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1.
Pollution by heavy metals presents an environmental concern, and their toxicity threats soil, water, animals and human health. Phytoremediation can be used as a solution to remediate contaminated soils. The aim of this study was to identify native plants collected from tailings: material of Pb–Zn mine sites of Fedj Lahdoum and Jebel Ressas (two abandoned mines located, respectively, in the northwest of Tunisia and in the south of Tunis City). The tolerance of plant to heavy metals (lead, zinc and cadmium) is evaluated. Soil samples were collected and analyzed for Pb, Zn and Cd concentration. The total soil Pb, Zn and Cd are, respectively, reached 6132 mg kg?1, 11,052 mg kg?1 and it doesn’t exceed 479 mg kg?1 for Cd. The highest content of Zn in plants was detected in shoots of Rumex bucephalophorus (1048 mg kg?1), and the highest Pb concentration was detected in roots of Chrysopogon zizanioides (381 mg kg?1), while for Cd Silene colorata it accumulated the highest content in roots (51 mg kg?1). From all plants, only 12 have a translocation factor for Pb which is higher than one. Among all plants, only 17 have a translocation factor that is higher than one for Zn, while for Cd only 13 plants indicate TF > 1. As for the biological absorption coefficient, all samples indicate a rate which is lower than one. These plants can be primarily hyper accumulators and useful in remediation of lead- and zinc-contaminated soils after further biochemistry researches in mechanism of accumulation and translocation of heavy metals in plants.  相似文献   

2.
The concentration and dynamic of soil trace metals in natural ecosystems, in particularly, is dependent on the lithology of parent rock as well as topography and geopedological processes. To ascertain more knowledge for this dependency, soils on three parent rocks involving peridotite, pegmatite, and dolerite in two contrasting topography aspects were investigated. The total values of Fe, Mn, Zn, Cu, and Ni were determined and compared for different soil pedons. The concentration of Fe, Mn, and Ni were highest in soils developed from peridotite (127, 1.8 g kg?1, and 218 mg kg?1, respectively), intermediate in soils derived from dolerite (81, 1.3 g kg?1, and 166 mg kg?1, respectively), and least in soil developed from pegmatite (50, 0.23 g kg?1, and 20 mg kg?1, respectively). The values of Zn and Cu, originated from different parent rocks, were in order of dolerite (78 mg kg?1) > peridotite (77 mg kg?1) > pegmatite (28 mg kg?1) and pegmatite (121 mg kg?1) > peridotite (111 mg kg?1) > dolerite (28 mg kg?1), respectively. For most of the studied pedons, profile metals distribution differed among the soils: The values of Fe, Cu, and Ni were enriched in the cambic horizons mainly as result of release, mobilization, and redistribution of the studied metals during geopedological processes, whereas those of Zn and Mn were concentrated in the surface horizons. Probably due to greater weathering rate of trace metal-bearing rocks on north-facing slope, the content of the trace metals along with the geoaccumulation index (I geo) and the degree of soil contamination (C d) were higher than on south-facing slope. Based on assessment of soil pollution indices, the soils were categorized as unpolluted [I geo ≤ 0 (class 0)], unpolluted to moderately polluted levels [0 < I geo < 1 (class 1)], and very low [C d < 1.5 (class 0)] to low degree of contamination [1.5 < C d < 2 (class 1)].  相似文献   

3.
In this work, the total and each fraction concentration of toxic metals (Pb, Zn, Cu and Cd) in soils as well as in plants from a typical metallurgical industrial area in southwest of China were determined. The obtained experimental results demonstrated that the total toxic metal content in contaminated soils was in the order of Zn > Pb > Cu > Cd. Modified microwave-assisted extraction showed that the distributions of each fraction of toxic metals in soils were different and some soil properties may play a role in the fraction distributions. The content of Cu, Zn, Cd and Pb in different vegetables ranged from 9.82 ± 1.02 to 39.3 ± 1.13 mg kg?1, 1,321 ± 10.50 to 3,153 ± 11.30 mg kg?1, 4.47 ± 0.21 to 18.9 ± 0.37 mg kg?1 and 28 ± 1.2 to 102 ± 1.5 mg kg?1, respectively. And the accumulation of toxic metals in plants was in the order of Cd > Zn > Cu > Pb. The bioconcentration factor (BCF) values of Cd, Zn, Cu and Pb in the different tissues of plants were in the range of 0.03–0.43, 0.027–0.35, 0.014–0.12 and 0.004–0.051, respectively. The distribution of each toxic metal in plants indicated that the ability for plants to accumulate toxic metals in different tissues followed the sequence of leaf > stem.  相似文献   

