Distribution, transfer, ecological and human health risks of antibiotics in bay ecosystems

Unveiling the characteristics of fluoroquinolones in China marginal seas: Spatiotemporal distribution, environmental fate, and mass inventory

Fluoroquinolones (FQs) are widely used antibiotics, frequently detected in marine environments with serious ecological risks. This study reviewed FQs usage in China, their spatiotemporal distribution in offshore waters, and their marine fates. FQs consumption initially declined but increased after 2013. Studies on antibiotics in China's offshore areas were concentrated in the Bohai Sea, particularly in Bohai Bay and Laizhou Bay, while fewer studies were conducted in the East and South China Seas. NOR, OFL, CIP, and ENR exhibited the highest detection frequencies and concentrations, with enoxacin (ENO) also commonly found in the South China Sea. The total concentration of FQs (∑FQs) in seawater ranged from 0.2 to 960 ng/L, following the order Bohai Sea > Yellow Sea ≈ East China Sea > South China Sea, with a decreasing trend in the Bohai and South China Seas since 2013. ∑FQs concentrations in sediments were lower, ranging from 0.02 to 170.18 ng/g, with no regional differences. Estimated ∑FQs mass inventories ranged from 7.42 to 671.13 tons in the Bohai Sea and from 7.90 to 478.23 tons in the Yellow Sea. Seawater exchange influenced FQs accumulation, with long-term discharge retention in the Bohai Sea and recent inputs in the Yellow Sea. A strong correlation was observed between FQs usage and their marine inventories, with NOR and CIP exhibiting higher environmental stability than OFL and ENR. This study provides important scientific evidence for a systematic understanding of the relationship between the use, occurrence, and environmental fate of FQs in China.

Urbanization Gradients Affect Occurrence and Distribution of Antibiotic Contamination in the Baixi Reservoir and Yongjiang Estuary, China

Urbanization has promoted the development of human society, but is often accompanied by environmental pollution. To investigate the extent to which differing levels of urbanization might affect antibiotic heterogeneity and distribution in the aquatic environment, we contrast the Yongjiang Estuary, an area of intense urbanization, with the Baixi Reservoir- whose hinterland is much less urbanized. We found that antibiotic residues in Baixi Reservoir and Yongjiang Estuary were significantly different due to urbanization gradient. 14 antibiotics were detected in Yongjiang Estuary with an average concentration of 0.74 ng/L, and the dominant classes being was macrolides. 13 antibiotics were detected in Baixi Reservoir with an average concentration of 0.12 ng/L, and the dominant class being tetracyclines. Total nitrogen, total suspended particulate matter and dissolved organic carbon (DOC) were found to have strong effect on the concentration of quinolones in Baixi Reservoir. However, salinity, ammonia nitrogen, DOC and chloride ion concentration were found to have strong effect on the concentration of quinolones in Yongjiang Estuary. DOC was the common factor affecting the concentration of antibiotics. This study provides data which reveal the distribution characteristics of antibiotics under different urbanization level and elucidates the risks posed by antibiotics resistance associated with rapid urbanization occurring in China and throughout the developing world.

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.

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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Grants Collapse

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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Impacts of root exudates on the toxic response of Chrysanthemum coronarium L. to the co-pollution of nanoplastic particles and tetracycline

Nano polystyrene (PS) particles and antibiotics universally co-exist, posing a threat to crop plants and hence human health, nevertheless, there is limited research on their combined toxic effects along with major influential factors, especially root exudates, on crop plants. This study aimed to investigate the response of Chrysanthemum coronarium L. to the co-pollution of nanoplastics and tetracycline (TC), as well as the effect of root exudates on this response. Based on a hydroponic experiment, the biochemical and physiological indices of Chrysanthemum coronarium L. were measured after 7 days of exposure. Results revealed that the co-pollution of TC and PS caused significant oxidative damage to the plants, resulting in reduced biomass. Amongst the two contaminants, TC played a more prominent role. PS could enter the root tissue, and the uptake of TC and PS by plant roots was synergetic. Malic acid, oxalic acid, and formic acid could explain 65.1% of the variation in biochemical parameters and biomass of the roots. These compounds affected the photosynthesis and biomass of Chrysanthemum coronarium L. by gradually lowering root reactive oxygen species (ROS) and leaf ROS. In contrast, the impact of rhizobacteria on the toxic response of the plants was relatively minor. These findings suggested that root exudates could alleviate the toxic response of plants to the co-pollution of TC and PS. This study enhances our understanding of the role of root exudates, providing insights for agricultural management and ensuring food safety.

