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1.
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   

2.
Distillery and tanneries are major source of heavy metals pollution in natural wetland sites in India. Present study deals with the heavy metals accumulation potential of Typha angustifolia and Cyperus esculentus growing in distillery and tannery effluent polluted wetland sites. The metal accumulation pattern in both macrophytes showed direct correlation with the metal content in sediments. Both macrophytes were observed root accumulator for Fe, Cr, Pb, Cu, and Cd. The metal accumulation in T. angustifolia was found higher than C. esculentus, and accumulation pattern was Fe > Mn > Cr > Zn > Pb > Cu > Ni > Cd. Simultaneously, chlorophyll, protein, cysteine, and ascorbic acid were also induced in T. angustifolia than C. esculentus. In addition, formation of multinucleolus in shoot of T. angustifolia was found an evidence of extra protein synthesis for tolerance under stress conditions. Hence, C. esculentus was observed potential but less tolerance for metals than T. angustifolia. Therefore, these wetland plants could be used for phytoremediation of heavy metals from wastewater.  相似文献   

3.
 Extensive irrigation by the effluents released from a paper mill near Nanjangud have led to the accumulation of heavy metals in the soil and different parts of the paddy crops. In this paper, the physicochemical characteristics of paper mill effluents and the accumulation of heavy metals (Cu, Zn, Pb, Co, Cd, Cr, and Ni) in the soil and different parts (root, leaf, and seed) of the paddy crops growing in the irrigated area are described and compared with the soil and paddy crops irrigated by natural waters (unpolluted). Chemical and biological oxygen demands of wastewater were found to be 437 and 1070 ppm respectively, which are beyond the tolerance limits set by Indian standards. The total dissolved and suspended solids are 1754 and 900 ppm respectively. The concentration of heavy metals (except Zn) in the seeds is remarkably less than that in the roots and leaves of the paddy crops. The heavy metal uptake by plants shows the greatest accumulation of Cu, Cr, Co, and Pb in the roots; Cd and Ni in the leaves; and Zn in the seeds of rice. The heavy metal content of the soil and their total uptake by paddy roots has the relation: Pb>Zn>Cu>Cd and Pb>Cu>Zn>Cd. Survival of paddy crops irrigated by polluted waters indicates tolerance to toxic heavy metals. In conclusion, since in many tropical countries the common diet of people is rice, the accumulation of toxic heavy metals in rice may lead to health disorders. Received: 18 July 1995 / Accepted: 24 February 1997  相似文献   

4.
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   

5.
Contamination of soils with heavy metals is widespread and poses a long-term risk to ecosystem health. Abandoned and active mining sites contain residues from ore-processing operations that are characterised by high concentrations of heavy metals. The distribution and mobility characteristics of heavy metals (As, Cd, Cu, Pb, and Zn) in paddy soil samples from Kočani Field (Macedonia) using ICP-EAS and a sequential extraction procedure was evaluated. The results indicate that highly elevated concentrations of As, Cd, Cu, Pb, and Zn were detected in the paddy soil sample from location VII-2 in the vicinity of Zletovo mine and Zletovska river in the western part of Kočani Field, which drains the untreated acid mine waters and mine wastes from the active Zletovo mine. The degree of contamination based on index of geoaccumulation (I geo) from strong to weak in the paddy soils samples is Pb > As > Cd > Zn > Cu. The mobility potential of heavy metals in all paddy soil samples increases in the order As < Cu < Pb < Zn < Cd. According to the results of the anthropogenic impact on the paddy soils, a further study on the heavy metal concentrations in rice and other edible crops, the remediation process of the paddy soils and a dietary study of the local population are needed.  相似文献   

6.
The study area covers two geologically different regions which have intensively been carpeted by tea plants in the eastern Black Sea. The rocks exposed in the region contain considerable amount of trace metals due to Upper Cretaceous massive sulfide formations and tertiary epithermal mineralizations. Tea plants that grow in soils derived from such mineralized rocks contain different concentrations of Cu, Pb, Zn, Fe, Cd, P, Al, Na, K, and S. The content ratios of most of the analyzed elements except Al are higher in basaltic and sedimentary rocks. To describe the transfer of metals from soil to tea leaf, the Freundlich-type model (log c plant = ac soil + log b) is used. The metal concentrations in leaves of tea plant in the studied soils are ranked as Zn > Cu > Pb > Al > Cd > Fe. The capacity of the plant to affect the metal accumulation decreased as follows: Fe > Cd > Pb > Cu > Zn > Al. Negative correlations were found between pH and availability of Cu, Pb, Zn, Mn, and Al elements by the tea plant. Experimental applications indicated that tea plant leaves growing on soils with high metal contents show some signs of toxicity. In soils where, particularly, ammonium sulfate fertilizer is used, metal uptake by the tea plant was found to be significantly higher as a result of extremely acidic character of the soil.  相似文献   

