The Residual Impact of Goethite-Modified Biochar on Cadmium and Arsenic Uptake by Maize in Co-Contaminated Soil

ABSTRACT

Cadmium (Cd) and arsenic (As) are toxic elements that threaten plants and human health. Due to the opposite transformations of Cd and As, their simultaneous immobilization poses numerous concerns. Thus, there is an urgent need to simultaneously reduce Cd and As mobility and plant uptake in co-contaminated soil. Our previous work found that goethite-modified biochar amendments effectively reduced Cd and As uptake by Chinese cabbage; however, their residual impact on subsequent crops must be investigated. In the current work, the following maize (Zea mays L.) was grown after Chinese cabbage in Cd and As co-contaminated soil amended by biochar (BC), goethite (G), and goethite-modified biochar (GBC) at a 1% application rate. The synthesis of GBCs involved two different initial mass ratios of iron/biochar (Fe/BC), with GBC1 having a Fe/BC ratio of 1:1 and GBC2 having a Fe/BC ratio of 2:1. The current study assessed the residual impacts of BC, G, and GBC amendments on Cd and As mobility, uptake by maize, and their impacts on maize growth. The results revealed that GBC amendments enhanced maize growth, chlorophyll content, and gas exchange parameters compared to raw BC and G. Moreover, the GBC1 amendment lowered Cd and As uptake by maize shoots (29.48% and 61.56%) and roots (33.07% and 37.32%), respectively, compared to unamended soil (CK). The GBC1 amendment decreased the bioaccessibility of Cd and As by 24.37% and 37.44%, respectively, compared with CK. In general, the results demonstrated that GBC has a significant residual impact on maize growth and Cd and As uptake in co-contaminated soil.

KEYWORDS:

• Residual impact
• goethite-modified biochar
• maize plant
• immobilization
• uptake

Acknowledgments

This work was supported by the Joint Key Funds of the National Natural Science Foundation of China (U21A20237) We are grateful to Ms. Zhang Limei, College of Resources and Environment, Huazhong Agricultural University, for helping to analyze the heavy metals in the soil and plant samples using the Inductively coupled plasma optical emission spectroscopy (ICP-OES). We would like to thank Mr. Zhang Xin, College of Resources and Environment, Huazhong Agricultural University, for providing the soil samples. And also, thanks to the China Scholarship Council (CSC) for granting a PhD scholarship.

Author contributions statement

Fatma Abdelrhman: conceptualization, investigation, methodology, software, original draft. Xuewei Wang: investigation, review and editing. Qingling Fu: investigation, review and editing. Hongqing Hu: conceptualization, funding acquisition, resources, review and editing. Linchuan Fang: funding acquisition, review and editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to thank the Joint Key Funds of the National Natural Science Foundation of China (U21A20237) for financially supporting this work