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Effect of Fe redox state caused by low soil pe+pH levels on Cd uptake by rice is unclear. Rice grown in pots of Cd-contaminated paddy soil were subjected to different irrigation regimes: flooding, intermittent flooding (Int-FL), and sustained soil moisture at 70% water holding capacity (WHC). Results showed low pe+pH (5.52 and 7.09) in flooding treatment significantly increased relative abundances of Fe-reducing bacteria (FeRB) (6.29% and 4.51%), especially members within the Clostridium, Geobacter and Desulfuromonadia genera. Stimulation of FeRB activity induced Fe(III) reduction and increased Fe2+ content in flooded soils, which promoted Cd sequestration in low-crystalline fraction of IP (IP-Feh-Cd) and Cd bonded to amorphous Fe-oxides (amFeox-Cd). The 24.9%-62.4% higher amFeox-Cd content was the important factor for 20.4%–44.2% lower CaCl2-extractable Cd content in flooding treatment than those in other treatments. Soil submergence reduced Cd uptake by rice at tillering and booting stages, the critical periods of Cd transport in the soil-rice system, which was attributed to the increases in dissolved Fe2+ and IP-Feh-Cd contents and decrease in CaCl2-Cd content. Therefore, maintaining flooding during the tillering and booting stages may be an effective strategy to reduce Cd uptake by rice cultivated in Cd-contaminated soil.
Shanshan Li; Xiaoqin Lei; Luyao Qin; Xiaoyi Sun; Lifu Wang; Shuwen Zhao; Meng Wang; Shibao Chen. Fe(III) reduction due to low pe+pH contributes to reducing Cd transfer within a soil-rice system. Journal of Hazardous Materials 2021, 415, 125668 .
AMA StyleShanshan Li, Xiaoqin Lei, Luyao Qin, Xiaoyi Sun, Lifu Wang, Shuwen Zhao, Meng Wang, Shibao Chen. Fe(III) reduction due to low pe+pH contributes to reducing Cd transfer within a soil-rice system. Journal of Hazardous Materials. 2021; 415 ():125668.
Chicago/Turabian StyleShanshan Li; Xiaoqin Lei; Luyao Qin; Xiaoyi Sun; Lifu Wang; Shuwen Zhao; Meng Wang; Shibao Chen. 2021. "Fe(III) reduction due to low pe+pH contributes to reducing Cd transfer within a soil-rice system." Journal of Hazardous Materials 415, no. : 125668.
Iron (Fe) in soil is closely related to cadmium (Cd) uptake by rice plants, and soil pe + pH significantly influences Fe redox behavior. This study aimed to explore the influential mechanisms of varying pe + pH conditions on the transformation of iron oxides in the rhizosphere and the subsequent effect on Cd accumulation in rice plants. A two-month pot experiment was conducted to investigate the effect of soil pe + pH on the fractions of iron oxides and formation of iron plaque (IP), as well as the effect of these changes on Cd uptake by rice plants (Oryza sativa L.). Different irrigation strategies, 70% water holding capacity (DY), continuous flooding (FL), and alternate flooding/drying weekly (AWD), were used to achieve various soil pe + pH levels. The results showed that low pe + pH conditions (under the FL and AWD treatments) were more beneficial to the transformation of crystalline iron oxides into amorphous forms in rhizosphere soil and the precipitation of IP on rice roots. The increase of amorphous iron oxides resulted in the reduction of Cd availability in rhizosphere soil by immobilizing more Cd on Fe oxides. Moreover, Cd adsorbed on rice root surfaces reacted with IP, inhibiting Cd soil-to-root transport. The two mechanisms combinatively functioned at decreasing Cd concentration in rice shoots by 14.1–33.1% at low pe + pH conditions compared to that of the high pe + pH (DY treatment). These results indicate that lowering soil pe + pH effectively reduced Cd accumulation in rice plants, probably through the immobilization of amorphous Fe oxides on Cd and sequestration of iron-plaque on Cd.
Shanshan Li; Shibao Chen; Meng Wang; Xiaoqin Lei; Han Zheng; Xiaoyi Sun; Lifu Wang; Yun Han. Iron fractions responsible for the variation of Cd bioavailability in paddy soil under variable pe+pH conditions. Chemosphere 2020, 251, 126355 .
AMA StyleShanshan Li, Shibao Chen, Meng Wang, Xiaoqin Lei, Han Zheng, Xiaoyi Sun, Lifu Wang, Yun Han. Iron fractions responsible for the variation of Cd bioavailability in paddy soil under variable pe+pH conditions. Chemosphere. 2020; 251 ():126355.
