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Ecosystem response to antibiotics entering the aquatic environment
Simon D Costanzo1, John Murby, John Bates
1National Research Centre for Environmental Toxicology, University of Queensland, 39, Kessels Road, Coopers Plains, Brisbane 4108, QLD, Australia. s.costanzo@uq.edu.au
Marine Pollution Bulletin
|March 11, 2005
Summary
Antibiotics like ciprofloxacin and norfloxacin are present in wastewater and aquatic environments, posing risks to ecosystems. Bacterial resistance to these and other antibiotics was observed, impacting ecosystem functions.
Area of Science:
- Environmental Science
- Microbiology
- Ecotoxicology
Background:
- Growing awareness of antibiotics as environmental pollutants.
- Improved analytical techniques facilitate detection in wastewaters and aquatic ecosystems.
Purpose of the Study:
- Evaluate the presence of specific antibiotics (ciprofloxacin, norfloxacin, cephalexin) in sewage effluent and receiving waters.
- Assess bacterial resistance to various antibiotics.
- Examine the impact of short-term antibiotic exposure on bacterial denitrification rates.
Main Methods:
- Detection of antibiotics in sewage treatment plant influent, effluent, and downstream environmental waters.
- Culturing bacteria from sewage bioreactors and receiving waters.
- Testing bacterial resistance against six different antibiotics.
- Measuring bacterial denitrification rates after 24-hour antibiotic exposure.
Main Results:
- Antibiotics were detected entering the sewage treatment plant and were present in effluent and receiving waters up to 500m downstream.
- Bacteria from the sewage bioreactor showed resistance to all six tested antibiotics; bacteria from receiving waters were resistant to two.
- Denitrification rates decreased with exposure to certain antibiotics, but only at concentrations higher than typically found in the environment.
Conclusions:
- Antibiotics are entering aquatic systems via sewage discharge.
- Widespread bacterial resistance to antibiotics in these environments is a concern.
- Antibiotics pose a potential threat to aquatic ecosystem function and possibly human health.