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1.
The Daliao River System (DRS) is one of the major river systems in the northeastern China and receives substantial discharges from industrial, municipal, and agricultural effluents. In this study, the contents and partition of toxic trace elements in the DRS sediments were evaluated in terms of contamination levels and ecological risks using geoaccumulation index (Igeo), relative enrichment factor (REF), sediment pollution index (SPI), and potential effect concentration quotient (PECQ). Fourteen samples were collected and measured for trace and major elements and sediment properties. The following concentration ranges (mg kg?1) of toxic trace elements were found: As, 1.6–18.0; Cd 0.1–0.9; Co 3.8–23.4; Cr 12.9–151.6; Cu 4.6–86.1; Hg 0.01–0.35; Ni 8.4–64.4; Pb 11.6–67.1; Sb 0.13–1.77; V 18.5–153.3; and Zn 20.4–211.3. The proportions of soluble and exchangeable trace metals were less than 1 %, while the proportions of trace metals bound to carbonate, amorphous oxides, organic matter, and crystalline oxides were usually each <10 %. However, 28.8 % of Cd, on average, was associated with carbonate. The average proportions of trace metals in the residual fraction ranged 57.3 % for Cd to 85.4 % for Cr, indicating low mobility and bioavailability. Cr, Ni, V, and Co in the sediments mainly originated from natural sources, while Cd, As, Pb, Sb, and Hg partially originated from anthropogenic sources. The Igeo, REF, SPI, and PECQ values of the heavy metals in the sediment were not in agreement with each another. The average REF values of Cd and As were higher than those of the other metals. However, the average PECQ value was higher for Cr and Ni than for the other metals, indicating that these two metals would cause higher adverse biological effects than the other metals. In addition, the sediments located adjacent to cities were more contaminated. Therefore, it is suggested that future management and pollution control within the DRS might focus on As, Cd, Cr, and Ni in the sediments, particularly in the sediments adjacent to cities.  相似文献   

2.
The distribution of trace metals in active stream sediments from the mineralized Lom Basin has been evaluated. Fifty-five bottom sediments were collected and the mineralogical composition of six pulverized samples determined by XRD. The fine fraction (<?150 µm) was subjected to total digestion (HClO4?+?HF?+?HCl) and analyzed for trace metals using a combination of ICP-MS and AAS analytical methods. Results show that the mineralogy of stream sediments is dominated by quartz (39–86%), phyllosilicates (0–45%) and feldspars (0–27%). Mean concentrations of the analyzed metals are low (e.g. As?=?99.40 µg/kg, Zn?=?573.24 µg/kg, V?=?963.14 µg/kg and Cr?=?763.93 µg/kg). Iron and Mn have significant average concentrations of 28.325 and 442 mg/kg, respectively. Background and threshold values of the trace metals were computed statistically to determine geochemical anomalies of geologic or anthropogenic origin, particularly mining activity. Factor analysis, applied on normalized data, identified three associations: Ni–Cr–V–Co–As–Se–pH, Cu–Zn–Hg–Pb–Cd–Sc and Fe–Mn. The first association is controlled by source geology and the neutral pH, the second by sulphide mineralization and the last by chemical weathering of ferromagnesian minerals. Spatial analysis reveals similar distribution trends for Co–Cr–V–Ni and Cu–Zn–Pb–Sc reflecting the lithology and sulphide mineralization in the basin. Relatively high levels of As were concordant with reported gold occurrences in the area while Fe and Mn distribution are consistent with their source from the Fe-bearing metamorphic rocks. These findings provide baseline geochemical values for common and parallel geological domains in the eastern region of Cameroon. Although this study shows that the stream sediments are not polluted, the evaluation of metal composition in environmental samples from abandoned and active mine sites for comparison and environmental health risk assessment is highly recommended.  相似文献   

