共查询到20条相似文献，搜索用时 31 毫秒
1.
Abstract We have identified Crassocephalum crepidioides (Benth.) S. Moore (Compositae) as a cadmium (Cd)-accumulator plant in a heavy-metal polluted environment. In soil polluted with Cd, 5.7–17.5 mg kg ?1 Cd, concentrations in the above-ground plant tissues were measured as 14.6–78.6 mg kg ?1 with transfer factors in the above-ground plant tissues (concentration in above-ground tissues/soil concentration) of 1.5–6.0. No other toxic heavy metals or plant micronutrients were found to have accumulated into the above-ground plant tissues. In a hydroponic culture with 1 µmol L ?1 Cd added to Hoagland's nutrient solution, Cd concentration in the above-ground plant tissues was 121.0 mg kg ?1, with a transfer factor of more than 1000. In a pot culture carried out for 9 weeks in a greenhouse, the highest Cd concentration in the above-ground plant tissues, 121.2 mg kg ?1, was found in a treatment with 5 mg kg ?1 Cd, whereas the highest Cd content in an above-ground plant tissue, 106.1 µg, was found in a treatment with 2 mg kg ?1 Cd. These results clearly showed that C. crepidioides is a Cd accumulator. In all samples, the Cd concentration in the above-ground plant tissues was higher than that in the roots. The results obtained in the present study show that this plant has a strong potential for use in phytoremediation in farm fields contaminated with Cd. 相似文献
2.
Abstract Soil washing is one of the methods used to remediate soil contaminated with heavy metals, and when the contaminated elements have been effectively removed the washed soil can be used for agriculture. Soil washing was conducted using 0.5 mol L ?1 CaCl 2 solution at pH 4 as an extracting agent to remediate a paddy field soil contaminated with Cd. Dolomite powder was applied to neutralize the soil to the original pH 6.2. After CaCl 2 washing, the content of Cd extractable in 0.1 mol L ?1 HCl decreased from 2.4 to 0.8 mg kg ?1. Subsequently, a pot experiment was carried out to evaluate the effect of soil washing on Cd concentration in polished rice (Cd pr) for three successive years. Using the washed soil, Cd pr was ≤ 0.2 mg kg ?1 with and without a treatment that simulates midseason drainage, whereas it was > 0.5 mg kg ?1 in the unwashed soil with the midseason drainage treatment. The reasons for low Cd pr growth in the washed soil were the low content of exchangeable Cd in the soil and the resultant high soil pH (> 7). To evaluate the effect of soil pH on Cd pr in the fourth year, we adjusted soil pH to 5 with H 2SO 4 before transplanting rice seedlings. The Cd pr in the washed soil with the midseason drainage treatment increased to 0.47 mg kg ?1, whereas it was less than 0.2 mg kg ?1 under continuous flooding. Thus, high pH or whole season flooding are important to keep Cd pr at ≤ 0.2 mg kg ?1 even after soil washing. With the application of dolomite and other ordinary fertilizers, soil properties were little affected by the present soil washing procedure because the difference in rice yield between the washed and unwashed plots was not significant within each year. 相似文献
3.
PurposeImidacloprid is a widely used seed dressing insecticide in Brazil. However, the effects of this pesticide on non-target organisms such as soil fauna still present some knowledge gaps in tropical soils. This study aimed to assess the toxicity and risk of imidacloprid to earthworms Eisenia andrei and collembolans Folsomia candida in three contrasting Brazilian tropical soils. Materials and methodsAcute and chronic toxicity assays were performed in the laboratory with both species in a tropical artificial soil (TAS) and in two natural soils (Oxisol and Entisol), at room temperature of 25 °C. The ecological risk was calculated for each species and soil by using the toxicity exposure ratio (TER) and hazard quotient (HQ) approaches. Results and discussionAcute toxicity for collembolans and earthworms was higher in Entisol (LC50?=?4.68 and 0.55 mg kg?1, respectively) when compared with TAS (LC50?=?10.8 and 9.18 mg kg?1, respectively) and Oxisol (LC50collembolans?=?25.1 mg kg?1). Chronic toxicity for collembolans was similar in TAS and Oxisol (EC50 TAS?=?0.80 mg kg?1; EC50 OXISOL?=?0.83 mg kg?1), whereas higher toxicity was observed in Entisol (EC50?=?0.09 mg kg?1). In chronic assays with earthworms, imidacloprid was also more toxic in Entisol (EC50?=?0.21 mg kg?1) when compared to TAS (EC50?=?1.89 mg kg?1). TER and HQ values indicated a significant risk of exposure of the species to imidacloprid in all soils tested, and the risk in Entisol was at least six times higher than in Oxisol or TAS. ConclusionsThe toxicity and risk of imidacloprid varied significantly between tropical soils, being the species exposure to this pesticide particularly hazardous in very sandy natural soils such as Entisol. 相似文献
4.
