## 1 Introduction  
Antibiotics are a crucial class of medications in modern healthcare, commonly used to prevent and treat infectious diseases in both humans and animals by either destroying bacteria or inhibiting their growth and reproduction [1]. Since [PERSON] first discovered the natural antibiotic penicillin in 1929, hundreds of antibiotics have been developed for clinical use through the extraction of natural compounds and the molecular modification of existing antibiotics. Currently, there are ten major classes of antibiotics categorized by their chemical structures: penicillin, macrolides, cephalospor, quinolones, beta-lactams, incosamides, tetracyclines, sulfonamides, glycoptides, and aminoglycosides. Among the antibiotic classes commonly detected in water are tetracyclines, beta-lactams, fluoroquinolones, sulfonamides, and macrolides [2]. Different types of antibiotics exert specific effects on various species of bacteria, with the primary mechanisms being (1) the targeted inhibition of protein synthesis through interactions with ribosomal subunits (e.g., tetracycline, chloramphenicol, and aminoglycosides), (2) the disruption of cell wall synthesis (e.g., \(\beta\)-lactams), (3) interference with nucleic acid processes (e.g., rifampicin and fluoroquinolones), (4) the disruption of metabolic pathways (e.g., folate analogs such as sulfonamides), and (5) the alteration of the bacterial membrane structure (e.g., polymyxins). The main classifications and mechanisms of the action of antibiotics are listed in Table 1.  
Antibiotics are extensively utilized in the management of infectious diseases in both humans and animals, as well as being employed as feed additives to promote growth in livestock and poultry. The research conducted by [PERSON] indicates that only a small percentage of ingested antibiotics are metabolized and absorbed by the body during their use. The majority of these substances (50-90%) and their primary metabolites are not fully metabolized by humans or animals, leading to their excretion through urine and feces. This excreted material retains significant bacteriostatic activity and ultimately enters the natural environment [3]. The excretion rates are 98% for sulfamethoxazole, 82% for amoxicillin, 60% for ciprofloxacin, and less than 50% for nonfloxacin and erythromycin. More concerningly, practices such as overuse, inadequate regulation, and improper handling have led to elevated levels of antibiotic residues being detected in various aquatic environments, with some even contaminating drinking water [4]. The main sources of antibiotic contamination in the environment are as follows: (1) Households--the vast majority of antibiotics used by humans (50-90%) are excreted in urine or feces as parent compounds or metabolite intermediates, which end up in municipal wastewater treatment plants (wwaterwater treatment plants (WWTPs)). (2) Hospitals--the major sources of large quantities of antibiotics in municipal wastewater, dominated by drugs originating from patients that are not metabolized and absorbed and excreted through urine (55-80%) and feces (4-30%). (3) Livestock and poultry farming--antibiotics are also widely used in animal husbandry (cattle, pigs, and poultry) and aquaculture; due to the excessive use of antibiotics in the process of livestock and poultry production and poor metabolic absorption in animals, a large number of antibiotics and their metabolite residues are transferred into the feces. (4) Aquaculture--the large-scale use of antibiotics in centralized aquaculture has led to the accumulation of large quantities of antibiotic residues in surface water and sediments