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1.
在积累镉油菜后茬种植白菜可否减少其对镉的吸收?   总被引:2,自引:0,他引:2  
Rapeseed (Brassica campestris L.), a Cd-accumulating crop, is effective in reducing plant-available Cd from soil. A pot experiment was conducted to test the hypothesis that the Cd uptake by Chinese cabbage (Brassica pekinensis Rupr.) grown in rotation with rapeseed would be reduced due to the efficient removal of bioavailable Cd from soil solution by the rapeseed crops. The Cd removal by shoot for the rapeseed cultivar Zhucang Huazi ranged from 0.24% to 0.99% in natural Cd-contaminated soil (soil A) and from 0.63% to 1.23% in artificial Cd-contaminated soil (soil B) during the growth period of 4–7 weeks; whereas that for the rapeseed cultivar Chuanyou II-93 ranged from 0.25% to 0.66% and from 0.38% to 1.02%, respectively. Chinese cabbage grown in the pots with soil A for five weeks after harvesting rapeseed exhibited a significantly lower Cd concentration compared to that grown in the control pots (uncropped with rapeseed). However, the rotation of rapeseed did not lower the Cd concentration of Chinese cabbage on soil B. Although an increase of Cd uptake was observed in the rapeseed cultivars with growth time, and the decrease of soil NH 4 OAc-extractable Cd was found only in the natural rather than artificial Cd-contaminated soil.  相似文献   

2.
The behaviour of metals mainly depends on soil p H, carbonate contents and contamination level, which should be considered for the management of contaminated soils. In this study, kitchen garden topsoils(0–25 cm) were sampled from the area around three smelters in France, with different Cd and Pb contamination levels. Effect of a phosphate amendment(a mixture of diammonium phosphate and hydroxyapatite) on the environmental availability and phytoavailability of Cd and Pb was evaluated by different chemical extractions and cultivating lettuce(Lactuca sativa L.), respectively. Changes in the distribution of Cd and Pb were found in most contaminated soils after phosphate amendment. An increase of Cd and Pb in the residual phase was highlighted in almost all carbonated contaminated soils, whereas a decrease of Pb in the exchangeable, water and acid-soluble phase was observed in most contaminated soils with the lowest carbonate contents. The concentrations of extractable Cd and Pb using calcium chloride and acetic and citric acids generally decreased after the soil amendment. Lettuces grown on amended soils were acceptable for human consumption as regard to Pb concentration. In contrast, some lettuces were unacceptable for human consumption, since the concentrations of Cd in the leaves were higher than the European legislation limit. Surprisingly, in carbonated soils with very low concentration of Cd, the Cd concentrations in lettuce reached up to the European legislation limit, making the lettuce unacceptable for human consumption.Our study highlighted the fact that the total metal concentration in soils does not always allow to predict the metal accumulation in the edible parts of vegetables in order to make a judgement about their acceptability or unacceptability for human consumption.  相似文献   

3.
Inoculating soil with an adapted microbial community is a more effective bioaugmentation approach than inoculation with pure strains in bioremediation.However,information on the potential of different inocula from sites with varying contamination levels and pollution histories in soil remediation is lacking.The objective of the study was to investigate the potential of adapted microorganisms in soil inocula,with different contamination levels and pollution histories,to degrade 1,2,4-trichlorobenzene (1,2,4-TCB).Three different soils from chlorobenzene-contaminated sites were inoculated into agricultural soils and soil suspension cultures spiked with 1,2,4-TCB.The results showed that 36.52% of the initially applied 1,2,4-TCB was present in the non-inoculated soil,whereas about 19.00% of 1,2,4-TCB was present in the agricultural soils inoculated with contaminated soils after 28 days of incubation.The soils inoculated with adapted microbial biomass (in the soil inocula) showed higher respiration and lower 1,2,4-TCB volatilization than the non-inoculated soils,suggesting the existence of 1,2,4-TCB adapted degraders in the contaminated soils used for inoculation.It was further confirmed in the contaminated soil suspension cultures that the concentration of inorganic chloride ions increased continuously over the entire experimental period.Higher contamination of the inocula led not only to higher degradation potential but also to higher residue formation.However,even inocula of low-level contamination were effective in enhancing the degradation of 1,2,4-TCB.Therefore,applying adapted microorganisms in the form of soil inocula,especially with lower contamination levels,could be an effective and environment-friendly strategy for soil remediation.  相似文献   

