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1.
Soil contamination by heavy metals has been a major concern for last few decades due to increase in urbanization and industrialization. The main objective of this research was to identify the heavy metal contaminated zones in the study area. Twenty five soil samples collected throughout the agriculture, residential and industrial areas were analysed by X-ray Fluorescence Spectrometer (XRF) for trace metals and major oxides. These metals can affect the quality of soil and infiltrate through the soil, thereby causing groundwater pollution. Based on the chemical analysis of major oxides (SiO2, Al2O3, ?Fe2O3, MnO, MgO, CaO, Na2O, K2O, TiO2, and P2O5) and their distribution; it is observed that these soils are predominantly siliceous type with slight enrichment of alumina component in the study area. Correlation matrix (CM) and factor analysis (FA) is employed to the heavy metal variables, viz., Ba, Cr, Cu, Ni, Pb, Rb, Sr, V, Y, Zn and Zr of the soil to determine the dominant factors contributing to the soil contamination in the area. In the analysis, five factors emerged as significant contributors to the soil quality. The total contribution of these five factors is about 90%. The contribution of the first factor is about 45% and has significant positive loadings of Co, Cr, Cu, Ni and Zn. The contribution of second factor is 22% and has significant positive loadings of Rb, Sr and Y. The contribution of third, fourth and fifth factors is 10, 8 and 5% and show positive loadings for lead, molybdenum and barium respectively to the soil contamination. The spatial variation maps deciphering different zones of heavy metal concentration in the soil were generated in a GIS (geographic information system) based environment using ArcGIS 9.3.1. The results reveal that heavy metal contamination in the area is mainly due to anthropogenic activities.  相似文献   

2.
The sediments of the raw sewage-fed fishpond system at East Kolkata Wetland (EKW) were analyzed for heavy metal content in a comprehensive way. Various indices of contamination like enrichment factor (EF), geo-chemical index (I geo), modified degree of contamination (mDC), and pollution load index (PLI) were assessed. In all cases, instead of literature values, the metal concentrations of less contaminated sites, separated by the statistical approach of the hierarchical cluster analysis, were used as baseline values. In the present study, about 70% of the pond sediments are found uncontaminated, 5% display low degree of contamination and 25% are designated as moderate degree of contamination. Both the EF and I geo indices highlighted that the metals lead (Pb), cadmium (Cd), and chromium (Cr) are responsible for the contamination while there is little anthropogenic input in cases of Cu, Zn, and Ni. Most of the ponds situated near the main sewage flowing canals as well as the main traffic highway and close to the solid waste dumping areas recorded higher degree of metal contamination as evident from spatial variation of mDC and PLI indices in the study area. Indices comparison study clearly indicates that although these are calculated using different methods, these may or may not produce the same indices values and hence the values should neither be compared nor be averaged. But all the above indices are directly related to a common term contamination factor (CF). Classification of contamination levels based on these CF values is found to be similar and this classification is only valid up to the level of high degree of contamination. Thus, the use of any one of these indices is sufficient to classify the degree of contamination of an area. However, to evaluate the contamination per metal, both I geo and EF are effective while, to assess the composite effect of all the metals, PLI is preferable to mDC.  相似文献   

3.
The study aimed to assess the heavy metals(K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Pb, Sr, Zr) contamination in the soil of mine affected Singaran river basin and to analyse spatial variation in the contamination level considering 32 soil samples. Elemental analysis of soil samples has been performed through Energy Dispersive X-ray Analysis(EDX) to quantify the elemental concentration(mg kgà1). Heavy metal concentrations have been assessed through geo-accumulation index(Igeo) and enrichment factor(EF).Indices showed soils have moderate accumulation of most of the metals with moderate enrichment of Sr,Zr, Zn, Cu and Ni. Soil contamination level assessment has been carried out using indices like Contamination Factor(CF), degree of contamination(C_(deg)), modified degree of contamination(m C_(deg)) and Pollution Load Index(PLI). CF shows moderate to considerable contamination by Sr, Zr, Ca, Cu, Mn, Zn and Ni. Mean indices values(m C_(deg)and PLI for the entire basin are 3.38 and 2.23 respectively) show low to moderate level of soil contamination. These indices result have been mapped and analysed in GIS platform to get spatial variation of pollution level. Opencast mines dominate middle catchment area and so is comparatively contaminated. Sample sites 11, 18 and 25 evidenced high values of all indices of pollution load. From the ecological standpoint Ecological Risk Factor(Er) and Potential Ecological Risk Index(RI) have been estimated to assess regional threat to native soil environment and it shows low ecological risk potential. Analysis shows that mine dominated soil of the entire Singaran basin is less contaminated in all respect but tends to the moderate contamination level at the mid-catchment area,especially by Sr, Zr, Zn, Cu and Ni.  相似文献   

