Comparison of the effects of competitive adsorption and reductive dissolution on migration of arsenic in lake sediment

ABSTRACT

Arsenic-contaminated sediment of Lake Yangzonghai (Yunnan province, China) and its overlying water was used to investigate the effects of phosphate ion (PO₄³⁻) and microbial activity on the migration of arsenic in the sediment. The results showed that the competitive adsorption of PO₄³⁻ was the primary factor for the release of arsenic from the sediment to the overlying water, while microbial activity played a minor role in promoting the reductive dissolution of iron/arsenic (hydro) oxides. The reductive dissolution of ferrous ion (Fe²+) occurred in the initial stage, and partly contributed to the increase of arsenic concentration in the overlying water. The increase of PO₄³− concentration in the overlying water enhanced the mobility and biological toxicity of the arsenic in the sediment. After PO₄³− in the overlying water was depleted, arsenic in the overlying water could be adsorbed and precipitated again by iron salts, resulting in the decrease of arsenic concentration in the overlying water. The study implies that among those arsenic-contaminated lakes, eutrophication will aggravate the risks of secondary pollution of arsenic.

GRAPHICAL ABSTRACT

KEYWORDS:

• Arsenic mobility
• phosphate
• competitive adsorption
• reductive dissolution

Acknowledgements

We gratefully acknowledge LetPub (A Editing Service Company) for revising the English language in our manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was financially supported by National Natural Science Foundation of China [Grant Number 51168047].

Notes on contributors

Zhongqing Huang

Zhongqing Huang, postgraduate in ecotoxicology field. She wrote manuscript in this study.

Changliang Yang

Changliang Yang, Ph.D. in School of Ecology and Environmental Science, Yunnan University, Kunming, China. He has 30 years of experience in the field of transport and transformation of pollutants in environments. He has completed several important research projects in the field of environmental toxicology, and published his research in domestic and international journals. He conceived and designed the experiments, and revised the manuscript.

Mengping Song

Mengping Song, postgraduate in ecotoxicology field. She performed some experiments in this study.

Jing Zhang

Jing Zhang, postgraduate in ecotoxicology field. She performed statistical analysis in this study.

Shaoyu Zeng

Shaoyu Zeng, postgraduate in ecotoxicology field. He performed some experiments in this study.

Jie Wang

Jie Wang, Ph.D. in School of Ecology and Environmental Science, Yunnan University, Kunming, China. He has 15 years of experience in the field of microbial removal of contaminants. He provided technical and editorial assistance in this study.