Occurrence profiling and environmental risk assessment of veterinary antibiotics in vegetable soils at Chongqing region, China

Eliminating antibiotics by white-rot-fungi Trametes versicolor from manure solids and synthetic wastewater

Antibiotics have been abused in livestock as veterinary drug and feed additive. Their incomplete metabolization by animals resulted in heavy accumulation in livestock manure, and therefore they can pose a threat to the environment. In this study, the mechanism of three antibiotics (oxytetracycline (OTC), sulfadiazine (SDZ), enrofloxacin (ENR)) removal/biodegradation by Trametes versicolor pellets in air-pulse fluidized-bed reactor was explored, and the effects of wood immobilized T. versicolor on four antibiotics (OTC, SDZ, ENR and chloramphenicol (CAP)) removal in solid cow manures were evaluated. T. versicolor could remove OTC, SDZ, ENR through adsorption and biodegradation, with the removal efficiency at 92% and 98% in 21 hours and 98% after 68 hours, respectively. The removal kinetics of those three antibiotics fitted well with the first-order kinetic model, with the removal constant k at -0.238 h-1, -0.102 h-1 and -0.023 h-1, respectively. T. versicolor could biodegrade those three antibiotics using laccase and cytochrome P450 system with the order SDZ≈OTC>ENR. Furthermore, wood immobilized T. versicolor promoted SDZ, OTC, ENR and chloramphenicol (CAP) antibiotic biodegradation in cow manure, especially in high inoculation ratio (wood immobilized T. versicolor: solid cow manures=1:2). This study revealed the mechanism of simultaneous SDZ, OTC, ENR and CAP antibiotic removal/biodegradation by white-rot fungi T. versicolor even by wood immobilized T. versicolor in solid cow manures, which provide a theoretical basis for future application of biological removal of antibiotics present in wastewater and solid manures.

Vertical migration of antibiotics during rainfall throughout a year in long-term manure-fertilized soils differing in pH

The vertical migration behavior of antibiotics in long-term manure-fertilized soils during rainfall remains unclear. Here, we examined antibiotics in soil profiles (0-60 cm) and leachates following each rainfall event throughout a year for three soils (acidic, neutral, and calcareous) with a 13-year history of manure application. The total concentrations of all the antibiotics in the soil profile (11.04-190.32 μg/kg) and the yearly cumulative load of these antibiotics in the leachate (4070-6900 ng/m2) were significantly higher in the acidic and neutral soils than in the calcareous soil. Rainfall caused the migration of antibiotics (especially tetracyclines, quinolones, and sulfonamides) from soil to leachate, while the migration dynamics of some antibiotics differed among the three soil profiles. Random forest analysis revealed that precipitation, soil organic carbon content, pH, sand content, and the partition coefficient (Kow) of antibiotics were the key factors influencing the migration of antibiotics. Environmental risk assessment suggested that antibiotics in leachates pose low toxicity risks to aquatic organisms. Nevertheless, the vertical migration of some antibiotics (e.g., sulfachaloropyridazine and sufamerazine) was positively correlated with the dissemination of high-risk antibiotic resistance genes in leachates. This study advances our understanding of the precipitation-caused vertical migration of antibiotics in soil exposed to manure application, considering future increases in severe rainfall events.

Flexible silver-metal-organic framework probe for highly sensitive and visual detection of tetracycline hydrochloride in freshwater fish

Tetracycline hydrochloride (TCH) is commonly used in aquaculture to prevent bacterial infections, renders the detection of its residues highly crucial for ensuring the safety of aquatic products. In this study, an Ag-based metal-organic framework, Ag-dcp (H3dcp = 3-(3,5-dicarboxyphenyl)-6-carboxypyridine), was synthesized through hydrothermal method. The Ag-dcp framework offers environmental advantages, including a green synthesis process and potential for sustainable, eco-friendly applications. The uncoordinated carboxyl groups in Ag-dcp provide potential interaction sites for TCH, while the rhombic channels in the flexible structure of Ag-dcp that match the size of TCH effectively facilitate host-guest interactions. The Ag-dcp enables ratiometric fluorescence detection with high sensitivity via intramolecular charge transfer (ICT) triggered by TCH-induced ether bond rotation. The probe demonstrates a fluorescence color changes from blue to orange, achieving a detection limit as low as 0.14 μM and offering an ultrafast response time of just 10 s. Principal component analysis (PCA) was employed to effectively distinguish TCH from other tetracycline analogs (minocycline hydrochloride (MH) and doxycycline hydrochloride (DOX)), thereby enhancing the selectivity of the Ag-dcp probe. The fluorescence probe demonstrated performance comparable to HPLC in detecting TCH in freshwater fish. The detection strategy proposed here, based on the MOF structure, offers valuable insights for designing MOF materials and their specialized applications.

