Iron fractions responsible for the variation of Cd bioavailability in paddy soil under variable pe+pH conditions

Li, Shanshan; Chen, Shibao; Wang, Meng; Lei, Xiaoqin; Zheng, Han; Sun, Xiaoyi; Wang, Lifu; Han, Yun

doi:10.1016/j.chemosphere.2020.126355

Cited by 65 publications

(11 citation statements)

References 44 publications

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“…To adapt to adverse anaerobic environment, the roots aerenchyma of rice plant released O 2 in the rhizosphere resulting in the deposition of Fe plaque on the root surfaces through the oxidation of Fe 2+ (ferrous iron) to Fe 3+ (ferric iron) [23]. Iron plaques mainly exist in the form of ferrihydrite (5Fe 2 O 3 .9H 2 O), goethite (α-FeOOH), and lepidocrocite (γ-FeOOH) on the root surfaces [24]. Iron plaque deposits possess ample functional groups with many sorption sites that are capable of binding metal ions in the root zone [25].…”

Section: Introductionmentioning

confidence: 99%

Influence of Iron Plaque on Accumulation and Translocation of Cadmium by Rice Seedlings

et al. 2021

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This study investigated the impact of soil type and rice cultivars on variations in the iron plaque formation and cadmium (Cd) accumulation by different portions of rice seedlings under the influence of Fe amendment. The experiments were performed in pots under glasshouse conditions using two typical paddy soils. Rice seedlings were exposed to three concentrations of Cd (0, 1 and 3 mg kg−1 soil) and Fe (0, 1.0 and 2.0 g kg−1 soil). The results revealed that shoot biomass decreased by 12.2–23.2% in Quest and 12.8–30.8% in Langi in the Cd1.0 and Cd3.0 treatments, while shoot biomass increased by 11.2–19.5% in Quest and 26–43.3% in Langi in Fe1.0 and Fe2.0 as compared to the Fe control. The Cd concentration in the roots and shoots of rice seedlings were in the order of Langi cultivar > Quest cultivar, but the Fe concentration in rice tissues showed the reverse order. Fe plaque formations were promoted by Fe application, which was 7.8 and 10.4 times higher at 1 and 2 g kg−1 Fe applications compared to the control Fe treatment. The Quest cultivar exhibited 13% higher iron plaque formation capacity compared to the Langi cultivar in both soil types. These results indicate that enhanced iron plaque formation on the root surface was crucial to reduce the Cd concentration in rice plants, which could be an effective strategy to regulate grain Cd accumulation in rice plants.

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Section: Introductionmentioning

confidence: 99%

Influence of Iron Plaque on Accumulation and Translocation of Cadmium by Rice Seedlings

et al. 2021

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“…Increases in soil pH under anaerobic conditions were due to the continuous consumption of H + , including the reduction process of iron oxide, manganese oxide and SO 4 2-(e.g. Fe [OH] 3 + 3H + +e -↔ 4 Fe 2+ + 3H 2 O) (Li et al, 2020;Li and Xu, 2017). After incubation, the pH of SBB and MBB treatments were 6.88 ± 0.02 and 6.90 ± 0.01, which were 13.21% and 13.01% respectively higher than the pH of treatment CK (Fig.…”

Section: Changes In Soil Phmentioning

confidence: 95%

Effects of magnetic biochar-microbe composite on Cd remediation and microbial responses in paddy soil

Wang

Chen

et al. 2021

Journal of Hazardous Materials

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There is growing global interest in the bioremediation of cadmium (Cd) using combinations of biochar and microorganisms. However, the interactions among biochar, introduced and indigenous microorganisms remain unclear. Accordingly, a 90 day microcosm experiment was conducted to investigate this by adding Bacillus sp. K1 strain inoculated rice straw biochar (SBB) and magnetic straw biochar (MBB) into a Cd contaminated paddy soil from Hunan, China. All treatments were incubated aerobically (60% water holding capacity) or anaerobically for 90 d. During both soil incubations, Bacillus sp. K1 successfully colonized in soil with composites applications. Soil pH was significantly increased from acid to neutral, and available Cd decreased with the addition of both composites. The better remediation efficiency of MBB than SBB under anerobic conditions was attributed to the transformation of acetic acid-extractable Cd into the residual fraction, caused by Cd 2+ bonding with crystal Fe 3 O 4 . The application of the two kinds of composites caused similar changes to both microbial communities. There was a slight decrease in indigenous microbial alpha diversity with the MBB aerobic application, while the total population number of bacteria was increased by 700%. Both the redundancy analysis and Mantel analyses indicated that pH and microbial biomass C contributed to the colonization of Bacillus sp. K1 with SBB under aerobic conditions, and with MBB under anerobic conditions, respectively. The research provides a new insight into interactive effects and investigates immobilization mechanisms involved of bacterial/biochar composites in anaerobic and aerobic soils.

