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1.
《毒物与环境化学》2012,94(3-6):281-299
Abstract

To investigate metal nanoparticle-induced phytotoxicity, Brassica nigra seeds were exposed to 50–1000?mg L?1 ZnO nanoparticles in culture media and 100–1000?mg kg?1 in soil. Plant length and weight were adversely affected in culture conditions, but with soil the effect was not significant. Determination of the radical-scavenging potential revealed that soil grown plants were less stressed than plants grown on culture medium. The total antioxidant and reducing power potential of soil grown plants were less variable compared to plants grown on culture medium. Total phenolic and flavonoid concentrations varied in plants, which changed with the nanoparticle’s concentrations in medium and soil. High performance liquid chromatography analysis showed that rutin was the major antioxidative molecule that significantly increased in nanoparticles-stressed B. nigra plants.  相似文献   

2.
The level of accumulation of selected essential and non-essential metals, namely; Ca, Cu, Fe, Zn, Mn, Cd, Pb, and Cr have been investigated in the seeds, fruits, and flowers of some medicinal plants utilized for tapeworm treatment in Ethiopia and their respective soil samples. These include seed of Cucurbita maxima (Duba), fruit of Embelia abyssinica (Ankoko), flowers of Hagenia abyssinica (Kosso), and fruits of Rosa abyssinica (Kega) and their respective soil samples. A wet digestion procedure with a mixture of conc. HNO3 and HClO4 for the plant samples and a mixture of conc. HNO3, HCl, and H2O2 for soil samples were used to solubilize the metals. Ca (1280–12,670?mg?kg?1) was the predominant metal followed by Fe (104–420?mg?kg?1), and Zn (18–185?mg?kg?1) in all the plant materials except for Hagenia abyssinica flower from Hirna in which Mn (16–42?mg?kg?1) followed by Fe. Among the non-essential toxic metals, Pb was not detected in Cucurbita maxima of Boji, Gedo and Hirna origins and in Rosa abyssinica of Hirna site. Similarly, Cr was not detected in Rosa abyssinica fruits of Boji and Gedo sites. The sampled soils were found to be between strongly acidic to weakly basic (pH: 4.7–7.1). In the soil samples, Ca (8528–18,900?mg?kg?1) was the most abundant metal followed by Fe (417–912?mg?kg?1), Zn (155–588?mg?kg?1), Mn (54–220?mg?kg?1), Cr (21–105. mg?kg?1), Cu (11–58?mg?kg?1), Pb (13–32?mg?kg?1) and Cd (2.8–4.8?mg?kg?1). The levels of most of the metals determined in the medicinal plants and the respective soil samples are in good agreement with those reported in the literature and the standards set for the soil by various legislative authorities.  相似文献   

3.
Present study aimed to investigate the bio-monitoring study of particulate matter (PM) pollutants of 12 roadside plant species, in Aizawl, Mizoram, India (an Indo-Burma hot spot region). While, the second part was ascribed to the bio-magnetic monitoring stidies. Pertaining to first part of study, highest dust deposition was noted for Ramrikawn (RKN-Med) site on Ficus bengalensis (1.2?mg?cm?2) and lowest in Bauhinia variegate (0.8?mg?cm?2). Further, increased concentration of heavy metals (Fe, Cu and Zn) was recorded at RKN-Med site. Roadside plant leaves of F. bengalensis recorded maximum accumulation of Fe (26.1?mg?kg?1) and Cu (19.5?mg?kg?1) while Cassia auriculata (12.1?mg?kg?1) showed lowest accumulation of Fe. B. variegate (1.88?mg?kg?1) recorded lowest accumulation of Cu. Zn was recorded maximum (48.2?mg?kg?1) in Mangifera indica while B. variegate showed lowest accumulation of 11.3?mg?kg?1 Cu at Ramrikawn site. In relation to second part of the study, M. indica, Ficus benghalensis, Psidium guajava and Artocarpus heterophyllus were found to be efficient in bio-magnetic monitoring because all the magnetic properties (magnetic susceptibility, anhysteretic remanent magnetisation and isothermal remanent magnetisation) were high and significantly correlated with ambient PM (R2?=?0.424 to R2?=?0.998) thus may act as proxy for ambient PM.  相似文献   

