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Chen S.,Key Laboratory of Production Environment and Agro Product Safety of Ministry of Agriculture | Chen S.,Shenyang University | Chao L.,Liaoning Academy of Environmental science | Sun L.,Shenyang University | Sun T.,Shenyang University
International Journal of Phytoremediation | Year: 2013

To investigate the effects of two cadmium-tolerant bacteria, Staphylococcus pasteuri (S. pasteuri X1) and Agrobacterium tumefaciens (A. tumefaciens X2), on cadmium uptake by the cadmium hyperaccumulator plant Beta vulgaris var. cicla L., a pot experiment with artificially contaminated soil was conducted. The results demonstrated that both cadmium-tolerant bacteria enhanced the dry weight of Beta vulgaris var. cicla L. The total dry weights of plants in the control CK20, S. pasteuri X1 and A. tumefaciens X2 treatments were 0.85, 1.13, and 1.38 g/pot, respectively. Compared with the control CK20 findings, the total dry weight of plants was increased by 32.8 and 61.1% after inoculation with S. pasteuri X1 and A. tumefaciens X2, respectively, indicating that A. tumefaciens X2 more strongly promoted the growth of Beta vulgaris var. cicla L. than S. pasteuri X1. In addition, inoculation with S. pasteuri X1 and A. tumefaciens X2 significantly (p < 0.05) promoted cadmium uptake by plants and improved the bioaccumulation of cadmium by the plants from the soil. Moreover, the inoculation of S. pasteuri X1 and A. tumefaciens X2 effectively facilitated the transfer of cadmium in the soil from the Fe-Mn oxide and residual fractions to the soluble plus exchangeable and weakly specially adsorbed fractions in the rhizosphere soils of plants. The bacterial enhancement of cadmium phytoavailability might provide a potential and promising method to increase the efficiency of phytoextraction. © 2013 Copyright Taylor and Francis Group, LLC.

Lei M.,Hunan Agricultural University | Lei M.,CAS Research Center for Eco Environmental Sciences | Tie B.,Hunan Agricultural University | Zeng M.,Central South University of forestry and Technology | And 5 more authors.
Environmental Geochemistry and Health | Year: 2013

Compared to other cereals, rice has particular strong As accumulation. Therefore, it is very important to understand As uptake and translocation among different genotypes. A field study in Chenzhou city, Hunan province of China, was employed to evaluate the effect of arsenic-contaminated soil on uptake and distribution in 34 genotypes of rice (including unpolished rice, husk, shoot, and root). The soil As concentrations ranged from 52.49 to 83.86 mg kg-1, with mean As concentration 64.44 mg kg-1. The mean As concentrations in rice plant tissues were different among the 34 rice genotypes. The highest As concentrations were accumulated in rice root (196.27-385.98 mg kg-1 dry weight), while the lowest was in unpolished rice (0.31-0.52 mg kg-1 dry weight). The distribution of As in rice tissue and paddy soil are as follows root ≫ soil > shoot > husk > unpolished rice. The ranges of concentrations of inorganic As in all of unpolished rice were from 0.26 to 0.52 mg kg-1 dry weight. In particular, the percentage of inorganic As in the total As was more than 67 %, indicating that the inorganic As was the predominant species in unpolished rice. The daily dietary intakes of inorganic As in unpolished rice ranged from 0.10 to 0.21 mg for an adult, and from 0.075 to 0.15 mg for a child. Comparison with tolerable daily intakes established by FAO/WHO, inorganic As in most of unpolished rice samples exceeded the recommended intake values. The 34 genotypes of rice were classified into four clusters using a criteria value of rescaled distance between 5 and 10. Among the 34 genotypes, the genotypes II you 416 (II416) with the lowest enrichment of As and the lowest daily dietary intakes of inorganic As could be selected as the main cultivar in As-contaminated field. © 2012 Springer Science+Business Media Dordrecht.

