[Show abstract][Hide abstract] ABSTRACT: A plant growth-promoting bacterial (PGPB) strain SC2b was isolated from the rhizosphere of Sedum plumbizincicola grown in lead (Pb)/zinc (Zn) mine soils and characterized as Bacillus sp. based on (1) morphological and biochemical characteristics and (2) partial 16S ribosomal DNA sequencing analysis. Strain SC2b exhibited high levels of resistance to cadmium (Cd) (300 mg/L), Zn (730 mg/L), and Pb (1400 mg/L). This strain also showed various plant growth-promoting (PGP) features such as utilization of 1-aminocyclopropane-1-carboxylate, solubilization of phosphate, and production of indole-3-acetic acid and siderophore. The strain mobilized high concentration of heavy metals from soils and exhibited different biosorption capacity toward the tested metal ions. Strain SC2b was further assessed for PGP activity by phytagar assay with a model plant Brassica napus. Inoculation of SC2b increased the biomass and vigor index of B. napus. Considering such potential, a pot experiment was conducted to assess the effects of inoculating the metal-resistant PGPB SC2b on growth and uptake of Cd, Zn and Pb by S. plumbizincicola in metal-contaminated agricultural soils. Inoculation with SC2b elevated the shoot and root biomass and leaf chlorophyll content of S. plumbizincicola. Similarly, plants inoculated with SC2b demonstrated markedly higher Cd and Zn accumulation in the root and shoot system, indicating that SC2b enhanced Cd and Zn uptake by S. plumbizincicola through metal mobilization or plant-microbial mediated changes in chemical or biological soil properties. Data demonstrated that the PGPB Bacillus sp. SC2b might serve as a future biofertilizer and an effective metal mobilizing bioinoculant for rhizoremediation of metal polluted soils.
Full-text · Article · Jul 2015 · Journal of Toxicology and Environmental Health Part A
[Show abstract][Hide abstract] ABSTRACT: The pollution characteristics, load and health risk assessment of 6 phthalate esters in soils from intensive vegetable fields in Nanjing, China were investigated by ultrasonic extraction combined with GC-MS and CalTOX model. The results showed that phthalate esters were detected in all soil samples, the total concentration of the 6PAEs ranged from 0.15~9.68 mg/kg, with a mean of 2.21 mg/kg. The dominant PAEs were di-n-butyl phthalate (DnBP), bis-(2-Ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) with 88.2%, 100% and 79.8% detection rate, the concentrations of which in soils ranged from n.d.~1.83, 0.02~9.03, n.d.~1.74 mg/kg, respectively. There was no significant correlation among soil organic carbon, pH and PAEs concentrations. Total pollution load of PAEs was about 4.31 kg/hm2 in the study area. Health risk assessment indicated that the risk of DnBP and DEHP was higher, and dermal contact was the primary exposure pathway to growers. Phthalate concentration, pollution load and health risks of intensive vegetable soils were significantly higher than these of surrounding outdoor vegetable soils.
No preview · Article · Dec 2013 · Zhongguo Huanjing Kexue/China Environmental Science
[Show abstract][Hide abstract] ABSTRACT: A pot experiment was conducted to investigate Cd accumulation in two genotypes of rice cultivars, different in Cd enriching capacity and to derive total and available Cd fraction based soil Cd threshold value in rice producing area. Results show that Cd, at 0 -1.5 mg kg1 had no significant inhibitive effect on growth or yield of rice. Cd accumulation in rice, in general, increased with increasing soil Cd concentration, and Cd concentration in different rice organs varied, showing an discending order of stalk, leaf, brown rice, and husk. However, no significant difference was found between the two rice genotypes in plant growth and Cd accumulation capacity in the experiment. Cd in brown rice was significantly related to soil total Cd and CaCl2 extractable Cd. Based on the national food hygienic standards (GB 2762 -2005) and Cd accumulation characteristics of the two rice genotypes, Cd threshold value of the Fluvo-aquic soils (pH 7.71) in Tianjin was derived to be 2. 1 mg kg1 and CaCl2 extractable Cd threshold value of the soil 5.7)g kg1. The findings of this study can be used as scientific reference for revision of the national standards for soil environment quality and for suitability assessment of soils for rice production.