3.
The concentrations of 16 trace elements (Ag, Al, As, B, Ba, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Se, Ti, U, and Zn) in drinking water from Najran City, Saudi Arabia, were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and compared with local, regional, and international guidelines. Water samples from 22 water treatment plants and 13 commercial bottled water brands were analyzed. Except for B and U, the trace element concentrations were below the permitted limits defined in SASO, GSO, and WHO drinking water quality guidelines. The B concentrations in three brands of bottled water were 533.19, 602.29, and 1471.96 μg/L, which were all higher than the GSO and SASO limit (500 μg/L). The U concentrations were higher than the SASO limits for drinking water in two samples; one in treatment plant (2.39 μg/L) and another in foreign bottled water (2.17 μg/L). The median As, Ba, Cu, Ni, U, and Zn concentrations were statistically significantly higher in the treatment plant water samples than those in the bottled water samples, and conversely, the B concentrations were higher in the bottled water samples. The Cd, Hg, and Ti concentrations were below the detection limits of ICP-MS in all of the water samples. Apart from few exceptions, trace element concentrations in drinking water of Najran City were all within limits permitted in the national, regional, and international drinking water quality guideline values.  相似文献   

4.
In this study, the concentrations of seven heavy metals (As, Cd, Cu, Cr, Ni, Pb, and Zn) in the water, sediments, and nine tissues of eight fish species in Chaohu Lake were detected. And the ecological risk of sediments and food safety caused by heavy metals were evaluated. The mean concentrations of metals (As: 8.21, Cd: 0.58, Cu: 2.56, Cr: 0.50, Ni: 26.47, Pb: 3.51, Zn: 23.05 μg/L) in the water were found lower than the threshold values for the first-grade water quality (China environmental quality standards for surface water). The mean concentrations of Cr, Cu, Ni, Pb, and Zn in the sediments were 41.79, 19.31, 7.61, 7.09, and 102.85 μg/g, respectively, while the concentration of As and Cd was recorded below the detection limit. The ecological risk assessment demonstrated that metals in the sediments posed low ecological risk. The bioaccumulation of metals in fish tissues showed relatively high concentrations in liver, brain, kidney, and intestines while low levels of metals were detected in muscle. A fascinating phenomenon was firstly noticed that all metals highly existed in fish brain and exhibited an especially significant positive correlation with the metal concentrations in sediment, indicating a health risk for Chinese due to their consumption favor of fish head.  相似文献   

5.
Microscopic morphology and elemental composition of atmospheric particulate matter (PM) in 13 different size fractions from 0.01 to 10 μm were studied using a Field Emission Scanning Electron Microscope with Energy-Dispersive Spectrometer (FESEM–EDX). The relative mass fractions exhibited a bimodal distribution with a major mode in the fine range (0.18–1 μm) and a minor mode in the coarse range (>1 μm), suggesting that the major pollution of PM is fine particles in this area of Urumqi atmosphere. The PM could be classified as follows: aluminosilicate/silica mineral, Si–Al rich fly ash, Fe oxide particle, Ti dominant particle, sulfate/carbonate crystal, carbonaceous aerosols (including soot, organic carbon, tar ball and irregularly shaped carbon). The soot and organic carbon with anthropogenic sources are dominant types in fine range samples (<1 μm). The natural source minerals and secondary synthesized sulfate/carbonate crystals were accumulated in the coarse range (>1 μm). Elemental composition of various types of particles (0.056–5.6 μm) was also analyzed by EDX. C, S, O, N, Si, Al, Fe, Ca, Na, K, Mg, Cl, F, Hg were detected in most samples. Si, Al and Ca accumulated in coarse fractions, while S and Hg mainly accumulated in fine fractions. Concentrations of 15 metallic elements in size range from 0.1 μm to 5.6 μm were divided into three groups based on their possible sources. (1) The crustal elements (Al, Mg, Fe, Mn and V), mainly present in coarse particles (>1 μm); and (2) the anthropogenic source elements (Ca, Ni, As, Cu, Pb, Cd and Hg). The concentrations of Ca and Ni increased with increasing particle size, while As, Cu, Pb, Cd and Hg showed opposite trends. As, Cu, Pb, Cd and Hg accumulated mainly in fine fraction (<1 μm). (3) The multi sources elements (Cr, Co and Se) possibly come from both natural and anthropogenic sources. High levels of heavy metals, especially Hg in nanosize particles, may pose great risk to human health.  相似文献   

