinary kriging within a narrow search window as shown in the fitted variogram models. The obtained maps show extremely high levels of pollution in Cd and W and strongly high levels of pollution in Cr, B, Ag, Zn and Pb. The accumulation of these elements in the studied stream sediments is higher on the abandoned mining areas and in their vicinity.  相似文献   

9.
Geochemical reconnaissance survey of Wadi Umm Khariga in the southern part of the Eastern Desert of Egypt was carried out in an area of 30 Km2. The results of 79 stream sediment samples analyzed for Co, Cr, Cu, Fe, K, Li, Mn, Ni, Pb, Rb, Ti, and Zn after hot extraction with aqua regia were treated with simple and multivariate statistical methods. Titanium, Cu, Co, Ni, and Cr show lognormal distribution, whereas the other elements are normally distributed. The correlation between Fe and Mn and most of the analyzed elements suggest coprecipitation process that could be significant in controlling the distribution of these elements. Regression analysis was effective in correcting the effects of Fe and Mn by calculating the residuals. R-mode factor analysis produced a four-factor model, which accounts for 79.1% of the total variance in the data. Factor 1 (rCr, rCo, Ni) scores are correlated spatially with the area underlain by the serpentinites, metarhyolites, and metadacites. Factor 2 (rLi, rZn, rTi, Rb, K) scores are correlated with the metarhyolites, metadacites, and metapyroclastics. Factor 3 (Cu, rTi, Pb) scores characterize the metabasalts, meta-andesites, metarhyolites, and metadacites, thus reflecting the parent rocks as dominant influencing factors. Factor 4 (Mn, Fe) scores reflect the secondary environment effects. Discriminant analysis delineated an anomalous area for Co, Ni, Cr, Cu, Ti, Mn, Pb, and Li with probable occurrence of economic mineral deposits.  相似文献   

10.
Grain size parameters, trace metals (Co, Cu, Ni, Pb, Cr, Zn, Ba, Zr and Sr) and total organic matter (TOM) of 38 surficial sediments and a sediment core of west-four Pearl River Estuary region were analyzed. The spacial distribution and the transportation procession of the chemical element in surficial sediments were studied mainly. Multivariate statistics are used to analyses the interrelationship of metal elements, TOM and the grain size parameters. The results demonstrated that terrigenous sediment taken by the rivers are main sources of the trace metal elements and TOM, and the lithology of parent material is a dominating factor controlling the trace metal composition in the surficial sediment. In addition, the hydrodynamic condition and landform are the dominating factors controlling the large-scale distribution, while the anthropogenic input in the coastal area alters the regional distribution of heavy metal elements Co, Cu, Ni, Pb, Cr and Zn. The enrichment factor (EF) analysis was used for the differentiation of the metal source between anthropogenic and naturally occurring, and for the assessment of the anthropogenic influence, the deeper layer content of heavy metals were calculated as the background values and Zr was chosen as the reference element for Co, Cu, Ni, Pb, Cr and Zn. The result indicate prevalent enrichment of Co, Cu, Ni, Pb and Cr, and the contamination of Pb is most obvious, further more, the peculiar high EF value sites of Zn and Pb probably suggest point source input.  相似文献   

