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1.
Effect of addition of organic residues on phosphorus release kinetics in some calcareous soils of western Iran 总被引:2,自引:0,他引:2
We investigated the effects on phosphorus (P) release of the addition of potato, wheat, and sunflower residues and fruit compost
to five calcareous soils. Residue was added at the rate of 20 g kg−1. After 2 months of incubation, P values in control and amended soils were used for kinetic studies and fractionated by a
sequential extraction procedure. The relative contribution of available P fraction (KCl-P) increased from 1.4% in control
soils to 1.8%, 1.9%, 2.2%, and 2.3% in soils amended by fruit, wheat, potato, and sunflower residue addition, respectively,
indicating that organic residues increased P in this fraction. In soils amended with different residues, the percentage of
Olsen-P released over 86-h successive extractions with 0.01 M CaCl2 ranged from 57.6% for fruit residue addition (average of five soils) to 60.5% for potato residue addition. The ability of
residues to release P depended on the soil properties, with 21.9 mg kg−1 (average of all residues) released to soil 2 and 77.4 mg kg−1 released to soil 4. Also residues behaved differently, with 31.5 mg kg−1 (average of five soils) released by fruit residues and 40.0 mg kg−1 released by sunflower residues. Release of P was best described by a parabolic diffusion model. The corresponding rate constant
(mg kg−1 h−1/2) for P release for amended soils, defined as the release rate averaged for five soils, was found to decrease in the order:
potato (2.73) > sunflower (2.61) > wheat (2.56) > fruit (2.50). The present study demonstrates that addition of residues improves
P availability of these calcareous soils by increasing extractable P and the release rate and could be an alternative, indigenous
source of P. However, the increase in P availability and the release rate following organic residue application suggests high
potential mobility to water sources. 相似文献
2.
Impact of treated sewage sludge application on phosphorus release kinetics in some calcareous soils 总被引:1,自引:0,他引:1
Treated sewage sludge contains significant amount of phosphorus and is widely used in agriculture. Kinetics of P release in
soils is a subject of importance in soil and environmental sciences. There are few studies about P release kinetics in treated
sewage sludge amended soils. For this purpose, sludge was mixed with ten soils at a rate equivalent to 100 Mg sludge ha−1, and P desorption was determined by successive extraction using 0.01 M CaCl2 over a period of 65 days at 25 ± 1°C. Phosphorus release rate was rapid at first (until about first 360 h) and then became
slower until equilibrium was approached. Average of P released within 360 h for the unamended and amended soils was about
65 and 73% of the total desorbed P, respectively. Zero-order, first-order, second-order, power function, simplified Elovich
and parabolic diffusion law kinetics models were used to describe P release. First-order, Elovich, power function and parabolic
diffusion models could well describe P release in the unamended and amended soils. Correlation coefficients between P release
rate parameters and selected soil properties showed that in the control soils, calcium carbonate equivalent and Olsen-extractable
P; and in the amended soils, calcium carbonate equivalent, cation exchange capacity, organic matter and Olsen-extractable
P were significantly correlated with P release parameters. The results of this study showed that application of sewage sludge
can change P release characteristics of soils and increase P in runoff. 相似文献
3.
The impact of acid rain on phosphorus leaching from a sandy loam calcareous soil of western Iran 总被引:1,自引:0,他引:1
Simulated acidic precipitation (1:1 equivalent basis H2SO4:HNO3) at pH values of 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 and 7.0 were conducted using column leaching to determine impacts of simulated
acid rain on phosphorus (P) leaching from a calcareous sandy loam soil over a 40-day period. Soil columns were irrigated every
day to make a total of 1,061 mm, equivalent to 3.5 years of rainfall (based on average annual rainfall). Leachates were collected
and analyzed for anions and cations. There was significant nonlinear correlation between the amount of P leached and the simulated
acid rain (R
2 = 0.61). Losses of P from the pH 2.5 and 7.0 treatments were 1.23, and 1.32 mg kg−1, respectively. The results showed that the amount of P leached from pH 4 (1.46 mg kg−1) and 5 treatments (1.52 mg−1 kg−1) were significantly larger than other treatments. Linear equation adequately described leaching of P in different treatments.