6.
Concentration and distribution of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn) in surface sediments collected from five stations located along the southwest coast of India were investigated seasonally to assess whether there is insidious buildup of heavy metals. Spatial variation was in accordance with textural characteristics and organic matter content. The concentration of the metals in sediments of the study area followed the order: Zn > Cr > Ni > Cu > Pb > Cd > Hg. The use of geochemical tools and sediment quality guidelines to account for the magnitude of heavy metal contamination revealed high contamination in monsoon and impoverishment during post-monsoon. Estimated total metal concentrations in the present investigation were comparable with other studies; however, concentrations of Ni and Zn were higher than that of other coastal regions. Concentrations of metals in sediment largely exceed NOAA effects range:low (e.g., Cu, Cr, Hg) or effects range:median (e.g., Ni) values. This means that adverse effects for benthic organisms are highly probable.  相似文献   

7.
The concentrations and speciation of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in the sediments of the nearshore area, river channel and coastal zones of the Yangtze estuary, China, were systematically investigated in this study. The concentrations of all heavy metals except Ni in the sediments of the nearshore area were higher than those of the river channel and coastal zones. In the nearshore area, the concentrations of most heavy metals except Hg in the sediments of the southern branch were higher than those of the northern branch because of the import of pollutants from the urban and industrial activities around. When compared with the threshold effect level (TEL) and geochemical background levels, Cr, Ni and As accumulated and posed potential adverse biological effects. The speciation analysis suggested that Cd, Pb and Zn in the sediments of the three zones showed higher bioavailability than the other heavy metals, and thus posed ecological risk. Significant correlations were observed among Cr, Cu, Ni and Zn (r > 0.77) in the nearshore area, Ni, Cu, Zn and Pb (r > 0.85) in the river channel and Ni, Cu, Cr, Pb and Zn (r > 0.75) in the coastal zone. Principal component analysis (PCA) indicated that the discharge of unban and industrial sewage, shipping pollution and the properties of the sediments (contents of Fe, Mn, Al, TOC, clay and silt) dominated the distribution of heavy metal in the nearshore area, river channel and coastal zones of the Yangtze estuary.  相似文献   

8.
Based on high spatial resolution monitoring, the first spatial distribution maps for the eight trace elements identified as priority contaminants in aquatic systems (i.e. As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in surface sediments of the Gironde Estuary (SW France) are presented. This large European fluvial–estuarine system is known for important historical multi-element (mainly Cd, Zn, Cu and Pb) pollution by former mining and mineral processing activation in the Riou-Mort watershed located 350 km upstream the estuary. As a consequence, oyster production in the estuary is prohibited, and Cd concentrations in oysters from the Marennes-Oléron area are close to consumption thresholds. Surface sediment samples were analysed for grain size, particulate organic C and trace element concentrations. Determination of trace elements was carried out by ICP-MS for As, Cd, Cr, Cu, Ni, Pb, Th and Zn, and by CV-AAS for Hg. Total and potentially released trace element stocks in the surface sediment were evaluated by using concentrations in the estuary and in selected sediment core. Assuming that sediment resuspension affects mainly the uppermost sediment layer, the total trace element stocks in the studied 0–10 cm depth range may represent the equivalent of one (Cd) to eight (As, Cr) times the annual fluvial trace element inputs into the estuary. Comparing total trace element concentrations in surface sediment with: (i) data on the regional geochemical baseline to evaluate the potentially remobilised fraction and (ii) the potentially bioavailable fraction aimed at establishing a first spatially resolved risk assessment of the trace element “cocktail” present in these sediments at the estuary scale. After correction for grain size effects by Th normalisation, potentially highly toxic metals such as Cd and Hg showed the highest enrichment factors. From ecotoxicological indices, areas were identified and quantified where trace element levels and mobility may bear a risk to benthic organisms. The GIS-based spatial distribution of ecotoxicological indices for the trace element “cocktail” suggests that ∼95% of the surface sediment are ‘Low–Medium’-priority zones, highlighting the need for further impact studies. The produced maps of trace element distributions and associated risk potentials are likely to be a useful tool to authorities in charge of sustainable estuarine management, e.g. for the optimisation of dredging activities or development of the estuarine infrastructure.  相似文献   