Abstract The effect of cadmium (Cd) and sulphur (S) on dry weight, biochemical parameters and anatomical features of mustard ( Brassica campestris L. cv. Pusa Bold) plant was investigated in a pot culture experiment using Cd (25, 50, and 100 mg kg ?1 of soil), S (40 mg kg ?1 of soil), and the combination of Cd+S (25+40 mg kg ?1 of soil, 50+40 mg kg ?1 of soil, and 100+40 mg kg ?1 of soil). Sulphur treatment was given at sowing and Cd treatment was given when seedlings were fully established. Observations were recorded at the flowering stage. A significant and antagonistic interaction of Cd and S was observed. Compared to the control, leaf dry weight, total chlorophyll content, sugar content, nitrate reductase activity, and protein content decreased significantly with each Cd treatment, whereas the reverse was observed with S treatment. Combined treatments of Cd+S also reduced these parameters, but this reduction was less than the one observed with Cd treatments alone. However, nitrate accumulation in the leaves was 2.35 times higher with treatment of 100 mg Cd+40 mg S kg ?1 of soil than in the controls, whereas it was 3.5 times higher with Cd (100 mg kg ?1 of soil) alone. The relative proportion of vasculature in the stem, stoma length and width, and stomata length and width were inhibited with Cd treatments, whereas the combined treatments mitigated the adverse effect caused by Cd. Thus, S could alleviate the Cd induced impairment of biochemical and anatomical features of the plant and the enhancement of nitrate accumulation in the leaves. 相似文献
5.
PurposePhosphorus (P)-containing passivators have a stabilizing effect on cadmium (Cd)-contaminated agricultural soils to be safely used, offering good potential for risk control of Cd-contaminated agricultural soils to be strictly controlled. In this study, an incubation experiment was conducted to evaluate the risk control effects of using hydroxyapatite (HAP) and monocalcium phosphate (MCP) on Cd-contaminated agricultural soils to be strictly controlled. Materials and methodsSamples of topsoil were collected (0–20 cm) from agricultural land near a lead–zinc mine in Southwestern China containing 32.07 mg kg?1 Cd with a pH of 7.28. The amounts of passivators added were equal to approximately 3% of the soil by weight. The soil Cd content, physicochemical properties, enzyme activity, and microbial community were analyzed. ResultsThe results showed that the application of HAP and MCP decreased the activity and mobility of Cd in soils to be strictly controlled. HAP was more effective in decreasing the exchangeable Cd (CdEx) than MCP (rate of decrease was 48.1% for HAP and 24.4% for MCP). According to the results of the geometric mean (GMean) and the integrated total enzyme activity (TEI) index, the total soil enzyme activity of the HAP treatment was higher than that of CK and MCP treatment. HAP and MCP significantly decreased the Chao and Shannon bacterial community indices and the Shannon index of the soil fungal community. HAP increased Actinobacteria abundance, which is beneficial to soil fertility enhancement and plant growth, and MCP increased Rhizobiales abundance, which promotes soil P cycling and plant growth. Primary driving factors for the changes in bacterial and fungal community composition in the stabilized soils were CEC and CdEx for bacteria and Cd bound to carbonates (CdCar) and residual Cd (CdRes) for fungi. ConclusionsHAP is more suitable for risk control of Cd-contaminated agricultural soils to be strictly controlled than MCP from the perspective of soil Cd activity and mobility, soil enzyme activity, and diversity and composition of the soil microbial community. 相似文献
6.