The slope (mg kg−1 day−1) in the linear equation was defined as the leaching rate and for the pH 2.5 was 0.0354, and 0.0382 and 0.0406 for pH 4.5
and 7.0, respectively. The geochemical code Visual MINTEQ was used to calculate saturation indices. Leaching of P in different
treatments was controlled by rate-limited dissolution of hydroxyapatite, β-tricalcium phosphate and to some extent octacalcium
phosphate. The results indicate that acid rain in calcareous sandy loam soils may pose a risk in terms of groundwater contamination
with P. 相似文献
4.
Nitrogen and phosphorus mineralization in sediments of Taihu Lake after the removal of light fraction organic matter 总被引:1,自引:1,他引:0
Chunxia Yang Shengrui Wang Xiangcan Jin Fengchang Wu 《Environmental Earth Sciences》2010,59(7):1437-1446
Mineralization of organic matter (OM) in sediment is crucial for biogeochemical cycle of nitrogen (N) and phosphorus (P) in
lake ecosystem. Light fraction OM (LFOM) is a reactive pool in sediment and is considered as labile fraction contributing
to N and P cycling. In our study, the effect of LFOM on the process and characteristics of N and P mineralization in sediments
of Taihu Lake were investigated with 77-day waterlogged incubation plus intermittent leaching at 27°C. Sediments from Yuantouzhu
(Y) and Gonghu (G) were used, which were removed the LF. Results indicated that the organic nitrogen mineralized ranged from
14.3 to 19.5% of total nitrogen (193.49–378.93 mg kg−1 sediment) and the organic phosphorus mineralized ranged from 5.7 to 7.9% of total phosphorus (19.86–60.65 mg kg−1 sediment). The heavily polluted sediment had a higher mineralization rate and net mineral-N and mineral-P than slightly polluted
sediment. LF stimulated the initial amounts of inorganic N and P and also can be the potential source for mineralization.
After the LFOM removal, the net mineral-N of Y and G decreased 116.47 mg kg−1 sediment and 48.03 mg kg−1sediment, respectively, and the net mineral-P decreased 2.67 mg kg−1sediment for Y and 4.82 mg kg−1sediment for G. Two models were used to fit the observed mineral-N data vs. incubation days using a non-linear regression
procedure: one is the effective cumulated temperature model, a thermodynamic model which assumes that N mineralization is
affected by temperature; the other is the single first-order exponential model, which is a dynamic model. Based on root mean
square error values for the two models, the effective cumulated temperature model made a better prediction of N mineralization
than the other model for all the four treatments. The single first-order exponential model underestimated N mineralization
during the first 14 days and the last 21 days, and overestimated it in the other days during the 77-day incubation. This indicated
that temperature was the primary factor influencing N mineralization and the amount of mineral-N were correlated significantly
with the effective cumulated temperature (T ≥ 15°C) and incubation time when waterlogged incubation plus intermittent leaching was used. 相似文献
5.
The Cu–Co–Ni Texeo mine has been the most important source of Cu in NW Spain since Roman times and now, approximately 40,000 m3 of wastes from mine and metallurgical operations, containing average concentrations of 9,263 mg kg−1 Cu, 1,100 mg kg−1 As, 549 mg kg−1 Co, and 840 mg kg−1 Ni, remain on-site. Since the cessation of the activity, the abandoned works, facilities and waste piles have been posing
a threat to the environment, derived from the release of toxic elements. In order to assess the potential environmental pollution
caused by the mining operations, a sequential sampling strategy was undertaken in wastes, soil, surface and groundwater, and
sediments. First, screening field tools were used to identify hotspots, before defining formal sampling strategies; so, in
the areas where anomalies were detected in a first sampling stage, a second detailed sampling campaign was undertaken. Metal
concentrations in the soils are highly above the local background, reaching up to 9,921 mg kg−1 Cu, 1,373 mg kg−1 As, 685 mg kg−1 Co, and 1,040 mg kg−1 Ni, among others. Copper concentrations downstream of the mine works reach values up to 1,869 μg l−1 and 240 mg kg−1 in surface water and stream sediments, respectively. Computer-based risk assessment for the site gives a carcinogenic risk
associated with the presence of As in surface waters and soils, and a health risk for long exposures; so, trigger levels of
these elements are high enough to warrant further investigation. 相似文献
6.