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“…According to the authors, low pe + pH may promote the activity of Fe reduction bacteria to produce Fe 2+ , which is re-oxidized to amorphous Fe oxides. However, this hypothesis still needs to be verified by further studies [48]. CBR A and CBR B, respectively, followed by Ca bound P that represents the 37.4% and 32.8% of total P extracted from CBR A and CBR B, respectively (Fig.…”

Section: Iron Mobilization In Cbrmentioning

confidence: 95%

“…7A, was already observed in soils in the presence of living microorganisms [26,47,48], and it was primarily attributed to microbial reduction of crystalline Fe 3+ (hydr)oxides probably followed by the precipitation of amorphous Fe 2+ complexes [47]. Li et al [48] observed that a decrease of pe + pH from 11.06 to 8.29 was accompanied by a 110% increase of amorphous Fe content in rhizosphere soils. According to the authors, low pe + pH may promote the activity of Fe reduction bacteria to produce Fe 2+ , which is re-oxidized to amorphous Fe oxides.…”

Section: Iron Mobilization In Cbrmentioning

confidence: 96%

“…5 are established for Fe(OH)3 solution in pure water. The presence of organic matter and/or microorganisms, and the related microbial activities, can play a key role in Fe mobilization from solid matrices [26,[46][47][48]. Under anoxic conditions, microorganisms can use Fe 3+ as a terminal electron acceptor to oxidize organic matter during the anaerobic respiration process, thus reducing Fe 3+ to more soluble Fe 2+ .…”

Section: Iron Mobilization In Cbrmentioning

confidence: 99%

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Phosphorus removal from wastewater by carbonated bauxite residue under aerobic and anoxic conditions

Barca

Scanu

Podda

et al. 2021

Journal of Water Process Engineering

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This study aimed at evaluating the potential use of carbonated bauxite residue (CBR) as filter substrate to upgrade phosphorus (P) removal in small wastewater treatment plants such as constructed wetlands. Comparative experiments of P removal were performed in two columns continuously fed with synthetic and real wastewater to investigate the behavior of CBR under aerobic (column A) and anoxic biotic conditions (column B). The effect of various parameters, including pH, temperature, addition of organic carbon, and dissolved oxygen concentration, was investigated. Also, a series of chemical extractions was performed to elucidate the main mechanisms of P removal achieved by CBR. Over 140 days of operation, columns A and B showed a total P removal performance of 98.5% and 91.6%, thus reaching a total P removal capacity of 0.63 mg P/g CBR and 0.61 mg P/g CBR, respectively. The results indicate that 2 aeration conditions and microbial activity can significantly affect the performance of CBR filters. Under aerobic conditions, precipitation of CaP complexes appears to be the main mechanism leading to P removal. Under anoxic biotic conditions, microbially driven mobilization of Fe from CBR may provide Fe ions for Fe-P precipitation, but also it may lead to Fe release from the filters. This study provides crucial information to evaluate the potential use of CBR at different steps of the wastewater treatment process. Overall, the results indicate that the use of CBR filters is particularly suitable as a tertiary treatment step to remove P from effluents with low organic load under aerobic conditions.

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Iron fractions responsible for the variation of Cd bioavailability in paddy soil under variable pe+pH conditions

Cited by 65 publications

References 44 publications

Influence of Iron Plaque on Accumulation and Translocation of Cadmium by Rice Seedlings

Influence of Iron Plaque on Accumulation and Translocation of Cadmium by Rice Seedlings

Effects of magnetic biochar-microbe composite on Cd remediation and microbial responses in paddy soil

Phosphorus removal from wastewater by carbonated bauxite residue under aerobic and anoxic conditions

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