Occurrence, distribution and potential environmental risks of pollutants in aquaculture ponds during pond cleaning in Taihu Lake Basin, China

During the process of cleaning aquaculture ponds, the drainage contributes significantly to antibiotic pollution in the surrounding water environment. Therefore, we conducted a study on the distribution of 26 antibiotics in 57 ponds within the Taihu Lake basin. The results revealed that the detection frequency of antibiotics ranged from 1.75 % to 80.7 %, with the overall detection concentrations ranging from 3.27 to 708.72 ng/L. Among them, the detection rate of 8 antibiotics exceeded 50 %. Regarding the spatial distribution, the concentration of antibiotics was relatively high in aquaculture ponds located in the Changzhou area, with the highest concentration reaching 708.72 ng/L. This observation is likely due to the large size and intensive breeding practices in Changzhou. Fish ponds exhibited a significantly higher total antibiotic concentration of 3.27 to 445.57 ng/L compared to crab ponds (13.01 to 206.30 ng/L) and shrimp ponds (23.17 to 107.40 ng/L). Quinolones and sulfonamides were the predominant antibiotic classes found in fish ponds, accounting for 51.49 % of the total antibiotic concentration. Notably, sulfamethoxazole (SMX) and enrofloxacin (ENR) exhibited the highest antibiotic concentrations. Risk assessments demonstrated that SMX, ENR, and ofloxacin (OFX) contributed significantly to ecological risks. Furthermore, the study found that the tertiary constructed wetland treatment process achieved a remarkable removal rate of 92.44 % for antibiotics in aquaculture wastewater, while other treatment processes displayed limited effectiveness in removing antibiotics. This study addresses the knowledge gap concerning antibiotic pollution during the cleaning process of aquaculture ponds within the Taihu Lake basin.

Data-Driven Insights into the Contamination of Polycyclic Aromatic Hydrocarbons in Marine Bays

The synthesis of polycyclic aromatic hydrocarbon (PAH) data allows us to quantify and gain insights into the spatiotemporal dynamics of PAH contamination in marine bays. Here, a data synthesis framework was developed to understand data-driven insights into the spatiotemporal levels, compositional profiles, and potential sources of PAHs in water and sediment of marine bays. PAHs were detected in 69 bays worldwide, with contamination hotspots located in Asian bays. PAH concentrations in pre-2000 were significantly lower than those in the 2000s and post-2010, while the dominant species in water and sediment were 2-3 ring and 4-6 ring PAHs, respectively. The composition patterns of PAHs included 2-3 ring, 3-5 ring, and 4-5 ring dominant categories, but no significant distance decay relationship was found in the composition similarity due to international energy trade. Temporal dynamic patterns of concentrations included Descending-, Ascending-, and Inverted V-type, whereas over longer time spans, the pattern is more similar to the Inverted V-type owing to the reductions in emission intensity. PAHs were derived from both petrogenic and pyrolytic sources, with combustion from both coal and petroleum being the dominant source. These data-driven discoveries provide quantitative insights into the spatiotemporal patterns in the concentration and composition of PAHs, contributing to the mitigation of PAH contamination.

Combined effects of cadmium and sulfamethoxazole on Eisenia fetida: Insights into accumulation, subcellular partitioning, biomarkers and toxicological responses