4.
A pot experiment was conducted to monitor the dynamic response of photosynthesis of Amorpha fruticosa seedlings to different concentrations of petroleum-contaminated soils from April to September. The results showed that the photosynthetic rates, stomatal conductance and transpiration rate of seedlings significantly decreased in 5–20 g kg?1 petroleum-contaminated soil during the three given sampling period of July 31 (early), August 30 (mid-term) and September 29 (late). However, the intercellular CO2 concentration significantly increased in 10 g kg?1 contaminated soil, while declined in 20 g kg?1 contaminated soil during the early sampling period as well as in 20 g kg?1 contaminated soil during the late sampling period. The leaf relative water content of seedlings significantly increased in 20 g kg?1 contaminated soil during the early sampling period, while it dropped dramatically in 15–20 g kg?1 contaminated soil during the late sampling period. The contents of chlorophyll a, chlorophyll b and the total chlorophyll of seedlings showed a sharp decline during the three sampling periods in contaminated soil. Comprehensively, considering the negative effects of petroleum on the photosynthesis, growth performance and remediation effect on petroleum of A. fruticosa seedlings, this plant was tolerant of petroleum-contaminated soil and was potentially useful for the phytoremediation of petroleum-contaminated sites in northern Shaanxi, China.  相似文献   

5.
At present, the prior-established threshold values are widely used to classify contaminated agricultural soils with heavy metals under the cultivation of a variety of crops, without considering the different sensitivity of plants to heavy metals. Evaluation of the characteristics of cadmium transfer from a polluted calcareous soil to cultivated wheat crop and assessment of the efficiency of using the threshold values to reflect the soil pollution risk by cadmium in Zanjan Zinc Town area at the northwest of Iran were the goals of this study. Totally, 65 topsoil (0–20 cm) and corresponding wheat samples of an agricultural region in the proximity of a metallurgical factory were collected and analyzed for cadmium concentration. The results revealed that industrial activities strongly control cadmium distribution in the studied soils. Relatively high bioavailable cadmium contents (mean 0.77 mg kg?1) were found in the soils, notwithstanding their alkalinity. It was observed that just 22.5% of the studied area around the Zinc Town is covered by polluted soils with the cadmium concentration exceeding the maximum permissible concentration of 5 mg kg?1, whereas cadmium concentration in wheat grains of 19 sampled plants is higher than the threshold value of 0.2 mg kg?1. Among these polluted plants, a total of eight samples were grown in areas classified as unpolluted soils with cadmium, based on the soil threshold value. It seems that this misclassification of polluted soils is mainly related to the crop sensitivity to heavy metals uptake from the soil which should be considered.  相似文献   