9.
Heavy metals and metalloids in sediments from the Llobregat basin,Spain   总被引：1，自引：0，他引：1  
The concentration of heavy metals and metalloids (As, Cd, Cr, Cu, Hg, Ni, Pb, Sb and Zn) in sediments from the River Llobregat and its tributaries (Anoia and Cardener) was studied. Samples collected at 17 locations during four different periods were analysed by ICP-MS. The heavy metal enrichment at some sites along the rivers reflects the effects of agricultural activities, sewage treatment plant effluents, collectors' discharges and industrial activities. Principal component analysis (PCA) was used to describe trends in contamination and to find groupings among the investigated areas. The Llobregat and Cardener sediments appeared to have features of an unpolluted river, even though significant amounts of domestic and industrial wastewater are discharged into these rivers. On the other hand, the sediments from the River Anoia showed high Cr and Hg levels originating from industrial activities. The concentrations of Cr and Hg ranged from 91–540 and 0.28–2.29 µg/g respectively.  相似文献   

10.
This article presents the results on distribution and enrichment pattern of acid-leachable trace metals (ALTMs) from roadside soil of Miri city, Sarawak, East Malaysia. The city is one of the fastest developing in the Malaysian region with huge petroleum resources. ALTMs Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn and Cd along with organic carbon and carbonates (CaCO3) were analyzed in 37 soil sediments collected from roadside. The enrichment of ALTMs [especially Cu (0.4–13.1 μg g?1), Zn (9.3–70.7 μg g?1), Pb (13.8–99.1 μg g?1)] in the roadside soils indicate that these metals are mainly derived from sources related to traffic exhausts, forest fires and oil refineries. The comparative study and enrichment pattern of elements indicates that Mn, Cu, Zn and Pb are enriched multi-fold than the unpolluted soil and Ni, Pb, Cd in some samples compared to Sediment Quality Guidelines like Lowest Effect Level (LEL) and Effects Range Low (ERL) in the region which is mainly due to the recent industrial developments in the region.  相似文献   

11.
地球化学基线是区分地球化学背景和异常的重要参数.在采集和测试自贡市龙潭镇内168个表层土壤样品的基础上,采用了地质统计学方法建立了研究区内重金属元素As、Cd、Cr、Pb、Hg、Cu、Ni、Zn的地球化学基线.在此基础上,应用地质累积指数方法评价了表层土壤重金属的污染状况.结果表明:区内各重金属元素基线值为As(3.86 μg/g)、Cd(0.183μg/g)、Cr(66.41 μg/g)、Pb(28.19 μg/g)、Hg(0.037 μg/g)、Cu( 23.1 μg/g)、Ni(24.5 μg/g)、Zn(62μg/g);研究区内Cd和Hg的污染较突出,各重金属元素的地质累积指数排序为:Cd＞H g＞Zn＞Cu＞As＞Cr＞Ni＞Pb.  相似文献   

12.
Serpentinite soils, common throughout the world, are characterized by low calcium-to-magnesium ratios, low nutrient levels and elevated levels of heavy metals. Yet the water quality and heavy metal concentrations in sediments of streams draining serpentine geology have been little studied. The aim of this work was to collect baseline data on the water quality (for both wet and dry seasons) and metals in sediments at 11 sites on the Marlborough Creek system, which drains serpentine soils in coastal central Queensland, Australia. Water quality of the system was characterized by extremely hard waters (555–698 mg/L as CaCO3), high dissolved salts (684–1285 mg/L), pH (8.3–9.1) and dissolved oxygen (often >110% saturation). Cationic dominance was Mg > Na > Ca > K and for anions HCO3 > Cl > SO4. Al, Cu and Zn in stream waters were naturally high and exceeded Australian and New Zealand Environment and Conservation Council guidelines. Conductivity displayed the highest seasonal variability, decreasing significantly after wet season flows. There was little seasonal variation in pH, which often exceeded regional guidelines. Stream sediments were enriched with concentrations of Ni, Cr, Co and Zn up to 35, 21, 10 and 2 times the world average for shallow sediments, respectively. Concentrations for Ni and Cr were up to 60 and 16 times those of the relevant Interim Sediment Quality Guidelines Low Trigger Values, respectively. The distinctive nature of the water and sediment data suggests that it would be appropriate to establish more localized water quality and sediment guidelines for the creek system for the water quality parameters conductivity, Cu and Zn (and possibly Cr and Cd also), and for sediment concentrations of Cd, Cr and Ni.  相似文献   