Cadmium (Cd) and sulfamethoxazole (SMX) frequently coexist in farmlands, yet their synergistic toxicological impacts on terrestrial invertebrates remain unexplored. In this study, earthworms were exposed to artificial soils percolated with Cd (5 mg/kg), SMX (5 mg/kg) or combination of them for 7 days, followed by a 12-day elimination phase in uncontaminated soil. The uptake of Cd and SMX by the earthworms, along with their subcellular distribution, was meticulously analyzed. Additionally, a suite of biomarkers-including superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and weight loss-were evaluated to assess the health status of the earthworms and the toxicological effects of the Cd and SMX mixture. Notably, the cotreatment with Cd and SMX resulted in a significantly higher weight loss in Eisenia fetida (41.25 %) compared to exposure to Cd alone (26.84 %). Moreover, the cotreatment group exhibited substantially higher concentrations of Cd in the total internal body, fraction C (cytosol), and fraction E (tissue fragments and cell membranes) in Eisenia fetida compared to Cd alone counterparts. The combined exposure also significantly elevated the SMX levels in the total body and fraction C compared with the SMX-only treated earthworms. Additionally, Eisenia fetida subjected to the combined treatment showed markedly increased activities of SOD, CAT, and MDA compared to those treated with Cd alone. The effect addition indices (EAIs), ranging from 1.00 to 2.23, unequivocally demonstrated a synergistic effect of the combined treatments. Interestingly, relocating the earthworms to clean soil did not mitigate the observed adverse effects. These findings underscore the increased risk posed by the Cd-SMX complex to terrestrial invertebrates in agricultural areas.

Significant regional disparities in riverine microplastics

Research on riverine microplastics has gradually increased, highlighting an area for further exploration: the lack of extensive, large-scale regional variations analysis due to methodological and spatiotemporal limitations. Herein, we constructed and applied a comprehensive framework for synthesizing and analyzing literature data on riverine microplastics to enable comparative research on the regional variations on a large scale. Research results showed that in 76 rivers primarily located in Asia, Europe, and North America, the microplastic abundance of surface water in Asian rivers was three times higher than that in Euro-America rivers, while sediment in Euro-American rivers was five times more microplastics than Asia rivers, indicating significant regional variations (p < 0.001). Additionally, based on the income levels of countries, rivers in lower-middle and upper-middle income countries had significantly (p < 0.001) higher abundance of microplastics in surface water compared to high-income countries, while the opposite was true for sediment. This phenomenon was preliminarily attributed to varying levels of urbanization across countries. Our proposed framework for synthesizing and analyzing microplastic literature data provides a holistic understanding of microplastic disparities in the environment, and can facilitate broader discussions on management and mitigation strategies.

Groundwater systems under siege: The silent invasion of microplastics and cock-tails worldwide

Microplastics (MPs) contamination is one of the significant escalating environmental concerns worldwide, and this stems from the increasing production and unlawful disposal of plastic materials. Regretfully, the synthesis of plastic materials is expected to triple in the upcoming years. Nevertheless, MPs pollution in marine, aquatic, and terrestrial settings has received much attention, unlike in groundwater systems. This study exhaustively reviewed varying degrees of recent publications in various search engines and provided a detailed state of current knowledge and research progress vis-à-vis MPs and cock-tail pollution in groundwater systems. Evidently, groundwater sources are severely contaminated as a result of growing anthropogenic activities and vertical movement of MPs and cock-tails from the atmospheric, terrestrial, and aquatic environments, however, fewer researchers have fixated their attention on estimating the occurrence of MPs in groundwater resources, while sufficient information regarding their sources, sampling methods, abundance, transport pathways, fate, modeling techniques, appropriate and adequate data, sorption properties, separation from other environmental media, toxicity, and remedial measures are extensively lacking. In addition, MPs may combine with other toxic emerging contaminants to improve migration and toxicity; however, no research has been conducted to fully understand cock-tail migration mechanisms and impacts in groundwater systems. Over time, groundwater may be regarded as the primary sink for MPs, if effective actions are neglected. Overall, this study detected a lack of concern and innumerable voids in this field; hence, vital and nascent research gaps were identified for immediate, advanced, and interdisciplinary research investigations.

A meta-analysis of antibiotic residues in the Beibu Gulf

Antibiotic residue stands as a significant ongoing environmental issue, with aquaculture being a major source of annual antibiotic discharge into the ocean. Nevertheless, there is still an incomplete evaluation of antibiotic residues in the Beibu Gulf, an area encompassed by two prominent aquaculture nations, China and Vietnam. The present systematic review and meta-analysis was conducted to examine the presence antibiotic residues in the Beibu Gulf based on published studies. Data were obtained through eight databases up to December 19th, 2023, and were updated on April 15th, 2024. The pooled concentration of antibiotic residues in seawater was 5.90 (ng/L), ranging from 5.73 to 6.06 (ng/L), and was 8.03 (ng/g), ranging from 7.77 to 8.28 (ng/g) in sediments. Fluoroquinolones, tetracyclines, and macrolides were identified as the main antibiotics found in both seawater and sediment samples. The Beibu Gulf showed higher antibiotic levels in its western and northeastern areas. Additionally, the nearshore mangrove areas displayed the highest prevalence of antibiotic residues. It is strongly advised to conduct regular long-term monitoring of antibiotic residues in the Beibu Gulf. Collaborative surveys covering the entire Beibu Gulf involving China and Vietnam are recommended.