6.
Sewage sludge usually contains significant amount of Zinc (Zn) and is widely used in agricultural lands. A laboratory experiment was performed to determine Zn desorption characteristics in unamended and amended soils with sewage sludge. Ten calcareous soils were amended with 1 % (w/w) sewage sludge. Amended and unamended soils were incubated at field capacity at 25 ± 1 °C for 1 month. After incubation, the kinetics of Zn desorption in amended and unamended soils were determined by successive extraction with DTPA-TEA (diethylenetriaminepentaacetic acid-triethanolamine) in a period of 1–504 h at 25 ± 1 °C. The results of kinetics study showed that extracted Zn and desorption rate constants in the amended soils were significantly (p < 0.01) higher than in the unamended soils. The results showed that Zn desorption increased from 201 to 343 % in amended soil with respect to unamended soils. The amounts of desorbed Zn in the unamended soils ranged from 3.73 to 8.79 mg kg?1, while the amounts of desorbed Zn in amended soils ranged from 11.47 to 17.66 mg kg?1. Desorption kinetics of Zn in two soils conformed fairly well to first-order, parabolic diffusion and power function equations. The results of stepwise regression analysis indicated that calcium carbonate equivalent and clay could be used to estimate Zn desorption characteristics in DTPA-TEA solution in the amended and unamended calcareous soils. It can be concluded that sewage sludge applied to calcareous soils may enhance the source of Zn for the plants.  相似文献   

7.
Genetically engineered Pseudomonas putida reporters (BMB-PL and BMB-ME), which, respectively, carried phnS-luxCDABE and merR-egfp cassette, were used to determine bioavailable phenanthrene and mercury. Over a spiked range of concentrations and aged for 6 days in red soil samples, the reporters were tested to determine the optimal assay conditions and the bioavailable phenanthrene (0–60 mg kg?1) and Hg2+ (0–240 μg kg?1) were evaluated by the signal of the relative fluorescent units and relative luminescence units. Single contamination was carried out and good correlations were obtained between signal strength and pollutant concentrations, whereas interference and bioavailability repression were observed in dual-contamination experiments. Other heavy metal ions at nanomolar level did not interfere with BMB-ME measurement while BMB-PL showed some response to other polycyclic aromatic hydrocarbons or their intermediate products during degradation. Comparing high-performance liquid chromatography methods with the bacterial reporters, both BMB-ME and BMB-PL appeared to have a detection limit (mercury <40 μg kg?1; phenanthrene <24 mg kg ?1) similar to the instrumental analysis. Although physical parameters may affect the interaction of pollutants with bioreporter cells, advantages include the inherent biological relevance of the response, rapid response time, and potential for field deployment. Our results strongly suggest that the BMB-ME and BMB-PL bioreporters constitute an adaptable system for easily detecting the bioavailability of mercury and phenanthrene in the red soils.  相似文献   

8.
The goal of this study was to evaluate the soil properties and their modifications within the rhizosphere of spontaneous vegetation as key factors to assess the phytomanagement of a salt marsh polluted by mining wastes. A field survey was performed based on a plot sampling design. The results provided by the analyses of rhizospheric soil (pH, electrical conductivity (EC), organic carbon, total nitrogen, etc.) and metal(loid)s’ phytoavailability (assessed by EDTA) were discussed and related to plant metal uptake. The averages of pH and EC values of the bulk soil and rhizospheric samples were in the range of neutral to slightly alkaline (pH 7–8) to saline (>2 dS m?1), respectively. Heavy metal and As concentrations (e.g. ~600 mg kg?1 As, ~50 mg kg?1 Cd, ~11,000 mg kg?1 Pb) were higher in the rhizosphere for both total and EDTA-extractable fraction. Phragmites australis uptaked the highest concentrations in roots (e.g. ~66 mg kg?1 As, ~1,770 mg kg?1 Zn) but not in shoots, for which most of plant species showed low values for Zn (<300 mg kg?1) but not for Cd (>0.5 mg kg?1) or Pb (~20–40 mg kg?1). Vegetation distribution in the studied salt marsh looked to be more affected by salinity than by metal pollution. The free availability of water for plants and the incoming nutrient-enriched effluents which flow through the salt marsh may have hindered the metal(loid)s’ phytotoxicity. The phytomanagement of these polluted areas employing the spontaneous vegetation is a good option in order to improve the ecological indicators and to prevent the transport of pollutants to nearby areas.  相似文献   