PurposeDecarboxylation of organic anions in crop straw is recognized as one of the mechanisms for increasing pH in acidified soils. However, the effectiveness of specific compounds in alleviating soil acidification from nitrification has not been well determined. This study examined three organic anions commonly found in crop straws and their effect on soil acidity and N transformation processes following urea application to a red soil (Ferralic Cambisol). Materials and methodsA 35-day incubation experiment was conducted using soil after receiving 26 years of two different nutrient treatments: (1) chemical nitrogen, phosphorus, and potassium fertilization (NPK, pH 4.30) and (2) NPK plus swine manure (NPKM, pH 5.88). Treatments included three rates (0.25, 0.5, and 1.0 g C kg?1) of calcium citrate, 0.5 g C kg?1 calcium oxalate, 0.5 g C kg?1 calcium malate, urea-only (control) soil, and a non-treated soil as a reference. Soil acidity, mineral N species, decarboxylation, and their correlations were determined. Results and discussionAll three organic anions significantly increased pH in both soils and the effectiveness was positively correlated with application rate. The change in total exchangeable soil acidity was dominated by aluminum concentration in the NPK soil, but by proton concentration in the NPKM soil. At ≥?0.5 g C kg?1, the anions decreased soil exchangeable acidity by 25–68% in NPK soil and by 63–88% in NPKM soil as compared with control. Oxalate was the most effective in increasing soil pH by 0.70 and 1.31 units and reducing exchangeable acidity by 3.79 and 0.33 cmol(+) kg?1 in NPK and NPKM soils, respectively, and also resulted in the highest CO2 production rate. Addition of organic anions led to a lower nitrification rate in NPKM soil relative to the NPK soil. ConclusionsThese results imply that crop straws rich in organic anions, especially oxalate, would have a higher potential to alleviate soil acidification. 相似文献
7.
PurposeCalcareous soils are characterized by high pH and phosphorus (P) fixation capacity. Increasing application of P fertilizer recently has significantly improved soil P concentration, especially available P (Olsen-P) and inorganic phosphate (Pi) fractions. However, there are few data available on the ability of soils with different initial Olsen-P levels to continuously supply P (i.e., P desorption capacity) to crops without additional P fertilization and on which Pi fraction exerts the greatest influence on P desorption capacity. Materials and methodsFive soils with different initial Olsen-P levels (0.5, 14.3, 38.4, 55.4, 72.3 mg kg?1, hereafter refer as OP1, OP2, OP3, OP4, and OP5) but similar other soil properties were selected to evaluate the capacity of P desorption and its relationship with Pi fractions. Soil P was sequentially extracted once daily for 16 consecutive days using Olsen solution. Results and discussionThe content and proportions of dicalcium phosphate fraction (Ca2-P), octacalcium phosphate fraction (Ca8-P), aluminum phosphorus fraction (Al-P), and iron phosphorus fraction (Fe-P) in Pi increased significantly with the increase of initial Olsen-P (P?<?0.01). Applied P fertilizer was mostly stored as Ca8-P in the soil. Soil P desorbed reached an equilibrium after 16 extractions for all soils, and P desorption capacity (12–358 mg kg?1) showed a significant linear relationship with initial Olsen-P (P?<?0.01), with an increase of 4.2 mg kg?1 desorbed P per 1 mg kg?1 increase of initial Olsen-P. Ca2-P exerted the conclusive effect on P desorption in the first four extractions, but Ca8-P played a more important role in the 16 extractions. ConclusionsCa8-P was the greatest potential pool for P desorption after Ca2-P was depleted. P desorption capacity was significantly linearly related to initial Olsen-P (P?<?0.01). Different fertilizer use strategies were developed based on P desorption capacity for soils with different initial Olsen-P levels. The present study provided basic data on how to reduce effectively the application amount of chemical P fertilizer. 相似文献
8.