4.
镉在中性和碱性土柱中不同深度处的运移模拟   总被引:2,自引:0,他引:2  
Human health has been potentially threatened by cadmium (Cd) contained in sewage irrigation water.Previous studies of Cd transport in soils were mainly conducted using small soil cores with pH values less than 6.The objectives of this study were to determine the parameters of the convection-dispersion equation (CDE) for Cd transport in relatively larger columns with neutral and alkaline soils,and to investigate the parameters' variability with depth.The soil columns were 50 cm in length and 12.5 cm in diameter.Ceramic suction lysimeters were buried at depths of 2.5,7.5,17.5,27.5,and 37.5 cm to abstract soil solution.Cd concentration in the soil solution samples were subsequently analyzed to obtain breakthrough curves (BTCs).Equilibrium and nonequilibrium models in CXTFIT program were used to estimate parameters of the CDE.The results suggested that both equilibrium and non-equilibrium models performed well in modeling Cd transport.The hydrodynamic dispersion coefficient (D) ranged from 0.18 to 10.70 cm 2 h 1,showing large differences among different depths.The retardation factor (R d) ranged from 25.4 to 54.7 and the standard deviation of R d value was lower than 30% of the mean value.Precipitation coefficient (R p) decreased consistently with increasing depth,varying from 1.000 × 10 10 to 0.661 h 1.Sensitivity tests showed that D was less sensitive than R d.These results would be helpful in understanding the transport and retention of Cd in non-acidic soils.  相似文献   

5.
Batch equilibrium experiments were conducted to investigate cadmium (Cd) sorption by two permanent-charge soils, a yellow-cinnamon soil and a yellow-brown soil, and two variable-charge soils, a red soil and a latosol, with addition of selected organic acids (acetate, tartrate, and citrate). Results showed that with an increase in acetate concentrations from 0 to 3.0 mmol L^-1, Cd sorption percentage by the yellow-cinnamon soil, the yellow-brown soil, and the latosol decreased. The sorption percentage of Cd by the yellow-clnnamon soil and generally the yellow-brown soil (permanent-charge soils) decreased with an increase in tartrate concentration, but increased at low tartrate concentrations for the red soil and the latosol. Curves of percentage of Cd sorption for citrate were similar to those for tartrate. For the variable-charge soils with tartrate and citrate, there were obvious peaks in Cd sorption percentage. These peaks, where organic acids had maximum influence, changed with soil type, and were at a higher organic acid concentration for the variable-charge soils than for the permanent charge soils. Addition of cadmium after tartrate adsorption resulted in higher sorption increase for the varlable-charge soils than permanent-charge soils. When tartrate and Cd solution were added together, sorption of Cd decreased with tartrate concentration for the yellow-brown soil, but increased at low tartrate concentrations and then decreased with tartrate concentration for the red soil and the latosol.  相似文献   

6.
Profile characteristics of accumulated P in 10 representative soils of vegetable fields in suburban districts of Beijing were investigated. Bioavailability of the accumuIated P and its potential effect on the environment were studied in a greenhouse pot experiment and a soil column experiment. The results showed that theconcentration of Olsen-P in the 0-20 cm soil samples of the vegetable fields ranged from 22.1 to 358.0 mg kg-1, which was 2 to 10 times higher than that of the crop fields in the suburbs of Beijing. Most of theexcessive phosphorus was accumulated in the topsoils. The longer the soils cultivated with vegetables, thehigher the soil total P, Olsen-P and organic matter concentration. Accumulated P in the soils from vegetablefields had higher bioavailability. Application of phosphorus fertilizer could not increase the dry weights ofcucumbers, Chinese cabbage, and rape seedlings continuously planted. The soil column study showed high P concentration (> 0.6 mg L-1) in the leachates from the columns of the vegetable field soils with high accumulated P, which has a potential effect on the groundwater and natural water quality.  相似文献   