The Sarcheshmeh copper mine smelter plant is one of the biggest copper producers in Iran. Long-time operation of about 25 years
of the smelter plant causes release of potentially toxic heavy metals into the environment. In this paper, geochemical distribution
of toxic heavy metals in 28 soil samples was evaluated around the Sarcheshmeh smelter plant. Soils developed over the nonmineralized
and uncontaminated areas have an average background concentration of 41.25 mg kg−1 Cu, 26.6 mg kg−1 As, 12.7 mg kg−1 Pb, 0.9 mg kg−1 Sb, 1.9 mg kg−1 Mo, 1.7 mg kg−1 Sn, 0.2 mg kg−1 Cd, 0.15 mg kg−1 Bi, 235 mg kg−1 S and 73.4 mg kg−1 Zn, respectively. As a result of smelting process, the upper soil layers (0–5 cm) were polluted by Cu (>1,397 mg kg−1), Cd (>3.42 mg kg−1), S (>821 mg kg−1), Mo (>10.3 mg kg−1), Sb (>11.7 mg kg−1), As (>120.6 mg kg−1), Pb (>83.8 mg kg−1), Zn (>214.9 mg kg−1), and Sn (>3.7 mg kg−1), respectively. These values are much higher than the normal concentration of the elements in the uncontaminated soil layers.
The elemental values decrease with distance travelled away of the smelter plant, especially at minimum wind direction. Furthermore,
high contaminated values of Cu (8,430 mg kg−1), As (500 mg kg−1), Pb (331 mg kg−1), Mo (61 mg kg−1), Sb (56.2 mg kg−1), Zn (664 mg kg−1), Cd (17.2 mg kg−1), Bi (13.4 mg kg−1), and S (3,780 mg kg−1) were observed in the upper soil layers close to the smelting waste dumps. Sequential extraction analysis shows that about
270 mg kg−1 Cu, 28 mg kg−1 Pb, 50.33 mg kg−1 Zn, and 47.84 mg kg−1 As were adsorbed by Fe and Mn oxides. The carbonate phases include 151 mg kg−1 Cu, 28 mg kg−1 Pb, 25 mg kg−1 Zn, and 32.99 mg kg−1 As. Organic matter adsorbed 314.6 mg kg−1 Cu and 29.18 mg kg−1 Zn. 相似文献
7.
Hyperaccumulation of lead,zinc, and cadmium in plants growing on a lead/zinc outcrop in Yunnan Province,China 总被引:3,自引:0,他引:3
A field survey was conducted to identify potential hyperaccumulators of Pb, Zn or Cd in the Beichang Pb/Zn mine outcrop in
Yunnan Province, China. The average total concentrations of Pb, Zn, and Cd in the soils were up to 28,438, 5,109, and 52 mg kg−1, respectively. A total of 68 plant species belonging to 60 genera of 37 families naturally colonizing the outcrop were recorded.
According to metal accumulation in the plants and translocation factor (TF), Silene viscidula was identified as potential hyperaccumulator of Pb, Zn, and Cd with mean shoot concentrations of 3,938 mg kg−1 of Pb (TF = 1.2), 11,155 mg kg−1 of Zn (TF = 1.8) and 236 mg kg−1 of Cd (TF = 1.1), respectively; S. gracilicanlis (Pb 3,617 mg kg−1, TF = 1.2) and Onosma paniculatum (Pb 1,837 mg kg−1, TF = 1.9) were potential Pb hyperaccumulators. Potentilla griffithii (Zn 8,748 mg kg−1, TF = 1.5) and Gentiana sp. (Zn 19,710 mg kg−1, TF = 2.7) were potential Zn hyperaccumulators. Lysimachia deltoides (Cd 212 mg kg−1, TF = 3.2) was a potential Cd hyperaccumulator. These new plant resources could be used to explore the mechanisms of Pb,
Zn and/or Cd hyperaccumulation, and the findings could be applied for the phytoremediation of Pb, Zn and/or Cd-contaminated
soils. 相似文献
8.
