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Effects of sulfamethoxazole on coupling of nitrogen removal with nitrification in Yangtze Estuary sediments.
- Source :
- Environmental Pollution; Feb2021, Vol. 271, pN.PAG-N.PAG, 1p
- Publication Year :
- 2021
-
Abstract
- Coupling of nitrogen removal processes with nitrification (NR n) are vital synergistic nitrogen elimination mechanisms in aquatic environments. However, the effects of antibiotics on NR n are not well known. In the present work, 20-day continuous-flow experiments combined with <superscript>15</superscript>N tracing techniques and quantitative PCR were performed to simulate the impact of sulfamethoxazole (SMX, a sulfonamide antibiotic) with near in situ concentration on NR n processes in sediments of Yangtze Estuary. Results showed that SMX with near in situ concentration significantly decreased NR n , NR w (uncoupling of nitrogen removal processes with nitrification) and actual nitrogen removal rates via inhibiting nitrogen transformation functional genes (AOB, narG , nirS , nosZ) and anammox 16S rRNA gene, while the coupling links between nitrification and nitrogen removal processes were not broken by the exposure. The proportion of NR n in total nitrogen removal processes decreased by approximately 10% with SMX addition, due to the different inhibition on AOB, denitrifying genes and anammox 16S rRNA gene. N 2 O production and nitrite accumulation remarkably increased with SMX addition under simultaneous nitrification and denitrification, and they strongly correlated with each other. The more severely inhibition on nirS gene (13.6–19.8%) than Nitrospira nxrB gene (0.3–8.2%) revealed that the increased nitrite accumulation with SMX addition mainly occurred in heterotrophic denitrification, suggesting that the increased N 2 O production was dominated by the heterotrophic nitrite reduction. Moreover, we estimated that the ratio of external inorganic N eliminated by actual nitrogen removal can upgrade to 6.4–7.4% under circumstances of no inhibition by SMX. This study revealed the effects of SMX with near in situ concentration on NR n processes and illustrated the microbial mechanism on functional genes level. Our results highlighted the inhibitory effects of SMX on NR n may contribute to reactive N retention and N 2 O production in estuarine and coastal ecosystems. Image 1 • SMX inhibits coupled, uncoupled and actual nitrogen removal rates. • SMX decreased the ratio of coupled nitrogen removal in total nitrogen removal. • Nitrification, denitrification and anammox functional genes were affected. • SMX increased N 2 O emission due to the increased heterotrophic nitrite reduction. SMX inhibited NR n rates and decreased NR n ratio in total nitrogen removal via suppressing AOB, denitrifying genes and anammox 16S rRNA gene. [ABSTRACT FROM AUTHOR]
- Subjects :
- NITRIFICATION
SULFAMETHOXAZOLE
GENES
NITROGEN
ESTUARIES
SULFONAMIDES
NITROGEN cycle
Subjects
Details
- Language :
- English
- ISSN :
- 02697491
- Volume :
- 271
- Database :
- Supplemental Index
- Journal :
- Environmental Pollution
- Publication Type :
- Academic Journal
- Accession number :
- 148365842
- Full Text :
- https://doi.org/10.1016/j.envpol.2020.116382