7.
The interaction between heavy metals and river sediment is very important because river sediment is the sink for heavy metals introduced into a river and it can be a potential source of pollutants when environmental conditions change. The Kumho River, the main tributaries of the Nakdong River in Korea, can be one of the interesting research targets in this respect, because it runs through different geologic terrains with different land use characteristics in spite of its short length. Various approaches were used, including mineralogical, geochemical, and statistical analyses to investigate the distribution and behavior of heavy metals in the sediments and their sources. The effect of geological factor on the distribution of these metals was also studied. No noticeable changes in the species or relative amounts of minerals were observed by quantitative X-ray diffraction in the sediments at different stations along the river. Only illite showed a significant correlation with concentrations of heavy metals in the sediments. Based on an average heavy metal concentration (the average concentrations of Cd, Co, Cr, Cu, Ni, Pb, and Zn were 1.67, 20.9, 99.7, 125, 97.6, 149, 298 ppm, respectively), the sediments of the Kumho River were classified as heavily polluted according to EPA guidelines. The concentrations of heavy metals in the sediments were as follows: Zn > Pb > Cu > Ni > Cr > Co > Cd. In contrast, contamination levels based on the average I geo (index of geoaccumulation) values were as follows: Pb > Cd > Zn > Cu > Co = Cr > Ni. The concentrations of heavy metals increased downstream (with the exception of Cd and Pb) and were highest near the industrial area, indicating that industrial activity is the main factor in increasing the concentrations of most heavy metals at downstream stations. Sequential extraction results, which showed increased heavy metal fractions bound to Fe/Mn oxides at the downstream stations, confirmed anthropogenic pollution. The toxicity of heavy metals such as Ni, Cu, and Zn, represented by the exchangeable fraction and the fraction bound to carbonate, also increased at the downstream stations near the industrial complexes. Statistical analysis showed that Pb and Cd, the concentrations of which were relatively high at upstream stations, were not correlated with other heavy metals, indicating other possible sources such as mining activity.  相似文献   

8.
The purpose of this study was to investigate the concentration levels of heavy metals in different species of the main three marine algal divisions from the Gulf of Aden coastal waters, Yemen. The divisions included Chlorophyta—green plants (Halimeda tuna, Rhizoclonium kochiamum, Caldophora koiei, Enteromorpha compressa, and Caulerpa racemosa species), Phaeophyta—brown seaweeds (Padina boryana, Turbinaria elatensis, Sargassum binderi, Cystoseira myrica, and Sargassum boveanum species), and Rhodophyta—red seaweeds (Hypnea cornuta, Champia parvula, Galaxaura marginate, Laurencia paniculata, Gracilaria foliifere, and species). The heavy metals, which included cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), Iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn), and vanadium (V) were measured by Atomic Absorption Spectrophotometer (AAs). The concentrations of heavy metals in all algal species are in the order of Fe >> Cu > Mn > Cr > Zn > Ni > Pb > Cd > V > Co. The results also showed that the uptake of heavy metals by different marine algal divisions was in the order of Chlorophyta > Phaeophyta > Rhodophyta. These heavy metals were several order of magnitude higher than the concentrations of the same metals in seawater. This indicates that marine alga progressively uptake heavy metals from seawater.  相似文献   

9.
Xiamen Bay (XMB) has received substantial loadings of pollutants from industrial and municipal wastewater discharged since the 1980s. To assess ecological risks and the current spatial changes of metal contaminants in bottom surface sediments, 12 samples were collected. Samples were subjected to a total digestion technique and analyzed by ICP–OES for Cu, Pb, Zn, Cr, and Cd, and by AFS for Hg and As. Among these metals, Zn had the highest values (68–268 mg kg−1), followed by Pb (27–71 mg kg−1), and lower concentrations were found for Cd (42–1,913 μg kg−1) and Hg (0–442 μg kg−1). In comparison with the average crustal abundance values, the results indicated that nearly half of the sediment samples of XMB and its adjacent areas were contaminated by Cd, Pb, Zn, and As. Furthermore, based on the modified BCR sequential extraction procedure, the chemical speciation of heavy metals (Cd, Cr, Cu, Pb, Zn, Hg, and As) in selected sediment samples were evaluated in this study. Data from BCR sequential extractions indicated that Cd posed a medium ecological risk, whereas, Cr posed low risk since its exchangeable and carbonate fractions were below 4%, and the mobility of heavy metals in XMB decreased in the order Cd > Pb > Cu > Zn > Hg > As > Cr. By applying mean effects range median quotients (mERMQ), the results showed that Yuandang Lagoon with mERMQ value >0.5 would be expected to have the greatest potential toxic risk in amphipod within XMB and its adjacent areas.  相似文献   