13.
This paper reports on the aquatic chemistry of trace elements in terms of spatial and temporal distribution, but also pollution sources in the transboundary watershed of the Seversky Donets River (Ukraine/Russia). Bed sediments and filtered water were collected from the Udy and Lopan Rivers at sites from the river source in the Belgorod region (Russia) to rural and urban areas in the Kharkiv region (Ukraine) in May and August 2009. Priority trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn), an urban tracer (Ag) and additional metals (Co, Mo, V) and Th were measured in stream water and sediments. The low levels and variability of Th-normalized concentrations indicated the absence of geochemical anomalies in the upstream part of the rivers and suggested that these data represent a regional baseline for trace elements in bed sediments. In contrast, water and sediments within the city of Kharkiv were contaminated by Ag, Pb, Cd, Cu, Cr and Zn, which are mainly attributed to municipal wastewater inputs and urban run-off. Results of the environmental quality assessment showed that element concentrations in the sediments can be considered as potentially toxic to aquatic organisms in sites downstream of the wastewater discharges.  相似文献   

14.
A set of forty-one surface sediment samples were collected in River Pánuco and its adjoining lagoon areas in NE Mexico to identify the enrichment pattern of trace elements. The samples were analyzed for sediment texture, carbonates, organic carbon and acid leachable trace elements (ALTEs) using autoclave method [Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, V, Be, Ba, Sr, As]. Geochemical results of Fe, Cr, Ni, Co, V and Sr in zone 1 indicate that erosion in the upland region (Sierra Madre Oriental Mountains) is very high. The above feature is supported by the supremacy of finer sediments (82.12 %), carbonates (44.67 %) and organic carbon (10.74 %), which are brought down from the drainage basin. The overall average concentration of ALTEs Mn (607 μg g?1), Cu (28.29 μg g?1), Ni (16.56 μg g?1), Pb (46.11 μg g?1), Cd (1.81 μg g?1) and Zn (92.18 μg g?1) indicates higher values than the lowest effect level (LEL) and effects range low (ERL) of environmental indicators. The results suggest that they are due to the increase in oil refineries, metal based industries, shipping activities and the effluent input which could enter the biological cycle and might create human health problems.  相似文献   

15.
为探讨渤海西部在多重环境因素变化下沉积物中重金属的环境地球化学行为,分析了渤海西部44个站位表层沉积物样品中8种重金属元素含量,研究了重金属元素的分布特征、环境影响因素及其生态风险。结果表明,渤海西部表层沉积物中As、Cu、Cd、Cr、Hg、Ni、Pb、Zn的平均含量分别为117 mg/kg、255 mg/kg、014 mg/kg、689 mg/kg、0037 mg/kg、303 mg/kg、223 mg/kg、757 mg/kg;Cu、Cr、Ni、Zn含量与有机碳含量、小于63 μm细粒沉积物呈显著正相关,其在表层沉积物中的分布明显受到有机质含量和沉积物粒径的控制,而As、Hg分布没有明显受到有机质含量的影响。富集系数显示,Cr、Ni、Pb和Zn为无富集,Cu、As为轻度富集,Cd和Hg为中度富集。与多种背景值和一致性沉积物质量基准相比较,渤海西部表层沉积物Pb、Cd的含量超出背景值,而Cu、Zn、Ni、Cr、As、Hg含量也存在一定的异常,但其含量水平引发有害生物效应的可能性不大,尽管重金属元素含量偏高,但生态风险较小。  相似文献   

