High grain-Cd-accumulating rice variety Yongyou 9 was planted in Cd-contaminated farmland in Taizhou City, Zhejiang Province, China to study the effects of 5-aminolevulinic acid(ALA) and24-epibrassinolide(EBR) on Cd a...High grain-Cd-accumulating rice variety Yongyou 9 was planted in Cd-contaminated farmland in Taizhou City, Zhejiang Province, China to study the effects of 5-aminolevulinic acid(ALA) and24-epibrassinolide(EBR) on Cd accumulation in brown rice. Results showed that the exogenous ALA and EBR had no significant effects on agronomic traits, soil pH and total Cd content in soil, but had some effects on the available Cd content in soil, and significantly influenced the Cd accumulation in the different parts of rice. Results also showed that 100 mg/L exogenous ALA significantly reduced the Cd accumulation in brown rice to blow the food safety standard(0.2 mg/kg), and also significantly reduced the Cd contents in the roots and culm of rice. However, 200 mg/L exogenous ALA treatment increased the Cd content in brown rice remarkably. In addition, 0.15 mg/L EBR treatment increased Cd accumulation in roots, culm, leaves and brown rice notably, whereas 0.30 mg/L exogenous EBR treatment reduced the Cd accumulation in brown rice properly, but it was not significant. Therefore,proper concentration of ALA can effectively reduce the Cd accumulation in brown rice, which can be used as an effective technical method for the safe production of rice in Cd polluted farmland.展开更多
Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd an...Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd and posing potential ecological and human health risks. The blocky biochar is also difficult to separate from the soil due to its fragile nature. One of the keys to overcome the difficulties in separating biochar from soil is to improve its mechanical strength. Blocky zeolite-biochar composites(ZBC) that have good mechanical strength were obtained after pyrolyzing the mixture of 50% feedstock and 50% zeolite powder at 400 ℃. ZBC and NaOH-activated ZBC(ZBC_a) were applied to remove Cd from soil. After sieving Cd-loaded ZBC and ZBC_a from soil, the bioavailable Cd content in the soil decreased by 59.70% and 68.54%,respectively. Zeolite contributed to improving both adsorption performance and mechanical properties of the composites. After repeating the process of “remediation-sieving-desorption-regeneration” three times, the recoveries of ZBC and ZBC_a were above 97.00%, and regeneration rates were 48.70-83.26%,respectively. Under simulated mechanical sieving conditions, ZBC and ZBC_a lost only 4.06% and 5.40%of their mass and retained their integrity. Remediation of Cd-contaminated soil with blocky zeolitebiochar composite is sustainable and safe because the removal of bioavailable Cd from soil is permanent rather than a temporary decrease of bioavailability. This study provides a reference for the preparation of separable and recyclable adsorbents for the removal of contaminants from soil.展开更多
The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH, enzyme activities and microbial communities, TCLP-Cd (toxicity characteristic leaching procedure-Cd) concentration, and ...The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH, enzyme activities and microbial communities, TCLP-Cd (toxicity characteristic leaching procedure-Cd) concentration, and spinach (Spinacia oleracea) growth and Cd uptake and accumulation were investigated. Results showed that the addition of sepiolite could increase soil pH, while the TCLP-Cd concentration in soil was decreased with increasing sepiolite. The changes of soil enzyme activities and bacteria number indicated that a certain metabolic recovery occurred after the sepiolite treatments, and spinach shoot biomass increased by 58.5%-65.5% in comparison with the control group when the concentration of sepiolite was ~ 10 g/kg. However, the Cd concentrations in the shoots and roots of spinach decreased with an increase in the rate of sepiolite, experiencing 38.4%-59.1% and 12.6%--43.6% reduction, respectively, in contrast to the control. The results indicated that sepiolite has the potential for success on a field scale in reducing Cd entry into the food chain.展开更多
