Elevated nano-α-Fe2O3 enhances arsenic metabolism and dissolved organic carbon release of Microcystis aeruginosa under a phytate environment

Yinchai Luo; Jieru Zheng; Qiuyao Ren; Zhenhong Wang; Fen Huang; Zixi Liu; Zhuanxi Luo

doi:10.1007/s11356-023-28658-8

Elevated nano-α-Fe₂O₃ enhances arsenic metabolism and dissolved organic carbon release of Microcystis aeruginosa under a phytate environment

Environ Sci Pollut Res Int. 2023 Aug;30(37):87659-87668. doi: 10.1007/s11356-023-28658-8. Epub 2023 Jul 10.

Authors

Yinchai Luo^{1

2}, Jieru Zheng², Qiuyao Ren², Zhenhong Wang³, Fen Huang¹, Zixi Liu², Zhuanxi Luo^{4

5}

Affiliations

¹ Key Laboratory of Karst Dynamics, Ministry of Natural Resources (MNR) and Guangxi, Institute of Karst Geology, CAGS, Guilin, 541004, China.
² College of Chemical Engineering, Huaqiao University, Xiamen, 361021, China.
³ College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Key Laboratory of Modern Separation and Analysis Science and Technology, Key Laboratory of Pollution Monitoring and Control, Zhangzhou, 363000, China.
⁴ Key Laboratory of Karst Dynamics, Ministry of Natural Resources (MNR) and Guangxi, Institute of Karst Geology, CAGS, Guilin, 541004, China. zxluo@hqu.edu.cn.
⁵ College of Chemical Engineering, Huaqiao University, Xiamen, 361021, China. zxluo@hqu.edu.cn.

PMID: 37430079
DOI: 10.1007/s11356-023-28658-8

Abstract

Little information is available on the effects of nano-α-Fe₂O₃ on arsenic (As) metabolism of algae and potential associated carbon (C) storage in As-contaminated water with dissolved organic phosphorus (DOP) as a phosphorus (P) source. In this study, Microcystis aeruginosa (M. aeruginosa) was used to investigate impacts of nano-α-Fe₂O₃ on cell growth and As metabolism of algae under a phytate (PA) environment as well as potential associated C storage. Results showed that nano-α-Fe₂O₃ had a subtle influence on algal cell growth in a PA environment. Herein, algal cell density (OD₆₈₀) and chlorophyll a (Chla) were inhibited at elevated nano-α-Fe₂O₃ levels, which simultaneously limited the decrease of Yield. As suggested, the complexation of PA with nano-α-Fe₂O₃ could alleviate the negative influence on algal cell growth. Furthermore, the elevated nano-α-Fe₂O₃ increased As methylation in the PA environment due to higher monomethylarsenic (MMA) and dimethylarsenic (DMA) concentrations in the test media. Additionally, microcystins (MCs) in the media changed consistently with UV₂₅₄, both of which were relatively lower at 10.0 mg·L^-1 nano-α-Fe₂O₃. Enhanced As(V) methylation of algal cells was found to simultaneously reduce the release risk of As(III) and MC while increasing dissolved organic carbon (DOC) content in media, suggesting unfavorable C storage. Three-dimensional fluorescence analysis revealed that the main DOC constituent was the tryptophan-like component in aromatic proteins. Correlation analysis showed that decreases in pH and the zeta potential and an increase in Chla may lead to metabolic As improvements in M. aeruginosa. The obtained findings highlight the need for greater focus on the potential risks of DOP combined with nano-α-Fe₂O₃ on algal blooms as well as the biogeochemical cycling processes of As and C storage in As-contaminated water with DOP as the P source.

Keywords: Arsenic species; Carbon storage; Microcystis aeruginosa; Phytate.

MeSH terms

Arsenic* / metabolism
Chlorophyll A / metabolism
Dissolved Organic Matter
Microcystins / metabolism
Microcystis*
Phytic Acid / metabolism
Water / metabolism

Substances

Arsenic
Chlorophyll A
Dissolved Organic Matter
Phytic Acid
Microcystins
Water