4.
The aim of this study is to determine the contents of aluminum, iron, manganese, nickel, copper, zinc, chromium, cadmium, lead, and mercury in sediments at 1–30?m depths of the Band?rma and Erdek Gulfs in the Southern Inner Shelf of the Marmara Sea. Sediment samples were collected from different depths (1?m, 5?m, 10?m, 20?m, 30?m) at each region in February 2008. Primary hydrographic conditions, such as temperature (6.6–14.5°C), salinity (22.6–26.875 psu), percentage of dissolved oxygen saturation (35–83 %), and pH (8.0–8.4) were recorded for each sampling point. Moreover the total organic carbon (0.5–2.9%) and the total calcium carbonate contents (0.8–60%) of sediment samples were determined. In surface sediments of both gulfs, Pb (21–62?mg?kg?1) and Cd (0.52–0.86?mg?kg?1) contents were determined to be higher than the shale average (Pb 20?mg?kg?1, Cd 0.2?mg?kg?1) while the other metal contents were measured to be lower in general. On the other hand, generally Hg (0.06–1.1?mg?kg?1) contents were higher than the shale average (0.3?mg?kg?1)at all of the examined stations in the Band?rma Gulf and lower than the shale average in the Erdek Gulf.  相似文献   

5.
This study determined the heavy metal concentration in soil and plants at a bone char site in Umuahia, Nigeria. Soil and plant samples collected in a randomized complete block design (RCBD) were analyzed for zinc (Zn), lead (Pb), cadmium (Cd), nickel (Ni), and arsenic (As). The concentration of metals in soil and plants in the vicinity of the bone char site are as follows: Zn (172?mg?kg?1) and Ni (0.62?mg?kg?1) in soil were highest at site P3, Pb (2.37?mg?kg?1) and As (0.08?mg?kg?1) at site P1, and Cd (18.30?mg?kg?1) at site P2. In plants, the concentrations of Zn (41.17?mg?kg?1) and Cd (3?mg?kg?1) were highest in Albizia ferruginea, Ni in Dialium guineense (0.09?mg?kg?1), while Pb was in D. guineense (0.08?mg?kg?1) and Spathodea companulata (0.06?mg?kg?1). The levels of Zn, Cd, Pb, Ni, and As in soil ranged from 11.2 to 172, 2.68 to 18.2, 0.026 to 2.37, 0.33 to 0.62, and 0.02 to 0.08?mg?kg?1, respectively. In plants, the concentration of Zn, Cd, Pb, and Ni ranged from 2.01 to 41.17, 0.12 to 3, 0.02 to 0.08, and 0.03 to 0.09?mg?kg?1, respectively. There were significant correlations between Zn and Cd, and Pb and As in soil. The high concentration of Cd in soil might affect soil productivity.  相似文献   

6.
A study on the toxicokinetic behavior, metabolism of chlorpropham, and its effect on cytochrome P450 from liver microsomes was carried out in albino rats after a single and consecutive oral administration at 500?mg?kg?1 body weight for 10 and 20 days. Chlorpropham was detected in the blood at 0.08?h (11.43?±?1.72?µg?mL?1) reaching a maximum concentration at 2?h (30.90?±?2.55?µg?mL?1) and a minimum at 48?h (1.95?±?0.20?µg?mL?1) after a single oral administration of 500?mg?kg?1. The absorption rate constant (K a) was 0.66?±?0.48?h?1. The Vd area (18.01?±?2.78?L?kg?1) and t 1/2 β (12.23?±?1.96?h) values suggested a wide distribution and long persistence of the compound in the body, respectively. The higher ClR (0.82?±?0.00?L?kg?1?h?1) compared to ClH (0.18?±?0.02?L?kg?1?h?1) value indicated that a major portion of chlorpropham was excreted through the urine (30%) compared to the faeces (2.81%). Chlorpropham residue was detected in all tissues of rat at 0.25?h while its metabolite, meta-chloroaniline was detected in liver, kidney, heart, lung, and spleen tissue at 0.25?h. Meta-chloroaniline was not detected in skeletal muscle, brain, fat, and stomach tissue at any time of the observation period. Maximum concentrations of chlorpropham and meta-chloroaniline were detected at 2?h (except in the spleen), and minimum concentrations of chlorpropham at 24 (heart, lung, spleen, skeletal muscle, and stomach) and 48?h (liver, kidney, brain, and fat tissue) respectively; and meta-chloroaniline at 24?h (except heart and spleen). The tissue half-life of chlorpropham in rat varied from 3.80 to 11.60?h. Repeated oral administration of chlorpropham at 500?mg?kg?1 for 10 and 20 days caused an induction of the liver microsomal pellet of rat.  相似文献   

