Synergistic Effects of Unmodified Tea Leaves and Tea Biochar Application on Remediation of Cr-Contaminated Soil

Overview

Journal Toxics

Date 2025 Jan 8

PMID 39771103

Authors

Weili Qi

Yun Yang

Yan Xu

Xiaowen Teng

Jiawei Ma

Weijie Xu

Zhengqian Ye

Xianzhi Fang

Dan Liu

Affiliations

Soon will be listed here.

Abstract

Hexavalent chromium (Cr(VI)) contamination in soil presents significant risks due to its high toxicity to both the environment and human health. Renewable, low-cost natural materials offer promising solutions for Cr(VI) reduction and soil remediation. However, the effects of unmodified tea leaves and tea-derived biochar on chromium-contaminated soils remain inadequately understood. In this study, tea tree pruning waste was converted into biochar at various temperatures, and the impacts of both unmodified tea leaves and tea biochar on soil Cr(VI) content, chromium fractionation, and soil biochemical properties were assessed using a soil incubation experiment. The results showed that the combined treatment of tea and tea biochar produced at 500 °C reduced Cr(VI) content by up to 49.30% compared to the control. Chromium fractionation analysis revealed a significant increase in the residual chromium fraction, accounting for 32.97% of total chromium, substantially reducing its bioavailability and mobility. Soil properties were markedly improved, with notable increases in pH (14.89%), cation exchange capacity (CEC; up to 100.24%), and organic matter content (up to 167.12%) under the combined treatments. Correlation analysis confirmed that Cr(VI) content reductions were positively correlated with increases in pH, nutrient retention, and enzyme activities, highlighting their role in chromium stabilization. This study underscores the synergistic potential of unmodified tea leaves and tea biochar as an innovative, eco-friendly strategy for Cr(VI) remediation, enhancing both soil quality and heavy metal stabilization.

References

Chen Y, Wu H, Sun P, Liu J, Qiao S, Zhang D . Remediation of Chromium-Contaminated Soil Based on WHX-1 Immobilized on Biochar: Cr(VI) Transformation and Functional Microbial Enrichment. Front Microbiol. 2021; 12:641913. PMC: 8027096. DOI: 10.3389/fmicb.2021.641913. View

Sarker A, Masud M, Deepo D, Das K, Nandi R, Ansary M . Biological and green remediation of heavy metal contaminated water and soils: A state-of-the-art review. Chemosphere. 2023; 332:138861. DOI: 10.1016/j.chemosphere.2023.138861. View

Sharma P, Singh S, Parakh S, Tong Y . Health hazards of hexavalent chromium (Cr (VI)) and its microbial reduction. Bioengineered. 2022; 13(3):4923-4938. PMC: 8973695. DOI: 10.1080/21655979.2022.2037273. View

Sun J, Mao J, Gong H, Lan Y . Fe(III) photocatalytic reduction of Cr(VI) by low-molecular-weight organic acids with alpha-OH. J Hazard Mater. 2009; 168(2-3):1569-74. DOI: 10.1016/j.jhazmat.2009.03.049. View

Duan Y, Shang X, Liu G, Zou Z, Zhu X, Ma Y . The effects of tea plants-soybean intercropping on the secondary metabolites of tea plants by metabolomics analysis. BMC Plant Biol. 2021; 21(1):482. PMC: 8532361. DOI: 10.1186/s12870-021-03258-1. View

Feng C, Yi Z, Qian W, Liu H, Jiang X . Rotations improve the diversity of rhizosphere soil bacterial communities, enzyme activities and tomato yield. PLoS One. 2023; 18(1):e0270944. PMC: 9836298. DOI: 10.1371/journal.pone.0270944. View

Xu T, Nan F, Jiang X, Tang Y, Zeng Y, Zhang W . Effect of soil pH on the transport, fractionation, and oxidation of chromium(III). Ecotoxicol Environ Saf. 2020; 195:110459. DOI: 10.1016/j.ecoenv.2020.110459. View