16.
A study of agricultural lands around an abandoned Pb–Zn mine in a karst region was undertaken to (1) assess the distribution of heavy metals in the agricultural environment, in both dry land and paddy field; (2) discriminate between natural and anthropogenic contributions; and (3) identify possible sources of any pollution discovered. Ninety-two samples of cultivated soils were collected around the mine and analyzed for eight heavy metals, pH, fluoride (F?), cation exchange capacity, organic matter, and grain size. The eight heavy metals included Cd, Cr, Cu, Ni, Pb, Zn, As, and Hg. The average concentrations (mg/kg) obtained were as follows: Cd 16.76 ± 24.49, Cr 151.5 ± 18.24, Cu 54.28 ± 18.99, Ni 57.5 ± 14.43, Pb 2,576.2 ± 1,096, Zn 548.7 ± 4,112, As 29.1 ± 6.36, and Hg 1.586 ± 1.46. In a site where no impact from mining activities was detected, the mean and median of Cd, Cu, Ni, Pb, Zn, As, and Hg concentrations in investigated topsoils were higher than the mean and median of heavy metal concentrations in reference soils. An ensemble of basic and multivariate statistical analyses was performed to reduce the multidimensional space of variables and samples. Two main sets of heavy metals were revealed as indicators of natural and anthropogenic influences. The results of principal component analysis (PCA) and categorical PCA demonstrated that Cd, Cu, Pb, Zn, and Hg are indicators of anthropogenic pollution, whereas Cr, As and Ni concentrations are mainly associated with natural sources in the environment. The contamination from Pb–Zn mining operations, coupled with the special karst environment, was a key contributing factor to the spatial distribution of the eight heavy metals in the surrounding soil. The values of heavy metals in the soil samples suggested the necessity of conducting a rigorous assessment of the health and environmental risks posed by these residues and taking suitable remedial action as necessary.  相似文献   

17.
The concentrations of Cd, Cu, Mn, Ni, Pb, Fe and Zn were determined in superficial sediments extracted from nine zones of Budi Lagoon, located in the Araucanía Region (Chile). The concentrations of these metals were determined by flame atomic absorption spectroscopy and the method was validated using certified reference material (marine sediment). The concentration ranges found for the trace elements were: Pb < 0.5; Cd < 0.2–3.9; Cu 21.8–61.9; Ni 31.2–59.4; Zn 54.5–94.8 mgkg?1 (dry weight). The elements that registered the highest concentrations were Mn 285.4–989.8 mgkg?1 and Fe 4.8–10.6 %. The lagoon cluster analysis of the stations was divided into three groups (Temo station with high Cu and low Mn concentrations, Bolleco, Comué, Allipén and Deume 3 stations presented highest Cd concentration, and another group Botapulli, Río Budi, Deume 2 and Deume 1 stations presented low levels of Cd). The textural characteristics of the sediment were determined (gravel, sand and mud) and the results were correlated with the concentrations of the metals in the various study zones. The sediments of Budi Lagoon presented high levels of Fe and Mn, which are of natural origin and exceed the maximum values recorded by many authors. With respect to the recorded concentrations for Cd, Cu, Ni and Zn, are within the ranges published by other authors in similar works. The Pb element was not detected. The results were subjected to statistical analysis to evaluate the correlations between the content of the elements and obtain the site of sediment.  相似文献   

18.
Heavy metal accumulation due to industrial activities has become a very sensitive issue for the survival of the aquatic life. Therefore, distributions of several heavy metals have been studied in the surface sediments of Tapti–Hazira estuary, Surat, to assess the impact of anthropogenic and industrial activities near estuary. Totally 60 sediment samples were collected from four different sites at Tapti–Hazira estuary, Surat from January 2011 to May 2011 and examined for metal contents. The average heavy metal load in the study area are found to be 43.28–77.74 mg/kg for Pb, 48.26–72.40 mg/kg for Cr, 117.47–178.80 mg/kg for Zn, 71.13–107.82 mg/kg for Ni, 123.17–170.52 mg/kg for Cu, 0.74–1.25 mg/kg for Cd, 14.73–21.69 mg/kg for Co. Calculated enrichment factors (EF) reveal that enrichment of Pb and Cd is moderate at all sites, whereas other metals Cr, Ni, Zn, Co, and Cu show significant to very high enrichment. Geo-accumulation index (I geo) results revealed that the study area is nil to moderately contaminated with respect to Cd, moderately to highly polluted with respect to Pb, Zn, and Cu and high to very highly polluted with respect to Co and Cr.  相似文献   