Leaf N/P ratio and nutrient reuse between dominant species and stands: predicting phosphorus deficiencies in Karst ecosystems,southwestern China 总被引:2,自引:0,他引:2
Youxin Du Genxing Pan Lianqing Li Zhongliang Hu Xinzhou Wang 《Environmental Earth Sciences》2011,64(2):299-309
Variation of vegetation coverage and canopy height may reflect the complex spatial heterogeneity of nutrient storage and supply
capacity, soil moisture, and surface hydrology in the karst terrains suffering from severe land degradation. To assess the
patterns of nutrient limitation under different vegetation covers in the subtropical karst ecosystems from Guizhou province,
southwestern China, topsoil and leaf samples of dominant tree species were collected in forest stand (FO), shrub stand (SH)
and shrub-grass stand (SG), respectively. Nutrient concentrations of both soil and leaf were determined, and ratios of N to
P and vegetation nutrient reuse capacity (VNR) calculated as well as vegetation coverage, vegetation canopy height and tree
density measured across the three stands. Mean leaf N/P ratio was lowest (16.1 ± 1.4) in FO and highest (33.5 ± 3.2) in SG.
Vegetation nutrient reuse increased with the decline in N and P availability in soils for these three stands. VNR of N and
P ranged from 8.5 to 25.2 mg N g−1 and from 0.4 to 1.1 mg P g−1, respectively, and appeared lowest in SG (10.4 mg N g−1 and 0.5 P mg g−1 on average, respectively) and highest in FO (22.4 mg N g−1 and 0.9 mg P g−1 on average, respectively). Although there was no substantial difference in phosphorus reuse efficiencies between plant species
and vegetation stands, concentrations of N and P of senesced leaves (SLs) were, respectively, found in positive correlation
with the concentrations of mature leaves. The variation of VNR with elements indicated that P is cycled within vegetation
much more efficiently than N across the stands. This study demonstrated that the karst vegetations were generally at P-limited
or N- and P- co-limited stresses and that N/P ratio could be an effective indictor for nutrient limitation in the karst ecosystems
at vegetation community level rather than at tree species level. It is proposed that phosphorus reuse by mature leaves could
be an adaptation strategy by the dominant species to the low P availability in the karst soil. 相似文献
9.
Fe and Al oxides distribution in some ultisols and inceptisols of southeastern Nigeria in relation to soil total phosphorus 总被引:3,自引:1,他引:2
Ten highly weathered soils in southeastern Nigeria were sampled from their typical A and B horizons for analyses. The objectives
were to determine the different forms of Fe and Al oxides in the soils and relating their occurrence to phosphate availability
and retention in the soils. The soils are deep and often physically degraded but are well drained and coarse in the particle
size distribution. They are mostly dominated by kaolinite in their mineralogy with very high values of SiO2. The soils are acidic with low soil organic carbon (SOC) contents. The elements in the exchange complex are also low thus
reflecting in the low CEC of the soil. Available phosphorus (P) in the soils are generally low while total P ranged from 157
to 982 mg kg−1 with an overall average of 422 mg kg−1. Total Fe in the soil is highest and their order represented as follows: Fet > Fed > Feox ≥ Fep. The pyrophosphate extractable Fe was always higher in the top soil than in the subsoil and was attributed to the fact that
these forms of Fe are associated with organic matter which is more abundant in topsoil than in subsoil. Like in Fe forms,
the order of Al occurrence could generally be presented as; Alt > Ald > Alox > Alp. More Fe and Al oxides in the soils are strongly crystalline while a small quantity is poorly crystalline Fe forms. The amorphous
forms of both Fe and Al are very low in the soils when compared with the crystalline forms. The oxides that show very strong
affinity to total P are Fed–Feox, Fed, Ald, Fet, Feox and Alox/Ald. To overcome this problem of P retention in the soil, we recommend constant liming of these soils to neutralize them, application
of organic matter and of high dosage of phosphate fertilizer to the soils. 相似文献
10.