Wang F.,Agro Environmental Protection Institute | Wang F.,Key Laboratory of Production Environment and Agro Product Safety of Ministry of Agriculture | Zhu Y.,Agro Environmental Protection Institute | Chen S.,Agro Environmental Protection Institute | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

The phenomenon of freezing-thawing is very prevalent in China, especially in northwest, northeast China and North China Plain. Soil chemical properties may be affected in freeze-thaw process, and then crop growing in next year. To explore transformation of nitrogen (N), phosphorous (P) and enzyme activity affected by freeze-thaw cycles, 3 typical cultivated soils (black soil, loess and fluvo-aquic soil from northeast, northwest and North China Plain) were collected and frozen for 72 hour at two temperature (-20°C and -10°C), and thawed at 24°C for 24 hour as one freeze-thaw cycles. These three kinds of soils were all subjected to two freeze-thaw cycles. And soil NO3 --N, NH4 +-N, available phosphorous and two enzyme activities were determined before soil frozen at each cycle. The results showed that NO3 --N contents in 3 kinds of soil increased sharply after the second freeze-thaw cycle, and NO3 --N increments were ranked as Loess > fluvo-aquic soil > black soil. NO3 --N contents increased significantly in Loess and fluvo-aquic soil compared with control. Soil NH4 +-N contents decreased in all 3 soil samples with freeze-thaw cycle increasing, and NH4 +-N decrement followed as black soil > loess and fluvo-aquic soil. Whereas NH4 +-N content in black soil dropped significantly by four times compared to control after second freeze-thaw cycle. The content of available phosphorus significantly increased (P>0.05) in black soil after two freeze-thaw cycle in both two frozen temperatures, But freeze-thaw cycle had no significant affected to loess and fluvo-aquic soil compared to control respectively. The soil catalase activity increased significantly with freeze-thaw cycle increasing in all three soil samples at -10°C. While, a little decrease appeared after second freeze-thaw cycle at -20°C. In contrary, the urease activity generally decreased in all three soils after the first freeze-thaw cycle. But great decrement of urease activity occured after the second freeze-thaw cycle. In conclusion, compared with freeze-thaw, freezing temperature had a slight influence on availability nutrients and enzyme activity in cultivated soils. NO3 --N increments in loess and fluvo-aquic soil after freezing should be considered to crop fertilization management, which is also necessary to be combined with the precipitation value, crops species and other soil environmental factors with different actual conditions.

Liang X.,Agro Environmental Protection Institute | Liang X.,Key Laboratory of Production Environment and Agro Product Safety of Ministry of Agriculture | Xu Y.,Agro Environmental Protection Institute | Xu Y.,Key Laboratory of Production Environment and Agro Product Safety of Ministry of Agriculture | And 7 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2011

In-situ immobilization field experiments were carried out in a cadmium and lead contaminated agricultural field in Tianjin. Lactuca sativa L, Brassica campestris L and Raphanus sativus were selected as model vegetables. Phosphate fertilizer, natural clays such as sepiolite and bentonite, and composites of the above were employed as immobilization materials for heavy metal pollution. The effects of immobilization materials on the biomass of vegetables, the concentrations of cadmium and lead in the edible parts and speciation transformation of cadmium and lead were investigated. It was found that the phosphate fertilizer and its composite with sepiolite or bentonite could increase the biomass of vegetables. All the immobilization materials decreased the cadmium and lead contents in the vegetables to different degrees. The composite of sepiolite and phosphate fertilizer had the best performance, and the contents of cadmium in Lactuca sativa L and Brassica campestris L were below the level of national standard for food safety. All the immobilization treatments inhibited the bioavailability of heavy metals by reducing the contents of exchangeable fractions and increasing the residual fraction of heavy metals. Therefore using natural clays combined with phosphate fertilizer is efficient for the in-situ remediation of cadmium and lead contaminated agricultural fields.

Liang X.,Agro Environmental Protection Institute | Liang X.,Key Laboratory of Production Environment and Agro Product Safety of Ministry of Agriculture | Hou W.,Shandong University | Xu Y.,Agro Environmental Protection Institute | And 8 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2010

Mg2Al layered double hydroxide (Mg2Al LDH) samples intercalated with diethylenetriaminepentaacetic acid (DTPA) (Mg2Al-DTPA LDH in short) were prepared by co-precipitation and well characterized by XRD, SEM, TEM, IR and XPS. The sorption behaviors and mechanisms of Pb2+ on the samples were studied in detail while Mg2Al-Cl LDH as a reference. The maximum sorption amounts were about 170 and 40mg/g for Mg2Al-DTPA LDH and Mg2Al-Cl LDH, respectively. Langmuir isotherm was proved to describe the sorption data better and pseudo-second order kinetic model could fit the sorption kinetic processes better for both LDHs samples. The mechanisms of Pb2+ sorption on Mg2Al-DTPA LDH can be explained by Pb-DTPA chelating while that for Mg2Al-Cl LDH is primary surface-induced precipitation. The Mg2Al-DTPA LDH could provide a potential remedy for heavy metal contamination in soils and water. © 2010 Elsevier B.V.

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