Chemical Fate and Partitioning Behavior of Antibiotics in the Aquatic Environment—A Review

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 This article is protected by copyright. All rights reserved. Accepted Articleclass, 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 (K d ) varies between different classes of ABs, where tetracyclines and fluoroquinolones show the highest K d values. Adsorption 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 K d , therefore, several values exist in literature for the same compound.

Legacy and Emerging Pollutants in an Urban River Stretch and Effects on the Bacterioplankton Community

“…However, a key factor is the "dilution effect", which in turn depends on river discharge and seasonal rainfall [65] and is particularly significant when WWTP effluents enter natural river water. Moreover, abiotic (e.g., photodegradation) and biotic degradation times and sorption onto particles can also determine contaminant concentrations [5,24]. In this study, emerging contaminants, and in particular pharmaceuticals, were found in higher amounts than PAHs, and this can be ascribed to the different chemical-physical properties of these molecules and different emission sources.…”

“…Antibiotics are emerging contaminants commonly found as river micro-pollutants [23,24] downstream from wastewater treatment plant outlets. Owing to their antimicrobial activity, they can kill or inhibit natural microbial populations involved in specific ecosystem functions (e.g., denitrification) [25] and, at the same time, they can select antibiotic resistant bacteria (ARB) [26].…”

Transport of tetracycline in saturated porous media: combined functions of inorganic ligands and solution pH

“…Consequently, large amounts of unused TC antibiotics will inevitably be released into the environment due to incomplete metabolism in humans, sewage effluents released from healthcare units, 1 and/or disposal of wastewater from the pharmaceutical factory, 2 resulting in increasing concern about their potential negative effects on the environment and public health. 3 Recently published studies have shown that antibiotics could cause toxic effects on micro-organisms, animals, and humans. 4,5 Note that antibiotics can potentially enter the groundwater environment through infiltration, runoff, and leaching, causing groundwater contamination and water quality reduction.…”

Facile Synthesis of MOFs-Templated Carbon Aerogels with Enhanced Tetracycline Adsorption Performance

“…Antibiotics enter wastewater treatment plants in various forms as persistent substances due to their low metabolic rate and low biodegradation [3,4]. The presence and concentration enrichment of tetracycline in the aquatic environment can cause the enhancement and spread of tetracycline-resistant bacteria and resistance genes, even posing a potential risk to the ecosystem and human health [5][6][7]. The advanced treatment techniques include adsorption, flocculation, advanced oxidation technology, chemical degradation, and biological treatment [8][9][10][11].…”