Speciation and phytoavailability of heavy metals in sediments in Nanjing section of Changjiang River 总被引:3,自引:1,他引:2
Heavy metal pollution and their fractionations in the sediments of Changjiang River in Nanjing Reach was monitored for cadmium
(Cd), lead (Pb), zinc (Zn), chromium (Cr), and copper (Cu). Moreover, the biological enrichment of metals by riverine plants
was studied. The results demonstrated there were highly significant variations among different sampling stations for the concentrations
of tested metals. The highest range was for Cu (38.8–120.4 mg kg−1), followed by Cr (74.4–120.0 mg kg−1), Zn (80.9–121.1 mg kg−1), Ni (26.0–55.5 mg kg−1), Pb (15.8–46.7 mg kg−1) and Cd (0.28–0.48 mg kg−1). Cd was the element with highest biological enrichment factor (BEF). The highest BEF of Cd in Erigeron bonariensis reached 3.0, indicating a significant Cd enrichment in this aquatic plant. In addition, 60% of Cd was found in reducible
fraction and exchangeable and acid-soluble fraction, which was consistent with its high mobility. The consistency of Cd fraction
in sediment and suspended particle indicated they came from the same source. Accumulated Cd concentration calculated according
to the release curve showed significant relativity with the total Cd concentration in the sediment. 相似文献
11.
P. Conde Bueno E. Bellido J. A. Martín Rubí R. Jiménez Ballesta 《Environmental Geology》2009,56(5):815-824
Mercury (Hg) is one of the elements with increasing environmental significance. A total of 22 samples (soils, rocks and gels)
were collected along a 6 km transect around the Valdeazogues River valley in the southwest of the Iberian Peninsula (Almadén,
Spain). Samples were characterized by different soil types of depositional sequences associated with mining tailings, type
and system tracts: 15 surface soil samples included in the transect; 3 of a Haploxerept soil profile developed on slates;
2 of quartzite and slates rocks (reference rocks in the area). Moreover, two of a gel substance (in the lower tract of the
river). Soil samples were analyzed for Hg, Cu, Ni, Cr, V, Pb, Cd and As, as well as for organic matter, pH abrasion and calcium
carbonate content. All samples were collected from the Almadén mining district. The level of occurrence of the elements (especially
Hg) and the effect of some properties on its concentration distributions were investigated. The total mercury contents varied
in the range 7,315–3.44 mg kg−1. The mean concentration of total mercury in soils and rocks was 477.03 mg kg−1dry mass. This value is very high compared to the regional background value of other areas. Only rarely is it higher than
1%: in one sample (7,315 mg kg−1) it was almost eight times in comparison with the affected zones, with a high value of 1,000 mg kg−1. Significant differences between samples were found in the total content of mercury. A large percentage of the samples registered
detectable levels of V, Cr, Ni, Pb, As and Cu. Cd readings were below the detectable range for all samples tested. Cr mean
concentration was 216.95 mg kg−1 (minimun concentration 86, maximun 358); V mean concentration was 119.09 mg kg−1 (minimun concentration 69, maximun 1,209); As mean concentration was 51.24 mg kg−1 (minimun 13.3 and maximun 319.4); Ni mean concentration was 45.64 mg kg−1 (minimun concentration 21.2 and maximun 125.6); Cu mean concentration was 33.25 mg kg−1 (minimun concentration 19.3 and maximun 135); Pb mean concentration was 15.19 mg kg−1 (minimun 1.12 and maximun 1013). Metal distribution generally showed spatial variability ascribed to significant anthropogenic
perturbation by mining tailing type. Hg showed vertical profile characterized by surface enrichment, with concentrations in
the upper layer (93.7–82.2 mg kg−1 in front of 3.4 of the rock value) exceeding, in several occasions, the background value. The results obtained denote a potential
toxicity of some heavy metals in some of the studied samples. Water-soluble mercury could enter the aquatic system and accumulate
in sediments. Mercury and other heavy metals contamination depended on the duration and intensity of mining activities. 相似文献
12.
Copper contamination in soils and vegetables in the vicinity of an abandoned copper mine in China was investigated. The Cu
concentrations of 93 soil samples ranged from 30.4 to 3,191 mg kg−1 soil for a mean of 816.8 mg kg−1 soil. Among 15 samples from a 0 to 20-cm soil layer used for the toxicity characteristic leaching procedure (TCLP) test,
the highest value of Cu-TCLP was 133.8 mg kg−1 soil and the TCLP values were positively correlated with the total Cu content of the soils. The sequential extraction of
soils in the 0–20-, 20–40-, and 40–60-cm soil layers showed that Cu existed mainly in the Fe–Mn oxide fraction, sulfide/organic
fraction, and residual fraction. The copper contamination of 21 species of vegetables from in situ sampling was also examined.