Chicago/Turabian StyleShanshan Li; Shibao Chen; Meng Wang; Xiaoqin Lei; Han Zheng; Xiaoyi Sun; Lifu Wang; Yun Han. 2020. "Iron fractions responsible for the variation of Cd bioavailability in paddy soil under variable pe+pH conditions." Chemosphere 251, no. : 126355.
The objective of this study was to investigate the responses of cadmium (Cd) availability and transfer in the soil-rice system to added sulfur (S) under unstable pe + pH conditions. Different water management conditions (flooding and aerobic treatments) cause changes in the soil pe + pH. We conducted a pot experiment to investigate the influence of S supply on soil Cd availability and Cd accumulation in rice plants (Oryza sativa L.), using three water regimes (continuous dryness, alternating dry-wet for one cycle, and continuous flooding) combined with two S concentrations (0 and 300 mg/kg). The results showed that the flooding treatment was more effective in decreasing soil pe + pH, Cd availability, and Cd accumulation in rice tissues than were the aerobic treatments. S-induced reduction in Cd uptake and translocation in rice was attributed to the decreased soil pe + pH values and enhanced biosynthesis of phytochelatins (PCs) and glutathione (GSH) in rice roots. Microscopic examination showed that the flooding treatment with added soil S resulted in better rice root growth. Element dispersive spectrometer (EDS) analysis indicated that S addition and flooding treatment promoted the formation of iron plaques and increases in Fe concentration in rice tissues. Conversely, partial disintegration of the root epidermis was observed in the dry treatment without added S.
Han Zheng; Meng Wang; Shibao Chen; Shanshan Li; Xiaoqin Lei. Sulfur application modifies cadmium availability and transfer in the soil-rice system under unstable pe+pH conditions. Ecotoxicology and Environmental Safety 2019, 184, 109641 .
AMA StyleHan Zheng, Meng Wang, Shibao Chen, Shanshan Li, Xiaoqin Lei. Sulfur application modifies cadmium availability and transfer in the soil-rice system under unstable pe+pH conditions. Ecotoxicology and Environmental Safety. 2019; 184 ():109641.
Chicago/Turabian StyleHan Zheng; Meng Wang; Shibao Chen; Shanshan Li; Xiaoqin Lei. 2019. "Sulfur application modifies cadmium availability and transfer in the soil-rice system under unstable pe+pH conditions." Ecotoxicology and Environmental Safety 184, no. : 109641.
The objectives of this study were to investigate the response of cadmium (Cd) distribution and stability in soil aggregates as affected by applying different amendments and to understand the relationship between changes in soil aggregates and alleviation of Cd phytotoxicity to rice after amendment application. In the present study, rice (Oryza sativa L.) was cultivated on a Cd-polluted soil. Five soil amendments were applied, which are as follows: rice husk biochar (BC), Fe-added rice husk biochar (Fe-BC), attapulgite-based mixture (AM), zeolite-based mixture (ZM), and cow manure-based mixture (MM). The effect on Cd redistribution in soil and Cd accumulation in rice plant was evaluated. The results showed that the five amendments applied at the rate of 3% (w/w) significantly increased soil pH and decreased Cd mobility in soil and Cd accumulation in rice plants. The reduction rate of Cd content in rice grains ranged from 41 to 62% after amendment application. The remediation efficiency of the different amendments for decreasing Cd accumulation in rice tissues followed the order of Fe-BC > MM > BC > ZM > AM. Adding amendments promoted the formation of large aggregates (0.2–2.0 mm) with more mass loading of Cd and enhanced aggregate stability. Comparatively, Fe-BC was more effective than others for remediation of acid Cd-polluted paddy soil, as a significantly decreased Cd concentration in rice grain after its application was observed. Structural equation modeling (SEM) analysis revealed that DTPA-extractable Cd in small aggregates was the main factor affecting Cd accumulation in rice grain; soil pH directly affected aggregate stability; and aggregate stability was closely related to Cd availability in different size soil particles. These results indicated that the applied amendments were effective in reducing Cd bioavailability, most likely through raising the soil pH, improving aggregate stability, and re-distributing Cd from smaller soil aggregates to larger ones.
Shanshan Li; Meng Wang; Zhongqiu Zhao; Xiaoyue Li; Shibao Chen. Use of soil amendments to reduce cadmium accumulation in rice by changing Cd distribution in soil aggregates. Environmental Science and Pollution Research 2019, 26, 20929 -20938.
AMA StyleShanshan Li, Meng Wang, Zhongqiu Zhao, Xiaoyue Li, Shibao Chen. Use of soil amendments to reduce cadmium accumulation in rice by changing Cd distribution in soil aggregates. Environmental Science and Pollution Research. 2019; 26 (20):20929-20938.
Chicago/Turabian StyleShanshan Li; Meng Wang; Zhongqiu Zhao; Xiaoyue Li; Shibao Chen. 2019. "Use of soil amendments to reduce cadmium accumulation in rice by changing Cd distribution in soil aggregates." Environmental Science and Pollution Research 26, no. 20: 20929-20938.