Occurrence, removal efficiency, and emission of antibiotics in the sewage treatment plants of a low-urbanized basin in China and their impact on the receiving water

Sewage treatment plants (STPs) are primary sources of antibiotics in aquatic environments. However, limited research has been conducted on antibiotic attenuation in STPs and their downstream waters in low-urbanized areas. This study analyzed 15 antibiotics in the STP sewage and river water in the Zijiang River basin to quantify antibiotic transport and attenuation in the STPs and downstream. The results showed that 14 target antibiotics, except leucomycin, were detected in the STP sewage, dominated by amoxicillin (AMOX), ofloxacin, and roxithromycin. The total antibiotic concentration in the influent and effluent ranged from 158 to 1025 ng/L and 99.9 to 411 ng/L, respectively. The removal efficiency of total antibiotics ranged from 54.7 % to 75.7 % and was significantly correlated with total antibiotic concentration in the influent. The antibiotic emission from STPs into rivers was 78 kg/yr and 4.6 g/km2yr in the Zijiang River basin. The total antibiotic concentration downstream of the STP downstream was 23.6 to 213 ng/L and was significantly negatively correlated with the transport distance away from the STP outlets. Antibiotics may pose a high ecological risk to algae and low ecological risk to fish in the basin. The risk of AMOX and ciprofloxacin resistance for organisms in the basin was estimated to be moderate. This study established antibiotic removal and attenuation models in STPs and their downstream regions in a low-urbanized basin, which is important for simulating antibiotic transport in STPs and rivers worldwide.

Occurrence, distribution, and risk assessment of antibiotics in a typical aquaculture area around the Dongzhai Harbor mangrove forest on Hainan Island

The trees of the Dongzhai Harbor mangrove forest suffer from antibiotic contamination from surrounding aquaculture areas. Despite this being one of the largest mangrove forests in China, few studies have focused on the antibiotic pollution status in these aquaculture areas. In the present study, the occurrence, distribution, and risk assessment of 37 antibiotics in surface water and sediment samples from aquaculture areas around Dongzhai Harbor mangrove forests were analyzed. The concentration of total antibiotics (∑antibiotics) ranged from 78.4 ng/L to 225.6 ng/L in surface water (except S14-A2) and from 19.5 ng/g dry weight (dw) to 229 ng/g dw in sediment. In the sediment, the concentrations of ∑antibiotics were relatively low (19.5-52.3 ng/g dw) at 75 % of the sampling sites, while they were high (95.7-229.0 ng/g dw) at a few sampling sites (S13-A1, S13D, S8D). The correlation analysis results showed that the Kd values of the 9 antibiotics were significantly positively correlated with molecular weight (MW), Kow, and LogKow. Risk assessment revealed that sulfamethoxazole (SMX) in surface water and SMX, enoxacin (ENX), ciprofloxacin (CFX), enrofloxacin (EFX), ofloxacin (OFX), and norfloxacin (NFX) in sediment had medium/high risk quotients (RQs) at 62.5 % and 25-100 %, respectively, of the sampling sites. The antibiotic mixture in surface water (0.06-3.36) and sediment (0.43-309) posed a high risk at 37.5 % and 66.7 %, respectively, of the sampling sites. SMX was selected as an indicator of antibiotic pollution in surface water to assist regulatory authorities in monitoring and managing antibiotic pollution in the aquaculture zone of Dongzhai Harbor. Overall, the results of the present study provide a comprehensive and detailed analysis of the characteristics of antibiotics in the aquaculture environment around the Dongzhai Harbor mangrove system and provide a theoretical basis for the source control of antibiotics in mangrove systems.