Ma L, Chen N, Feng C, Yang Q . Recent advances in enhanced technology of Cr(VI) bioreduction in aqueous condition: A review. Chemosphere. 2024; 351:141176. DOI: 10.1016/j.chemosphere.2024.141176. View

Hossan S, Hossain S, Islam M, Kabir M, Ali S, Islam M . Bioremediation of Hexavalent Chromium by Chromium Resistant Bacteria Reduces Phytotoxicity. Int J Environ Res Public Health. 2020; 17(17). PMC: 7504174. DOI: 10.3390/ijerph17176013. View

10.

Li Y, Wang W, Zhou L, Liu Y, Mirza Z, Lin X . Remediation of hexavalent chromium spiked soil by using synthesized iron sulfide particles. Chemosphere. 2016; 169:131-138. DOI: 10.1016/j.chemosphere.2016.11.060. View

11.

Liu L, Li W, Song W, Guo M . Remediation techniques for heavy metal-contaminated soils: Principles and applicability. Sci Total Environ. 2018; 633:206-219. DOI: 10.1016/j.scitotenv.2018.03.161. View

12.

Li C, Wang C, Liu L . Effects of Microplastics and Organic Fertilizer Regulation on Soil Dissolved Organic Matter Evolution. Toxics. 2024; 12(10). PMC: 11511232. DOI: 10.3390/toxics12100695. View

13.

Jiang X, Long W, Peng L, Xu T, He F, Tang Y . Reductive immobilization of Cr(VI) in contaminated water by tannic acid. Chemosphere. 2022; 297:134081. DOI: 10.1016/j.chemosphere.2022.134081. View

14.

Su Q, He Y, Pan H, Liu H, Mehmood K, Tang Z . Toxicity of inorganic arsenic to animals and its treatment strategies. Comp Biochem Physiol C Toxicol Pharmacol. 2023; 271:109654. DOI: 10.1016/j.cbpc.2023.109654. View

15.

Chen Y, Tsai C, Rekha P, Ghate S, Huang H, Hsu Y . Agricultural management practices influence the soil enzyme activity and bacterial community structure in tea plantations. Bot Stud. 2021; 62(1):8. PMC: 8131499. DOI: 10.1186/s40529-021-00314-9. View

16.

Han C, Wang M, Ren Y, Zhang L, Ji Y, Zhu W . Characterization of pruned tea branch biochar and the mechanisms underlying its adsorption for cadmium in aqueous solution. RSC Adv. 2022; 11(43):26832-26843. PMC: 9037675. DOI: 10.1039/d1ra04235a. View

17.

Jiang Y, Wang X, Zhao Y, Zhang C, Jin Z, Shan S . Effects of Biochar Application on Enzyme Activities in Tea Garden Soil. Front Bioeng Biotechnol. 2021; 9:728530. PMC: 8490741. DOI: 10.3389/fbioe.2021.728530. View

18.

Siddika A, Islam M, Parveen Z, Hossain M . Remediation of Chromium (VI) from Contaminated Agricultural Soil Using Modified Biochars. Environ Manage. 2022; 71(4):809-820. DOI: 10.1007/s00267-022-01731-7. View

19.

Liu J, Jiang J, Meng Y, Aihemaiti A, Xu Y, Xiang H . Preparation, environmental application and prospect of biochar-supported metal nanoparticles: A review. J Hazard Mater. 2020; 388:122026. DOI: 10.1016/j.jhazmat.2020.122026. View

20.

Sun Y, Zheng F, Wang W, Zhang S, Wang F . Remediation of Cr(VI)-Contaminated Soil by Nano-Zero-Valent Iron in Combination with Biochar or Humic Acid and the Consequences for Plant Performance. Toxics. 2020; 8(2). PMC: 7357137. DOI: 10.3390/toxics8020026. View