Abstract This study was carried out to investigate whether an insoluble polyacrylate polymer could be used to remediate a sandy soil contaminated with cadmium (Cd) (30 and 60 mg Cd kg ?1 of soil), nickel (Ni) (50 and 100 mg Ni kg ?1 of soil), zinc (Zn) (250 and 400 mg Zn kg ?1 of soil), or the three elements together (30 mg Cd, 50 mg Ni, and 250 mg Zn kg ?1 of soil). Growth of perennial ryegrass was stimulated in the polymer‐amended soil contaminated with the greatest amounts of Ni or Zn, and when the three metals were present, compared with the unamended soil with the same levels of contamination. Shoots of plants cultivated in the amended soil had concentrations of the metals that were 24–67% of those in plants from the unamended contaminated soil. After ryegrass had been growing for 87 days, the amounts of water‐extractable metals present in the amended soil varied from 8 to 53% of those in the unamended soil. The results are consistent with soil remediation being achieved through removal of the metals from soil solution. 相似文献
9.
PurposeSoil pollution indices are an effective tool in the computation of metal contamination in soil. They monitor soil quality and ensure future sustainability in agricultural systems. However, calculating a soil pollution index requires laboratory measurements of multiple soil heavy metals, which increases the cost and complexity of evaluating soil heavy metal pollution. Visible and near-infrared spectroscopy (VNIR, 350–2500 nm) has been widely used in predicting soil properties due to its advantages of a rapid analysis, non-destructiveness, and a low cost. MethodsIn this study, we evaluated the ability of the VNIR to predict soil heavy metals (As, Cu, Pb, Zn, and Cr) and two commonly used soil pollution indices (Nemerow integrated pollution index, NIPI; potential ecological risk index, RI). Three nonlinear machine learning techniques, including cubist regression tree (Cubist), Gaussian process regression (GPR), and support vector machine (SVM), were compared with partial least squares regression (PLSR) to determine the most suitable model for predicting the soil heavy metals and pollution indices. ResultsThe results showed that the nonlinear machine learning models performed significantly better than the PLSR model in most cases. Overall, the SVM model showed a higher prediction accuracy and a stronger generalization for Zn (R2V?=?0.95, RMSEV?=?6.75 mg kg?1), Cu (R2V?=?0.95, RMSEV?=?8.04 mg kg?1), Cr (R2V?=?0.90, RMSEV?=?6.57 mg kg?1), Pb (R2V?=?0.86, RMSEV?=?4.14 mg kg?1), NIPI (R2V?=?0.93, RMSEV?=?0.31), and RI (R2V?=?0.90, RMSEV 3.88). In addition, the research results proved that the high prediction accuracy of the three heavy metal elements Cu, Pb, and Zn and their significant positive correlations with the soil pollution indices were the reason for the accurate prediction of NIPI and RI. ConclusionUsing VNIR to obtain soil pollution indices quickly and accurately is of great significance for the comprehensive evaluation, prevention, and control of soil heavy metal pollution. 相似文献
10.
PurposeNatural organic acids, such as humic acid (HA), play crucial roles in biogeochemistry of anions and cations in soil due to their numerous functional groups on their surfaces. Selenium (Se) and cadmium (Cd) could bind strongly to HA; nevertheless, it is still unclear as to the effects of HA on Se and Cd uptake in rice which will be focused on in this paper. Materials and methodsPot experiments were carried out at Huazhong Agricultural University, Wuhan City, Hubei Province, China. Agricultural soils were treated with different concentrations of HA (0, 4, and 8 g kg?1 soil) and Se (SeIV or SeVI) (0 and 2 mg kg?1 soil) as well as with base fertilizer 3 days prior to planting. For Cd treatment, experimental soils were treated with Cd (0 and 2 mg kg?1 soil) 1 month before sowing. For element determination, root (after DCB extraction) and shoot samples were digested with a mixed solution of HNO3-HClO4, and the Se and Cd in digest solution were measured by HG-AFS and ICP-MS, respectively. Fe, Se, and Cd in iron plaque were extracted by DCB extraction and measured by AAS, HG-AFS, and ICP-MS, respectively. Results and discussionHA reduced Se (or Cd)-induced growth stimulation and Se and Cd uptake in rice seedlings, whereas iron plaque formation varied little with different treatments. HA inhibited SeIV (or SeVI) uptake in rice seedlings by reducing Se translocations from soil to iron plaque (or by increasing Se adsorption capacity of iron plaque and decreasing Se transport from iron plaque to root). HA reduced Cd uptake in rice seedlings by reducing Cd transport from soil to iron plaque and from iron plaque to root. Compared with single addition of SeIV or SeVI or HA, adding HA combined with SeIV or SeVI could further reduce Cd uptake in rice seedlings, whereas Se contents of aerial tissues did not change obviously. ConclusionsHA inhibited the accumulation of Se (SeIV or SeVI) and Cd in rice seedlings; nevertheless, the mechanism was different. Compared with adding Se (or HA) alone, application of Se mixed with HA might be a more effective way to produce Se-enriched and Cd-deficient crop in Cd-contaminated soil. 相似文献
11.