4.
Street dust is one of the important indicators that reflect the status of urban environmental pollution. There are many studies of heavy metals contamination of street dust in capital cities; however, little attention has been paid to this kind of study in medium cities, including China. The dust samples were collected in the district of traffic crossroads in Xianyang city, Shaanxi Province. Pb, Cd, Cu, Ni, Zn, Cr and Mn concentrations were determined using atomic absorption spectrometry (AAS). The results indicate that the concentrations of heavy metals are higher than the background values of soils in Shaanxi Province. The contamination level of heavy metals is assessed by potential ecological risk index (E r), geoaccumulation index (I geo), enrichment factor (EF) and pollution index (Pi). The low I geo, EF, E r, Pi and PIn (integrated pollution index) for Mn in street dusts indicate an absence of distinct Mn pollution. The high EF, Pi and PIn of Cu and Zn indicate that there is considerable Cu and Zn pollution. It is suggested that more attention should be paid to heavy metals contamination of Cu and Zn. The assessment results of Pi and PIn suggest that Pb, Ni and Cr present strong pollution; however, their EFs indicate that they cause moderate pollution and their I geo indicates that they are unpolluted to moderately polluted. The contamination class value with different assessing methods is of the order: Pi ≈ PIn > EF > I geo > E r.  相似文献   

5.
The adsorption of cadmium (Cd) and zinc (Zn) with similar chemical properties is examined onto three soil samples: one is alkaline and the others are acidic. The distribution coefficient (K d) and the Freundlich constant (K F) for Zn are slightly higher than those for Cd, implying that the adsorption affinity of Zn is a little greater and less mobile. However, Cd and Zn usually show comparable results in the kinetic, isotherm, and envelope experiments. The adsorption of the heavy metals is relatively rapid and the reaction is almost completed within 15 min. The kinetics for both Cd and Zn are very well explained by the parabolic diffusion model. The maximum adsorption of the heavy metals is obtained at high pH, high temperature, and low ionic strength. The adsorption capacity on the alkaline soil is more significantly affected by the temperature as compared to the acidic soil. It is found that the adsorption affinity of the two heavy metals is mainly affected by the soil properties, such as pH, pHPZC, organic matter, and total carbon. It is also confirmed that the chemical properties of the heavy metals are important factors in their adsorption onto soil. The adsorption isotherms of Cd and Zn are well described in both Freundlich and Langmuir models at the usual pH (soil pH). Under acidic and alkaline pHs, however, only the Freundlich model describes the adsorption of both heavy metals satisfactorily.  相似文献   

6.
The study area is very important in terms of anthropogenic activity like rapid industrial, urban development, pesticides, pharmacy, granite polishing and agro based industries. Soils represent an excellent media to monitor heavy metal pollution. The results of soil samples analyzed in the present work using XRF reveal anomalous heavy metal and major oxide concentrations. The geogenic and anthropogenic activities for a long period in the study area are responsible for the anomalous heavy metal pollutants. Hence, this work is of immense societal benefit in terms of prevailing human health hazards in the study area with a direct relevance to such industrially populated regions elsewhere. Soil samples collected from study area were analyzed for heavy metals (As, Ba, Cr, Cu, Ni, Co, Mo, Pb, Rb, Sr, V, Y, Zn and Zr and major oxides (SiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O, TiO2, and P2O5 ) using Philips PW 2440 X-ray Fluorescence Spectrometer (XRF). The minimum 0.08 for molybdenum and maximum 21.99 enrichment factor for arsenic is observed. The minimum -2.5 and maximum 17.97 geoaccumulation index values is observed for barium and molybdenum. The minimum 0.07 and maximum 4.3 contamination factors is observed for molybdenum and lead. High contamination degree 19.21 for SMP-1 and least 7.8 for SMP-12 is observed. The minimum 0.41 and maximum 0.95 pollution load index is observed for SMP-12 and SMP-20. Factor analysis results shows that, three factors emerged as significant contributors to the soil quality is about seventy six percent for heavy metals and sixty eight percent for major oxides. The spatial variation maps deciphering heavy metal concentration of both natural and anthropogenic origin by three zones i.e. low, moderate and high of the study area based on environment using Arc-GIS.  相似文献   

