Co-existing antibiotics alter the enantioselective dissipation characteristics of zoxamide and drive combined impact on soil microenvironment

Abstract

Co-existence of antibiotics (ABX) in soil may expand the environmental harm of pesticide pollution. Our study investigated the combined effects of five antibiotics chlortetracycline (CTC), oxytetracycline (OTC), tetracycline (TC), sulfamethoxazole (SMX), enrofloxacin (ENR) on enantioselective fate of zoxamide (ZXM) and soil health. The results showed that S-(+)-ZXM preferentially dissipated in soil. ABX prolonged dissipation half-life and reduced enantioselectivity of ZXM. Soil was detected to be more acidic after long-term treatment of ZXM and ABX. Lowest soil available N, P, K were found in ZXM + SMX, ZXM + OTC and ZXM + SMX groups at 80 days, respectively. ABX had demonstrated effective promotion of catalase (S-CAT), urease (S-UE) and negative impact on dehydrogenase (S-DHA), sucrase (S-SC) activities. Bacteria Lysobacter, Sphingomonas and fungus Mortierella were identified as the most dominant genera, which possessed as potential microbial resources for removal of composite pollution from ZXM and ABX. SMX and TC, SMX, ENR, respectively, contributed to the alteration of bacteria and fungi community abundance. Soil acidity, available N and enzyme activity showed stronger correlations with bacteria and fungi compared to other environmental factors. Our findings highlighted the interactions between ZXM and ABX from the perspective of soil microenvironment changes. Moreover, a theoretical basis for the mechanism was actively provided.