Antibiotics in Leachate Do Not Necessarily Decrease De-nitrification Rate in Municipal Solid Wastes Landfill Soil

Nitrogen deposited in the municipal solid waste (MSW) stream is primarily in form of nitrate and ammonia, and they currently has been identified as an emerging hotspot of NOx. The microbial denitrification is reckoned as a dominant pathway in reactive nitrogen removal. And the emerging of antibiotics in landfill system were though to exacerbate this N-imbalance. In our text, the emission flux of nitrogen oxides are reported 1 to 2 magnitudes higher than fertilized soil with presence of antibiotics (SMT and OTC). However, the long-term exposure (~ 50 days) to SMT and OTC both reduced the emission flux of N2O and NO. And our metagenomics sequencing results proves that the although abundance of Nir and Nos genes reduced significantly in antibiotic incubation group compared with the control, the enhancing ARGs level seems alleviate the inhibition on denitrification process.