7.
Diffusion coefficients of chlorde ions in four soils of different exture with varying effective moisture content and varying bulk density from 1.1 to 1.6 g cm^3 under three different temperatures were determined by the diffusion-cell method using ^36Cl-labelled CaCl2 solution.The result showed that activation energy decreased with water content,which indicated that the threshold fro diffusion was lower at a higher soil moisture rate .Therefor,the diffusion coefficient(D) of chloride ions in soil increased consistently with soil moisture,Although a near linear increase in the diffusion coefficient with increasing soil moisture or bulk density in all the soils was observed,the increase rate in different soils was not the same.The D value increased with teperature,and with temperature increased by 10℃ in the range from 5℃to 45℃ the D valve increased by 10%-30%,averaging about 20%.  相似文献   

8.
High concentrations of antimony(Sb) in soils and vegetables can cause potential health risk. However, the effect of Sb on the growth and response of crops are not well known and to date, there is still no Sb limit standard for Allitic Udic Ferrisols in China. In this study, a greenhouse experiment was carried out to investigate the effect of antimony(Sb) on biomass, physiological performances,and macro- and micronutrient element concentrations of green Chinese cabbage(Brassica chinensis L.), as well as enzyme activities,in Allitic Udic Ferrisols from Hunan Province, China. Antimony was supplied at rates of 0(control), 2, 5, 10, 20, and 50 mg kg-1and thus with the background value of 1.0 mg kg-1, the Sb concentrations in the treated soil samples were 1, 3, 6, 11 21, and 51 mg kg-1, respectively. The results showed the leaf biomass and ascorbic acid content of cabbage significantly(P < 0.05) decreased by 30.6% and 48.3%, respectively, and soil urease and dehydrogenase activities also significantly(P < 0.05) decreased by 33.6%and 32.5%, respectively, when soil Sb concentration was 21 mg kg-1as compared with the control. The uptake of essential nutrient elements such as Mg, Cu, and Zn by cabbage was obviously affected, while the leaf soluble sugar content slightly changed when the soil Sb concentration exceeded 21 mg kg-1. Based on cabbage physiological responses and soil enzyme activities, the permissible concentration of 21 mg kg-1for Sb in Allitic Udic Ferrisols should be recommended.  相似文献   

9.
北京城乡交错带土壤重金属的空间变异特征   总被引:22,自引:0,他引:22  
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10.
In order to optimise land use systems, to prevent erosion-induced degradation and to restore the degraded red soils in subtropical China, five cropping systems and four agroforestry systems were conducted in red soils with a slope of 7° from 1993 to 1995. The results showed that erosion risk period occurred from April to June, and the annual runoff and the losses of soil and nutrients with sediment were alarming for two conventional farming systems, whereas they were negligible for the farming systems with ridge tillage. Enrichment ratios of the lost soils from erosion were more than 1.20 for all nutrients with much higher values for hydrolysable N and organic matter. Compared with the control, the alley cropping systems also distinctly decreased runoff by 30% or 50%. However, the coverage of soil surface varied with alley cropping systems for the competition of nutrients and soil water, which made a profound difference in runoff. The cropping systems of sweet potato intercropped with soybean, the alley cropping systems and the measures of mulching and ridge tillage were the alternatives for red soil reclamation so as to prevent erosion-induced degradation.  相似文献   

11.
Chinese cabbage and surface soil samples (0–20 cm) from a periurban market garden in Yunnan Province (P.R. China) were collected to determine variations of cadmium (Cd) and zinc (Zn) contents in Chinese cabbage and the influence of soil factors. Mean Cd content was 0.49 mg kg?1 dry materials (DM) in Chinese cabbage, ranging between 0.23 and 1.34 mg kg?1 DM (n = 21 samples). Mean Zn content was 51.2 mg kg?1 DM, ranging from 34.9 to 157.5 mg kg?1 DM (n = 21 samples). The soil factors best predicting Chinese cabbage Cd and Zn contents were total and available Cd and Zn contents and cation exchange capacity (CEC). Soil samples and corresponding Chinese cabbage samples were divided into two groups: soils with low pH (<6.5, n = 10) and soils with high pH (>6.5, n = 11). Positive correlation between CEC with pH > 6.5 and Cd and Zn contents in Chinese cabbage were observed. Available trace element contents and CEC explained 77% and 69% of variation of Cd and Zn contents in Chinese cabbage, respectively. AEC (enrichment coefficient related to trace element availability) and BCF (bioaccumulation factors) could be used to understand Cd and Zn accumulation in Chinese cabbage.  相似文献   

12.

