Occurrence, distribution, and potential ecological risks of antibiotics in a seasonal freeze-thaw basin

Metagenomic analysis reveals the diversity, transmission and potential ecological risks of yak nasal bacteria-carried antibiotic resistance genes in the Sichuan region of Qinghai-Tibet plateau

The Qinghai-Tibet Plateau (QTP) and yaks play respectively vital roles in global and plateau ecosystems. Antibiotic resistance is a global threat to public health, with antibiotic resistance genes (ARGs) being one of the emerging contaminants. However, few studies have investigated the abundance and diversity of ARGs and mobile genetic elements (MGEs) in the yak upper respiratory tract and their surrounding pastures. Moreover, the possible pathways for ARG transmission within these ecosystems have not yet been elucidated. Therefore, we investigated the ARG profiles, MGE profiles, and ARG-carrying host bacteria in yaks and their pasture collected from Ganzi and Aba region in Sichuan Province. Metagenomic analyses showed that 22 ARG types and 5 MGEs types were identified in 18 samples. Multidrug resistance gene (mexT) and bacitracin resistance gene (bacA) was identiffed as hotspots, which may compromise medical treatment options. Co-occurrence network analysis revealed that 12 bacterial genera may be potential hosts at the genus level. The enrich of ARGs and MGEs diversity were observed in QTP (Sichuan province) pasture ecosystems which demands evidence-based interventions to mitigate ARGs transmission risks.

Trophic transfer of sulfonamide antibiotics in aquatic food chains: A comprehensive review with a focus on environmental health risks

Antibiotics, which have been identified as emerged pollutants, are creating an increase in environmental concerns, with sulfonamide antibiotics (SAs) being among the most commonly discovered antibiotics. Due to their widespread usage and inadequate sewage treatment, SAs are frequently released into the aquatic environment. The introduction of SAs into aquatic environments can kill or inhibit the growth or metabolic activity of microorganisms, thereby affecting biological communities and ecological functions and disrupting the equilibrium of aquatic ecosystems. The transmission of SAs to human beings can occur through trophic transfer of food chains, particularly when humans consume aquatic food. This study examines the trophic transfer of SAs along the aquatic food chain, provides a summarize of the spatial distribution of SAs in aquatic environments, and evaluates the environmental risks associated with it. The prevalence of SAs was predominantly noted in the aqueous phase, with relatively lower concentrations detected in sediments, solidifying their status as one of the most widespread antibiotics among aquatic organisms. SAs, characterized by their high biomagnification capacity and strong bioaccumulative properties in invertebrates, emerge as the antibiotic type with the greatest ecological risks. The ecological risk posed by sulfonamide antibiotics to aquatic organisms is more pronounced than the health risk to humans, suggesting that the adverse effects on aquatic life warrant greater attention. Additionally, this study offers practical recommendations to address the limitations of previous research, emphasizing the importance of regulating exposure and establishing a robust health risk prediction system as effective measures for antibiotic control.

Seasonal dynamics, sources, and ecological risk of estrogens in a freeze-thaw basin: Implications for aquatic ecosystems

Estrogens have attracted extensive attention because of their harmful effects on organisms such as endocrine disturbance and reproductive toxicity. This study investigated the spatial and temporal distribution and ecological risk assessment of 7 targeted estrogens in surface water in a seasonal freeze-thaw basin. It mainly includes three natural estrogens, estrone (E1), 17β-estradiol (E2) and estriol (E3), two synthetic estrogens, 17α-ethinylestradiol (EE2) and diethylstilbestrol (DES), and two phenolic environmental estrogens, bisphenol-A (BPA) and nonylphenol (NP). The total estrogen concentration was 15.30-489.62 ng·L-1. BPA, NP, DES and E3 were the major estrogenic pollutants in the basin. The targeted estrogens showed significant seasonal differences in the freeze-thaw process, and the total concentration was from high to low in wet, thawing and freezing seasons. Principal sources of estrogens primarily originated from mixed discharge of livestock and domestic sewage and landfill leachate. Increased runoff promoted pollution sources into rivers, increasing the concentration during wet and thawing seasons, and the latter posed a higher ecological risk to aquatic organisms that would be in the breeding season. Targeted estrogens posed a high total ecological risk to fish and a moderate ecological risk to algae and crustaceans. The total estradiol equivalent concentrations (EEQT) of targeted estrogens in all seasons exceeded the safe concentration threshold. Therefore, it is suggested to strengthen the monitoring frequency of estrogens in different seasons and adopt strict sewage treatment measures and discharge monitoring to reduce the harm to the ecological environment.