11.
The Pliocene aquifer receives inflow of Miocene and Pleistocene aquifer waters in Wadi El Natrun depression. The aquifer also receives inflow from the agricultural activity and septic tanks. Nine sediment samples were collected from the Pliocene aquifer in Wadi E1 Natrun. Heavy metal (Cu, Sr, Zn, Mn, Fe, Al, Ba, Cr, Ni, V, Cd, Co, Mo, and Pb) concentrations of Pliocene aquifer sediments were investigated in bulk, sand, and mud fractions. The determination of extractable trace metals (Cu, Zn, Fe, Mn, and Pb) in Pliocene aquifer sediments using sequential extraction procedure (four steps) has been performed in order to study environmental pathways (e.g., mobility of metals, bounding states). These employ a series of successively stronger chemical leaching reagents which nominally target the different compositional fractions. By analyzing the liquid leachates and the residual solid components, it is possible to determine not only the type and concentration of metals retained in each phase but also their potential ecological significance. Cu, Sr, Zn, Mn, Fe, and Al concentrations are higher in finer sediments than in coarser sediments, while Ba, Cr, Ni, V, Cd, Co, Mo, and Pb are enriched in the coarser fraction. The differences in relative concentrations are attributed to intense anthropogenic inputs from different sources. Heavy metal concentrations are higher than global average concentrations in sandstone, USEPA guidelines, and other local and international aquifer sediments. The order of trace elements in the bulk Pliocene aquifer sediments, from high to low concentrations, is Fe?>?Al?>?Mn?>?Cr?>?Zn?>?Cu?>?Ni?>?V?>?Sr?>?Ba?>?Pb?>?Mo?>?Cd?>?Co. The Pliocene aquifer sediments are highly contaminated for most toxic metals, except Pb and Co which have moderate contamination. The active soluble (F0) and exchangeable (F1) phases are represented by high concentrations of Cu, Zn, Fe, and Mn and relatively higher concentrations of Pb and Cd. This may be due to the increase of silt and clay fractions (mud) in sediments, which act as an adsorbent, retaining metals through ion exchange and other processes. The order of mobility of heavy metals in this phase is found to be Pb?>?Cd?>?Zn?>?Cu?>?Fe?>?Mn. The values of the active phase of most heavy metals are relatively high, indicating that Pliocene sediments are potentially a major sink for heavy metals characterized by high mobility and bioavailability. Fe–Mn oxyhydroxide phase is the most important fraction among labile fractions and represents 22% for Cd, 20% for Fe, 11% for Zn, 8% for Cu, 5% for Pb, and 3% for Mn. The organic matter-bound fraction contains 80% of Mn, 72% of Cu, 68% of Zn, 60% of Fe, 35% of Pb, and 30% of Cd (as mean). Summarizing the sequential extraction, a very good immobilization of the heavy metals by the organic matter-bound fraction is followed by the carbonate-exchangeable-bound fraction. The mobility of the Cd metal in the active and Fe–Mn oxyhydroxide phases is the highest, while the Mn metal had the lowest mobility.  相似文献   

12.
Sixty-eight samples of sediment collected on a variably-spaced grid pattern from Pamlico River Estuary of North Carolina were analyzed for As, Cd, Co, Cr, Cu, F, Ni, Pb, U, Zn, clay, and organic matter. The major objectives of the study were to determine background and anomalous levels of trace elements in the sediments, and the effects of human activities on concentration and distribution of trace elements in the sediments. Clay and organic matter are more concentrated near the center of the estuary. This causes the highest concentration of trace elements in the sediments to be located there also owing to their preferential uptake of these elements. Highest trace element concentrations were observed in clay and organic matter near industrial sites, housing developments, and tributary mouths that drain areas of human activity. The apparent increase in trace element contents of fine sediments in Pamlico River Estuary owing to human activities is 4 to 1,750 times normal background levels.  相似文献   

13.
《Applied Geochemistry》1995,10(2):229-235
A 3.6 m sediment profile from brackish Lake Jinzai in western Japan was studied for Hg and other trace metals (Fe, Mn, Zn, Cu, Pb, Ni, Cr, and Co) in order to understand the level of Hg pollution in the lake which has no point source discharges of municipal or industrial pollutants. Possible sedimentation rate was established based on the activity of137Cs in the sediments. The relative increases in the metal concentration of sediments commenced at the beginning of this century while that of Fe and Cu started 150 years ago. The highest level of Hg (303 ng/g) was reported at the 50–55 cm level and Hg concentration in pre-industrial time was indicated in the deepest parts of the core. It was noted that significant contamination events had occurred in the mid 1950s and 1960s. In Lake Jinzai sediments, Hg appears to be associated mainly with Fe-oxides, hydrated iron or iron sulfides (Fe-phase) coated grains. The relationship among the geochemical variables revealed that Zn, Cu and Pb are seemingly associated with the Fe-phase and Cr, Co are mainly associated with the Mn-phase.  相似文献   