(pp. 33–39) The purpose of this study is to investigate utilization of Akadama soil and evaluate its ion removal efficiency for seawater desalination. The chemical composition of the Akadama soil was Al 203 0.334 kg kg ?1, SiO 2 0.470 kg kg ?1, Fe 203 0.157 kg kg ?1 by weight. X-ray powder diffraction pattern, electron diffraction pattern and IR spectrum of Akadama soil showed that allophane was the main phase and low crystallinity kaolin was generated from the allophane. The column method was carried out to evaluate seawater desalination efficiency, the best mixture ratio of the Akadama soil (particle size was less than 250 m), aluminum silicate adsorbent, aluminium magnesium adsorbent, and magnesium oxide adsorbent was 3:1:1:1. Removal percentages of Na +, Mg 2+, Ca 2+, K + and Cl ? from artificial seawater were 87.7, 84.4, 91.1, 97.3 and 90.7%, respectively. In the batch method, where the mixed adsorbent was used for removal of heavy metals from 20 mg L ?1 solution, the removal percentages of Cu 2+, Ni 2+, Mn 2+, Zn 2+, Cd 2+ and Pb 2+ were higher than 98%. The removal percentage of PO 4 from river water was 100%. 相似文献
12.
ABSTRACT The ability to tolerate and accumulate arsenic (As) and cadmium (Cd) was compared between Brassica juncea (Indian mustard) and Crambe abyssinica (Hochst.) (Crambe or Abyssinian mustard). Plants were grown hydroponically and treated with 70 μM sodium arsenate or 50 μ M cadmium chloride for two weeks. When nutrients were omitted during the As treatment, leaves of C. abyssinica accumulated an average of 140 mg As kg ?1, compared with 34 mg kg ?1 for B. juncea. When quarter-strength Hoagland's nutrient solution was provided during As treatment, leaves of C. abyssinica accumulated an average of 270 mg As kg ?1, compared with 13 mg kg ?1 for B. juncea. Cadmium accumulation on a dry-weight basis was approximately two times greater in shoots of B. juncea. Shoot biomass production in the presence or absence of metals was greatest for C. abyssinica. Because of its larger biomass and more efficient accumulation of As, C. abyssinica should be considered for use in phytoremediation research. 相似文献
13.
A screen-house experiment was conducted to study cadmium (Cd) and lead (Pb) phytoextraction using mustard and fenugreek as test crops. Cadmium was applied at a rate of 20 mg kg ?1 soil for both crops, and Pb was applied at 160 and 80 mg kg ?1 soil for mustard and fenugreek, respectively. The disodium salt of ethylenediamine tetraacetic acid (EDTA) was applied at 0, 0.5, 1.0, and 1.5 g kg ?1 soil. Dry-matter yield (DMY) of both crops decreased with increasing rates of EDTA application. Application of 1.5 g EDTA kg ?1 soil caused 23% and 70% declines in DMY of mustard and fenugreek shoots, respectively, in the soils receiving 20 mg Cd kg ?1 soil. Similarly, in soil with 160 mg Pb kg ?1 soil, application of 1.5 g EDTA kg ?1 resulted in 25.4% decrease in DMY of mustard shoot, whereas this decrease was 55.4% in fenugreek grown on a soil that had received 80 mg Pb kg ?1 soil. The EDTA application increased the plant Cd and Pb concentrations as well as shoot/root ratios of these metals in both the crops. Application of 1.5 g kg ?1 EDTA resulted in a 1.50-fold increase in Cd accumulation and a 3-fold increase in Pb accumulation by mustard compared to the control treatment. EDTA application caused mobilization of Cd and Pb from carbonate, manganese oxide, and amorphous iron oxide fractions, which was evident from decrease in these fractions in the presence of EDTA as compared to the control treatment (no EDTA). 相似文献
14.