7.
This study determined the concentration of three heavy metals zinc (Zn), lead (Pb), and cadmium (Cd) in soil and in a woody plant species, Milicia excelsa, at Ishiagu quarry, Nigeria. The highest soil concentrations of Zn, Pb, and Cd in soil were obtained at 1?m from the quarry site. In M. excelsa, the highest concentrations of Zn, Pb, and Cd were 3.12–9.1, 3.9–6.01, and 0.51–1.12?mg?kg?1, respectively. There were significant positive correlations between Cd and Zn (r?=?0.963) and Cd and Pb (r?=?0.974) in plants as well as between Cd and Pb (r?=?9.84) in soil. The level of Cd in soil reflected significant pollution compared to average global concentrations in soils.  相似文献   

8.
The study involved assessing the potential of the native plant species (Berkheya coddii) for the phytoextraction of nickel, palladium, and platinum contaminated sites. Plant and soil samples were randomly collected from Barberton area, near Agnes mine, Mpumalanga Province, South Africa. Samples were analysed for total nickel, palladium, and platinum concentrations together with other elements found in the soil and in the plants' roots, and leaves. Soil versus leaves and soil versus roots uptake of these metals by the plant were compared. The mean concentration of nickel in the leaves/canopy was found to be 13,980?±?10,780?mg?kg?1?dry mass, in the roots it was 2046?±?789?mg?kg?1 dry mass, and in the soil it was 1040?±?686?mg?kg?1?dry mass. This resulted in a mean concentration ratio in the leaves to soil of 13.44. The platinum mean concentration in the leaves was 0.22?±?0.15?mg?kg?1?dry mass, in the roots it was 0.14?±?0.04?mg?kg?1?dry mass, and in the soil it was 0.04?±?0.03?mg?kg?1?dry mass. This resulted in a mean concentration ratio in the leaves to soil of 5.5. Palladium was found to have a mean soil concentration of 0.07?±?0.045?mg?kg?1?dry mass. The mean concentrations in the roots and in the leaves were 0.18?±?0.07 dry mass and 0.71?±?0.52?mg?kg?1?dry mass, respectively. This gave a mean concentration ratio in the leaves to soil of 10.1 for palladium. Other elements that were found to have a mean concentration ratio in the leaves to soil of around 2.5 or above are sodium, potassium, magnesium, calcium, and sulfur. Berkheya coddii was found to be most efficient in accumulating nickel, palladium, and platinum from the soil. The results for the first time revealed that the plant may have the potential to uptake platinum and palladium; both metals are in the same group of the periodic table as nickel.  相似文献   

9.
Food is the major source of metal exposure for the nonsmoking general population. Food samples of plant and animal origin from Ismailia, Egypt, were analyzed for the content of cadmium (Cd), lead (Pb), chromium (Cr), zinc (Zn), and copper (Cu) using AAS. The Cr, Zn, and Cu concentrations were in the range of 1.7–249?µg?kg?1 wet weight (ww), 2–66?mg?kg?1?ww, and 0.5–3.46?mg?kg?1?ww, respectively. The mean daily intake of Cr, Zn, and Cu was 28.9?µg day?1, 8.55?mg day?1, and 1.7?mg day?1, respectively. The intake estimates are within the range of the recommended intake established internationally. Concentrations of Cd and Pb were in the range of 10–321?µg?kg?1?ww and 31–1200?µg?kg?1?ww, respectively. The weekly dietary intake for Cd and Pb (4.02 and 20.4?µg?kg?1 b.w, respectively) is lower than the FAO/WHO PTWI. Bread is the foodstuff that provided the highest rate of Pb and Cd (62 and 46% of the daily intake) to adults in Ismailia city.  相似文献   