Purpose

The area of cadmium (Cd)-contaminated soil in China is increasing due to the rapid development of the Chinese economy. To ensure that the rice produced in China meets current food safety and quality standards, the current soil quality standards for paddy soils urgently need to be updated.

Materials and methods

We conducted a pot experiment with 19 representative paddy soils from different parts of China to study the effects of soil properties on bioaccumulation of Cd in rice grains. The experiment included a control, a low treatment concentration (0.3 mg kg–1 for pH?<?6.5 and 0.6 mg kg–1 for pH?≥?6.5), and a high treatment concentration (0.6 mg kg–1 for pH?<?6.5 and 1.2 mg kg–1 for pH?≥?6.5) of Cd salt added to soils.

Results and discussion

The results showed that the Cd content in grains of the control and low and high Cd treatments ranged from 0.021 to 0.14, 0.07 to 0.27, and 0.12 to 0.33 mg kg–1, respectively. Stepwise multiple regression analysis indicated that soil pH and organic carbon (OC) content could explain over 60 % of the variance in the (log-transformed) bioaccumulation coefficient (BCF) of Cd in grains across soils. Aggregated boosted trees analysis showed that soil pH and OC were the main factors controlling Cd bioavailability in paddy soils. Validation of the models against data from recent literature indicated that they were able to accurately predict the BCF in paddy soils.

Conclusions

These quantitative relationships between the BCF of Cd in grains and soil properties are helpful for developing soil-specific guidance on Cd safety threshold value for paddy soils.  相似文献   

13.
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   

14.
菌渣生物炭对镉污染土壤性质及小白菜吸收镉的影响   总被引:9,自引:0,他引:9  
为探讨以菌渣为原料制备的生物炭修复重金属镉污染土壤的可行性。采用盆栽试验,以香菇菌渣生物炭(SC)和平菇菌渣生物炭(PC)为研究对象,设置0.5%,1%,2%的生物炭施用量(w/w,%),研究其对镉污染土壤理化性质、土壤各形态镉分布、小白菜生长及镉吸收的影响。结果表明:施用SC和PC均能显著提高土壤pH和有机质(SOM)含量。与对照相比,2%的生物炭处理,土壤pH分别提高1.05和1.10个单位,SOM含量分别提高80.6%和61.2%。施用SC和PC使土壤可交换态镉降低,而提高残渣态镉含量。相关分析表明,土壤可交换态镉与pH、SOM和蔗糖酶呈显著负相关。与对照相比,2%处理下SC和PC显著降低小白菜镉含量,分别降低57.5%和54.1%;1%用量下小白菜产量分别提高53.4%和41.6%,表明高投加量菌渣生物炭对小白菜生长有不利影响。总体看来,SC和PC均有利于改善土壤性质,减轻镉对植物的毒害,促进小白菜生长。  相似文献   

15.
Pot and field experiments were carried out from 1994 to 1997 to investigate Cd and Tl uptake by various genotypes of maize, spring rape and kale on soils contaminated with i) Cd by the addition of river sediments (aqua regia-extractable Cd: 24 mg kg—1 soil) and ii) with Tl by deposits from a cement plant (HNO3-extractable Tl:1.4 mg kg—1 soil). In field experiments on the Cd-contaminated soil, Cd concentrations in shoots and kernels of fifty maize inbred lines differed by a factor of about twenty (from < 1 to 15 mg Cd kg—1 DM in shoots and from 0.02 to 0.5 mg Cd kg—1 DM in kernels). After crossing inbred lines having high and low Cd concentration, Cd concentration of the resulting hybrids decreased, mainly as a result of a higher dry matter production (a dilution effect). In pot and field experiments on the Tl-contaminated soil, the selected cultivars of spring rape showed only small differences in Tl uptake, whereas Tl concentration in shoots of the kale cultivars differed more than twenty-fold (in the pot experiment from < 1 to 24 mg Tl kg—1 DM and in the field experiment from 0.5 to 11.7 mg Tl kg—1 shoot DM). Two groups of cultivars with low and high Tl concentrations could be distinguished. A nutrient solution experiment with radioactively labeled Tl showed that higher Tl concentration of kale in comparison to white cabbage can be attributed mainly to a higher uptake rate in kale (about 30-fold) with subsequent root-to-shoot translocation. The results show that, depending on plant species, selection and growing of cultivars with low heavy metal uptake on contaminated soils can substantially contribute to reduce the concentration of Cd and Tl in food and fodder plants.  相似文献   