In a screen-house study, the effects of artificially contaminating the soil with lead (Pb) at levels ranging from 0 to 1500 mg kg ?1 soil on the growth and uptake of Pb and micronutrients by Indian mustard [ Brassica juncea (L.) Czern.] grown on a loamy sand soil (Typic Ustorthent) were investigated. The crop was grown for 60 days with adequate basal fertilization of nitrogen, phosphorus, and potassium, and dry matter was recorded. The plants were analyzed for total Pb and micronutrients, and the soil was analyzed for diethylenetriaminepentaacetic acid (DTPA)-extractable Pb. The DTPA-extractable Pb measured before sowing of Indian mustard increased consistently and significantly with increase in rates of Pb application to soil. It increased from 0.65 mg kg ?1 in the control to 199.8 mg kg ?1 in soil treated with 1500 mg Pb kg ?1 soil. Significant reduction in the dry-matter yield of Indian mustard occurred with Pb applications of 500 mg kg ?1 soil and greater. The concentration as well as uptake of Pb by Indian mustard increased significantly over control at all rates of its application. It increased from 9.4 μg pot ?1 in the control to 220.6 μg pot ?1 at Pb application of 1500 mg kg ?1 soil. Applications of Pb to the soil decreased the concentration of micronutrients in plants, but a significant reduction occurred only for iron at rates greater than 500 mg Pb kg ?1 soil. However, the uptake of iron, manganese, and copper registered a significant decline at Pb application of 500 mg kg ?1 and greater and that of zinc at 750 mg kg ?1 and greater. In a Typic Ustorthent soil, a DTPA-extractable Pb level of 59.5 mg kg ?1 and plant content of 44.2 μg Pb g ?1 dry matter was found to be the upper threshold levels of Pb for Indian mustard. This study suggests that once the soil is contaminated by Pb, it remains available in the soil for a long time, and such soils, if ingested with food crops, may be a significant source of Pb toxicity to both humans and grazing animals. 相似文献
15.
ABSTRACTCadmium (Cd) in the soil solution is in dynamic equilibrium with the reservoir of bioavailable Cd attached to the solid phase, i.e. the labile pool (Cd E). Traditionally, Cd E is estimated using the radioisotope 109Cd, which has severely restricted access to estimates of Cd E. Using stable isotope dilution and isotope ratio measurement by inductive coupled plasma-quadrupole mass spectroscopy (ICP-QMS) would increase access to estimates of Cd E; however, detail remains scant about the optimal conditions for equilibration and measurement. We report optimal conditions for spiking with 110Cd, batch equilibration and ICP-QMS measurement of the ratio of 110Cd to 111Cd using results for six acidic soils with total Cd concentrations of 0.19–6.4 mg Cd kg ?1, suspended in three background electrolytes (10 mM CaCl 2, 1 M NH 4NO 3, and 1 M NH 4Cl). Our optimised procedure produces robust estimates of Cd E. Application of this approach will greatly increase access to estimates of Cd E and to the investigation of its role in Cd uptake by plants. 相似文献
16.