Influence of dietary status on the obesogenic effects of erythromycin antibiotic on Caenorhabditis elegans

As emerging pollutants, antibiotics were widely detected in water bodies and dietary sources. Recently, their obesogenic effects raised serious concerns. So far, it remained unclear whether their obesogenic effects would be influenced by water- and diet-borne exposure routes. In present study, Caenorhabditis elegans, nematodes free-living in air-water interface and feeding on bacteria, were exposed to water- and diet-borne erythromycin antibiotic (ERY). The statuses of the bacterial food, inactivated or alive, were also considered to explore their influences on the effects. Results showed that both water- and diet-borne ERY significantly stimulated body width and triglyceride contents. Moreover, diet-borne ERY's stimulation on the triglyceride levels was greater with alive bacteria than with inactivated bacteria. Biochemical analysis showed that water-borne ERY inhibited the activities of enzymes like adipose triglyceride lipase (ATGL) in fatty acid β-oxidation. Meanwhile, diet-borne ERY inhibited the activities of acyl-CoA synthetase (ACS) and carnitine palmitoyl transferase (CPT) in lipolysis, while it stimulated the activities of fatty acid synthase (FAS) in lipogenesis. Gene expression analysis demonstrated that water-borne ERY with alive bacteria significantly upregulated the expressions of daf-2, daf-16 and nhr-49, without significant influences in other settings. Further investigation demonstrated that ERY interfered with bacterial colonization in the intestine and the permeability of the intestinal barrier. Moreover, ERY decreased total long-chained fatty acids (LCFAs) in bacteria and nematodes, while it decreased total short-chained fatty acids (SCFAs) in bacteria but increased them in nematodes. Collectively, the present study demonstrated the differences between water- and diet-borne ERY's obesogenic effects, and highlighted the involvement of insulin and nhr-49 signaling pathways, SCFAs metabolism and also the interaction between intestinal bacteria and the host.

Highly Sensitive Ratiometric Fluorescent Flexible Sensor Based on the RhB@ZIF-8@PVDF Mixed-Matrix Membrane for Broad-Spectrum Antibiotic Detection

Antibiotics play an essential role in the treatment of various diseases. However, the overuse of antibiotics has led to the pollution of water bodies and food safety, affecting human health. Herein, we report a dual-emission MOF-based flexible sensor for the detection of antibiotics in water, which was prepared by first encapsulating rhodamine B (RhB) by a zeolite imidazolium ester skeleton (ZIF-8) and then blending it with polyvinylidene difluoride (PVDF). The luminescent properties, structural tunability, and flexible porosity of the MOF-based composites were combined with the processability and flexibility of polymers to prepare luminescent membranes. The sensor is capable of dual-emission ratiometric fluorescence sensing of nitrofurantoin (NFT) and oxytetracycline (OTC), exhibiting sensitive detection of fluorescence burst and fluorescence enhancement, respectively, with detection limits of 0.012 μM and 8.9 nM. With the advantages of visual detection, high sensitivity, short detection time, and simplicity, the highly sensitive ratiometric fluorescent flexible sensor has great potential for detecting antibiotics in an aqueous environment. It will further stimulate interest in luminescent MOF-based mixed matrix membranes and their sensing applications.

Synthesis of Cu Nanoparticles Incorporated Mesoporous C/SiO2 for Efficient Tetracycline Degradation

In this study, a Cu NPs-incorporated carbon-containing mesoporous SiO2 (Cu/C-SiO2) was successfully synthesized through a grinding-assisted self-infiltration method followed by an in situ reduction process. The obtained Cu/C-SiO2 was then employed as a Fenton-like catalyst to remove tetracycline (TC) from aqueous solutions. TEM, EDS, XRD, N2 adsorption-desorption, FTIR, and XPS methods were used to characterize the crystal structure, morphology, porosity, chemical composition, and surface chemical properties of the catalyst. The effects of initial TC concentration, catalyst dosage, H2O2 dosage, solution pH, HA addition, and water media on the TC degradation over Cu/C-SiO2 were investigated. Scavenging and electrochemical experiments were then carried out to analyze the TC degradation mechanism. The results show that the Cu/C-SiO2 can remove 99.9% of the concentrated TC solution (C0 = 500 mg·L-1), and it can be used in a wide pH range (R.E. = 94-99%, pH = 3.0-11.0). Moreover, hydroxyl radicals (•OH) were detected to be the dominant reactive species in this catalytic system. This study provides a simple and promising method for the synthesis of heteroatom-containing mesoporous catalysts for the decomposition of antibiotics in wastewater.