9.
The heavy metal content of particulate matter was investigated in the city of Guangzhou in southern China. Samples of urban foliage near 36 pedestrian bridges were analyzed to determine their Zn, Pb, Cu, Cr, V, Ni, and Co contents after digestion in a mixture of strong acids composed of HNO3, HCl, HF, and HClO4. The results revealed a severe heavy metal pollution compared with the background levels in Chinese soils, except for Co and V. The mean concentrations of Zn (1,024 mg kg?1), Pb (233 mg kg?1), Cu (203 mg kg?1), Cr (118 mg kg?1), V (41.9 mg kg?1), Ni (41.4 mg kg?1), and Co (11.3 mg kg?1) in urban dust were higher than the reference levels, and were highest in samples located near high-traffic areas. Multivariate statistical methods (correlation analysis, principal-components analysis, and clustering analysis) were used to identify the possible sources of the metals. Three main pollutant sources are assigned: Zn, Cu and Ni levels were strongly correlated and were possibly related to combustion processes and vehicles; Pb, Cr and Co were mainly derived from traffic sources, combined with soil sources; and V mainly originated from natural sources.  相似文献   

10.
Pollution from mining activities is a significant problem in several parts of the Republic of Macedonia. A geochemical study of the surficial sediments of Lake Kalimanci in the eastern part of the Republic of Macedonia was carried out to determine their elemental compositions and to evaluate the pollution status of lake sediments by employing an enrichment factor (EF). The major and trace element contamination in surficial lake sediments was studied to assess the effects of metalliferous mining activities. The mean concentrations of major elements (wt%) Si 23.5, Al 7.9, Fe 6.6, Mg 1.3, Ca 3.8, Na 1.1, K 2.3, Ti 0.4, P 0.2, Mn 0.6 and trace elements ranged within Mo 1.0–4.6 mg kg?1, Cu 144.4–1,162 mg kg?1, Pb 1,874–16,300 mg kg?1, Zn 2,944–20,900 mg kg?1, Ni 21.7–79.3 mg kg?1, Cd 16.5–136 mg kg?1, Sb 0.6–3.6 mg kg?1, Bi 3.0–24,3 mg kg?1 and Ag 1.4–17.3 mg kg?1. The EF ranged within 0.12–590.3. Among which, Cd, Pb, Zn and As have extremely severe enrichment. The data indicate that trace elements had extremely high concentrations in Lake Kalimanci surficial sediments owing to the anthropogenic addition of contaminants.  相似文献   

11.
The role of rhizospheric microbes of giant reed (Arundo donax L.) in Cr uptake from hydroponic culture was investigated. The control group was exposed to Cr in range of 25–100 mg L?1 containing a control itself (with no metal addition). The experimental group received same Cr treatments, but in addition was exposed to antibiotic treatment in order to inhibit rhizospheric bacteria. The range of Cr accumulated in the roots was 3–7.65 mg L?1; in stem it ranged 2.15–42.4 mg kg?1; while in leaves, the range of Cr content was 13.7–15 mg kg?1. Overall, Cr uptake in A. donax (without rhizobacterial inhibition) was root < leaf < stem. However, the amount of Cr uptake in plants with rhizobacterial inhibition was significantly less (~4.6-folds in 100 mg L?1 Cr treatment) than those without such inhibition clearly highlighting that rhizobacterial inhibition decreased the Cr uptake. The experimental results clearly demonstrated that the inhibition of the rhizobacterial populations had great influence on the Cr uptake. However, Cr uptake could not be completely inhibited as some metal uptake was observed after the rhizobacterial inhibition although it was significantly less than the Cr uptake of plants without such inhibition.  相似文献   

