Effective stabilization of arsenic in contaminated soils with biogenic manganese oxide (BMO) materials

The role of biogenic manganese oxide (BMO) materials on the stabilization of arsenic (As) in contaminated soil was investigated. Experimental results indicated that the addition of BMO proved to be highly effective to stabilize As in soils. Soluble content of As decreased 49.5–67.4% with a dosage of 0.013–0.063% BMO. X-ray absorption near edge structure results confirmed that BMO is mainly responsible for oxidizing As(III) to As(V) through a two-step pathway. Five-step sequential extraction results indicated that such extractable fractions of As decreased, and consequently residual fractions increased, which can decrease the risk of As in contaminated soils. BMO had a higher efficiency in stabilizing As than two types of abiotic Mn oxides. High throughput sequencing analysis indicated that the bacterial community and diversity significantly changed after BMO treatment. High amounts of BMO (with a dosage of 0.063%) significantly increased the abundance of Proteobacteria phylum, including Massilia, Phenylobacterium and Sphingomonas genera. These findings suggested that BMO can be considered a high effectiveness, low cost, and environmental friendliness material for the remediation of As contaminated soils. Copyright © 2019 Elsevier Ltd. All rights reserved.