Application of mixotrophic acidophiles for the bioremediation of cadmium-contaminated soils elevates cadmium removal, soil nutrient availability, and rice growth

• Published in: Ecotoxicology and environmental safety 2022-05, Vol.236, p.113499-113499, Article 113499
• Main Authors: Yuan, Baoxing, Huang, Lihua, Liu, Xueduan, Bai, Lianyang, Liu, Hongwei, Jiang, Huidan, Zhu, Ping, Xiao, Yunhua, Geng, Jibiao, Liu, Qianjin, Hao, Xiaodong
• Format: Article
• Language: English
• Subjects: Biodegradation, Environmental; Cadmium - analysis; Cd contamination; Growth promoting effect; Humans; Microbial community; Microbial extraction; Mixotrophic acidophiles; Nutrients - analysis; Oryza; Soil; Soil Pollutants - analysis
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2022.113499

A major challenge in radically alleviating the threats posed by Cd-contaminated paddy fields to human health is to reduce the Cd levels in both soils and rice grains. In this study, the microbial extraction (ME) treatment using a mixotrophic acidophilic consortium was used for the bioremediation of Cd-contaminated soils. The results showed that the ME treatment enhanced the total Cd (40%) and diethylenetriamine pentaacetic acid-soluble Cd (DTPA-Cd, 64%) removal efficiencies in contaminated soils. In addition, ME treatment decreased the levels of Cd acid-soluble and reducible fractions and thereby reduced Cd uptake in rice tissues. Microbial community analysis indicated that the indigenous soil microbial diversity and composition were not changed after the ME treatment, but the relative abundance of functional microbes associated with Cd removal was improved. Notably, soil available nutrient levels were elevated upon inoculation with mixotrophic acidophiles, resulting in an increase in rice growth and grain weight. This study provides a scientific basis for the potential application and evaluation of ME treatment in the field for remediating Cd-contaminated paddy soils. [Display omitted] •Cd-polluted paddy soils were remediated using the mixotrophic acidophiles.•ME treatment enhanced the total Cd and DTPA-Cd removal of polluted soils.•ME treatment reduced the Cd availability in soils and Cd uptake in rice tissues.•ME treatment didn’t alter indigenous soil microbial diversity and composition.•ME treatment improved the available nutrient levels and supported rice growth.