12.
Aluminium smelters are major sources of F emission to the environment. We studied, in laboratory experiments, the sorption and desorption of fluoride on organic and mineral horizons of soils located within 2 km from one of these factories, situated in the northern coast of Galicia (NW Spain). The soils, developed from granite, are acid (pH H2O 3.9–5.5), rich in organic matter (4–16 % C in the A horizon) and most A horizons have high Al saturation in the exchange complex. All samples showed a notable F sorption, between 1,066 and 1,589 mg kg?1, after adding 200 mg F L?1, which accounts for 53–80 % of F added. The sorption was slightly higher in the A horizons than in the respective organic horizons (differences of up to 194 mg kg?1). The fluoride sorption upon addition of 200 mg F L?1 correlated significantly (p < 0.05) with soil pH in water (r = ?0.77), iron extracted by acid ammonium oxalate (r = 0.68), aluminium plus iron extracted by acid ammonium oxalate (r = 0.63), exchange aluminium (r = 0.52) and clay percentage in soil (r = 0.76). The F sorption fitted to both Langmuir and Freundlich models. Desorbed F accounted for only 12–22 % of sorbed fluoride and correlated (p < 0.05) negatively with non-crystalline (extracted by acid ammonium oxalate) Fe (r = ?0.51) and clay content (r = ?0.74) and positively with organic matter (r = 0.69) and with the effective cation exchange capacity of the soil (r = 0.50).  相似文献   

13.
Greenhouse tests were conducted to study the effect of chelates on the phytoextraction of cadmium and lead, and the rhizodegradation of used engine oil present as a mixed contaminant in a sandy soil. Indian mustard plants were grown in test pot soil for 30 days and chelates ethylenediamine tetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (EDDS) were individually applied to the test soil. The soil was spiked earlier with 50 mg kg?1 of CdCl2, 500 mg kg?1 of PbCl2 and 500 mg kg?1 of used engine oil to form the mixed soil contaminant. At the same concentration of chelates, EDTA was found to be more effective than EDDS in increasing the concentration of metal contaminants Cd and Pb in the plant. Compared to EDDS, EDTA was also more effective in promoting rhizodegradation of the organic contaminant formed by used engine oil. The study demonstrated that the application of chelates to soils containing mixed contaminants such as heavy metals (Cd and Pb) and organics (used engine oil) can simultaneously assist metal accumulation at higher concentrations in the biomass of Indian mustard plant and also reduce the amount of used engine oil in the soil through rhizodegradation.  相似文献   

14.
Initial risk assessment characterization carried out in a tailing pond, called “El Lirio”, came from metal mining showed that these soils have low fertility; low amounts of nitrogen, organic carbon, phosphorous, and carbonates; and high concentrations of total metals (10,719 mg Zn kg?1, 2,821 mg Pb kg?1, and 30 mg Cd kg?1), diethylenetriaminepentaacetic acid (DTPA)-extractable metals, and water-soluble metals, which suggest an urgent need for remediation. Different amendments have been selected, including three anthropogenic wastes: pig manure, sewage sludge, and lime; all were added to the constructed plots in the mine pond. The objectives were to: (1) reduce acid mine drainage, metal mobilization, and toxicity and (2) provide nutrients which enable plant establishment. Results showed an increase in pH, electrical conductivity, total nitrogen, organic carbon, and equivalent calcium carbonate contents. Although water- and DTPA-extractable Zn, Pb, and Cd were reduced, there was an increment in DTPA- and water-extractable Cu due to the addition of organic matter. The amendments also enhanced the establishment of plants. This study constitutes the first stage of a successful remediation programme that can be applied in similar mining areas. The chemical stabilization of metals is a cost-effective alternative for remediation of mine areas in SE Spain.  相似文献   

15.
Aljustrel mine is located in SW Portugal, in the western sector of the Iberian Pyrite Belt. The Aljustrel village was developed around the exploitations of massive polymetallic sulphides that occur in the area (4 orebodies mined, 2 in exploration phase). The pyrite ore was extensively exploited from 1850 to 1993, when production was discontinued. A mining restart occurred in 2008, only during a few months. The objectives of the study were to assess the levels of soil contamination, to determine associations between the different chemical elements and their spatial distribution, as well as to identify possible sources of contamination that can explain the spatial patterns of soil pollution in the area. Principal component analysis combined with spatial interpretation successfully grouped the elements according to their sources and provided evidence about their geogenic or anthropogenic origin. From this study, it is possible to conclude that soils around Algares/Feitais tailing deposits, Estéreis and Águas Claras mine dams and S. João mine show severe contamination. The highest concentrations of As (up to 3,936 mg kg?1) and certain heavy metals (up to 321.7 mg kg?1 for Bi, 5,414 mg kg?1 for Cu, 20,000 mg kg?1 for Pb, 980.6 mg kg?1 for Sb, and 22 mg kg?1 Cd) were obtained near Algares area while the highest concentration of Cd (up to 61.6 mg kg?1) and Zn (up to 20,000 mg kg?1) were registered in samples collected in the S. João area. The highest pollution load index (>4.0) was recorded at the Algares area where the metal concentrations exceed typical soil background levels by as much as two orders of magnitude.  相似文献   