10.
Many studies have been conducted on model transfer in soil–plant systems. However, relatively little information is available on modeling metal transfer in soil–rice system and associated risk assessment in real paddy fields. Based on a random sampling method from Nanxun, Shengzhou and Wenling in Zhejiang province, China, 15 pairs of rice and the corresponding soil samples were respectively collected for analysis of heavy metals and soil pH. The results showed that the accumulation ability of rice for different heavy metals was significantly different (p < 0.05), and was in the order of Cd > Zn > Cu > Ni > Cr > Pb. The relationships of heavy metals in rice with those in soil, along with soil pH, were well described by linear regression models. Except for Pb, the contents of most metals in rice were positively correlated with those of the soil. Soil pH was negatively correlated with the contents of Cd, Zn and Ni in rice, and positively correlated with Pb in rice; however, it had less effect on Cr and Cu. Based on risk reference dose (RfD), the risk assessment data indicated that the rice grown in Zhejiang paddy fields does pose some potential Cd and Cr contamination risk to food safety; rice in Shengzhou posed light Ni risk.  相似文献   

11.
During the last two decades, the coastal environment of southeast India has experienced intense developments in industry, urbanization and aquaculture. Moreover, the 2004 mega tsunami has devastated this coast, thus affecting the coastal sediment characteristics. These two phenomena prompted a study to characterize the sediment, to understand the mechanisms influencing the distribution of heavy metals and to create baseline data for future impact assessment. Results showed that the coastal sediment was carpeted with a mosaic of sand and silty sand with a minor amount of clay. Heavy metal values showed maximum variation for Fe and minimum for Cd. Their average values showed the following decreasing trend: Fe > Cu > Zn > Pb > Cr > Ni > Cd. This study shows that the major source of metals at Kalpakkam coast are land-based anthropogenic ones, such as, discharge from industrial waste, agricultural waste, urban, municipal and slum sewage into the Buckingham canal, which in turn discharges into the sea through backwaters, particularly during northeast monsoon period. A clear signature of the role of backwater discharge increasing the concentration of a few metals in the coastal sediments during monsoon period was observed. Assessments of the degree of pollution, concentration factor (CF), geoaccumulation index (I geo) and pollution load index (PLI) have been calculated. CF values and I geo indicated that the coastal sediment is moderately polluted by Cu and Cd. Increase in Cu, Pb and Zn concentration during the monsoon period (October–January) compared to the rest of the year was noticed. Factor analysis and correlation among the heavy metals concluded that Cr, Ni, Cd and Fe are of crustal origin, whereas, Cu, Pb and Zn are from anthropogenic sources. Organic carbon content in the sediment increased during monsoon period, pointing to the role of land runoff and backwater discharge in enhancing its content. The study also elucidates the impact of the recent tsunami in depleting metal content in the coastal sediment as compared to the pre-tsunami period.  相似文献   

12.
The total concentrations and oral bioaccessibility of heavy metals in surface-exposed lawn soils from 28 urban parks in Guangzhou were investigated, and the health risks posed to humans were evaluated. The descending order of total heavy metal concentrations was Fe > Mn > Pb > Zn > Cu > Cr > Ni > Cd, but Cd showed the highest percentage bioaccessibility (75.96%). Principal component analysis showed that Grouped Cd, Pb, Cr, Ni, Cu and Zn, and grouped Cr and Mn could be controlled two different types of human sources. Whereas, Ni and Fe were controlled by both anthropogenic and natural sources. The carcinogenic risk probabilities for Pb and Cr to children and adults were under the acceptable level (<1 × 10−4). Hazard Quotient value for each metal and Hazard Index values for all metals studied indicated no significant risk of non-carcinogenic effects to children and adults in Guangzhou urban park soils.  相似文献   

