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Assessment of the Use of Natural Materials for the Remediation of Cadmium Soil Contamination.

de O Pinto T, García AC, Guedes Jdo N, do A Sobrinho NM, Tavares OC, Berbara RL - PLoS ONE (2016)

Bottom Line: Our results show that under the conditions in this study, biochar and humin were not effective for soil remediation.These characteristics were especially notable for VCR, which was most effective for soil remediation.The results of our study demonstrate that in the tested materials, the bioavailability of Cd2+ to plants is related to their structural characteristics, which in turn determine their retention of Cd2+.

View Article: PubMed Central - PubMed

Affiliation: Soil Science Department, Federal Rural University of Rio de Janeiro (UFRRJ), Rodovia BR 465, Km 07, Seropédica-Rio de Janeiro, CEP, Brazil.

ABSTRACT
Rice plants accumulate cadmium (Cd2+) within the grain, increasing the danger of human exposure. Natural materials have been used in soil remediation, but few studies have examined the risks (based on the bioavailability of these metals to plants) of using these materials, so the practice remains controversial. In the present study, we evaluated the effectiveness of biochar produced from sugarcane bagasse, vermicompost (VC), vermicompost solid residue (VCR) and humin for remediation of Cd2+-contaminated soils. We characterized the interactions between these materials and Cd2+ and evaluated their capacity to alter Cd2+ availability to rice plants. Our results show that under the conditions in this study, biochar and humin were not effective for soil remediation. Although biochar had high Cd2+ retention, it was associated with high Cd2+ bioavailability and increased Cd2+ accumulation in rice plants. VC and VCR had high Cd2+ retention capacity as well as low Cd2+ availability to plants. These characteristics were especially notable for VCR, which was most effective for soil remediation. The results of our study demonstrate that in the tested materials, the bioavailability of Cd2+ to plants is related to their structural characteristics, which in turn determine their retention of Cd2+.

No MeSH data available.


Related in: MedlinePlus

Root and Leaf Cd2+ Contents of Rice Plants from the First Harvest until 28 Days after Seedling Transfer (DAT) (A and B); on the x axis, 1st, 2nd, 3rd and 4th indicate, respectively, the first, second, third and fourth harvests from each experiment, conducted at seven-day intervals. Values are reported as averages ± the standard error (n = 30). (C) The translocation index (TI) and (D) the bioconcentration factor (BCF) were calculated at 28 DAT.
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pone.0157547.g006: Root and Leaf Cd2+ Contents of Rice Plants from the First Harvest until 28 Days after Seedling Transfer (DAT) (A and B); on the x axis, 1st, 2nd, 3rd and 4th indicate, respectively, the first, second, third and fourth harvests from each experiment, conducted at seven-day intervals. Values are reported as averages ± the standard error (n = 30). (C) The translocation index (TI) and (D) the bioconcentration factor (BCF) were calculated at 28 DAT.

Mentions: Quantification of Cd2+ in the roots and leaves of rice plants showed how much Cd2+ was released by each of the substrate materials (Fig 6A and 6B). Plants growing on substrates containing humin or biochar or with bioavailable Cd2+ had higher Cd2+ accumulation in roots. In contrast, plants growing in substrate containing VC and VCR had lower Cd2+ accumulation in roots, with slightly higher root accumulation than in the control plants. These results indicate that the Cd2+ retained in humin and biochar is readily available for plant uptake, whereas VC and VCR decrease the Cd2+ available for plant uptake. The plant Cd2+ contents suggested that Cd2+ is retained through weaker interactions in humin and biochar or that the Cd2+ binding sites in these materials are structurally more superficial than those in VC and VCR. Either of these conditions would give the plant roots better access to the metal; the interaction of these materials with roots, as well as acid exudation and resulting rhizosphere acidification, could facilitate the release of weakly or superficially retained Cd2+.


Assessment of the Use of Natural Materials for the Remediation of Cadmium Soil Contamination.

de O Pinto T, García AC, Guedes Jdo N, do A Sobrinho NM, Tavares OC, Berbara RL - PLoS ONE (2016)

Root and Leaf Cd2+ Contents of Rice Plants from the First Harvest until 28 Days after Seedling Transfer (DAT) (A and B); on the x axis, 1st, 2nd, 3rd and 4th indicate, respectively, the first, second, third and fourth harvests from each experiment, conducted at seven-day intervals. Values are reported as averages ± the standard error (n = 30). (C) The translocation index (TI) and (D) the bioconcentration factor (BCF) were calculated at 28 DAT.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920433&req=5

pone.0157547.g006: Root and Leaf Cd2+ Contents of Rice Plants from the First Harvest until 28 Days after Seedling Transfer (DAT) (A and B); on the x axis, 1st, 2nd, 3rd and 4th indicate, respectively, the first, second, third and fourth harvests from each experiment, conducted at seven-day intervals. Values are reported as averages ± the standard error (n = 30). (C) The translocation index (TI) and (D) the bioconcentration factor (BCF) were calculated at 28 DAT.
Mentions: Quantification of Cd2+ in the roots and leaves of rice plants showed how much Cd2+ was released by each of the substrate materials (Fig 6A and 6B). Plants growing on substrates containing humin or biochar or with bioavailable Cd2+ had higher Cd2+ accumulation in roots. In contrast, plants growing in substrate containing VC and VCR had lower Cd2+ accumulation in roots, with slightly higher root accumulation than in the control plants. These results indicate that the Cd2+ retained in humin and biochar is readily available for plant uptake, whereas VC and VCR decrease the Cd2+ available for plant uptake. The plant Cd2+ contents suggested that Cd2+ is retained through weaker interactions in humin and biochar or that the Cd2+ binding sites in these materials are structurally more superficial than those in VC and VCR. Either of these conditions would give the plant roots better access to the metal; the interaction of these materials with roots, as well as acid exudation and resulting rhizosphere acidification, could facilitate the release of weakly or superficially retained Cd2+.

Bottom Line: Our results show that under the conditions in this study, biochar and humin were not effective for soil remediation.These characteristics were especially notable for VCR, which was most effective for soil remediation.The results of our study demonstrate that in the tested materials, the bioavailability of Cd2+ to plants is related to their structural characteristics, which in turn determine their retention of Cd2+.

View Article: PubMed Central - PubMed

Affiliation: Soil Science Department, Federal Rural University of Rio de Janeiro (UFRRJ), Rodovia BR 465, Km 07, Seropédica-Rio de Janeiro, CEP, Brazil.

ABSTRACT
Rice plants accumulate cadmium (Cd2+) within the grain, increasing the danger of human exposure. Natural materials have been used in soil remediation, but few studies have examined the risks (based on the bioavailability of these metals to plants) of using these materials, so the practice remains controversial. In the present study, we evaluated the effectiveness of biochar produced from sugarcane bagasse, vermicompost (VC), vermicompost solid residue (VCR) and humin for remediation of Cd2+-contaminated soils. We characterized the interactions between these materials and Cd2+ and evaluated their capacity to alter Cd2+ availability to rice plants. Our results show that under the conditions in this study, biochar and humin were not effective for soil remediation. Although biochar had high Cd2+ retention, it was associated with high Cd2+ bioavailability and increased Cd2+ accumulation in rice plants. VC and VCR had high Cd2+ retention capacity as well as low Cd2+ availability to plants. These characteristics were especially notable for VCR, which was most effective for soil remediation. The results of our study demonstrate that in the tested materials, the bioavailability of Cd2+ to plants is related to their structural characteristics, which in turn determine their retention of Cd2+.

No MeSH data available.


Related in: MedlinePlus