16.
目的

本研究旨在了解连续5年施鸡粪发酵有机肥、生石灰和Si-Ca-Mg土壤调理剂后,对水稻根际土壤镉(Cd)活性、水稻各部位Cd累积量和转运系数产生的累积作用效果。

方法

选取Cd污染风险管制的酸紫泥田为研究对象,应用大田配对试验,于2015年开始单施三种钝化剂,并于2019年晚稻黄熟期,采集土壤及植株样品,测定根际土壤和水稻各部位Cd含量,研究根际土壤Cd活性和水稻各部位Cd的累积及转运对连续5年钝化剂施用的响应。

结果

连续施有机肥、石灰和土壤调理剂处理后,分别显著降低水稻糙米、茎叶和根系Cd含量60% ~ 75%、40% ~ 77%和17% ~ 48%(P < 0.05);其中,连续施石灰、土壤调理剂处理后,糙米Cd平均含量降至国家食品中污染物限量值(0.2 mg kg−1)以下。此外,连续施有机肥、石灰和土壤调理剂后,分别显著降低了Cd由水稻根系向茎叶、茎叶向糙米的转运系数26% ~ 38%、29% ~ 58%和根际土壤DTPA提取态Cd(DTPA-Cd)含量13% ~ 33%,但也提高了根际土壤pH值0.2 ~ 0.9个单位,根际土壤活性有机碳和速效养分含量也呈上升趋势(P < 0.05)。糙米Cd含量主要与水稻植株Cd转运系数、土壤pH、DTPA-Cd、交换态钙和络合态铁含量相关。

结论

土壤Cd污染风险管制的酸紫泥田,连续5年施生石灰、Si-Ca-Mg土壤调理剂后,可实现稻米达标生产。稻米Cd累积量下降与水稻根际土壤Cd活性降低、植株Cd富集转运能力降低有关。

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17.
A pot experiment was conducted to investigate the influence of phosphate (P) application on diethylene triamine pentaacetic acid (DTPA)–extractable cadmium (Cd) in soil and on growth and uptake of Cd by spinach (Spinacia oleracea L.). Two soils varying in texture were contaminated by application of five levels of Cd (NO3)2 (0, 20, 30, 40, and 60 mg Cd kg–1). Three levels of KH2PO4 (0, 12, and 24 mg P kg–1) were applied to determine immobilization of Cd by P. Spinach was grown for 60 d after seeding. Progressive contamination of soils through application of Cd affected dry‐matter yield (DMY) of spinach shoot differently in the two soils, with 67% reduction of DMY in the sandy soil and 34% in the silty‐loam soil. The application of P increased DMY of spinach from 4.53 to 6.06 g pot–1 (34%) in silty‐loam soil and from 3.54 to 5.12 g pot–1 (45%) in sandy soil. The contamination of soils increased Cd concentration in spinach shoots by 34 times in the sandy soil and 18 times in the silty‐loam soil. The application of P decreased Cd concentration in shoot. The decrease of Cd concentration was higher in the sandy soil in comparison to the silty‐loam soil. Phosphorus application enhanced DMY of spinach by decreasing Cd concentration in soil as well as in plants. The results indicate that Cd toxicity in soil can be alleviated by P application.  相似文献   

18.
Solution cadmium (Cd) concentrations and sorption and desorption of native and added Cd were studied in a range of New Zealand soils. The concentration of Cd in solution and the concentrations and patterns of native soil Cd desorbed and added Cd sorbed and desorbed varied greatly between the 29 soils studied. Correlation analysis revealed that pH was the most dominant soil variable affecting solution Cd concentration and sorption and desorption of native and added Cd in these soils. However, organic matter, cation exchange capacity (CEC) and total soil Cd were also found to be important. Multiple regression analysis showed that the log concentration of Cd in solution was strongly related to soil pH, organic matter and total Cd, which in combination explained 76% of the variation between soils. When data from the present study were combined into a single multiple regression with soil data from a previously published study, the equation generated could explain 81% of the variation in log Cd solution concentration. This reinforces the importance of pH, organic matter and total Cd in controlling solution Cd concentrations. Simple linear regression analysis could at best explain 53% of the total variation in Cd sorption or desorption for the soils studied. Multiple regression analysis showed that native Cd desorption was related to pH, organic matter and total Cd, which in combination explained 85% of the variation between soils. For sorption of Cd (from 2 μg Cd g–1 soil added), pH and organic matter in combination explained 75% of the variation between soils. However, for added Cd desorption (%), pH and CEC explained 77%. It is clear that the combined effects of a range of soil properties control the concentration of Cd in solution, and of sorption and desorption of Cd in soils. The fraction of potentially desorbable added Cd in soils could also be predicted from a soil’s Kd value. This could have value for assessing both the mobility of Cd in soil and its likely availability to plants.  相似文献   