A greenhouse experiment was designed to determine the cadmium (Cd) and lead (Pb) distribution and accumulation in parsley plants grown on soil amended with Cd and Pb. The soil was amended with 0, 5, 10 20, 40, 60, 80, and 100 mg Cd kg ?1 in the form of cadmium nitrate [Cd(NO 3) 2] and 0, 5, 10, 50 and 100 mg Pb kg ?1 in the form of lead nitrate [Pb(NO 3) 2]. The main soil properties; concentrations of the diethylenetriaminepentaacetic acid (DTPA)–extractable metals lead (Pb), Cd, copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn) in soil; plant growth; and total contents of metals in shoots and roots were measured. The DTPA-extractable Cd was increased significantly by the addition of Cd. Despite the fact that Pb was not applied, its availability was significantly greater in treatments 40–100 mg Cd kg ?1 compared with the control. Fresh biomass was increased significantly in treatments of 5 and 10 mg Cd kg ?1 as compared to the control. Further addition of Cd reduced fresh weight but not significantly, although Cd concentration in shoots reached 26.5 mg kg ?1. Although Pb was not applied with Cd, its concentration in parsley increased significantly in treatments with 60, 80, and 100 mg Cd g ?1 compared with the others. Available soil Pb was increased significantly with Pb levels; nevertheless, the increase was small compared to the additions of Pb to soil. There were no significant differences in shoot and root fresh weights between treatments, although metal contents reached 20.0 mg Pb kg ?1 and 16.4 mg Pb kg ?1 respectively. Lead accumulation was enhanced by Pb treatments, but the positive effect on its uptake was not relative to the increase of Pb rates. Cadmium was not applied, and yet considerable uptake of Cd by control plants was evident. The interactive effects of Pb and Cd on their availability in soil and plants and their relation to other metals are also discussed. 相似文献
17.
PurposeAntibiotics are emerging contaminants of increasing concern in recent years. A total of 71 representative farmland soils along the Fenhe River in Shanxi Province were collected to investigate the occurrence of tetracyclines (TCs), sulfonamides (SAs), and quinolones (QLs). Additionally, the effects of population, livestock and poultry density, and soil properties on antibiotic distribution were also evaluated. Materials and methodsFarmland topsoil samples along the Fenhe River were collected and freeze-dried at ??20 °C. The antibiotics in soils were extracted with a mixture of acetonitrile, EDTA-SPB, and Mg(NO3)2-NH3·H2O at the ratio of 2:1:1 (v/v/v). The extracted antibiotics were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Results and discussionThe antibiotics were universally detected. The detection frequencies of sulfaclozine, enrofloxacin, norfloxacin, and ciprofloxacin reached 100%. Norfloxacin was the most abundant antibiotic in soils (27.21 μg kg?1). The distribution of antibiotics in soils along Fenhe River varied as midstream (8.62 μg kg?1) > downstream (4.58 μg kg?1) > upstream (3.49 μg kg?1). Oxytetracycline along the upstream and midstream was mainly caused by the emission of livestock and poultry and the overuse of human. The main sources of antibiotics along the downstream were livestock and poultry farms. Antibiotics were generally negatively correlated with sand content, pH, and organic matter, while cation exchange capacity had positive correlation with most of antibiotics such as tetracycline, sulfamonomethoxine, enrofloxacin, sulfameter, and sulfachinoxalin. SAs and TCs had little ecological risk, while QLs posed low or medium ecological risks. ConclusionsThis study provided a scientific basis for antibiotic pollution control and agricultural safety supervision along the Fenhe River. Although no high risk of antibiotics was observed in soil samples based on the calculation, the widespread distribution of antibiotics in farmland soil along Fenhe River should be addressed. 相似文献
18.