No preview · Article · Jan 2013 · Journal of Ecology and Rural Environment
[Show abstract][Hide abstract] ABSTRACT: Based on the advantages of fungi as a bioremediation agent for copper-containing wastewater, bioremediation potential of Trichoderma reesei FS10-C for copper-containing wastewater was investigated. Flask tests were conducted on analyzing the development, growth and accumulation rate of FS10-C under copper stress in aqueous solutions. Scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDX) were used to observe the morphology and element variations of FS10-C, and bio-safety assessment of the strain was also performed. The results show that the spore of FS10-C can grow and develop in aqueous solutions with pH of (4.0±0.2)-(5.6±0.2) and Cu(II) concentration below 600 mg/L. Copper accumulation rates of FS10-C under 100, 200 and 400 mg/L Cu(II) concentrations were 50.6%, 30.3% and 4.7%, respectively. The SEM showed no morphological variation in FS10-C at 100 mg/L Cu(II) and mostly complete cell structure at 400 mg/L Cu(II). EDX results showed that weight percentages of copper in FS10-C were 18.50% and 30.40% at 100 and 400 mg/L Cu(II), respectively, and biosorption ability of mycelium was higher than that of spore. Bio-safety assessment indicated that both FS10-C and its metabolites were harmless to human and animal health. The results suggest that Trichoderma reesei FS10-C may be a good bioremediation agent for copper-containing wastewater.
No preview · Article · Jul 2012 · Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology
[Show abstract][Hide abstract] ABSTRACT: Spores of Trichoderma reesei FS10-C were made into Trichoderma sp. preparation with alfalfa powder by solid-state fermentation. And a pot experiment was carried out to investigate effect of the preparation on plant growth and Cu accumulation of Elsholtzia splendens in soils spiked with 0,100,200 and 400 mg/kg of CuSO 4. The results indicated that the plant biomass of Elsholtzia splendens showed an increasing trend in soils with all spiked Cu concentrations after applying of the preparation, except for shoot dry weight in soils with external Cu levels of 400 mg/kg. The preparation increased NH 4OAc-extractable Cu in all Cu contaminated soils significantly in comparison with that in the control (P<0.05), and also led to an increasing trend in Cu accumulations of all plants, except for that in shoot in soils with external Cu level of 100 mg/kg. Cu accumulations were significantly enhanced in shoots in soils with external Cu levels of 200 and 400 mg/kg, in roots in soils with external Cu levels of 100 mg/kg and in individual plants in soils with external Cu levels of 100 and 400 mg/kg (P<0.05). The results suggested that this Trichoderma reesei FS10-C preparation could be a potential bioremediation agent for Cu contaminated soil by promoting growth of Elsholtzia splendens and increasing Cu phytoavailability in soil.
No preview · Article · Jun 2012 · Zhongguo Huanjing Kexue/China Environmental Science
[Show abstract][Hide abstract] ABSTRACT: Sedum plumbizincicola X.H. Guo et S.B. Zhou ex L.H. Wu (Crassulaceae), a new species restricted to lead–zinc mining areas in Zhejiang Province, China, is described and illustrated. This taxon belongs to sect. Sedum (H. Ohba) S.H. Fu based on the adaxially gibbous carpels and follicles. It superficially resembles S. alfredii Hance and three other Sedum species found in the same area, but differs from these other taxa in bearing 4-merous flowers. Differences in geographical distribution, growth habit, phenology, macromorphology, leaf and stem anatomy, as well as seed micromorphology among S. plumbizincicola, S. alfredii and other related taxa in the genus Sedum are also reported. nrDNA internal transcribed spacers (ITS) sequences from seven populations of S. plumbizincicola support the recognition of this as a taxonomic entity distinct from S. alfredii.