Regional distribution differences of antibiotics in tropical marine aquaculture area: Insights into antibiotic management and risk assessment

In recent years, global demand for marine aquaculture products has led to a significant rise in antibiotic use, particularly in tropical coastal aquaculture areas However, research on antibiotic residues in these environments remains limited, hindering a comprehensive understanding of their environmental presence and associated risks. This study investigates the regional distribution, ecological risks, and sources of 44 antibiotics in seawater across four coastal aquaculture areas in Hainan island (Wenchang, Sanya, Danzhou, and Wanning). Among the 44 antibiotics tested across 42 sampling sites, all were detected with a 100 % detection rate. Antibiotics such as Trimethoprim (TMP), Sulfanitran (APNPS), Sulfaquinoxaline (SQ), Sulfadimethoxine (SDT), Chloramphenicol (CHP), and Florfenicol (FLO) were consistently detected across all sampling sites. Total concentrations of detected antibiotics ranged from 0 to 818.79 ng.L-1, with sulfonamide antibiotics ranging from 0 to 629.49 ng.L-1, chloramphenicol antibiotics from 0 to 87.39 ng.L-1, tetracyclines from 0 to 221.39 ng.L-1, and fluoquinolones from 0 to 272.08 ng.L-1. The highest levels of antibiotic pollution were observed at the W5 sampling site in Wenchang, attributed to aquaculture wastewater discharge, while no antibiotics were found at D12 in Danzhou. In these regions, source analysis identified aquaculture and domestic sewage as the primary contributors to antibiotic pollution in these regions. Correlation analysis with environmental factors revealed significant influences of factors such as SAL, kPa, TN, SPC, and pH on sulfonamide and chloramphenicol antibiotics. Health risk assessment indicated moderate to high risks to aquatic organisms from antibiotics like NOR, CIP, ENR, OFL, TMP, and SMX in the study areas, underscoring the need for preventive measures, stricter regulation of antibiotic use, and enhanced ecological risk monitoring in aquaculture regions. This study provides critical insights into antibiotic contamination in Hainan's coastal aquaculture areas, highlighting the urgent need for further research into the occurrence and ecological impacts of these emerging pollutants in marine environments.

Occurrence and risk assessment of quinolones and sulfonamides in freshwater aquaculture ponds in Northeast Zhejiang, China

Antibiotics play an essential role in the aquaculture industry, but their overuse and weak degradability inevitably lead to light to severe residues in natural and aquaculture environments. Most studies were interested in the occurrence, distribution, and ecological risks of a limited number of antibiotics in natural environments (rivers, lakes, and coastal regions) with a minor focus on antibiotic presence in either water, sediments, or organisms in aquaculture environments located in specific regions. In this study, we conducted a comprehensive investigation into the occurrence and distribution of up to 32 antibiotics [including 15 quinolones (QNs) and 17 sulfonamides (SAs)] in organisms and their corresponding environmental matrices from 26 freshwater aquaculture ponds in Northeast Zhejiang, China. A total of 13, 9, 7, and 7 antibiotics were detected in pond water, sediments, feeds, and aquaculture organisms, respectively, with concentration ranges of 0.6-92.2 ng/L, 0.4-1169.3 ng/g dw, Collapse

Key Words

• Antibiotics
• Contamination
• Cultured ponds
• Ecological risk
• Farming
• Health risk

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MESH Headings

• Water Pollutants, Chemical/analysis
• Aquaculture
• Sulfonamides/analysis
• China
• Quinolones/analysis
• Risk Assessment
• Environmental Monitoring
• Ponds/chemistry
• Anti-Bacterial Agents/analysis
• Animals
• Fresh Water/chemistry

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Affiliation(s)

Hongmei Hu Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Mengyu Qi Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Pengfei He Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Xuechang Chen Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Zhenhua Li Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China.
Heyong Cheng College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, PR China.