Spatial variability, source identification and risks assessment of antibiotics in multimedia of North China's largest freshwater lake using positive matrix factorization and Monte Carlo simulation

Antibiotics are widely found in aquatic ecosystems and pose a serious threat to human and the ecological system. Samples of surface water (SW), overlying water (OW), pore water (PW) and sediments (Sedi) were collected to investigate the spatial variability, potential sources, ecological risk (RQs) and health risks (HQs) of nine common antibiotics in Baiyangdian Lake using positive matrix factorization (PMF), and Monte Carlo simulation. Significant spatial autocorrelation of most antibiotics were observed in PW and Sedi samples rather than in SW and OW samples, and higher antibiotic levels were found in the northwest of waters and the southwest of sediments. Livestock (26.74-35.57%) and aquaculture (21.62-37.70%) were identified as primary sources of antibiotics in the water and sediments. Norfloxacin and roxithromycin showed high levels of RQ and HQ in more than 50% of samples, respectively. The combined RQ (ΣRQ) in the PW can be used as a sign of across multimedia risk. Notably, appreciable health risks were observed for the combined HQ (ΣHQ) in about 80% of samples, indicating the importance of taking health risk of antibiotics into consideration. The findings of this work provides a reference for antibiotics pollution control and risk management in shallow lake.

Occurrence, risk assessment, and in vitro and in vivo toxicity of antibiotics in surface water in China

Antibiotics have been widely detected in the water environment and thus pose a potential threat to human health. Although antibiotics have health-promoting properties, whether and how they affect health at environmental concentrations remains uncharacterised. We detected antibiotics in surface water and groundwater in China. Sulfonamides (851 ng/L) and tetracyclines (1322 ng/L) showed the highest concentrations in surface water, while the highest concentration of sulfonamides detected in groundwater was 250 ng/L. We analysed the distribution of four classes of antibiotics (sulfonamides, tetracyclines, macrolides, and quinolones) and evaluated the associated health risks in the surface water of seven cities. We found that antibiotic pollution caused health risks to the 0-3-months age group, but not to other age groups. We further demonstrated that simulated long-term exposure to environmental concentrations of antibiotics had concentration-dependent toxic effects on L-02 hepatocytes, affected cell proliferation, and induced oxidative damage and DNA damage. Chronic exposure to mixed sulfonamides affected growth, caused liver damage, and reduced the abundance of intestinal flora in mice. Under exposure to antibiotics, the abundance of Helicobacter pylori in the gut flora significantly increased and posed a health risk to humans. These results indicated that exposure to antibiotics at environmental concentrations can cause oxidative damage and inflammation both in vitro and in vivo. These findings add to the body of basic data on the distribution of antibiotics in the water environment, and provide a scientific basis for the evaluation of antibiotic toxicity.

Antibiotics-induced changes in intestinal bacteria result in the sensitivity of honey bee to virus

Antibiotics are omnipresent in the environment due to their widespread use, and they have wide-ranging negative impacts on organisms. Virus resistance differs substantially between domesticated Apis mellifera and wild Apis cerana, although both are commonly raised in China. Here, we investigated whether antibiotics can increase the sensitivity of honey bees to viral infection using the Israeli acute paralysis virus (IAPV) and tetracycline as representative virus and antibiotic. Although IAPV multiplied to lower levels in A. cerana than A. mellifera, resulting in decreased mortality (P < 0.01), there was no significant difference in immune responses to viral infection between the two species. Adult worker bees (A. cerana and A. mellifera) were treated with or without tetracycline to demonstrate the prominent role of gut microbiota against viral infection, and found Lactobacillus played a vital antiviral role in A. cerana. In A. cerana but not A. mellifera, tetracycline treatment reduced clearly bee survival and increased susceptibility to IAPV infection (P < 0.01). Our findings revealed that long-term antibiotic treatment in A. mellifera had altered the native gut microbiome and promoted the sensitivity to viral infection. We highlight the effects of antibiotics exposure on resistance to microbial and viral infection.