Full-text · Article · Mar 2012 · Plant Systematics and Evolution
[Show abstract][Hide abstract] ABSTRACT: We investigated the occurrence of 14 selected antibiotics including five therapeutic classes of tetracyclines, sulfonamides, macrolides, fluoroquinolones and chloramphenicols in manures collected from four swine farms of different sizes in eastern China. Tetracyclines (tetracycline, oxytetracycline, chlortetracycline, and doxycycline) and sulfadiazine were the most prominent contaminants in the manure samples, with maximum concentrations reaching 98.2 x 10(3), 354.0 x 10(3), 139.4 x 10(3), 37.2x 10(3), and 7.1x 10(3) mu g/kg, respectively. The occurrence of these compounds was dependent on breeding scale, animal type, and breeding season. Manure storage and vermiculture were not able to effectively deplete the heavier contaminants (tetracyclines and sulfadiazine), resulting in high levels of these chemicals remaining in manures. Therefore, the occurrence of these antibiotics in agricultural soils (0.1-205.1 mu g/kg) collected from four types of agricultural land (pear orchard, tea plantation, bamboo forest, and paddy field) near the studied farms, was a reflection of manure application. However, the extremely high concentrations of antibiotics in manures were unlikely from feed consumption, but from other direct forms of medicine application.
Full-text · Article · Feb 2012 · Chinese Science Bulletin
[Show abstract][Hide abstract] ABSTRACT: The root exudates of peanut collected by a modified continuous collecting device and XAD-4 ion exchange resin were identified by GC-MS, and their allelophatic effects on Ralstonia solanacearum were studied. The root exudates mainly contained acetophenone, glycerol, benzoic acid, 3,5-dimethyl benzaldehyde, stearic acid, palmitic acid, and lactic acid, among which, only acetophenone had obvious promotion effect on the growth of R. solanacearum at concentration <0. 1 g · L-1, and significant inhibitory effect at concentration >0.1g · L-1. These findings could provide a credible basis for using acetophenone to control the occurrence of R. solanacearum.
No preview · Article · Jan 2011 · Chinese Journal of Ecology
[Show abstract][Hide abstract] ABSTRACT: A field microzone experiment was carried out to study the co-remediation effect of PCBs contaminated farmland soils under different planting models for using three plant species, alfalfa (Medicago sativa L), Elsholtzia splendens and Sedum plumbizincicola. The results indicated that mixed croppings of alfalfa with Elsholtzia splendens or Sedum plumbizincicola could enhance PCBs removal in soils compared to the monoculture with alfalfa. About 43.0% of PCBs were removed from the soils in mixed cropping of alfalfa and Elsholtzia splendens at the end of the 120 d experiment, and 47.8% in mixed cropping of three plants. The mixed croppings of alfalfa with Elsholtzia splendens or Sedum plumbizincicola could increase the total biomass of plants, facilitate the uptake and accumulation of the PCBs in plants. Analysis of PCBs composition showed that the planted treatments could decrease the concentration of lower chlorinated PCBs in soils, and multi-species phytoremediation could improve the transformation of higher chlorinated PCBs into lower chlorinated PCBs. The mixed croppings of alfalfa with Elsholtzia splendens or Sedum plumbizincicola show a good potential in the remediation of PCBs contaminated farmland soils.