14.
The Gulf of Mannar along the Tuticorin coast is a coral base of the southeast coast of India. To obtain a preliminary view of its environmental conditions, geochemical distribution of major elements (Si, Al, Fe, Ca, Mg, Na, K, P), trace elements (Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) and acid leachable elements (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) were analyzed in surface sediment samples from two seasons. Geochemical fractionation confirmed the lithogenic origin of metals, which were mainly associated with the detrital phase. The sediments in the gulf are sandy with abundant calcareous debris, which controls the distribution of total and acid leachable elements. Enrichment factors relative to crust vary by a magnitude of two to three and the presence of trace metals indicates the input of Cr, Pb, Cd, Cu and Zn in both forms through industrial activities. Factor analysis supports the above observation with higher loadings on acid leachable elements and its association with CaCO3. The increase in concentration of trace metals (Cr, Pb, Cd, Cu, Co, Ni, Zn) along the Gulf of Mannar indicates that the area has been contaminated by the input from riverine sources and the industries nearby. The present study indicates that other sources should be evaluated in the long-term monitoring program.  相似文献   

15.
丁帅帅  郑刘根  程桦 《岩矿测试》2015,34(6):629-635
煤矸石是我国堆存量最大的工业固体废物,本文应用电感耦合等离子体发射光谱法、逐级化学提取法和相关性分析研究了淮北临涣矿区低硫煤矸石中10种微量元素的含量及赋存状态,并运用风险评价指数法评价其环境效应。结果表明,低硫煤矸石中Ba、Co、Cr、Mn、Ni、Pb、V含量均高于淮北煤和中国煤均值,Mn、V的富集系数大于1,有一定迁移风险。微量元素主要以残渣态和铁锰氧化物结合态存在,两者质量分数之和为68.87%~92.93%,其中Cd、Co、Cr、Cu、Ni、Pb、Zn赋存于硫化物矿物中,V赋存于黏土矿物中,Mn赋存于碳酸盐矿物和硫化物矿物中。10种微量元素对环境的危害性大小为:MnZnNiPbCdCuBaVCrCo,表明低硫煤矸石堆存过程中活性态Mn对生态环境造成危害的可能性最大,由Mn可能引起的煤矸石山周边地区土壤及水体污染应当重视。  相似文献   

16.
The heavy metal contents of Mn, Ni, Cu, Zn, Cr, Co, Pb, Cd, Fe, and V in the surface sediments from five selected sites of El Temsah Lake was determined by graphite furnace atomic absorption spectrophotometer. Geochemical forms of elements were investigated using four-step sequential chemical extraction procedure in order to identify and evaluate the mobility and the availability of trace metals on lake sediments, in comparison with the total element content. The operationally defined host fractions were: (1) exchangeable/bound to carbonate, (2) bound to Fe/Mn oxide, (3) bound to organic matter/sulfides, and (4) acid-soluble residue. The speciation data reveals that metals Zn, Cd, Pb, Ni, Mn, Cu, Cr, Fe, and V are sink primarily in organic and Fe–Mn oxyhydroxides phases. Co is mainly concentrated in the active phase. This is alarming because the element is enriched in Al Sayadin Lagoon which is still the main site of open fishing in Ismailia. Average concentration of the elements is mostly above the geochemical background and pristine values of the present study. There is a difference on the elemental composition of the sediment collected at the western lagoon (Al Sayadin Lagoon), junction, the shoreline shipyard workshops, and eastern beach of the lake. Depending upon the nature of elements and local pollution source, high concentration of Zn, Pb, and Cu are emitted by industrial wastewater flow (shoreline workshops), while sanitary and agricultural wastewater (El Bahtini and El Mahsama Drains) emit Co and Cd in Al Sayadin Lagoon. On the other hand, there is a marked decrease in potentially toxic heavy metal concentrations in the sediments at the most eastern side of the lake, probably due to the successive sediment dredging and improvements in water purification systems for navigation objective. These result show that El Temsah receives concentrations in anthropogenic metals that risk provoking more or less important disruptions, which are harmful and irreversible on the fauna and flora of this lake and on the whole ecobiological equilibrium.  相似文献   