In China, 1/5 of the total farmland area is Cd-enriched; the wide occurrence of Cd-contaminated soil in China has already posed significant public health risk and deserves immediate action. In situ immobilization has been regarded as one of the most promising agricultural extension-technologies for remediating low-to-medium levels of heavy metal contaminated land in China. Although extensive research has been conducted to examine the effectiveness of different amendments on remediation of Cd-contaminated soils, the influence of changed soil properties on secondary release of Cd from Cd-amendment to soil is rarely known. The objective of this study was to evaluate the effectiveness of four soil amendments (denoted as Ad1, Ad2, Ad3 and Ad4, their main components being clay mineral, base mineral, humus and biochar, respectively) on reducing Cd availability and increasing Cd stability in soil. The maximum adsorption capacity of test amendments on Cd ranged from 7.47 to 17.67 mg g−1. The characterizations of test amendments before and after Cd loading provided the evidence that surface precipitation and ion exchange were the main reasons for Ad1 and Ad2 to adsorb Cd, and complexation was for Ad3 and Ad4. In addition, there was significant increase in the desorption percentages of Cd from amendments as pH decreased (from 7 to 1) or ion strength increased (from 0 to 0.2 M). Comparatively, Ad3 and Ad4 could be more effective for in situ immobilization of Cd in contaminated soils, due to their high adsorption capacities (12.82 and 17.67 mg g−1, respectively) and low desorption percentages (4.46–6.23%) at pH from 5 to 7 and ion strengths from 0.01 to 0.1 mol L−1. The results obtained in this study could provide a guideline for in-situ remediation of Cd polluted field-soil in China.
Shanshan Li; Meng Wang; Zhongqiu Zhao; Changbao Ma; Shibao Chen. Adsorption and Desorption of Cd by Soil Amendment: Mechanisms and Environmental Implications in Field-Soil Remediation. Sustainability 2018, 10, 2337 .
AMA StyleShanshan Li, Meng Wang, Zhongqiu Zhao, Changbao Ma, Shibao Chen. Adsorption and Desorption of Cd by Soil Amendment: Mechanisms and Environmental Implications in Field-Soil Remediation. Sustainability. 2018; 10 (7):2337.
Chicago/Turabian StyleShanshan Li; Meng Wang; Zhongqiu Zhao; Changbao Ma; Shibao Chen. 2018. "Adsorption and Desorption of Cd by Soil Amendment: Mechanisms and Environmental Implications in Field-Soil Remediation." Sustainability 10, no. 7: 2337.
Soil aggregates exert a significant influence on the retention and bioavailability of Cd in soil.
Shanshan Li; Meng Wang; Zhongqiu Zhao; Xiaoyue Li; Yun Han; Shibao Chen. Alleviation of cadmium phytotoxicity to wheat is associated with Cd re-distribution in soil aggregates as affected by amendments. RSC Advances 2018, 8, 17426 -17434.
AMA StyleShanshan Li, Meng Wang, Zhongqiu Zhao, Xiaoyue Li, Yun Han, Shibao Chen. Alleviation of cadmium phytotoxicity to wheat is associated with Cd re-distribution in soil aggregates as affected by amendments. RSC Advances. 2018; 8 (31):17426-17434.
Chicago/Turabian StyleShanshan Li; Meng Wang; Zhongqiu Zhao; Xiaoyue Li; Yun Han; Shibao Chen. 2018. "Alleviation of cadmium phytotoxicity to wheat is associated with Cd re-distribution in soil aggregates as affected by amendments." RSC Advances 8, no. 31: 17426-17434.
Meng Wang; Cheng He; Shibao Chen; Shumei Wen; Xia Wu; Ngmei Zhang; Qipeng Yuan; Cong Wei. Corrigendum to “Microalgal cell disruption via extrusion for the production of intracellular valuables” [Energy 142 (2018) 339–345]. Energy 2018, 153, 1088 .
AMA StyleMeng Wang, Cheng He, Shibao Chen, Shumei Wen, Xia Wu, Ngmei Zhang, Qipeng Yuan, Cong Wei. Corrigendum to “Microalgal cell disruption via extrusion for the production of intracellular valuables” [Energy 142 (2018) 339–345]. Energy. 2018; 153 ():1088.
Chicago/Turabian StyleMeng Wang; Cheng He; Shibao Chen; Shumei Wen; Xia Wu; Ngmei Zhang; Qipeng Yuan; Cong Wei. 2018. "Corrigendum to “Microalgal cell disruption via extrusion for the production of intracellular valuables” [Energy 142 (2018) 339–345]." Energy 153, no. : 1088.