[Show abstract][Hide abstract] ABSTRACT: Using artificial soil test, physiological activities in earthworms (Eisenia foetida), which included superoxide dismutase (SOD, Cu-Zn SOD), catalase (CAT) and gulathione-S-transferase (GST), and other biochemical activities, such as GSH and MDA, exposed to dioxin-like PCBs at the levels of 0.1, 1, 10, 100, 1000 μg/kg, were observed after 2, 7, 14 and 28d exposure. Dioxin-like PCBs could significantly increase SOD, Cu-Zn SOD, CAT, GST activities and GSH and MDA levels (P < 0.05), and induce starting of antioxidant systems in the earthworms. The relationships results showed that the best response times of various physiological activities in earthworms to dioxin-like PCBs were different. The best response time of Cu-Zn SOD activities was 7 days, whereas that of GST activities was 28 days. The best response times of others physiological activities were all 14 days. During the best response times, there were significantly dose-response relationships between the dioxin-like concentrations logarithms and physiological activities logarithms (P < 0.001).
No preview · Article · May 2010 · Zhongguo Huanjing Kexue/China Environmental Science
[Show abstract][Hide abstract] ABSTRACT: A Cd and Zn contaminated soil was mixed and equilibrated with an uncontaminated, but otherwise similar soil to establish a gradient in soil contamination levels. Growth of Thlaspi caerulescens (Ganges ecotype) significantly decreased the metal concentrations in soil solution. Plant uptake of Cd and Zn exceeded the decrease of the soluble metal concentrations by several orders of magnitude. Hence, desorption of metals must have occurred to maintain the soil solution concentrations. A coupled regression model was developed to describe the transfer of metals from soil to solution and plant shoots. This model was applied to estimate the phytoextraction duration required to decrease the soil Cd concentration from 10 to 0.5 mg kg(-1). A biomass production of 1 and 5 t dm ha(-1) yr(-1) yields a duration of 42 and 11 yr, respectively. Successful phytoextraction operations based on T. caerulescens require an increased biomass production.
No preview · Article · Dec 2008 · Environmental Pollution
[Show abstract][Hide abstract] ABSTRACT: Soil organic matter can be divided into different organic carbon (C) pools with different turnover rates. The organic pollutants in soils associated with these organic C pools may have different bioavailability and environmental risks during the decomposition of soil organic matter. We studied the distribution patterns of 15 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in different particle-size separates (clay, fine silt, coarse silt, fine sand and coarse sand) and density fractions (light and heavy fractions) of nine agricultural topsoils (0–20 cm depth) from a contaminated area in the Yangtze River Delta region of east China. There was a decreasing trend in PAH concentration in particle-size separates with decreasing particle size. However, the different particle-size separates had similar PAH composition. The concentration of PAHs in the light fraction ranged from 13 037 to 107 299 μg kg−1, far higher than in the heavy fraction, which ranged from 222 to 298 μg kg−1. Although the light fraction accounted for only 0.4–2.3% of the soils, it was associated with 31.5–69.5% of soil PAHs. The organic matter in coarse silt had the strongest capacity for enrichment with PAHs. Combining the distributions of PAHs and the turnover rates of organic matter in different soil fractions, the environmental risks of PAH-polluted soils may be due mainly to the PAHs associated with sand and the light fraction.
No preview · Article · Nov 2008 · European Journal of Soil Science
[Show abstract][Hide abstract] ABSTRACT: Chemical fractions of copper (Cu) and zinc (Zn) in the organic-rich particles collected from filtered aqueous extracts (< 20 mu m) of an acid soil were determined. A sequential extraction procedure was used to partition the particulate Cu and Zn into four operationally defined chemical fractions: adsorbed (ADS), iron (Fe) and manganese (Mn) oxides bound (FeMnOX), organic matter bound (OM) and residual (RESD). Total extractable concentrations of Cu and Zn in the fine particles were higher than their total concentrations in the original bulk soil. The concentration of particulate Cu was usually much higher than that of particulate Zn. Addition of lime stabilized sewage sludge cake and/or inorganic metal salts markedly increased the concentrations of particulate Cu and Zn in aqueous extracts, especially from limed soil. The proportional distributions of particulate Cu and Zn were quite similar. The two particulate metals were present predominantly in the ADS and FeMnOX fractions, with less (about 20%) in the OM and RESD fractions. Some of the ADS metal fraction was associated with dissolved organic substances. The concentrations of particulate Cu and Zn in the various extractable fractions were significantly affected by the application of lime, lime stabilized sewage sludge cake, or inorganic metal salts.