13.
The present study deals with the characterization of effluent released from sponge iron industries and distribution of heavy metals in soil and macrophytes near to effluent discharge channel. Apart from this, accumulation of heavy metals in nearby soil and vegetation system irrigated with effluent-contaminated water is also the subject of this study. Physico-chemical analysis of effluent reveals that the concentration of total suspended solids (TSS), total hardness (TH), iron (Fe2+), and oil and grease are greater than the IS (1981) norms for discharge of water into inland water body. The soil along the sides of the effluent channel also shows higher concentration of heavy metals than the background soil. The enrichment of the heavy metals are in the order of Chromium (Cr) > Iron (Fe) > Manganese (Mn) > Zinc (Zn) > Copper (Cu) > Cadmium (Cd). Macrophytes growing along the sides of the effluent channel also show significant accumulation of heavy metals almost in the same order as accumulated in soil. Higher uptake of heavy metals by these varieties reveals that these species can be used for future phytoremediation. The effluent as well as contaminated water is extensively used for irrigation for growing vegetables like tomato (Lycopersicon esculatum) in the surrounding areas. Heavy metal accumulation in this agricultural soil are in the sequence of Cr > Fe > Mn > Zn > Cu > Cd. More or less similar type of accumulation pattern are also found in tomato plants except Fe and Zn exceeding Cr and Mn. Transfer Factor of heavy metals from soil to tomato plants (TFS) shows average value of <1, suggesting less uptake of heavy metals from soil. Among the plant parts studied, fruit shows least accumulation. Although tomato plants show some phenotypic changes, the survival of tomato plants as well as least accumulation of metals in fruit reveals their tolerance to heavy metals. Therefore it may be suggested that this plant can be grown successfully in the heavy metal contaminated soil. Further research work on in situ toxicity test will be necessary in order to identify the most resistive variety on this particular type of contaminated site.  相似文献   

14.
Sixteen soil samples were collected from the vicinity of an abandoned lead–zinc mine in Shangyu City, eastern China, and the heavy-metal speciation and wheat phytotoxicity in the soils were studied. The results showed that the concentrations of free Cu2+, Zn2+, Cd2+ and Pb2+ were highly variable and ranged from <0.01 to 0.32, 0.06 to 10.62, <0.01 to 1.40 and 0.02 to 37.10 μmol l−1, respectively. The concentrations of soluble Cu, Zn, Cd and Pb ranged from 0.38 to 3.24, 0.72 to 78.74, <0.01 to 1.95 and 0.15 to 639.34 μmol l−1, respectively. The general trend of mean solid/liquid partition coefficient and percentage of free metal ion to total soluble metal concentration were Cu > Pb > Zn > Cd and Cd > Zn > Cu > Pb, respectively. Stepwise multiple linear regression with pH, log(total metal) and log(organic matter) showed that log(total metal) was an important factor that controlled log(free metal ion) and log(soluble metal). Of the variability in log(free Cu2+), log(free Cd2+) and log(free Pb2+), 55.2, 58.6 and 64.3% could be explained by log(total Cu), log(total Cd) and log(total Pb) alone, respectively. Of the variability in log(soluble Cu) and log(soluble Cd), 77.1 and 72.5% could be explained by log(total Cu) and log(total Cd) alone, respectively. Wheat root length was controlled by the various metals with different free and soluble concentrations, and 99.2% of the variability in root length could be explained by concentrations of free and soluble Pb, soluble Cu and total Zn in the soils.  相似文献   

15.
Heavy metal pollution of soils has become a major concern in China as a consequence of rapid urbanization and industrialization in recent years. However, the evaluation on soil heavy metal pollution in Shenyang, the largest heavy industrial base city in China, has not yet been conducted. In this study, accumulation, chemical speciation, and vertical distribution Cu, Zn, Pb and Cd in soils were studied and pollution condition was assessed in Tiexi Industrial District of Shenyang, the largest and oldest industrial zone in Northeastern China. The results showed that in topsoil, the average concentration of total Cu, Zn, Pb, and Cd was 209.06, 599.92, 470.19 and 8.59 mg kg−1, respectively, much higher than the national threshold limit. The values of pollution index and integrated pollution index showed that the pollution level was Cd > Cu > Zn > Pb, and Cd, Cu and Zn belong to heavy pollution level. The residual, Fe and Mn oxide-bound, and organic-bound species accounted for about 90%, while carbonate-bound and exchangeable species accounted for about 10%. This study indicates that the soils in the industrial zone were widely and extremely polluted by multi-heavy metals as a result of long-term industrial activities.  相似文献   

16.
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   

17.
The presence of heavy metal concentrations was examined in natural sediments from four sites along the Jajrood river in northeast of Tehran, the capital of Iran. Besides determination of elemental concentrations (Pb, Cu, Zn, Cd, Ni and Cr), X-ray fluorescence and X-ray diffraction tests were carried out to determine other chemical components in these adsorbents. Also the ability of sediments to adsorb these heavy metal ions from aqueous solutions was investigated. Results show that the extent of adsorption increases with increase in adsorbent concentration. The amount of adsorbed Pb, Cu and Zn in sediments was much greater than that of the other metals, and Cr was adsorbed much less than others. The adsorbabilities of sediments to heavy metals increased in the order of Pb > Cu > Zn > Cd > Ni > Cr. Based on the adsorption data, equilibrium isotherms were determined at selected areas to characterize the adsorption process. The adsorption data followed Freundlich and Langmuir isotherms in most cases. Correlation and cluster analysis was performed on heavy metals adsorption and sediment components at each site to evaluate main adsorbing compounds in sediments for each metal. Results demonstrated that heavy metals sorption is mostly related to load of organic matter in the Jajrood river sediments.  相似文献   