Simulation and risk assessment of typical antibiotics in the multi-media environment of the Yangtze River Estuary under tidal effect

Frequent human activities in estuary areas lead to the release of a large number of antibiotics, which poses a great threat to human health. However, there are very limited studies about the influence of the special natural phenomena on the occurrence and migration of antibiotics in the environment. In this study, we simulated the migration and transformation of six typical antibiotics, including oxytetracycline (OTC), tetracycline (TC), norfloxacin (NOR), ofloxacin (OFX), erythromycin (ETM), and amoxicillin (AMOX), in the environmental media from 2011 to 2019 in the Yangtze River Estuary, by using the level III multi-media fugacity model combined with the factor of tides. The simulation results showed that the most antibiotics mainly existed in soil and sediment while erythromycin were found mainly in water. The concentrations of antibiotics in air, freshwater, seawater, groundwater, sediment, and soil were 10^-23-10^-25, 0.1-12 ng/L, 0.02-7 ng/L, 0.02-16 ng/L, 0.1-13 ng/g, and 0.1-15 ng/g respectively. Sensitivity analysis showed that the degradation rate (K_m) and the soil-to-water runoff coefficient (K_l) were important model parameters, indicating that hydrodynamic conditions had a significant impact on the migration of antibiotics in various environmental phases in estuarine areas. Tide can enhance the exchange between water bodies and cause the transformation of the antibiotics from freshwater to seawater and groundwater, which improved the accuracy of the model, especially the seawater and soil phase. Risk assessments showed that amoxicillin, erythromycin, ofloxacin, and norfloxacin posed a threat to the estuarine environment, but the current source of drinking water did not affect human health. Our findings suggested that, when one would like to exam the occurrence and migration of antibiotics in environment, more consideration should be given to the natural phenomena, in addition to human activities and the nature of antibiotics.

Widespread occurrence of microplastics in marine bays with diverse drivers and environmental risk

Microplastic contamination in the sediment of marine bays has attracted widespread attention, whereas the distribution, sedimentation, morphology and risk of microplastics at regional scale remain poorly understood. By introducing a data mining framework into microplastic research, we compiled a microplastic dataset of 649 samples from 24 bays to enhance the understanding of geographical difference and drivers, transfer, composition profile and environmental risk of sedimental microplastics. Microplastic abundance varied from 0.72 to 1963.96 items/kg dry weight, with higher concentrations mainly occurring in East Asian bays. The spatial pattern in abundance was driven by the river plastic emissions, aquaculture production and hydrodynamic condition. A significantly positive correlation between microplastic abundance in water and sediment was found, and microplastic sedimentation was related to polymer density, hydrodynamic conditions and sediment properties. The dominant shape and polymer of sedimental microplastics were fiber and polypropylene, respectively, and the similarity of microplastic composition decreased with increasing geographical distance. The environmental risks of microplastics were partitioned into three classes (Rank II-Rank IV) with a two-dimensional assessment system considering the bioavailability and toxicity of microplastics, and Asian bays were identified as potential high-risk areas. To reduce the environmental risk of sedimental microplastics in bays, priority should be given to the removal of microfibers, and control measures depend on the risk classes and dominant polymers. Microplastic abundance and composition were significantly affected by methodological choices regarding sampling, pretreatment and identification, suggesting a unified methodology is essential to further enhance our knowledge on the distribution and risk of microplastics in marine bays.

Recent developments on graphene and its derivatives based electrochemical sensors for determinations of food contaminants

The sensing of food contaminants is essential to prevent their adverse health effects on the consumers. Electrochemical sensors are promising in the determination of electroactive analytes including food pollutants, biomolecules etc. Graphene nanomaterials offer many benefits as electrode material in a sensing device. To further improve the analytical performance, doped graphene or derivatives of graphene such as reduced graphene oxide and their nanocomposites were explored as electrode materials. Herein, the advancements in graphene and its derivatives-based electrochemical sensors for analysis of food pollutants were summarized. Determinations of both organic (food colourants, pesticides, drugs, etc.) and inorganic pollutants (metal cations and anions) were considered. The influencing factors including nature of electrode materials and food pollutants, pH, electroactive surface area etc., on the sensing performances of modified electrodes were highlighted. The results of pollutant detection in food samples by the graphene-based electrode have also been outlined. Lastly, conclusions and current challenges in effective real sample detection were presented.

Fabrication of an imprinted polymer based graphene oxide composite for label-free electrochemical sensing of Sus DNA

An innovative label-free electrochemical sensor was developed for selective detection of Sus (pig) Deoxyribonucleic acid (DNA) through adenine imprinted polypyrrole fabricated on the surface of allyl mercaptan modified GO (MIP/mGO).