10.
About 500 samples of coal, pyritic coal balls, pyritic gangue and coal seam gangue were collected from different coal basins and geologic periods of coal formation to determine the arsenic (As) content and distribution pattern in China. The Permian-Carboniferous and Jurassic coals in the North China Plate and Northwest China account for nearly 85% of total Chinese coal reserves and data showed that As content ranged from 0.1 to 94?mg?kg?1, with the majority between 1 and 14.9?mg?kg?1. The As content of some Late Permian coals in Southwest Guizhou Province and stone coal in the South Qinling Mountain area were exceedingly high (30–534?mg?kg?1), but the majority of coal in the Southwest Guizhou Province contained low to medium amounts. Only the coals, which are situated in or near igneous rocks and are not considered a part of Chinese coal reserves, possessed unusually high As content (>30?mg?kg?1). Arsenic was also concentrated in pyritic coal balls and the pyritic gangue of the coal seam with values ranging from 21.5 to 142.46?mg?kg?1 and an average of 69?mg?kg?1 in Shaanxi and 78?mg?kg?1 in Shandong. Arsenic contents in coal gangue in the Northwest and North China Plate is about 0.2–15?mg?kg?1, a little lower than coals in the same seam. Washing gangue (waste from coal washing) generally contained more As than coal, because the washed gangue has more pyrite than the natural gangue (black shale). Washing coal reduced the content of the pyritic sulfur, heavy metals and As. Based on amounts of coal used with different As content in Chinese coal reserves, the average As content of Chinese coals is about 4.5?mg?kg?1.  相似文献   

11.
Metal contents of waste mobile phones represent a major environmental risk, especially considering the adoption of inappropriate management options in developing countries including open burning and disposal into surface water bodies. In this study the metal contents of mobile phone printed wiring board (PWB) samples were assessed. Sixty-two waste mobile phones of 15 brands were collected, dismantled, and their PWB samples were analyzed for Cu, Pb, Ag and Cd. The metal concentrations in the samples varied widely between and within brands. Among these metals, Cu and Pb were found to be at very high concentrations. The range (mean?±?SD) of Cu and Pb concentrations were 94.1–532?g?kg?1 (250?±?92.3?g?kg?1) and 7.0–46.2?g?kg?1 (20.1?±?8.4?g?kg?1), respectively. All Cu and Pb concentrations exceeded toxicity threshold limit concentration (TTLC) regulatory limits used in characterizing wastes as hazardous in the state of California, USA. The mean Cu and Pb concentrations exceeded the corresponding TTLC limits by factors of 100 and 20, respectively. The Ag and Cd concentrations were in the range 59.4–759?mg?kg?1 (mean 227?±?104?mg?kg?1) and ND – 15.6?mg?kg?1 (2.1?±?3.3?mg?kg?1), respectively.  相似文献   

12.
The concentrations of lead and copper in sclerotium of the mushroom Pleurotus tuber-regium widely consumed in Southeastern Nigeria were determined. The specimens purchased from different markets were mineralized with H2SO4 and H2O2 and analyzed using flame atomic absorption spectrophotometer. The concentrations of Pb ranged from 0.2?±?0.1?mg?kg?1 to 0.8?±?0.5?mg?kg?1 with approximately 91% of the results being below 1?mg?kg?1. The concentrations of Cu ranged from 0.5?±?0.2?mg?kg?1 to 1.2?±?0.6?mg?kg?1 with 78% of the results below 1?mg?kg?1. The results were compared with the literature and levels set by regulatory authorities, with the conclusion that the consumption of sclerotium does not pose a toxicological risk. The low Pb content of the studied products would contribute to only about 1% of the provisional tolerable weekly intake of Pb. The Cu contents would contribute to nutritional intake of the metal in the general population. It is recommended that the outer layers of the sclerotia be properly scrapped before use to reduce metal contamination from exogenous sources.  相似文献   

13.
Residues of organochlorine pesticides (OCPs) namely 1,2,3,4,5,6-hexachlorocyclohexane isomers (HCH-isomers), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) and its metabolites, and endosulfan stereoisomers were analyzed in dry and green fodder samples from rural areas of Ambala, Gurgaon, and Hisar districts of Haryana, India during winter, summer, and post-monsoon seasons. The HCH isomers γ-HCH and β-HCH, and DDT and its metabolites p,p′-DDD, p,p′-DDE, and p,p′-DDT had more traceability in test samples as compared to other isomers and metabolites studied. Total OCPs (ΣOCPs), i.e., ΣHCH, ΣDDT, and Σendosulfan were found to be the highest in wheat straw (1.1–1.2?mg?kg?1) from Ambala and Gurgaon, followed by that in sorghum straw (0.46?mg?kg?1) from Hisar. Dry fodder samples were found to have relatively higher residue levels than green fodders. In case of green fodder samples, maximum ΣOCP residues of 0.44?mg?kg?1 were found in whole plant samples of sorghum from Gurgaon district followed by that in pearl millet (0.40?mg?kg?1) from Ambala. The findings indicate highly significant differences (p?>?0.0001) in ΣOCPs and ΣDDT in wheat straw between different districts and reveal the persistence of OCP residues in both dry and green fodder samples in the study area.  相似文献   