17.
  相似文献   

18.
We analyzed 77 surface sediment samples collected in the southwestern East/Japan Sea from the Korea Strait through the Ulleung Basin and the Korea Plateau for grain size, calcium carbonate, organic carbon, and major (Na, Mg, Al, Fe, K, Ca, and Ti) and trace elements (P, Mn, Sr, Li, Sc, V, Cr, Co, Ni, Zn, Cu, and Pb).The chemical composition of the surface sediments was found to be highly variable spatially. Cluster analysis of surface sediment chemical compositions indicated five major geochemical sedimentary environments: basin, lower slope, coast and upper slope, inner shelf, and outer shelf. Continental-shelf sediments were rich in shell fragments and had relict and coarse-grained characteristics. Recent fine-grained sediments were only distributed in coastal, slope, and basin areas. Concentrations of Al, K, Ca, Ti, Cr, and Sc were highest in the coastal and upper slope areas and decreased with water depth. Elemental ratios using major and trace elements indicated that coastal and upper slope detrital sediments were mixtures of sediments derived from the Changjiang (Yangtze) and Nakdong Rivers. Although the concentrations of organic carbon, P, Mn, V, Co, Ni, Cu, and Pb increased with water depth, their distribution patterns indicated authigenic (V, Cu, and Pb) and diagenetic (Fe, P, Mn, Co, and Ni) origins. The distribution pattern with water depth suggested that the chemical composition of surface sediment was determined by sedimentologic and geochemical processes, such as the supply of detrital and biogenic materials, and authigenic and post-depositional diagenetic processes in sediments.  相似文献   

19.
Surface sediments of nine islands of Lakshadweep were evaluated for their heavy metal concentration (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Sediments of thirteen seagrass and seven non seagrass sites were collected randomly and analysed for heavy metal concentration using Inductively Coupled Plasma Optical Emission Spectrometer. Heavy metals like Cu, Ni and Zn were found in higher concentrations in the seagrass sediments, whereas other heavy metals such as Cd, Co, Cr, Fe, Mn and Pb were higher in non seagrass sediments. Different pollution indices were calculated to evaluate contamination level of all heavy metals in the sediments. Cadmium recorded higher contamination factor (1.733–21.067), enrichment factor (276.10–12,270) and Geo-accumulation Index (0.208–3.811) both in seagrass and nonseagrass sediments. Multivariate statistical analysis such as principal component analysis and cluster analysis coupled together with correlation co-efficient was used to identify the possible sources of heavy metal pollution in the region. Average concentrations of Cd in Lakshadweep islands were slightly higher than effective range, low but still below effective range medium. All other metals were still below these ranges indicating fairly uncontaminated sediment in the region.  相似文献   

20.
Water, sediment, and mine spoil samples were collected within the vicinity of the Okpara coal mine in Enugu, Southeastern Nigeria, and analyzed for trace elements using ICP-MS to assess the level of environmental contamination by these elements. The results obtained show that the mine spoils and sediments are relatively enriched in Fe, with mean values of 1,307.8(mg/kg) for mine spoils and 94.15% for sediments. As, Cd, Cr, Mn,Ni, Pb, and Zn in the sediments were found to be enriched relative to the mean values obtained from the study area, showing contamination by these elements. The mean values of Fe, Mn, Cu, and Cr in the mine spoils and mean values of Fe, Cu, Pb, Zn, Ni, Cr, and Mn in sediments, respectively, are above the background values obtained from coal and shale in the study area, indicating enrichment with these elements. The water and sediments are moderately acidic, with mean pH values of 4.22?±?1.06 and 4.66?±?1.35, respectively. With the exception of Fe, Mn, and Ni, all other elements are within the Nigerian water quality standard and WHO limits for drinking water and other domestic purposes. The strong to moderate positive correlation between Fe and Cu (r?=?0.72), Fe and Zn (r?=?0.88), and Fe and As (r?=?0.60) at p?<?0.05 as obtained for the sediments depict the scavenging effect of Fe on these mobile elements. As also shows a strong positive correlation with Mn (r?=?≥ 0.70, p?<?0.05), indicating that Mn plays a major role in scavenging elements that are not co-precipitated with Fe. In water, the strong positive correlation observed between Cr and Cd (r?=?1.00), Cu and Ni (r?=?0.94), Pb and Cu (r?=?0.87) and Zn and Cu (r?=?0.99); Ni and Pb (r?=?0.83) and Zn and Ni (r?=?0.97); and between Pb and Zn (0.84) at p?<?0.05 may indicate similar element–water reaction control on the system due to similarities in chemical properties as well as a common source. Elevated levels of heavy metals in sediments relative to surface water probably imply that sorption and co-precipitation on Al and Fe oxides are more effective in the mobilization and attenuation of heavy metals in the mine area than acid-induced dissolution. The level of concentration of trace elements for the mine spoils will serve as baseline data for future reference in the study area.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号