7.
An exploratory study on soil contamination of heavy metals was carried out surrounding Huludao zinc smelter in Liaoning province, China. The distribution of total heavy metals and their chemical speciations were investigated. The correlations between heavy metal speciations and soil pH values in corresponding sites were also analyzed. In general, Cd, Zn, Pb, Cu and As presented a significant contamination in the area near the smelter, comparied with Environmental Quality Standards for Soils in China. The geoaccumulation index showed the degree of contamination: Cd > Zn > Pb > Cu > As. There was no obvious pollution of Cr and Ni in the studied area. The speciation analysis showed that the dominant fraction of Cd and Zn was the acid soluble fraction, and the second was the residual fraction. Pb was mostly associated with the residual fraction, which constituted more than 50% of total concentration in all samples. Cu in residual fraction accounted for a high percentage (40–80%) of total concentration, and the proportion of Cu in the oxidizable fraction is higher than that of other metals. The distribution pattern of Pb and Zn was obviously affected by soil pH. It seemed that Pb and Zn content in acid solution fraction increased with increasing soil pH values, while Cd content in acid soluble fraction accounted for more proportion in neutral and alkaline groups than acidic one. The fraction distribution patterns of Cu in three pH groups were very similar and independent of soil pH values. And the residual fraction of Cu took a predominant part (50%) of the total content.  相似文献   

8.
Concentration and distribution of heavy metals (Cd, Cu, Pb and Zn) in urban soils of Hangzhou, China, were measured based on different land uses. The contamination degree of heavy metals was assessed on the basis of pollution index (PI), integrated pollution index (IPI) and geoaccumulation index (I geo). The 0.1 mol l−1 HCl extraction procedure and gastric juice simulation test (GJST) were used to evaluate the potential mobility and environmental risk of heavy metals in urban soils. The average concentration of Cd, Cu, Pb and Zn in urban soils was measured at 1.2 (with a range of 0.7–4.6), 52.0 (7.4–177.3), 88.2 (15.0–492.1) and 206.9 (19.3–1,249.2) mg kg−1, respectively. The degree of contamination increased in the order of industrial area (IA) > roadside (RS) > residential and commercial areas (RC) > public park and green areas (PG). The PIs for heavy metals indicated that there is a considerable Cd, Cu, Pb and Zn pollution, which originate from traffic and industrial activities. The IPI of these four metals ranged from 1.6 to 11.8 with a mean of 3.5, with the highest IPI in the industrial area. The assessment results of I geo also supported that urban soil were moderately contaminated with Cd and to a lesser extent also with Cu, Pb and Zn. The IP and I geo values reveal the pollution degree of heavy metal was the order of Cd > Pb > Zn ≈ Cu. It was shown that mobility and bioavailability of the heavy metals in urban soils increased in the order of Cd > Cu > Zn ≈ Pb. Owing to high mobility of Cd and Cu in the urban soils, further investigations are needed to understand their effect on the urban environment and human health. It is concluded that industrial activities and emissions from vehicles may be the major source of heavy metals in urban contamination. Results of this study present a rough guide about the distribution and potential environmental and health risk of heavy metals in the urban soils.  相似文献   