14.
The artificially high soil cadmium (Cd) concentration screening method was used to screen Cd-hyperaccumulators from floricultural plants. Among the five species of floricultural plants screened, Cosmos bipinnata showed the characteristics of Cd-accumulators. A pot experiment was conducted to further study Cd accumulation characteristics of C. bipinnata. The results showed that the biomass, chlorophyll content, superoxide dismutase activity, peroxidase activity and soluble protein content of C. bipinnata first increased and later decreased with the increase in soil Cd concentration, but the carotenoid content and catalase activity of C. bipinnata reduced. Cd contents in roots, stems, leaves and shoots of C. bipinnata increased with increasing soil Cd concentration. When the soil Cd concentration was 50?mg?kg?1, the Cd content in shoots was up to 112.62?mg?kg?1, which was higher than the Cd-hyperaccumulator critical value. The root and shoot bioconcentration factors exceeded 1 in various Cd treatments, but the translocation factors were less than 1. When the soil Cd concentration was 50?mg?kg?1, the Cd accumulation in shoots achieved the maximum of 224.30?μg plant?1. Therefore, considering the tolerance and accumulation of Cd, C. bipinnata is a Cd-accumulator that could be used to remediate Cd-contaminated urban soil.  相似文献   

15.
The study aimed to examine the contamination status of arsenic (As) in excavated small water bodies, commonly known as ponds – the integral part of daily life in the arsenic-affected rural areas of West Bengal, India in comparison to the unaffected areas. The ponds of the contaminated area had higher levels of As: water 2–174 µg L?1 (mean 31 ± 2 µg L?1) and sediment 1.3–37.3 mg kg?1 (mean 10.3 ± 0.4 mg kg?1), than those from the unaffected area: water 1–8 µg L?1 (mean 4 ± 0 µg L?1) and sediment 1.4–5.3 mg kg?1 (mean 3.0 ± 0.1 mg kg?1). A moderate positive correlation was observed between the water and sediment arsenic content of the ponds of the arsenic-affected region (r = 0.688, n = 277, p < 0.0001). Contaminated ground water, either as direct input or through agricultural washings, was found to be the major contributor of arsenic pollution to these ecosystems. Seasonal variations were not prominent. This study emphasized the beneficial role of using the studied ecosystems over the highly contaminated ground water for various livelihood activities in the Gangetic delta region.  相似文献   

16.
The concentrations of four essential (Ca, Mg, Zn, and Cu) and two nonessential elements (Pb and Cd) in feathers and kidneys, livers, gut walls, and muscles of eight carcasses of migratory red-crowned cranes (Grus japonensis) from Zhalong Wetland, northeastern China, were examined. The concentrations of Cd in the feathers were between 0.4 mg kg?1 dry weight (dw) and 3.1 mg kg?1 dw, in the livers between 0.4 and 4.4 mg kg?1 dw, the maximum of which exceeded a level considered to be environmental exposure risk (i.e., 3 mg kg?1 dw in the liver or kidney). High Pb levels (0.4–3.2 mg kg?1 dw, with an average of 1.8 mg kg?1) were also detected in livers, which exceeded a level considered toxicosis in birds (1.7 mg kg?1 dw). Pb and Cd had the highest scores in principal component analysis. Relatively high Pb and Cd concentrations in the migratory cranes were thought to be associated with their habitat and prey.  相似文献   

