Environ Toxicol Chem. 2021 Aug 11. doi: 10.1002/etc.5191. Online ahead of print.
ABSTRACT
Antibiotics (ABs) in the aquatic environment is a major problem due to the emergence of antibiotic resistance. The long-term ecological impact on the aquatic environment is unknown. Many sources allow entry of ABs into the environment, including Wastewater Treatment Plants (WWTPs), agricultural run-off, hospital effluent and landfill leachate. Concentrations of ABs in the aquatic environment vary significantly, studies have shown fluoroquinolones, tetracycline, macrolides, sulphonamides and penicillins to reach 2900, 1500, 9700, 21400 and 1600 ngL-1 in wastewater effluent samples, however, concentrations are highly variable between different countries and depend on several factors including seasonally variation, prescription, and WWTP operating procedures. Likewise, the reported concentrations that cause environmental effects varies greatly between ABs, even within the same class, however, this predicted concentration for the ABs considered was frequently <1000 ngL-1 indicating that when discharged into the environment along with treated effluent, these have a potential detrimental effect on the environment. Antibiotics are generally quite hydrophilic in nature; however, they can ionise in the aquatic environment to form charged structures, such as cations, zwitterions, and anions. Certain classes, particularly fluoroquinolones and tetracyclines, can adsorb onto solid matrices, including soils, sediment, and sludge, making it difficult to fully understand their chemical fate in the aquatic environment. The adsorption coefficient (Kd ) varies between different classes of ABs, where tetracyclines and fluoroquinolones show the highest Kd values. Ad sorption coefficients values for fluoroquinolones, tetracyclines, macrolides and sulphonamides have been reported as 54600, 7600, 130 and 1.37 Lkg-1 . Factors such as pH of the environment, solid matrix (sediment/soil sludge) and ionic strength can influence the Kd , therefore, several values exist in literature for the same compound. This article is protected by copyright. All rights reserved.
PMID:34379810 | DOI:10.1002/etc.5191