9.
In an attempt to delineate heavy metal contamination precincts and to evaluate the extent and degree of toxic levels, besides their possible sources, 38 water samples from Ankaleshwar Industrial Estate, south Gujarat, India were analyzed. By clutching geochemical analyses and GIS-based colour composites areas depicting anomalously high concentration of heavy metals (Mo, Zn, Pb, Ni, Co, Cd, etc.) in the groundwater were revealed. The multicomponent overlays in grey-scale facilitated in identifying situates of heavy metal ‘hot spots’, and lateral protuberances of the contamination plume around defile stretch of the main stream Amla Khadi flowing through the area. The multiple pollution plumes emerging from other parts of the area further coincide with effluent laden streams and small channels indicating industrial establishments as major sources of groundwater contamination. Influent nature of the streams, accelerated infiltration process, high mass influx and shallow groundwater table are the factors conducive for easy access of heavy metals to the phreatic aquifers affecting over 20 km2 area. On the basis of P/U ratios (concentration of metals in polluted water to unpolluted water), geogenic and anthropogenic sources have been identified. Very high levels of technogenic elements present in the ground water raise concerns about possible migration into food crops, as the area is an important horticultural locale and is highly cultivated.  相似文献   

10.
Due to the rapid urbanization and industrialization that has occurred in China over the last few decades, metals have been continuously emitted into the urban environment and now pose a serious threat to human health. Indeed, there is a growing concern over the potential for pollution of urban soils with heavy metals. Therefore, an extensive soil survey was conducted in urban areas of Changchun, China, to evaluate the current status of heavy metal contamination in soils and to evaluate its potential sources. A total of 352 samples of urban soils were collected from urban areas of Changchun using a systematic sampling strategy in which one sample per km2 was taken (0 ~ 20 cm). The levels of Cu, Pb, Zn and the major elements (Mn, Al2O3, CaO, Fe2O3, MgO, SiO2, K2O and NaO) were then determined by X-Ray fluorescence spectrometry (XRF), while the level of Cd was determined by graphite furnace atomic absorption spectrometry (GF-AAS), and the Hg and As concentrations were determined by atomic fluorescence spectroscopy (AFS). The results indicated that, when compared with the background values of topsoil in the Changchun region, the topsoil in urban areas were enriched with metals, particularly Cu, Cd, Zn, Pb and Hg. The results of correlation coefficient analysis showed that Hg, As, Cd, Cu, Pb and Zn were significantly positive correlated with each other, while Cr and Mn formed another group. Moreover, significantly positive correlations were observed between pH and Zn, Pb, Cu, Cd, As and Hg, indicating that pH influences the distributions of these metals in urban soils in Changchun. Principal component analysis (PCA) was conducted to identify sources of heavy metals and the results revealed distinctly different associations among the trace metals and the major elements in the urban soils. The concentration of Cr appeared to be controlled by the parent material (natural sources), while Cu, Pb and Zn were mainly from vehicle emissions, with Zn primarily coming from vehicle tires. Additionally, Hg and As primarily originated from coal combustion, while Cd was mainly associated with industrial sources. According to the pollution index (PI) of each metal, the overall levels of metal pollution were not especially high, but there were clearly contaminated sites concentrated in the central and northeast portion of the studied region. The Nemerow integrated pollution index (NIPI) of the seven metals also indicated that urban soils in Changchun city were classified as having low level of pollution.  相似文献   

11.
To assess the pollution of heavy metal in dust fall, nine dust fall samples were collected during the heating period and non-heating period from Jinan, a city in northeastern China. The samples were analyzed for Cu, Pb, Zn and Cr and the contamination level of heavy metals was assessed on the basis of the geo-accumulation index (I geo). The results indicated that all of the four investigated metals accumulated significantly in the dust fall of Jinan, and the metal concentrations were much higher than background values. During the heating period, the mean values for Cu, Pb, Zn and Cr in the dust fall were 354.9, 688.5, 2,585.5 and 478.6 mg kg−1. During the non-heating period, the mean values for Cu, Pb, Zn and Cr in the dust fall were 228.2, 518.2, 1,933.9 and 96.3 mg kg−1, respectively. The I geo values calculated based on background values revealed that the contamination level of heavy metal in the dust fall ranges from moderately contaminated to heavily contaminated, and it mainly originates from traffic and industry. In this work, the dust fall residue compared to the standard reference was also chosen as the background value to calculate the I geo value. This method is useful for situations in which the background value is difficult to obtain.  相似文献   