Cu concentrations in the edible portions of Brassica chinensis and Solanum melongena were higher than the FAO/WHO standard (40 mg kg−1 DW). The health risk of copper for local inhabitants from consuming these vegetables was assessed on the basis of the target
hazard quotient. Enriched concentrations of copper were also found in situ in eight cultivars of B. chinensis planted in the fields, with two levels of Cu concentration. The results showed that there is severe copper contamination
in this mine area, and the pollutant in soils show a high risk of leaching into the groundwater and diffusing through the
food chain. 相似文献
13.
Guo-Ping Wang Xiao-Fei Yu Jian Wang Hong-Mei Zhao Kun-Shan Bao Xian-Guo Lu 《Environmental Earth Sciences》2011,62(1):207-216
The rare earth elements (REEs) in the sediments of the Xianghai wetlands were measured by inductively coupled plasma spectrometry.
The REEs accumulation rates in two sedimentation cores derived from the riparian and depressional marshes were determined
by 210Pb method. The results showed that REEs concentrations in the Xianghai wetland sediments (∑REEs, 116 mg kg−1) were lower than the corresponding values in Chinese soils (181 mg kg−1) and river sediments (∑REEs, 158–191 mg kg−1). Under alkaline conditions (with pH, 8.2–10.3), the light REEs were more enriched than the heavy REEs. Cerium is the predominant
element, and accounts for 30–33% of the total REEs. REEs in the depressional marsh sediments were relatively high (∑REEs,
127 vs. 104 mg kg−1), especially light REEs contents. A significantly positive correlation was found between the neighboring elements except
Pr and Dy. The different types of vertical distribution of REEs between the riparian and the depressional marsh can partly
result from long-term differing hydrological regimes. Generally, depressional marsh had accumulated much more REEs than riparian
marsh (the mean accumulation rates of ∑REEs, 102.98 vs. 48.89 μg cm−2 year−1). 相似文献
14.
Phosphorus desorption kinetics in two calcareous soils amended with P fertilizer and organic matter 总被引:2,自引:1,他引:1
We studied the effects of poultry manure and pistachio compost with and without phosphorus fertilizer on the kinetics of phosphorus
desorption in two calcareous soils of Kerman and Koohbanan farms in the southeastern of Iran. For this purpose mono potassium
phosphate, at rates of 0, and 100 parts per million of phosphorus, and air-dried manure, at rates of 0 and 4% were mixed with
the soils. The soils were incubated at 24–25°C and near field capacity for 90 days in the greenhouse. Afterwards, the desorption
of P was studied by the successive extraction with 0.5 M NaHCO3. The results of this research indicated that application of OM and fertilizer P combined increased P recovery in each of
the extraction time, adding poultry manure and 100 mg phosphorus together to the soils, increased P desorption more than pistachio
compost in the soils. The phosphorus desorption rate was initially rapid and then became slower until equilibrium was approached.
Kinetic data were best described by power function and simple Elovich equations. Subsequent to these equations, parabolic
diffusion equation was also well fitted the time-dependent P desorption data. 相似文献
15.