No preview · Article · Nov 2008 · Communications in Soil Science and Plant Analysis
[Show abstract][Hide abstract] ABSTRACT: Effects of soil Cd contamination on growth of Brassica chinensis in three different soils were investigated through greenhouse pot trial. Chemical fractions of cadmium (extracted by 0.43 mol · L-1 HNO3, 0.05 mol · L-1 EDTA and 0.01 mol · L-1 CaCl2) were evaluated by using a single extraction procedure. The results show that the Cd content in the aboveground part of Brassica chinensis had a nonlinear relationship with the metal in soils. It has been found that Cd content in the aboveground part of Brassica chinensis has negative correlation with soil pH values. The Cd mobility was in the order of Fe-accumulic Gleyic Stagnic Anthrosols > Typic Gleyic Stagnic Anthrosols > Lithic Ochri-Aquic Cambosols. 0.43 mol · L-1 HNO3, 0.05 mol · L-1 EDTA and 0.01 mol · L-1 CaCl2 extractable Cd were significantly correlated with the Cd content in the aboveground part of Brassica chinensis. Considering the simplicity and low cost of 0.43 mol · L-1 HNO3, 0.05 mol · L-1 EDTA or 0.01 mol · L-1 CaCl2 extraction, the extraction solutions could serve as an alternative method for assessment of phytoavailability of soil Cd to plants.
No preview · Article · Jul 2008 · Journal of Ecology and Rural Environment
[Show abstract][Hide abstract] ABSTRACT: The remediation of polychlorinated biphenyls (PCBs) contaminated soil by inoculation with arbuscular mycorrhizal fungus (AM, Glomus versiforme) and/or rhizobium (Rhizobium meliloti) with a host plant (Medicago sativa L.) was studied in a field trial. Concentrations of PCBs decreased at a higher rate in all soils with this planted treatment compared with untreated soils. The planted' treatment that received the rhizobial inoculum decreased the concentration of PCBs by 42.6%, which was significantly higher than the other treatments. Analysis of PCBs composition showed that the percentage of lower chlorinated PCBs increased in all of the planted treatments, especially the plant treatment with rhizobium. Rhizobium could promote the growth of the plant and even facilitate the absorbability and the transportation of the PCBs in the plant. The field trial showed that the plant with rhizobium could be used to remediate soils contaminated with PCBs.
[Show abstract][Hide abstract] ABSTRACT: The contamination of Hg and As in the field contaminated by electronic waste treatment, located in Taizhou, Zhejiang Province was studied, in order to reveal the soil contamination caused by E-waste break-dividing. The soil were slightly contaminated with Hg. Approximately 61.4% of investigated soil samples were found with Hg content exceeded the first class of national soil environmental quality standard value (0.15 mg/kg), while 9% were found higher than the second class of 0.3 mg/kg. Of all soil samples, As contents were all below the first class of Chinese standard, suggesting the soil was not contaminated by As. The impact of sources on soil Hg and As content seemed to be quite different. Hg content was more affected by acid washing and E-waste treatment than smelting process, while As content was seemed to be more affected by smelting process and acid washing. As to spatial distribution, the trends of soil Hg and As content changed with distance from the potential sources was not very clearly in most directions. No significant correlation was found between Hg and As content in the soil, which indicated that input of Hg and As content to soil were likely influenced by varied factors at the same time.