12.
《Applied Geochemistry》1999,14(2):187-196
High concentrations of several heavy metals were suspected in soils in an area of some contemporary and extensive historical mining and smelting of Pb and Zn near the town of Bytom. In order to investigate the spatial distribution of heavy metals, 152 soil samples were taken at high sampling density in an area of 14 km2 on a regular grid as well as along an 11 km transect. The samples were analysed for total Pb, Zn and Cd content by ICP-AES; a selection of samples were also analysed for total As content.Significant levels of contamination were found. Median topsoil concentrations (0–10 cm) for Pb, Cd, Zn and As were 430 μg g−1, 13 μg g−1, 1245 μg g−1 and 35 μg g−1, respectively. The detected levels of Pb, Zn and Cd were mostly in reasonable agreement with findings from a previous low-density study, but As concentrations were up to 6 times higher than had previously been reported for the area. Additional zones of particularly high concentrations could be identified for all 4 elements by this higher-density survey. Contaminant concentrations were generally found to decrease substantially with increasing depth, on average by a factor of 3.5 for Cd, 3.0 for Zn and 2.6 for Pb. However, significant subsoil contamination (40–50 cm) was also detected, in particular for Zn, Pb and As, which appeared to be enriched at depth in certain locations.To assess the potential availability of the metals to plants, the exchangeable fraction (0.5 M MgCl2) was estimated for Pb, Zn and Cd for 84 samples. Levels were strongly influenced by soil pH and were generally low for Pb (less than 1% of total, max 15.6%), moderate for Zn (less than 10% of total, max 32.4%), and high for Cd (mean 35% of total, max 59.8%). For Zn and Pb, there seemed to be a threshold pH value of about 6, below which a significant increase in the exchangeable fraction was observed. No such threshold value appeared to exist for Cd, which was found to be relatively labile even in slightly alkaline soils (mean of 27.6% exchangeable Cd in pH range 7–8).The detected levels of total metal contamination exceed various national and international thresholds, indicating the need for further investigation and an assessment of the suitability of the land for agricultural use, particularly in view of the high levels of exchangeable Cd.The pattern of spatial variation of the metals in the topsoil indicates that a variety of sources might be responsible for the contamination, historical mining and smelting probably being the most important.  相似文献   

13.
In the present study, roadside-deposited sediment samples collected from Kuwait city district, in Kuwait, were analyzed for specific heavy metals (As, Cr, Cu, Mn, Ni, Pb, and Zn). Contamination assessment status of heavy metals in roadside sediments was made using mathematical models in terms of enrichment factor (EF), geoaccumulation index (I geo), and contamination factor (CF). The sediments showed remarkably high levels of all the metals, except Ni, above background concentrations in the following order (As, Cu, Pb, Zn, Mn, and Cr). CF and I geo revealed overall moderately uncontaminated and moderate contamination, respectively, but the EFs for all metals ranged between moderate and significant enrichment.  相似文献   

14.
Simultaneous competitive adsorption behavior of Cd, Cu, Pb and Zn onto nine soils with a wide physical–chemical characteristics from Eastern China was measured in batch experiments to assess the mobility and retention of these metals in soils. In the competitive adsorption system, adsorption isotherms for these metals on the soils exhibited significant differences in shape and in the amount adsorbed. As the applied concentration increased, Cu and Pb adsorption increased, while Cd and Zn adsorption decreased. Competition among heavy metals is very strong in acid soils with lower capacity to adsorb metal cations. Distribution coefficients (K dmedium) for each metal and soil were calculated. The highest K dmedium value was found for Pb and followed by Cu. However, low K dmedium values were shown for Zn and Cd. On the basis of the K dmedium values, the selectivity sequence of the metal adsorption is Pb > Cu > Zn > Cd and Pb > Cu > Cd > Zn. The adsorption sequence of nine soils was deduced from the joint distribution coefficients (K dΣmedium). This indicated that acid soils with low pH value had lower adsorption capacity for heavy metals, resulting in much higher risk of heavy metal pollution. The sum of adsorbed heavy metals on the soils could well described using the Langmuir equation. The maximum adsorption capacity (Q m) of soils ranged from 32.57 to 90.09 mmol kg−1. Highly significant positive correlations were found between the K dΣmedium and Q m of the metals and pH value and cation exchange capacity (CEC) of soil, suggesting that soil pH and CEC were key factors controlling the solubility and mobility of the metals in soils.  相似文献   