19.
通过温室盆栽试验和土壤培养试验,研究了重金属镉污染水稻土和人为模拟镉污染土壤上不同种类和不同量的作物秸秆还田后,土壤中可提取态镉的动态变化规律以及对白菜生长和吸收重金属镉的影响。结果表明,秸秆还田显著提高了2种镉污染土壤的pH值。镉污染水稻土上还田玉米和菜豆秸秆显著提高了土壤中醋酸铵提取态镉和DTPA提取态镉含量,秸秆还田后2周时醋酸铵提取态镉含量增加了17%~33%,随时间延长,土壤中可提取态镉增加变的不明显。模拟镉污染土壤上还田玉米和菜豆秸秆对土壤中醋酸铵提取态镉和DTPA提取态镉含量影响不明显。镉污染水稻土上秸秆还田量2%时显著降低了白菜体内镉含量,还田菜豆秸秆和玉米秸秆白菜体内镉含量分别降低了18%和27%。还田玉米秸秆影响了白菜生长,降低了白菜的产量;模拟镉污染土壤上还田菜豆秸秆对白菜生长和镉含量影响不明显,但还田2%玉米秸秆降低了白菜生物量,增加了白菜镉含量。  相似文献   

20.
Abstract

The cadmium (Cd) accumulation capacity of various vegetables and the relationship between Cd concentrations in edible parts of vegetables and those in soils were assessed by conducting field experiments at Cd-contaminated sites in northern and central Taiwan. In addition, to thoroughly assess Cd concentrations in vegetables and to understand the food safety of vegetables in Taiwan, 2257 paired vegetable and surface soil samples were collected from major vegetable production areas for Cd concentration analysis. According to the bioconcentration factors calculated, the Cd accumulation capacity varied considerably among the vegetable species tested, and the order of the five vegetables with the highest capacities is peanut (Arachis hypogaea L.) > amaranth (Amaranthus tricolor L.) > spinach (Spinacia oleraceae L.) > gynura (Gynura bicolor DC.) > okra (Hibiscus esculentus L.), whereas the order of the five vegetables with the lowest capacities is bitter gourd (Momordica charantia L.) < cucumber (Cucumis sativus L.) < asparagus bean (Vigna unguiculata (L.) Walp. ssp. sesquipedalis (L.) Verdc.) < snap bean (Phaseolus vulgaris L.) < sponge gourd (Luffa cylindrica Roem.). We derived 29 soil–plant transfer models of Cd for individual vegetable species based on available pools of the Cd, manganese (Mn), zinc (Zn), copper (Cu) and iron (Fe) concentrations; soil pH; and cation exchange capacity (CEC). According to the derived models, the available Cd, Mn and Zn concentrations, and pH, served as the main factors affecting Cd concentrations in the edible parts of vegetables, whereas the CEC and available Cu and Fe concentrations are less important factors. The data of previous studies and those of this study from major vegetable production areas, including 30 vegetable crops, were used to evaluate the safety of vegetables in Taiwan. The results indicated that the percentage of vegetables with Cd concentrations exceeding the regulatory concentration was 0.54%; therefore, the food safety concern is low. However, 9.8, 1.0, 0.9 and 0.6% of amaranth, cabbage (Brassica oleracea L. Capitata Group), Chinese cabbage (Brassica pekinensis Skeels.) and carrot (Daucus carota L.), respectively, had Cd concentrations in the edible parts exceeding the regulatory concentration. Particular attention should be paid when planning production areas for these vegetables. We recommend cultivating peanuts in fields with a soil Cd concentration < 0.33 mg kg?1. The bioconcentration factors and soil–plant transfer models derived in this study might serve as assessment tools for planning farming areas for these vegetables.  相似文献   

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