19.
The mineralogical and morphological characteristics, concentration of major and trace elements, and sulfur isotopic composition of three pyrite and two coal samples in the Upper Permian high-sulfur coals from Xingren, Zhijin, and Hefeng mining area, South China, were investigated, by using optical microscopy, field emission-scanning electron microscopy in conjunction with an energy-dispersive X-ray spectrometer (FE SEM-EDS), X-ray powder diffraction (XRD), X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), cold vapor atomic absorption spectrometry (CVAAS), and isotopic ratio mass spectrometer. The pyrite in Xingren and Zhijin coals mainly occurs as nodular, lens-shaped, thin-layer, and massive forms, and it occurs mainly as fine vein fillings in the Hefeng coals. Microscopically, pyrite in the coals from Xingren, Zhijin, and Hefeng mainly occurs as framboidal, cell-filling, and vein-filling forms, respectively. There is a distinct difference in X-ray powder diffractogram and diffraction data of the three pyrite samples. There is a maximum diffraction peak (2.709 Å) in pyrite in the coals from Xingren and (2.707 Å) in pyrite in the coals from Zhijin; however, the maximum diffraction peak is 3.343 Å in pyrite in the coals from Hefeng. The average unit cell length (a 0) is 5.4169 Å for the Xingren pyrite, 5.4159 Å for the Zhijin pyrite, and 5.4170 Å for the Hefeng pyrite. The ratio of S/Fe is 2.16 for the Xingren pyrite, 2.09 for the Zhijin pyrite, and 2.01 for the Hefeng pyrite. Copper (701 μg/g), Ni (369 μg/g), and Co (29.6 μg/g) concentrated in the Hefeng pyrite. The concentration of As is 126, 19.6, and 19.1 μg/g in the Hefeng, Zhijin, and Xingren pyrite, respectively. Mercury is 11.7 μg/g in the Xingren pyrite, 2.79 μg/g in the Zhijin pyrite, and 0.512 μg/g in the Hefeng pyrite. There is a clear tendency that elements Cu, Ni, Co, Cr, Se, Mo, and As are significantly enriched in the Hefeng pyrite. Mercury is greatly enriched in the Xingren pyrite, and Zn is enriched in Zhijin pyrite. Rare earth elements and yttrium (REY) are not abundant (8.276 μg/g) in the Hefeng pyrite and are characterized by maximum positive anomaly of Eu (Eu/Eu* = 6.54). The δ34S value is ?26.9 ‰ in the Xingren pyrite, +3.8 ‰ in the Zhijin pyrite, and +3.7 ‰ in the Hefeng pyrite. The trace elements in the Hefeng pyrite and coal are As (126 and 6.1 μg/g), Hg (0.512 and 0.158 μg/g), Zn (276 and 56.7 μg/g), Se (16.5 and 1.07 μg/g), Mo (45.5 and 9.93 μg/g), Cu (701 and 37.8 μg/g), Ni (369 and 16.9 μg/g), Co (29.6 and 8.63 μg/g), Sb (2.64 and 0.742 μg/g), Cd (3.49 and 0.366 μg/g), and Pb (62.8 and 33.5 μg/g), demonstrating that these potentially toxic trace elements were mainly concentrated in pyrites. The strongly positive Eu anomaly (Eu/Eu* = 6.54) in the netted pyrite vein filled in the cleats of the Hefeng coal may be the product of epigenetic hydrothermal fluid.  相似文献   

20.
 As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Se and Zn concentrations were determined and compared in lake and overbank sediments from 33 catchments without local pollution sources in southern Norway. There were no significant differences in concentrations of Be, Co, Cr, Cu, Ni, and V in overbank and pre-industrial lake sediments. In areas with shallow overburden, and significant influence from long-range atmospheric pollution, concentrations of As, Cd, Hg, Pb, Se, and Zn in overbank sediments were probably modified by vertical percolating water. In such areas, we suggest using lake sediments as a better sampling medium for mapping pre-industrial concentrations. Pre-industrial lake sediments yield natural concentrations of Hg and Se, which consist of both geogenic and natural atmospheric deposition. Important covariables like organic carbon content, Fe oxides, and fine mineral fraction were generally higher in pre-industrial lake sediments as compared to overbank sediments. By adjusting for such differences overbank sediments could be used as an alternative in mapping background concentrations of trace metals in regions with few lakes. Received: 19 February 1999 · Accepted: 17 April 1999  相似文献   

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