15.
Excessive soil copper (Cu) availability leads to plant growth retardation and leaf chlorosis, and the contamination of Cu in the food chain would be detrimental to human and animal health. The most important path for Cu accumulation in plants is uptake from soils. It is therefore important to understand the availability of soil Cu and its controlling factors to modify Cu availability and prevent excessive Cu from entering the food chain. The present study proposed a general regression neural network (GRNN) to simulate the availability index of soil Cu (available heavy mental concentrations/total heavy metal concentrations), based on the influencing factors of total Cu concentration, pH, organic matter (OM), available phosphorus (AP), and readily available potassium (RAK). Results showed that total Cu concentration, combined with OM and AP, achieved the lowest RMSE value (0.0524) for the modeled value of the availability index of soil Cu. The simulated results by GRNN and the ground truth values had better agreement (R 2 = 0.7760) than that by a linear model (R 2 = 0.6464) for 23 test samples. Moreover, GRNN obtained lower averaged relative errors than linear model. This demonstrated that GRNN could be used to simulate the availability index of soil heavy metals and gained better results than linear model.  相似文献   

16.
Emerging environmental issues related to heavy metal contamination in rice draw great concern about the soil quality of paddy farming lands irrigated with groundwater. Investigating the functioning of soil microorganisms exposed to heavy metal contamination is imperative for agricultural soil manipulations. The current study accentuates the influence of heavy metals on microbial activity and community composition in arable soil of West Bengal State of India. The result revealed that the fertility indicators (activity of all soil enzymes) and growth-limiting factors (soil N and P) were negatively correlated with the heavy metal stress except the soil total organic content which demonstrated significant positive correlation with the heavy metals. In case of functional diversity of soil, all the considered diversity indices exhibited no specific pattern along with the availability of heavy metals. Further, despite the heavy metal contamination, we observed a very complex and indifferent pattern of bacterial community composition along the heavy metal contamination sites. Overall, we found that γ-Proteobacteria had been the most abundant bacterial community followed by Actinobacteria, Firmicutes, β-Proteobacteria and α-Proteobacteria. Commemorating all the results, we can infer that arsenic and other heavy metal contamination is deteriorating the soil quality and hence warrants immediate attention of concerned soil scientist and agronomists.  相似文献   

17.
This study analyzed the concentrations and chemical forms of Zn,Cu,Pb,Sb,Cd and Mn in airborne particles,road dusts and soils collected along three expressways in Jiangxi Province,China,with different traffic densities,and identified the levels and sources of heavy metal contamination.The concentrations of Zn,Cu,Pb,Sb,and Cd except Mn in airborne particles,road dusts and soils were all in direct proportion to traffic volume.Cd concentrations were low compared with other metals.For instance,the concentrations of Zn,Cu,Pb,Sb,Mn and Cd were 6.6,0.7,2.2,0.1,0.1 and 0.1μg·m-3in PM10along the Changjiu Expressway,792.8,241.4,248.3,9.6,340.5and 8.0 mg·kg-1in road dusts,and 201.1,143.2,59.5,9.5,338.9 and 2.3 mg·kg-1in soils,respectively,but in the case of the ratio of concentration to the environmental background value,most serious contamination was caused by Cd.The sources of the heavy metals were judged by comparisons of the chemical forms of the heavy metals in different environmental media.Pb and Mn in airborne particles were both derived from traffic;Pb in road dusts and soils resulted mainly from the use of leaded gasoline in the past;and Mn in road dusts and soils was derived from parent rocks.Zn,Cu,Sb and Cd in airborne particles,road dusts and soils were derived primarily from traffic,and differences in chemical forms of the heavy metals in different media were due to the interaction between heavy metals in airborne particles and organic matter and other surfaces in road dusts and soils.We also discussed the change of chemical forms of heavy metals in particles of different sizes and under different weather conditions.Bioavailability of heavy metals in airborne particles was much higher than that in road dusts and soils,especially Pb(0.676 in airborne particles,0.159 in road dusts and 0.095 in soils).  相似文献   