17.
Persistence of cypermethrin and chlorpyriphos in okra and soil were studied following the application of pre-mix formulation of insecticides Action 505EC (chlorpyriphos 50%?+?cypermethrin 5%) at single (275?g a.i.?ha?1) and double dose (550?g a.i.?ha?1). The average initial deposits of chlorpyriphos in okra were observed to be 0.07 and 0.15?mg?kg?1 in single and double dose, respectively, which dissipated to 92% after 10 days for both the dosages. Residues of soil under okra crop were found to be 0.15?mg?kg?1 at the single and 0.36?mg?kg?1 at the double doses. These residues persisted up to 3 days at single and 5 days at double dose. The half-life (t 1/2) periods of chlorpyriphos on okra and soil were observed to be 0.6 days and 1.9 days for single and double dose, respectively. Residues of chlorpyriphos reached below detectable level (BDL) of 0.01?mg?kg?1 in okra fruits after 7 days at single dose and in 15 days in double dose. In soil, residues of chlopyriphos persisted up to 5 and 7 days in single and double dose, respectively. Following foliar applications of a insecticide formulation (Action 505EC, (chlorpyriphos 50%?+?cypermethrin 5%) on okra at @ 275 and 550?g active ingredient (a.i.)?ha?1 resulting in active applications of chlorpyriphos at the rate of 250 and 500?g a.i.?ha?1 the average initial deposits of chlorpyriphos in okra were observed to be 0.07 and 0.15?mg?kg?1, respectively. These residue levels dissipated to 92% after 10 days at both the dosages. Residues of soil under the okra crop were found to be 15?mg?kg?1 at the single and 36?mg?kg?1 at the double dose. The residues persisted up to 3 days at the single and 5 days at the double dose. The half-life (t 1/2) periods of chlorpyriphos on okra were observed to be 0.6 days for application rates, and 1.9 days for soil. Okra fruits and soil samples collected on the 7th and 15th day after application did not show any chlorpyriphos residues above their determination limits of 0.01 and 0.005?mg?kg?1, respectively.  相似文献   

18.
Nitrate concentrations in 326 recent vegetables and berries sold in Niigata, located in central Japan, were investigated. Maximum nitrate concentrations of 6600 mg kg?1 were detected in samples of komatsuna (Brassica campestris var. perviridis) and mizuna (B. campestris L.). Mean concentrations ranged from 4 mg kg?1(blueberry) to 3500 mg kg?1 (mizuna). Concentrations in spinach ranged from 10 to 6000 mg kg?1 (mean 1500 mg kg?1). Nitrate intake from spinach and Japanese radish (Raphanus sativus) were estimated to be 0.7 and 0.8 mg kg?1 day?1, respectively. These values are equivalent to 19% and 23% of the acceptable daily intake (ADI). Nitrate intake at the 90th percentile was estimated to be 1.3 mg kg?1 day?1 (35% of the ADI) from spinach and 1.6 mg kg?1 day?1 (43% of the ADI) from Japanese radish.  相似文献   

19.
The influence of dietary copper (Cu) exposure on accumulation, growth, and hematological parameters was investigated in Cyprinus carpio after sub-chronic ingestion of 0, 250, 500, 750 or 1000?mg?kg?1 for 60 days. The profile of Cu accumulation among tissues in C. carpio was dependent on the exposure period and Cu concentration. Liver of C. carpio was the predominant storage tissue and the order of Cu accumulation in tissues was liver?>?intestine?> gill?>?kidney?>?muscle. Cu concentration at >125?mg?kg?1 reduced growth rate, and was inversely related to growth. The RNA?:?DNA ratios were not affected by exposure and there was no correlation between growth rate and RNA?:?DNA ratio in liver and muscle. There were no significant effects of exposure on blood parameters except for magnesium. Cu exposure time and dose increased the serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamic-pyruvic transaminase (SGPT) activity levels.  相似文献   

20.
The concentration and potential ecological risk of Mn, Zn, Cu, and Cd in the surface soils (0–30?cm) belonging to 12 soil profiles and 4 soil types (Vertisols, Chernozems, Calcisols, and Cambisols) from the cultivated soils and the corresponding uncultivated soils were investigated. Long-term cultivation caused a considerable build-up diethylene-triamine pentaacetic acid (DTPA)-extractable Mn (7–55%), and Cd (12–31%) as well as the total form of Zn (3–14%), Cu (8–25%), and Cd (33–78%) in all soil types. Following long-time cropping, total Zn (mean?=?73?mg?kg?1), Cu (mean?=?33?mg?kg?1), and Cd (mean?=?3.14?mg?kg?1) and DTPA Zn (mean?=?1.2?mg?kg?1) and Cu (mean?=?2.44?mg?kg?1) were below their maximum allowable limits. However, the average amount of DTPA Cd in the tilled soils (min?=?0.4, max?=?0.75, mean?=?0.55?mg?kg?1) was above its maximum permissible limit mainly due to the over application of phosphate fertilisers and the pesticides. Considering the potential ecological risk (RI) assessment of the cultivated soils (min?=?44, max?=?70, mean?=?54), the soil types were categorised as low (RI?≤?50) to moderate (50?相似文献   

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