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Roxarsone exposure jeopardizes nitrogen removal and regulates bacterial community in biological sequential batch
Guowei Chen1, Huan Liu2, Wei Zhang3
1Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.
Ecotoxicology and Environmental Safety
|May 14, 2018
Summary
Long-term exposure to roxarsone significantly impairs nitrogen removal in agricultural wastewater treatment, decreasing efficiency by over 50%. This impacts crucial processes like nitrification and denitrification, affecting nitrogen cycling in agroecosystems.
Area of Science:
- Environmental microbiology
- Wastewater treatment engineering
- Agricultural science
Background:
- Roxarsone is a common contaminant in animal farm wastewater in China.
- The effects of chronic roxarsone exposure on biological nitrogen removal are poorly understood.
Purpose of the Study:
- To investigate the impact of long-term roxarsone exposure on nitrogen removal in a sequential batch reactor (SBR).
- To analyze changes in the bacterial community structure and function.
Main Methods:
- Operation of a biological SBR under chronic roxarsone exposure.
- Measurement of nitrogen removal efficiency (nitrification and denitrification).
- Analysis of bacterial enzymatic activities and 16S rRNA gene sequencing.
Main Results:
- Nitrogen removal decreased by 52.4% due to roxarsone exposure.
- Nitrification and denitrification processes were inhibited, with immediate effects on denitrification and delayed effects on nitrification.
- Bacterial activity declined, and the nitrogen-cycling bacterial community composition shifted, with changes in genera like Acinetobacter, Methylophilaceae, Flavobacterium, Methylotenera, and Aeromonas.
Conclusions:
- Chronic roxarsone exposure significantly suppresses nitrification and denitrification in biological wastewater treatment.
- These findings have implications for nitrogen use efficiency and nitrogen cycling in agricultural ecosystems.
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