16.
Rhizosphere has different chemical and biological properties from bulk soils. Information about copper (Cu) desorption characteristics in the rhizosphere soils is limited. The objectives of this study were to determine Cu desorption characteristics and the correlation of its parameters with Cu extracted by DTPA-TEA, AB-DTPA and Mehlich 3 in bulk and rhizosphere amended soils with sewage sludge (10 g of sewage sludge was added to 1 kg soil) under greenhouse conditions in a rhizobox. The kinetics of Cu desorption in the rhizosphere and bulk was determined by successive extraction with DTPA-TEA in a period of 1 to 504 h at 25 ± 1 °C. The results showed that Cu extracted using several chemical extractants in the rhizosphere were significantly (P < 0.05) lower than in the bulk amended soils. In addition, Cu extracted using successive extraction in the rhizosphere were significantly (P < 0.01) lower than in the bulk soils. The best model for describing extraction data for the bulk and rhizosphere soils was the parabolic diffusion equation. Desorption kinetics of Cu conformed fairly well to first order and power function models. The results indicated that Cu diffusion rate in the wheat rhizosphere soils lower than in the bulk soils. Cu desorption rate in parabolic diffusion ranged from 0.326 to 0.580 mg kg?1 h?1/2 in the bulk soils, while it ranged from 0.282 to 0.490 mg kg?1 h?1/2 in the rhizosphere soils. Significant correlation (P < 0.05) between determine R values of parabolic diffusion and Cu desorption during 504 h with extracted Cu using DTPA-TEA, AB-DTPA and Mehlich 3 were found in the bulk and the rhizosphere soils. The results of this research revealed that Cu desorption characteristics in the wheat rhizosphere soils are quite different from bulk soils amended with sewage sludge.  相似文献   

17.
The chemical analysis of plants and soils is a frequently used approach in understanding a serpentine ecosystem. Studies on vegetation growth in serpentine soils focused on various plant species for remediation purposes of soil contamination with heavy metals, emphasizing their role in the metal extraction or stabilization in the soil. The aims of this study were to measure the concentrations of Cr, Mn, and Ni in the soils and plants and to elucidate the phytoremediation potential of the studied plants. This study was performed at an abandoned site of serpentine mining in eastern Taiwan. Seven plant species were collected for analysis of Cr, Mn, and Ni, including Crotalaria micans, Miscanthus floridulus, Leucaena leucocephala, Bidens pilosa, Pueraria lobata, Melilotus indicus, and Conyza canadensis. The Cr and Ni concentrations in all studied plants were higher than those in general plants. In all species, the mean concentrations of Cr, Mn, and Ni in the shoots were lower than those in the root. None of the collected specimens exhibited hyperaccumulation of Cr, Mn, and Ni. All studied species may be used to remediate contaminated soils through phytostabilization of Cr and Mn, whereas M. floridulus and M. indicus are appropriate plants for phytostabilization of Ni. However, C. micans, L. leucocephala, B. pilosa, P. lobata, and C. canadensis have the potential to remove Ni from contaminated soils for the purpose of phytoextraction.  相似文献   

