Understanding the toxicity risk of antibiotic emissions of aquaculture from the perspective of fluctuations concentration

Huixiang Li; Weihao Zhang; Huimin Yan; Pan Gao

doi:10.1016/j.envpol.2024.124024

Understanding the toxicity risk of antibiotic emissions of aquaculture from the perspective of fluctuations concentration

Environ Pollut. 2024 Apr 27:351:124024. doi: 10.1016/j.envpol.2024.124024. Online ahead of print.

Authors

Huixiang Li¹, Weihao Zhang², Huimin Yan², Pan Gao³

Affiliations

¹ School of Resource and Environmental Sciences, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, 430079, PR China; Central & Southern China Municipal Engineering Design and Research Institute Co LTD, Jiefang Park Avenue, Wuhan, Hubei, 430063, PR China.
² School of Resource and Environmental Sciences, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, 430079, PR China.
³ Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, PR China. Electronic address: gaopan924989055@163.com.

PMID: 38685554
DOI: 10.1016/j.envpol.2024.124024

Abstract

Organisms are generally exposed to target contaminant with stable concentrations in traditional ecotoxicological studies. However, it is difficult to truly represent the dynamics and complexity of actual aquatic pollution for risk management. Contaminants may enter nearby aquatic systems in pulsed exposure, thus resulting in that aquatic organisms will be exposed to contaminants at fluctuating concentrations. Especially during the season of summer, due to the changes in displacement or periodic emissions of veterinary antibiotics in aquaculture, algal blooms occur frequently in surrounding waters, thus leading to eutrophication of the water. Florfenicol (FFC) is currently widely used as a veterinary antibiotic, but the aquatic ecological risks of FFC under concentration fluctuations are still unknown. Therefore, the acute exposure, chronic exposure and pulsed exposure effects of FFC on Microcystis aeruginosa were investigated to comprehensively evaluate the ecological risk of FFC and raise awareness of the pulsed exposure mode. Results indicated that the toxic effects of FFC on M. aeruginosa were dominated by exposure mode, exposure duration, exposure frequency, and exposure concentration. The maximum growth inhibition rate of the 10 μg/L FFC treatment amounted to 4.07% during chronic exposure of 18 days. However, the growth inhibition rate decreased from 55.1% to 19.31% when algae was exposure to 10 μg/L FFC during the first pulsed exposure (8 h). Therefore, when the concentration of FFC was equal under chronic and pulsed exposure, FFC exhibited greater toxicity on M. aeruginosa in short pulsed exposure than in continuous exposure. In addition, repetitive pulsed exposure strengthened the resistance of M. aeruginosa on FFC. The adaptive regulation of algae was related to the duration and frequency of exposure. Above results suggested that traditional toxicity assessments lacked consideration for fluctuating concentrations during pollutant emissions, thus underestimating the environmental risk of contaminant. This investigation aims to facilitate the standardization of pulsed exposure.

Keywords: Acute exposure; Chronic exposure; Exposure mode; Pulsed exposure.