基金supported by the Natural Science Foundation of Zhejiang Province,China(Grant No.LY17C020005)the Key Research and Development Project of Zhejiang Province,China(Grant No.2015C03020-4)+2 种基金the National Nature Science Foundation of China(Grant No.31401356)Jinhua Science and Technology Project(Grant No.2015-2-012)the National Training Program for College Students to Innovate and Start Enterprise(Grant No.201710356013)
文摘High grain-Cd-accumulating rice variety Yongyou 9 was planted in Cd-contaminated farmland in Taizhou City, Zhejiang Province, China to study the effects of 5-aminolevulinic acid(ALA) and24-epibrassinolide(EBR) on Cd accumulation in brown rice. Results showed that the exogenous ALA and EBR had no significant effects on agronomic traits, soil pH and total Cd content in soil, but had some effects on the available Cd content in soil, and significantly influenced the Cd accumulation in the different parts of rice. Results also showed that 100 mg/L exogenous ALA significantly reduced the Cd accumulation in brown rice to blow the food safety standard(0.2 mg/kg), and also significantly reduced the Cd contents in the roots and culm of rice. However, 200 mg/L exogenous ALA treatment increased the Cd content in brown rice remarkably. In addition, 0.15 mg/L EBR treatment increased Cd accumulation in roots, culm, leaves and brown rice notably, whereas 0.30 mg/L exogenous EBR treatment reduced the Cd accumulation in brown rice properly, but it was not significant. Therefore,proper concentration of ALA can effectively reduce the Cd accumulation in brown rice, which can be used as an effective technical method for the safe production of rice in Cd polluted farmland.
基金supported by the National Key Research and Development Program of China, China (2019YFC1904102)。
文摘Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd and posing potential ecological and human health risks. The blocky biochar is also difficult to separate from the soil due to its fragile nature. One of the keys to overcome the difficulties in separating biochar from soil is to improve its mechanical strength. Blocky zeolite-biochar composites(ZBC) that have good mechanical strength were obtained after pyrolyzing the mixture of 50% feedstock and 50% zeolite powder at 400 ℃. ZBC and NaOH-activated ZBC(ZBC_a) were applied to remove Cd from soil. After sieving Cd-loaded ZBC and ZBC_a from soil, the bioavailable Cd content in the soil decreased by 59.70% and 68.54%,respectively. Zeolite contributed to improving both adsorption performance and mechanical properties of the composites. After repeating the process of “remediation-sieving-desorption-regeneration” three times, the recoveries of ZBC and ZBC_a were above 97.00%, and regeneration rates were 48.70-83.26%,respectively. Under simulated mechanical sieving conditions, ZBC and ZBC_a lost only 4.06% and 5.40%of their mass and retained their integrity. Remediation of Cd-contaminated soil with blocky zeolitebiochar composite is sustainable and safe because the removal of bioavailable Cd from soil is permanent rather than a temporary decrease of bioavailability. This study provides a reference for the preparation of separable and recyclable adsorbents for the removal of contaminants from soil.
基金supported by the National Natural Science Foundation of China (No. 2117706840901154+2 种基金21107056)the Program for Distinguished Scholar and Innovative Team of MOA (No. 2012-jcrc-xym)the Central Public Research Institutes Basic Funds for Research and Development (No.2011-szjj-syb)
文摘The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH, enzyme activities and microbial communities, TCLP-Cd (toxicity characteristic leaching procedure-Cd) concentration, and spinach (Spinacia oleracea) growth and Cd uptake and accumulation were investigated. Results showed that the addition of sepiolite could increase soil pH, while the TCLP-Cd concentration in soil was decreased with increasing sepiolite. The changes of soil enzyme activities and bacteria number indicated that a certain metabolic recovery occurred after the sepiolite treatments, and spinach shoot biomass increased by 58.5%-65.5% in comparison with the control group when the concentration of sepiolite was ~ 10 g/kg. However, the Cd concentrations in the shoots and roots of spinach decreased with an increase in the rate of sepiolite, experiencing 38.4%-59.1% and 12.6%--43.6% reduction, respectively, in contrast to the control. The results indicated that sepiolite has the potential for success on a field scale in reducing Cd entry into the food chain.