18.
Industrial development, intensive agriculture and fast urbanization have caused the metal contents of soils to increase to many times the allowable limits. To assess this impact on urban and rural soils, we quantified the Cd, Cr, Cu, Pb, Ni and Zn contents of 258 soil samples from the Recife metropolitan region (RMR). The objectives of the study were to estimate the probability of ecological risk, to determine the spatial pattern of the metals’ accumulation in the soil and to identify potential sources for the metals using a multivariate geostatistical approach. Mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in soils were 65.2, 17.9, 16.5, 12.8, 6.3 and 1.5 mg kg?1, respectively. The results demonstrated that the Cd was anthropogenic in origin, the Cr and Ni were lithogenic (natural) in origin and the Cu, Pb and Zn were mixed in origin. Cd contaminated 91% of the samples; the median content of Cd (1.4 mg kg?1) was three times the quality reference value for soil. The Cd contents of sugarcane fields exceeded the allowable limit (3.0 mg kg?1) for agricultural areas. The spatial variability of the metals in the RMR showed that metallurgy, cement production, vehicle exhaust and vehicular traffic were the main sources of metals in urban areas, while phosphate-based fertilizers were the main sources in rural areas. More than 80% of the metropolitan region surveyed in the study was at moderate to high ecological risk.  相似文献   

19.
Understanding of the landscape response to agricultural practices mainly in relation to soil trace metals requires particular attention. Consistent with this, the trend and possible pollution of total and DTPA fraction of Mn, Zn, Cu, and Cd in the agricultural soils developed on different landscape positions involving piedmont alluvial plain (PAP), river alluvial plain (RAP), plateau (PL), and lowland (LL) were investigated. The content of the metal in different soil profiles, grouped by landscape positions, varied in the following orders: total and DTPA-Mn as LL > PAP > RAP > PL, total Zn and Cu as PAP > RAP > LL > PL, total Cd as RAP > PAP > PL > LL, DTPA-Zn as RAP > PAP > PL > LL, and DTPA-Cu as RAP > LL > PL > PAP. A wide variation in the total fraction of Mn (89–985 mg kg?1), Zn (24–152 mg kg?1), Cu (8–27 mg kg?1), and Cd (0.6–1.7 mg kg?1) and in the DTPA fraction of Mn (1.2–11 mg kg?1), Zn (0.3–4.4 mg kg?1), Cu (0.3–3 mg kg?1), Cd (0.03–0.09 mg kg?1) observed as a result of the effects of agricultural practices and landscape properties. The values of both total and DTPA-extractable Mn, Zn, and Cu were enriched in the AP horizon probably due to anthropogenic activities particularly successive use of agrochemical compounds and manure during numerous years. Using soil pollution indices [single pollution (PI) and comprehensive pollution (PIN)], the study soils were categorized mainly as low to moderate pollution and Zn was identified as the major element affecting on the yield of these indices.  相似文献   

20.
Bio-concentration of elements such as Mo, As, Se, Fe, Cu, Zn, Ni and Pb was analyzed in spring onion (Allium fistulosum L.) in three different locations of central Punjab, Pakistan. At location GW, relatively low level of hazardous elements was found in spring onion, suggesting that groundwater is a safe source of water for irrigating food crops. The pH of soil at wastewater irrigation was found less acidic (pH 7.4) than the other sites. The range of concentration in the different samples of spring onion was as follows: 6.15–8.16 mg kg?1 for Mo, 2.77–4.28 mg kg?1 for As, 0.395–0.705 mg kg?1 for Se, 36.73–48.17 mg kg?1 for Fe, 10.58–16.26 mg kg?1 for Cu, 28.87–39.79 mg kg?1 for Zn, 6.66–8.75 mg kg?1 for Ni and 4.33–6.09 mg kg?1 for Pb, respectively. High bio-concentration of Zn (15.37) from soil to spring onion was found at canal water irrigated location. The estimated daily intake of metal for spring onion was less, but the health risk index was higher than 1 for Mo, As, Cu, Pb and Ni, respectively. This was due to higher proportion of spring onion in diet, which consequently increased the health risk index for metals. Therefore, it is recommended to avoid growing vegetables in untreated urban and rural wastewater containing elevated amounts of metals.  相似文献   

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