Purpose The binary competitive effect could obviously influence the fate and transport behavior of oxytetracycline (OTC) and cadmium (Cd 2+) in cinnamon soil. However, two pollutants loading into soil usually are different, perhaps because of the three reasons including occurrence of OTC before Cd 2+, simultaneous occurrence of OTC and Cd 2+, or occurrence of Cd 2+ before OTC. The purpose of the study was to predict the competitive adsorption and desorption of OTC and Cd 2+ as a function of above input loadings on cinnamon soil. Materials and methods Adsorption and desorption were determined using the batch equilibrium method in a single or binary system. The Freundlich equation was applied to describe the adsorption/desorption data of OTC and Cd 2+ in order to obtain adsorption/desorption isotherms for each tested compound and the respective adsorption/desorption coefficients. Results and discussion The results indicated that cinnamon soil could strongly adsorb OTC with the adsorption affinity ( K f value) of more than 718 and Cd 2+ with K f value of more than 536 in the competitive and non-competitive system, and all adsorption and desorption isotherms of OTC and Cd 2+ on cinnamon soil were well fitted by the Freundlich equation with r value of more than 0.99 ( p?<?0.01). The coexistence of OTC and Cd 2+ on cinnamon soil promoted significantly Cd 2+ adsorption when Cd 2+ firstly or simultaneously occurred on soil, but their coexistence did not affect adsorption of OTC when OTC firstly or simultaneously occurred on soil. Among the three input loadings, the pollutant with later occurring mode had lower K f and hysteresis coefficient (HI) than the other two input loadings. According to the adsorption intensity parameter (1/ n), the presence of Cd 2+ or OTC with different input loadings could decrease the adsorption intensity of OTC or Cd 2+ when compared with single occurrence of OTC or Cd 2+. Conclusions The binary competitive effect influenced the adsorption/desorption of OTC and Cd 2+ differently. The presence of OTC had a stronger influence on the adsorption/desorption of Cd 2+ than the presence of Cd 2+ on the adsorption of OTC. The later occurring pollutant on soil had stronger ecological risk than the former occurring pollutant in the binary competitive system. The physical adsorption in the single or binary system could be identified as the dominant mechanisms of OTC and Cd 2+ adsorption. 相似文献
19.
Abstract A pot experiment was conducted to investigate the effects of three soluble zinc (Zn) fertilizers on cadmium (Cd) concentrations in two genotypes of maize ( Zea mays): Jidan 209 and Changdan 374. Zinc fertilizers were added to soil at four levels: 0, 80, 160, and 240 mg kg ?1 soil as nitrate [Zn(NO 3) 2], chloride (ZnCl 2), and sulfate (ZnSO 4). Cadmium nitrate [Cd(NO 3) 2] was added to all the treatments at a uniform rate equivalent to 10 mg kg ?1 soil. The biomass of maize plants was increased with the application of three zinc fertilizers, of which Zn(NO 3) 2 yielded more than others. Under ZnCl 2 treatment, plant growth was promoted at the lower level and depressed at the higher one. All the three fertilizers decreased Cd concentration in shoots in comparison with treatments without Zn, but there were variations with different forms, especially in plants treated with Zn(NO 3) 2, which had the minimal value. The orders of average Cd concentration in shoots with different zinc fertilizers were ZnSO 4>ZnCl 2>Zn(NO 3) 2 for Jidan 209 and ZnCl 2>ZnSO 4>Zn(NO 3) 2 for Changdan 374, respectively (P<0.001). There was no significant difference between ZnSO 4 and ZnCl 2 treatments. The lowest Cd concentration in shoots was found in the 80‐mg‐kg ?1 soil or 160‐mg‐kg ?1 soil treatment. Cadmium concentration in roots in the presence of ZnCl 2 was the lowest and under ZnSO 4 the highest. The mechanism involved needs to be studied to elucidate the characteristics of complexation of Cl ? and SO 4 2? with Cd in plants and their influence on transfer from roots to shoots. 相似文献
20.
Abstract The aim of study was to find the correlation between the concentration of the total amount of heavy metals of soils and that of plants because it shows which elements can be accumulated by different plants. The transfer coefficient is the metal concentration in plant tissues aboveground divided by the total metal concentration of soil. Pot experiments were conducted under greenhouse conditions. The total lead (Pb) content (about 21 mg · kg ?1 soil) of soils was higher than the cadmium (Cd) content (about 0.21 mg · kg ?1 soil). The Cd concentration of lettuce (averaging 0.93 mg · kg ?1) was higher than that of ryegrass (averaging 0.20 mg · kg ?1). The transfer coefficient of Cd was lower in ryegrass (averaging 0.95) than in lettuce (4.47). In this experiment, the concentration of Cd was almost five times higher in the four‐leaf lettuce than the Cd content of soil. The transfer coefficient of Pb was generally 0.064 in both plants. 相似文献
|