18.
Sixty-five sediment samples and 25 water samples were collected from Al-Mujib reservoir, central Jordan, in order to investigate the heavy metal and ionic contamination assessment. Therefore, to achieve this aim, water and sediment samples were collected during winter and summer seasons (2007) from Al-Mujib reservoir and the areas surrounding it. The study shows that there are elevated levels of SO4 2−, Cl− and Na+ in reservoir water, which might originate from anthropogenic activities in the reservoir catchment area. In addition, the reservoir water has higher total hardness (TH) values together with high Ca and Mg contents. This might be attributed to pH of reservoir water and the nature of the rocks exposed in the catchment area. The average levels of heavy metals in reservoir sediments are Fe = 14,888.1, Cu = 17.8, Zn = 88.6, Ni = 38.7, Cd = 4.4, Mn = 337.9 and Pb = 6.1 mg/kg, which are lower than that observed in Wadi Al-Arab reservoir, northern Jordan. The values of enrichment factor are Cd = 35.5, Ni = 3.02, Zn = 2.54, Cu = 1.26, Mn = 1.2 and Pb = 0.57; these values indicate that heavy metals in sediments of Al-Mujeb reservoir have a different anthropogenic incrimination inputs. The study showed that the sediments are polluted with Cd, relatively contaminated with Ni and Zn and uncontaminated with respect to Mn, Pb and Cu.  相似文献   

19.
The present study was conducted to investigate the concentrations of heavy metals (HMs) in deep groundwater from coal mining area, including cadmium (Cd), chromium (Cr), copper (Cu), zinc (Zn), lead (Pb), and nickel (Ni). The samples were collected from different aquifers in four coal mines of northern Anhui province, China, which were unconsolidated formation (UF), coal measure aquifer (CA), Taiyuan limestone aquifer (TA), and Ordovician limestone aquifer (OA), respectively. HM concentrations from the four different sources were analyzed by atomic absorption spectrometer, and were found in the order of Zn>Ni>Pb>Cu>Cd>Cr (in UF), Ni>Zn>Pb>Cu>Cr>Cd (in CA), Ni>Zn>Pb>Cu>Cd>Cr (in TA), and Zn>Ni>Pb>Cu>Cr>Cd (in OA), respectively. Concentrations of Cu, Zn, and Cr were found within the quality guidelines set by Bureau of Quality and Technical Supervision of China (GB/T 14848-93) and World Health Organization, while the concentrations of Cd, Pb, and Ni were higher than their respective permissible limits. The enhanced concentrations of Ni, together with Cr, were considered to be affected by anthropogenic sources, since they both had high variable coefficient. Moreover, the inter-dependence of HMs and their pollution sources were further discussed using statistical techniques, including one-factor analysis of variance, Pearson correlation analysis, and principle component analysis.  相似文献   

20.
The chemical composition of 29 bore well water samples throughout the Kalpakkam region, South India, was determined to identify the major hydrogeochemical processes and the suitability of groundwater for domestic and irrigation purposes. The hydrochemical data were analyzed with reference to World Health Organization (WHO) standards and their hydrochemical facies were determined. The Piper plot shows that most of the groundwater samples fall in the field of mixed calcium–sodium–bicarbonate type followed by sodium–chloride, calcium–bicarbonate and mixed calcium–magnesium–chloride water types. The concentration of total dissolved solids exceeds the desirable limit in about 14% of samples; alkalinity values exceed the desirable limit in about 34% of the samples. The concentration of sulphate is well within the desirable limit at all the locations. The dominance of various heavy metals in the groundwater followed the sequence: Zn > Fe > Mn > Cu > Ni > Pb > Cr > Cd. Among the metal ions, the concentration of chromium and cadmium are within the permissible limit. Data are plotted on the US Salinity Laboratory diagram, which illustrates that most of the samples fall in the field of high salinity and low sodium hazard, which can be used to irrigate salt tolerant and semi-tolerant crops under favorable drainage conditions. Based on the analytical results, chemical indices like sodium adsorption ratio and residual sodium carbonate were calculated which show that most of the samples are good for irrigation.  相似文献   

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