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Comprehensive analysis and risk assessment of Antibiotic contaminants, antibiotic-resistant bacteria, and resistance genes: Patterns, drivers, and implications in the Songliao Basin

The pervasive use of antibiotics has raised substantial environmental concerns, especially regarding their temporal and spatial distribution across diverse water systems. This study addressed the gap in comprehensive research on antibiotic contamination during different hydrological periods, focusing on the Jilin section of the Songliao Basin in Northeast China, an area with severe winter ice cover. The study examined the occurrence, distribution, influencing factors, and potential ecological risks of prevalent antibiotic contaminants. Findings revealed antibiotic concentrations ranging from 239.64 to 965.81 ng/L, with antibiotic resistance genes (ARGs) at 5.22 × 10-2 16S rRNA-1 and antibiotic-resistant bacteria (ARB) up to 5.76 log10 CFU/mL. Ecological risk assessments identified significant risks to algae from oxytetracycline, erythromycin, and amoxicillin. Redundancy analysis and co-occurrence networks with ordinary least squares (OLS) demonstrated that the dispersion of ARGs and ARB is significantly influenced by environmental factors such as total organic carbon (TOC), total phosphorus (TP), total nitrogen (TN), fluoride (F⁻), and nitrate (NO₃⁻). These elements, along with mobile genetic elements (MGEs), play crucial roles in ARG patterns (R2 = 0.94, p ≤ 0.01). This investigation offers foundational insights into antibiotic pollution dynamics in cold climates, supporting the development of targeted mitigation strategies for aquatic systems.

Unveiling the hidden risks: Pesticide residues in aquaculture systems

The present study systematically assessed the presence and ecological risks of 79 pesticides in various aquaculture systems, namely pond aquaculture (PA), greenhouse aquaculture (GA), and raceway aquaculture (RA) at different aquaculture stages, along with evaluating the pesticide removal of four tailwater treatment systems. Sixteen herbicides and two fungicides were identified, with the total concentrations ranging from 8.33 ng/L to 3248.45 ng/L. The PA system demonstrated significantly higher concentrations (p < 0.05) and a wider range of pesticide residues compared to the GA and RA systems. Prometryn, simetryn, atrazine, and thifluzamide were found to be the predominant pesticides across all three aquaculture modes, suggesting their significance as pollutants that warrant monitoring. Additionally, the findings indicated that the early aquaculture stage exhibits the highest levels of pesticide concentration, underscoring the importance of heightened monitoring and regulatory interventions during this phase. Furthermore, among the four tailwater treatment systems analyzed, the recirculating tailwater treatment system exhibited the highest efficacy in pesticide removal. A comprehensive risk assessment revealed minimal ecological risks in both the aquaculture and tailwater environments. However, the pesticide mixtures present high risks to algae and low to medium risks to aquatic invertebrates and fish, particularly during the early stages of aquaculture. Simetryn and prometryn were identified as high-risk pesticides. Based on the prioritization index, simetryn, prometryn, diuron, and ametryn are recommended for prioritization in risk assessment. This study offers valuable data for pesticide control and serves as a reference for the establishment of a standardized pesticide monitoring and management system at various stages of aquaculture.

Occurrence, fate, and risk assessment of antibiotics in conventional and advanced drinking water treatment systems: From source to tap

The occurrence and removal of 38 antibiotics from nine classes in two drinking water treatment plants (WTPs) were monitored monthly over one year to evaluate the efficiency of typical treatment processes, track the source of antibiotics in tap water and assess their potential risks to ecosystem and human health. In both source waters, 18 antibiotics were detected at least once, with average total antibiotic concentrations of 538.5 ng/L in WTP1 and 569.3 ng/L in WTP2. The coagulation/flocculation and sedimentation, sand filtration and granular activated carbon processes demonstrated limited removal efficiencies. Chlorination, on the other hand, effectively eliminated antibiotics by 48.7 ± 11.9%. Interestingly, negative removal was observed along the distribution system, resulting in a significant antibiotic presence in tap water, with average concentrations of 131.5 ng/L in WTP1 and 362.8 ng/L in WTP2. Source tracking analysis indicates that most antibiotics in tap water may originate from distribution system. The presence of antibiotics in raw water and tap water posed risks to the aquatic ecosystem. Untreated or partially treated raw water could pose a medium risk to infants under six months. Water parameters, for example, temperature, total nitrogen and total organic carbon, can serve as indicators to estimate antibiotic occurrence and associated risks. Furthermore, machine learning models were developed that successfully predicted risk levels using water quality parameters. Our study provides valuable insights into the occurrence, removal and risk of antibiotics in urban WTPs, contributing to the broader understanding of antibiotic pollution in water treatment systems.