18.
小秦岭金矿区土壤重金属生物有效性与影响因素   总被引：1，自引：0，他引：1  
张开军  魏迎春  徐友宁 《地质通报》2014,33(8):1182-1187
土壤中重金属生物有效性与影响因素分析是土壤重金属风险管控的关键问题。通过实地调查、现场采样、实验测试、综合分析等方法,分析了研究区100km2内Hg、Pb、Cd、Cr、As、Cu、Zn七种重金属元素的有效态含量特征,研究了这些重金属有效态含量之间、有效态含量与全量、有效态与土壤pH、有机质含量、粒度等基本理化参数之间的相关性,分析了重金属污染来源。结果表明,土壤中Hg、Pb、Cd、Cr、As、Cu、Zn七种重金属有效态的平均含量分别为2.29mg/kg、594mg/kg、2.52mg/kg、6.30mg/kg、2.16mg/kg、48.14mg/kg、50.21mg/kg,其变异系数大小为:HgPbCuZnCdAsCr。Hg的变异系数最大,是由于金矿选矿活动采用混汞法提金排放的尾矿堆(库)分布不均。Hg、Pb、Cd、Cu、Zn有效态量与全量之间均存在显著的相关性;土壤有机质与重金属有效态之间存在显著的相关性;土壤pH与有效态重金属之间存在显著的负相关性;土壤粒度对重金属有效态的累积影响不明显。  相似文献   

19.
Sediments and surface water contamination by the industrial effluents containing heavy metals is the most detrimental environmental impact. Therefore, the present work attempts to determine the status of eight heavy metal distribution in sediments and water samples, and their ecological risks’ assessment in the studied area. The distribution pattern of heavy metals in the water and sediment follows the sequences: Zn > Cu > Pb > Cr > Mn > Ni > As > Cd and Mn > Zn > Cr > Pb > Cu > Ni > As > Cd, respectively. Gross water pollution is observed at different sampling points of Dhalai Beel and Bangshi River. The comparison of sedimentary mean metal concentrations with several environmental contamination monitoring parameters, viz, threshold effect level (TEL), probable effect level (PEL), and severe effect lever (SEL) indicates that the metal levels are less than PEL except Cr. Moreover, the level of contamination degree (C d) and modified degree of contamination (mC d) indicates ‘low’ and ‘nil to low’ degree of contamination, respectively. Pollution load indices (PLI) of the studied area are lower than unity, indicates no pollution. Furthermore, a toxic-response factor is applied to assess the potential ecological risk of these heavy metals into the water body. The results of this study exhibit a low potential ecological risk of heavy metals. The Pearson’s correlation and cluster analysis are also performed to assess the heavy metal interactions in water and sediment samples.  相似文献   

20.
福建沿海地区土壤-稻谷重金属含量关系与影响因素研究   总被引：12，自引：8，他引：4  
福建沿海地区土壤Pb含量远高于我国其他地区及全国背景值,其对农产品安全、生态环境的影响值得关注。本文采集该地区典型耕作区58套土壤-水稻样品,查明Pb、Cd等重金属元素含量特征及其关键控制因素。研究表明从水稻根→茎叶→稻谷,重金属元素含量和富集系数呈现明显的下降趋势,有害重金属As、Pb等的递减速率远大于植物营养元素Cu、Zn,指示水稻根部对重金属元素具有一定的阻截作用。土壤-稻谷间Pb具有显著正相关性,显示土壤Pb是稻谷Pb的重要来源;稻谷Pb含量与土壤有机碳呈显著负相关关系,与土壤pH呈弱负相关关系,说明富含有机碳、相对碱性的土壤环境可降低土壤Pb的生物有效性,减少稻谷对土壤Pb的吸收富集。土壤理化条件对稻谷Cd富集系数有显著影响,富含有机碳、Al2O3、Fe2O3、CaO、MgO、S的土壤条件有利于阻断稻谷对土壤Cd的吸收,降低土壤Cd污染的生态风险。本项研究为开展水田土壤重金属污染治理修复、预测稻谷食用安全提供了重要的依据。  相似文献   

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