Heavy metals pollution in the soil of an irregular urban settlement built on a former dumpsite in the city of Tijuana, Mexico 总被引:1,自引:1,他引:0
Eustorgio C. Nava-Martínez Enrique Flores-García Heriberto Espinoza-Gomez Fernando T. Wakida 《Environmental Earth Sciences》2012,66(4):1239-1245
The aim of this study was to evaluate soil pollution by heavy metals in an irregular settlement built on a dumpsite. The soil
samples were analyzed for Cd, Cr, Cu, Pb and Ni. None of the concentrations found for the heavy metals analyzed were higher
than the established Mexican official standards for contaminated soils. The mean concentrations found for the analyzed metals
were as follows: 1.4 mg kg−1 for Cd, 4.7 in mg kg−1 for Cr, 304 mg kg−1 for Cu, 74 mg kg−1 for Pb and 6 mg kg−1 for Ni. The results of the geoacummulation index values show that the site was very polluted with Cu and Pb (class 7), polluted
to strongly polluted with Ni (class 4); moderately polluted to polluted with Cd (class 3), and moderately polluted with Cr
(class 1). The correlation analysis shows a high correlation between Pb and Cu (r
2 = 0.98), which would be explained if the main source of the polluting heavy metals was the result of electrical wire burning
to recover Copper. Principal component analysis shows three principal components. The first main component (PC1) encompasses
Cr, Cd, Pb and Cu. These heavy metals most likely have their origins from the open burning of municipal solid waste, tires
and wire. The other two components are encompassed by Cr (PC2) and Ni (PC3). The sources of these pollutants are more likely
related to the corrosion of junk metal objects and automobile use. 相似文献
16.
Mohsen Jalali 《Environmental Geology》2007,53(2):365-374
Phosphorus (P) application in excess of plant requirement may result in contamination of drinking water and eutrophication
of surface water bodies. The phosphorous buffer capacity (PBC) of soil is important in plant nutrition and is an important
soil property in the determination of the P release potential of soils. Phosphorus sorption greatly affects both plant nutrition
and environmental pollution. For better and accurate P fertilizer recommendations, it is necessary to quantify P sorption.
This study was conducted to investigate available P and P sorption by calcareous soils in a semi-arid region of Hamadan, western
Iran. The soil samples were mainly from cultivated land. Olsen’s biocarbonate extractable P (Olsen P) varied among soils and
ranged from 10 to 80 mg kg−1 with a mean of 36 mg kg−1. Half of the soils had an Olsen P > 40 mg kg−1 and >70% of them had a concentration >20 mg kg−1, whereas the critical concentration for most crops is <15 mg P kg−1. Greater average Olsen P in soils occurred under garlic (56 mg kg−1) and potato (44 kg kg−1) fields than in dry-land wheat farming (24 mg kg−1), pasture (30 mg kg−1), and wheat (24 mg P kg−1) fields. A marked increase in fertilizer P rates applied to agricultural soils has caused P to be accumulated in the surface
soil. Phosphate sorption curves were well fitted to the Freundlich equation. The standard P requirement (SPR) of soils, defined
as the amount of P sorbed at an equilibrium concentration of 0.2 mg l−1 ranged from 4 to 102 mg kg−1. Phosphorus buffer capacity was relatively high and varied from 16 to 123 l kg−1 with an average of 58 l kg−1. In areas of intensive crop production, continual P applications as P fertilizer and farmyard manure have been used at levels
exceeding crop requirements. Surface soil accumulations of P are high enough that loss of P in surface runoff and a high risk
for P transfer into groundwater have become priority management concerns. 相似文献
17.
Heavy metal concentrations and their possible sources in paddy soils of a modern agricultural zone,southeastern China 总被引:5,自引:0,他引:5
In a typical modern agricultural Zone of southeastern China, Haining City, 224 topsoil samples were collected from paddy fields
to measure the total concentrations of copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr), mercury (Hg), arsenic
(As) and cobalt (Co). The total concentrations ranged from 15.30 to 78.40 mg kg−1 for Cu, 20.10 to 41.40 mg kg−1 for Pb, 54.98 to 224.4 mg kg−1 for Zn, 0.04 to 0.24 mg kg−1 for Cd, 54.90 to 197.1 mg kg−1 for Cr, 0.03 to 0.61 mg kg−1 for Hg, 3.44 to 15.28 mg kg−1 for As, and 7.17 to 19.00 mg kg−1 for Co. Chemometric techniques and geostatistics were utilized to quantify their spatial characteristics and define their
possible sources. All eight metals had a moderate spatial dependency except that Pb had a strong spatial dependency. Both
factor analysis and cluster analysis successfully classified the eight metals into three groups or subgroups, the first group
included Cu, Zn and Cr, the second group included Cd, As and Co, and the last group included Pb and Hg. The Cu, Zn and Cr
concentrations in majority samples were higher than their local background concentrations and they were highly correlated
(r > 0.80), indicating that they had similar pollution source and anthropic factor controlled their spatial distribution; the
Cd, As and Co concentrations in majority samples were lower than their local background concentrations, indicating that the
source of these elements was mainly controlled by natural factors; the mean concentration of Pb exhibited generally low level,
close to its local background concentration, the Hg concentration in about half of samples was higher than its local background
concentration, and they were poor correlated with the other metals, indicating that the source of Pb and Hg was common controlled
by natural factor and anthropic factor. 相似文献
18.