The Piezocatalytic Degradation of Sulfadiazine by Lanthanum-Doped Barium Titanate

Piezocatalysis, a heterogeneous catalytic technique, leverages the periodic electric field changes generated by piezoelectric materials under external forces to drive carriers for the advanced oxidation of organic pollutants. Antibiotics, as emerging trace organic pollutants in water sources, pose a potential threat to animals and drinking water safety. Thus, piezoelectric catalysis can be used to degrade trace organic pollutants in water. In this work, BaTiO3 and La-doped BaTiO3 were synthesized using an improved sol-gel-hydrothermal method and used as piezocatalytic materials to degrade sulfadiazine (SDZ) with ultrasound activation. High-crystallinity products with nano cubic and spherical morphologies were successfully synthesized. An initial concentration of SDZ ranging from 1 to 10 mg/L, a catalysis dosage range from 1 to 2.5 mg/mL, pH, and the background ions in the water were considered as influencing factors and tested. The reaction rate constant was 0.0378 min-1 under the optimum working conditions, and the degradation efficiency achieved was 89.06% in 60 min. La-doped BaTiO3 had a better degradation efficiency, at 14.98% on average, compared to undoped BaTiO3. Further investigations into scavengers revealed a partially piezocatalytic process for the degradation of SDZ. In summary, our work provides an idea for green environmental protection in dealing with new types of environmental pollution.

Tetracycline and sulfadiazine toxicity in human liver cells Huh-7

As typical antibiotics, tetracycline (TC) and sulfadiazine (SDZ) enter the human body through the food chain. Therefore, it is necessary to understand their individual and combined toxicity. In this study, the effects of TC, SDZ, and their mixture on cell viability, cell membrane damage, liver cell damage, and oxidative damage were evaluated in in vitro assays with human liver cells Huh-7. The results showed cytotoxicity of TC, SDZ, and their mixture, which induced oxidative stress and caused membrane and cell damage. The effect of antibiotics on Huh-7 cells increased with increasing concentration, except for lactate dehydrogenase (LDH) activity that commonly showed a threshold concentration response and cell viability, which commonly showed a biphasic trend, suggesting the possibility of hormetic responses where proper doses are included. The toxicity of TC was commonly higher than that of SDZ when applied at the same concentration. These findings shed light on the individual and joint effects of these major antibiotics on liver cells, providing a scientific basis for the evaluation of antibiotic toxicity and associated risks.

Spatiotemporal distribution and potential risks of antibiotics in coastal water of Beibu Gulf, South China Sea: Livestock and poultry emissions play essential effect

Antibiotics have been the subject of much attention in recent years due to their widespread use and the potential ecological risks and resistance risks. In this study, we conducted an extensive survey of 19 antibiotics in a wide range of waters of the Beibu Gulf during summer and winter (154 samples). The total concentrations of the 19 antibiotics (Σ19ABs, ng/L) were significantly higher in winter (n.d.-364) than in summer (n.d.-70.1) and were mainly concentrated in areas of seagoing rivers (1.50-364). The primary route for antibiotics entering Beibu Gulf was through riverine input. Precisely, florfenicol (FF) (n.d.-278 ng/L) discharged from livestock and poultry farms upstream of Nanliu River, predominantly in swine farming, constitutes the main pollutant in Beibu Gulf throughout the year. The Nanliu River (988 kg/a) accounts for 85% of the gulf's total annual antibiotic emission flux. Source analysis identified livestock and poultry farming, particularly swine farming, as the primary pollution source, contributing 58% in summer. Risk assessment reveals that algae (0.51 ± 0.56) exhibited relatively high sensitivity to antibiotics, presenting a medium-high risk at specific sites in Nanliu River during winter. Additionally, FF discharged from swine farming demonstrates a certain level of antibiotic resistance risk. Therefore, reinforcing control measures for antibiotic discharges from livestock and poultry farming, especially upstream of Nanliu River, can effectively mitigate antibiotic-related risks in the water bodies of Beibu Gulf.