Effect of sulfur and sulfur-iron modified biochar on cadmium availability and transfer in the soil–rice system. (May 2019)

• Record Type: Journal Article
• Authors: Rajendran, Manikandan; Shi, Lizheng; Wu, Chuan; Li, Waichin; An, Wenhui; Liu, Ziyu; Xue, Shengguo
• Is Part Of: Chemosphere. Volume 222(2019)
• Page Start: 314
• Page End: 322
• Publication Date: 2019-05
• Subjects: Biochar -- Sulfur and iron modified biochar -- Cadmium -- Iron plaque -- Oryza sativa L; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.01.149
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Cadmium (Cd) contamination in paddy soils has aroused global concern. Sulfur modified biochar (BC) could combine the benefits of BC and S for Cd remediation. However, no information is available on the impact of sulfur modified biochar on Cd phytoavailability in paddy soils. In this study, a pot experiment was conducted to investigate the effect of sulfur modified biochar (S-BC) and sulfur and iron (Fe) modified biochar (S-Fe BC) on Cd mobility and Cd transfer in the soil-rice system. The application of S-BC and S-Fe BC effectively reduced pore water Cd in the rhizosphere and non-rhizosphere pore water throughout the rice growth stages. S-BC and S-Fe BC addition increased the total chlorophyll content, as well as the root, shoot and grain biomasses of rice. Furthermore, S-BC and S-Fe BC amendments greatly increase the formation of Fe plaque on rice root surface, thus decreasing Cd accumulation in different rice tissues. In particular, S-Fe BC supplementation significantly reduced the Cd concentration in rice grains to 0.018 mg kg −1 in Cd-contaminated soil, which was lower than the China National standard for food contamination limit (0.2 mg kg −1 Cd). Sequential extraction results showed that S-BC and S-Fe BC can promote the transfer of exchangeable Cd to Fe-Mn oxide, organic and residual bound forms which reduce Cd in paddy soils. Thus, the amendment of S-Fe BC to Cd-contaminated paddy soil is an effective strategy to decrease Cd accumulation in rice grains and thereby protect public health. Highlights: S-BC and S-Fe BC efficiently reduced bioavailable Cd in pore waters by increasing pH. Rice growth and chlorophyll content was increased by S-BC and S-Fe BC amendments. S-Fe biochar increased Fe plaque formation, and its capacity to reduced Cd accumulation in brown rice. Addition of S-Fe biochar is an effective way to prevent Cd accumulation in rice grains and health risk to people.