Trace metals (Cd,Pb, Cu,Zn and Ni) in sediment of the submarine pit Dragon ear (Soline Bay,Rogoznica, Croatia) 总被引:1,自引:0,他引:1
Vertical profiles of trace metal (Cd, Pb, Zn, Cu, Ni) concentrations, organic matter content, carbonate content and granulometric
composition were determined in two sediment cores from the submarine pit Dragon Ear (Middle Adriatic). Concentrations of the
analyzed metals (Cd: 0.06–0.12 mg kg−1, Pb: 28.5–67.3 mg kg−1, Zn: 17.0-65.4 mg kg−1, Cu: 21.1–51.9 mg kg−1, Ni: 27.8–40.2 mg kg−1) were in usual range for Adriatic carbonate marine sediments. Nevertheless, concentrations of Cu, Zn, and especially Pb in
the upper layer of sediments (top 12 cm) were higher than in bottom layer, while Cd and Ni concentration profiles were uniform.
Regression analysis and principal component analysis were used to interpret distribution of trace metals, organic matter and
carbonate content in sediment cores. Results of both analysis showed that concentrations of all trace metals in the core below
the entrance to the pit were significantly positively correlated with organic matter and negatively correlated with carbonate,
while in the core more distant from the entrance only Pb showed significant positive correlation with organic matter. Obtained
results indicated that, except for lead which was enriched in surface sediment, in the time of sampling (before the building
of the nautical marina) investigated area belonged to unpolluted areas. 相似文献
19.
Fluorine is one of the many environmental harmful elements released by volcanic activity. The content of total oxalate-extractable
and water-extractable fluorine was determined in 96 topsoils of three active volcanic systems of southern Italy (Mt Etna,
Stromboli and Vulcano). Total fluorine (F) content (F
TOT) ranges from 112 to 7,430 mg kg−1, F extracted with oxalate (F
OX) ranges from 16 to 2,320 mg kg−1 (2–93% of F
TOT) and F extracted with distilled water (
) ranges from 1.7 to 159 mg kg−1 (0.2–40 % of F
TOT). Fluorine in the sampled topsoils derives both from the weathering of volcanic rocks and ashes and from the enhanced deposition
due to volcanic gas emissions either from open-conduit passive degassing (Mt Etna and Stromboli) or from a fumarolic field
(Vulcano). Fluorine accumulation in the studied soils does not generally present particular environmental issues except for
a few anomalous sites at Vulcano, where measured contents could be dangerous both for vegetation and for grazing animals. 相似文献
20.
Geochemical and statistical approach to evaluate background concentrations of Cd,Cu, Pb and Zn (case study: Eastern Poland) 总被引:2,自引:2,他引:0
Wojciech Zgłobicki Lesia Lata Andrzej Plak Marek Reszka 《Environmental Earth Sciences》2011,62(2):347-355
An attempt was made to evaluate background concentrations of Cd, Cu, Pb and Zn by means of geochemical and statistical approach.
As many as 753 samples taken from 51 profiles located in Eastern Poland were analysed. For the estimation of geochemical background
values, direct geochemical methods and a statistical analysis for the whole population of samples were applied. Average values
of heavy metal concentration in loess sediments (bedrock) as well as in profiles not affected by human activity were measured.
The iterative 2σ technique and calculated distribution function were chosen as statistical methods. The resulting values (background
concentrations range) were as follows: Cd 0.5–0.9 mg kg−1, Cu 5–16 mg kg−1, Pb 12–26 mg kg−1 and Zn 31–47 mg kg−1. All the methods applied gave similar results. The highest deviation of the background was noted for Cu and the lowest for
Zn. The lowest values of background were obtained for loess sediments and the highest in the case of the multiple 2σ method. 相似文献