[Show abstract][Hide abstract] ABSTRACT: The kinetics characters of enzymatic activities in soil contaminated with heavy metals in the lead-zinc tailing mine were studied. Soil enzyme activities decreased markedly with increasing degree of soil pollution caused by heavy metals in the mine area. The average Vmax values of soil urease, phosphotase and dehydrogenase in the mine area were 60%, 77% and 38% of those of non-mine area, and that the average Km values of soil urease, phosphotase were 2.73 and 2.25 times than those of non-mine area, respectively. The stepwise regression and path analysis further showed that kinetics parameters (Vmax and Km) of the reaction promoted by soil urease, phosphotase and dehydrogenase were significantly correlated with the concentrations of heavy metals such as Pb, Zn, Cu and Cd in soil of the mine area. However, the degree of the influence of each heavy metal on the activity of different enzymes was greatly different, and moreover, there was an interacting effect of four heavy metals.
[Show abstract][Hide abstract] ABSTRACT: Two pot experiments were conducted to investigate the time course effects of the (S, S)-N, N'-ethylenediamine disuccinic acid (EDDS) addition to contaminated soil on the uptake of Cu and Zn by the Cu accumulator Elsholtzia splendens and on plant Cu and Zn concentrations at different growth stages. EDDS increased the amounts of Cu and Zn soluble in the soil, taken up by plants, concentrated in the xylem sap, and translocated from roots to stems and leaves. The increase in soil-soluble metals, especially Cu, resulted in a corresponding increase in metal concentrations in the xylem sap and leaves. The addition of EDDS to the soil increased plant Cu and Zn concentrations, especially in the leaves, and changed the proportions of Cu and Zn taken up by different plant parts. The proportions of Cu and Zn taken up by the roots were higher than by the leaves of control plants, but EDDS-treated plants showed the opposite trend. EDDS exerted greater effects at the end of the vegetative growth stage than at the start of the flowering or reproductive stages.
No preview · Article · Jun 2007 · International Journal of Phytoremediation
[Show abstract][Hide abstract] ABSTRACT: Polycyclic aromatic hydrocarbons (PAHs) were quantified in 30 soil profiles from the Yangtze River Delta Region, in east China. Relative concentrations of PAH compounds with different benzene rings and ratios of fluoranthene to fluoranthene plus pyrene and benz(a)anthracene to benz(a)anthracene plus chrysene were used to identify the possible sources of soil PAHs. Total concentrations of 15 PAHs in topsoils ranged from 8.6 to 3881 microg kg(-1) with an average of 397 microg kg(-1). Half of the soil samples were considered to be contaminated with PAHs (>200 microg kg(-1)) and two sampling sites were heavily polluted by PAHs with concentrations >1000 microg kg(-1). Phenanthrene was found in soils below a depth of 100 cm in half of the sampling sites, but the detectable ratio of benzo(a)pyrene decreased sharply from 100% in topsoil to 0 in the 4th horizon.
No preview · Article · Jun 2007 · Environmental Pollution
[Show abstract][Hide abstract] ABSTRACT: Information on carbon (C) storages and the changes under the shifting of land use is of particular interest for estimating the gains and losses of soil C at a regional scale. The present study attempted to quantify the soil organic carbon (SOC) storage in the Hong Kong soils for the first time as well as to demonstrate the changes of SOC density after the transformations of paddy fields to other land usages due to the decline of agricultural activities. SOC storages were estimated by combining the land-use areas and profile data derived from our recent soil survey (248 samples were collected) and other reports. The results indicated that SOC densities to the upper 100 cm ranged from 25.06 Mg ha− 1 of urban park land to 288.65 Mg ha− 1 of swamp and mangrove, and total SOC storage in the upper 100 cm was 8.8548 × 106 t, approximately 0.51% of that in the soils of Guangdong Province China. Approximately 46.5% to 70.5% of the SOC pool was stored in the upper 40-cm depth, and SOC densities were much consistent in depth distributions under different land uses. Different changes of SOC density were evidenced after the conversion from paddy fields to orchards, vegetable land and grassland. The uncertainties were also discussed for lack of the data from a long term survey at a particular location.