TY - JOUR
T1 - Microbe mediated immobilization of arsenic in the rice rhizosphere after incorporation of silica impregnated biochar composites
AU - Herath, Indika
AU - Zhao, Fang Jie
AU - Bundschuh, Jochen
AU - Wang, Peng
AU - Wang, Jing
AU - Ok, Yong Sik
AU - Palansooriya, Kumuduni Niroshika
AU - Vithanage, Meththika
N1 - Funding Information:
This research was financially supported by the Natural Science Foundation of China (grant no. 21661132001 ). We also sincerely thank Mrs. Jane Macarthur, Ricegrowers Limited, Trading as SunRice, New South Wales 2705, Australia for providing rice husk biomass for this work.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/11/5
Y1 - 2020/11/5
N2 - This study mechanistically addressed for the first time, the contradiction between the application of many biochars to paddy soil and increased arsenic (As) release as employed by most of previous studies. Three types of biochar containing natural and chemical forms of Si: (i) unmodified rice husk biochar (RHBC), (ii) RHBC modified with Si fertilizer (Si-RHBC), and (iii) RHBC modified with nanoparticles of montmorillonite clay (NM-RHBC) were applied in As-contaminated paddy soil to examine their potential to control the mobility of As in the soil-microbe-rice system. Both Si-RHBC and NM-RHBC decreased As concentration in porewater by 40–65 %, while RHBC decreased by 30–44 % compared to biochar unamended soil from tillering to maturing stage. At tillering stage, RHBC, Si-RHBC and NM-RHBC amendments significantly decreased As(III) concentration in the rice rhizosphere by 57, 76 and 73 %, respectively compared to the control soil. The immobilization of As is due to: (i) lowering of microbe mediated As release from iron minerals, (ii) oxidation of As(III) to As(V) by aioA gene, and (iii) adsorption on a Si-ferrihydrite complex. The decrease of more toxic As(III) and its oxidation to less mobile As(V) by Si-rich biochar amendments is a promising As detoxification phenomenon in the rice rhizosphere.
AB - This study mechanistically addressed for the first time, the contradiction between the application of many biochars to paddy soil and increased arsenic (As) release as employed by most of previous studies. Three types of biochar containing natural and chemical forms of Si: (i) unmodified rice husk biochar (RHBC), (ii) RHBC modified with Si fertilizer (Si-RHBC), and (iii) RHBC modified with nanoparticles of montmorillonite clay (NM-RHBC) were applied in As-contaminated paddy soil to examine their potential to control the mobility of As in the soil-microbe-rice system. Both Si-RHBC and NM-RHBC decreased As concentration in porewater by 40–65 %, while RHBC decreased by 30–44 % compared to biochar unamended soil from tillering to maturing stage. At tillering stage, RHBC, Si-RHBC and NM-RHBC amendments significantly decreased As(III) concentration in the rice rhizosphere by 57, 76 and 73 %, respectively compared to the control soil. The immobilization of As is due to: (i) lowering of microbe mediated As release from iron minerals, (ii) oxidation of As(III) to As(V) by aioA gene, and (iii) adsorption on a Si-ferrihydrite complex. The decrease of more toxic As(III) and its oxidation to less mobile As(V) by Si-rich biochar amendments is a promising As detoxification phenomenon in the rice rhizosphere.
KW - High-throughput sequencing
KW - Montmorillonite clay
KW - Porewater
KW - Rice-husk biochar
KW - Silica transporter
UR - http://www.scopus.com/inward/record.url?scp=85086376496&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2020.123096
DO - 10.1016/j.jhazmat.2020.123096
M3 - Article
C2 - 32768840
AN - SCOPUS:85086376496
SN - 0304-3894
VL - 398
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 123096
ER -
