Simultaneous reduction of arsenic and lead bioaccumulation in rice ( Oryza sativa L.) by nano-TiO 2 : a mechanistic study

• Published in: Environmental science. Nano Vol. 10; no. 11; pp. 3084 - 3100
• Main Authors: Wu, Xinyi, Jia, Wenyi, Hu, Jing, Yu, Xuefeng, Yan, Chuanhao, White, Jason C., Liu, Junfeng, Yang, Yu, Wang, Xilong
• Format: Journal Article
• Language: English
• Published: 09.11.2023
• ISSN: 2051-8153; 2051-8161
• DOI: 10.1039/D3EN00266G

Heavy metals with opposite charges ( e.g. , arsenic and lead) generally have opposite environmental behaviors. Nano-enabled strategies to concurrently inhibit their accumulation in crops remain elusive. Here, nano-TiO 2 with an anatase (NAT) or rutile (NRT) structure or bulk TiO 2 (BT) was used at 10, 100, and 1000 mg L −1 to amend hydroponic rice seedling systems co-contaminated with arsenic (1 mg L −1 ) and lead (2 or 10 mg L −1 ) for mechanistic understanding of contaminant interactions. A simultaneous decrease of arsenic and lead bioaccumulation in rice plants and their retention in the root iron plaque were achieved by significant metal sorption to 1000 mg L −1 NAT and NRT. The arsenic uptake mitigation by NRT (82–93%) was much higher than that by NAT (46–65%), while their lead uptake inhibition was comparable (47–89% for NRT vs. 37–78% for NAT). When the lead/arsenic exposure ratio increased, 100 mg L −1 nano-TiO 2 and BT at all doses also significantly reduced the root metal content, attributable to their enhanced sorption on TiO 2 and iron plaque. TiO 2 amendment posed no risk to the plant and completely alleviated oxidative stress from exposure thus restoring it to healthy control levels. Our findings highlight the potential application of 1000 mg L −1 nano-TiO 2 , particularly with a rutile structure, for combined arsenic and lead reduction in rice, effectively enhancing both food safety and human health.