Ecological footprint of ionophores in livestock production: Environmental pathways and effects

Ionophores, a class of animal antibiotics, are widely used in intensive livestock farming to enhance feed efficiency and control coccidiosis. These compounds, known for their ability to transport cations across biological membranes, are crucial in maintaining cellular homeostasis. However, their extensive use raises environmental and human health concerns. This manuscript offers a comprehensive review of ionophores in livestock production, highlighting their environmental impact and potential to contribute to antimicrobial resistance (AMR). It emphasizes the fate and transport of ionophores in various environmental matrices, providing a holistic framework for assessing ecological risks. The study calls for improved management practices like enhanced waste management through anaerobic digestion, and composting is essential. Establishing Maximum Residue Limits (MRLs) and using LC-MS/MS for residue detection will help manage exposure. Educating livestock producers and researching alternatives like probiotics can decrease reliance on ionophores to mitigate the ecological footprint of ionophores, making it a timely and relevant piece of research. Ionophores can persist in the environment, potentially contributing to AMR in gram-positive bacteria. Furthermore, their presence in manure, runoff, and agricultural soils has been documented, leading to contamination of water bodies and sediments. Ionophores pose risks to terrestrial and aquatic ecosystems, with studies revealing hazardous effects even at low concentrations. This review highlights the need for improved management practices to mitigate the environmental impacts of ionophores, particularly regarding AMR development and ecosystem disruption. Careful monitoring and sustainable use of these antibiotics are essential to reduce their ecological footprint in livestock production. PRACTITIONER POINTS: Ionophores enhance feed efficiency, but pose environmental health risks. Their persistence may lead to antimicrobial resistance in gram-positive bacteria. Ionophore contamination threatens both terrestrial and aquatic ecosystems. Monitoring and management are crucial to mitigate ionophore-related risks.

Veterinary tetracycline residues: Environmental occurrence, ecotoxicity, and degradation mechanism

Tetracycline has been widely used in the intensive livestock and poultry breeding industry to prevent and treat infectious diseases or promote animal growth. Usually, about 40.0-90.0% of tetracycline is excreted in the form of original drugs or metabolites and finally enters the surrounding water and soil, causing a series of eco-toxic effects. In this review, the toxic effects on plants, soil animals, and microorganisms are systematically reviewed. The migration and degradation mechanisms of tetracycline are emphasized, which are closely related to the physical and chemical properties of soil. In addition, the residual tetracycline in soil and water can be efficiently degraded by "plant-microorganism". Based on summarizing the current research progress, this review puts forward some important problems to be solved in the study of tetracycline residue and looks forward to the future research direction.

Comprehensive tetracycline, ciprofloxacin and sulfamethoxazole toxicity evaluation to earthworm Dendrobaena veneta through life-cycle, behavioral and biochemical parameters

Veterinary antibiotics are widely spread in the environment, however, the knowledge about their impact on soil key species is still limited. This study evaluated the short-term and long-term effects of tetracycline (TC), ciprofloxacin (CIP) and sulfamethoxazole (SMX) (1-500 mg kg) on earthworm Dendrobaena veneta by measuring multiple parameters (survival, growth, reproduction, behavior and biochemical responses). Neither antibiotic induced acute toxicity and low mortality was observed after chronic exposure. TC and CIP had a negligible effect on the earthworm's weight from the 6th week of exposure, SMX inhibited the earthworm growth when was present in the range of 50-500 mg kg-1. In parallel, SMX reduced earthworm reproduction at environmentally relevant concentrations. Antibiotics altered superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and gluthathione-S-transferase (GST) activities and induced lipid peroxidation. Overall, earthworms showed no apparent acute response at environmentally relevant concentrations except for avoidance behavior; after long-term exposure earthworms experienced biochemical, physiological, and reproductive impairments and reduced survival at high soil contamination.

Assessing Lettuce Exposure to a Multipharmaceutical Mixture under Hydroponic Conditions: Findings through LC-ESI-TQ Analysis and Ecotoxicological Assessments

The escalating global water scarcity demands innovative solutions, one of which is hydroponic vegetable cultivation systems that increasingly use reclaimed wastewater. Nevertheless, even treated wastewater may still harbor various emerging organic contaminants, including pharmaceuticals. This study aimed to comprehensively assess the impact of pharmaceuticals, focusing on bioconcentration factors (BCFs), translocation factors (TFs), pharmaceutical persistence in aqueous environment, ecotoxicological end points, and associated environmental and health risks. Lettuce (Lactuca sativa) was cultivated hydroponically throughout its entire growth cycle, exposed to seven distinct concentration levels of contaminants ranging from 0 to 500 μg·L-1 over a 35-day period. The findings revealed a diverse range of BCFs (2.3 to 880 L·kg-1) and TFs (0.019-1.48), suggesting a high potential of pharmaceutical uptake and translocation by L. sativa. The degradation of 20 pharmaceuticals within the water-lettuce system followed first-order degradation kinetics. Substantial ecotoxicological effects on L. sativa were observed, including increased mortality, alterations in root morphology and length, and changes in biomass weight (p < 0.05). Furthermore, the estimated daily intake of pharmaceuticals through L. sativa consumption suggested considerable health risks, even if lettuce would be one of the many vegetables consumed. It is hypothetical, as the values were calculated. Moreover, this study assessed the environmental risk associated with the emergence of antimicrobial resistance (AMR) in aquatic environments, revealing a significantly high risk of AMR emergence. In conclusion, these findings emphasize the multifaceted challenges posed by pharmaceutical contamination in aquatic environments and the necessity of proactive measures to mitigate associated risks to both environmental and human health.

Selective increase of antibiotic-resistant denitrifiers drives N2O production in ciprofloxacin-contaminated soils

Agricultural systems significantly contribute to global N2O emissions, which is intensified by excessive fertilization and antibiotic residues, attracting global concerns. However, the dynamics and pathways of antibiotics-induced soil N2O production coupled with microbial metabolism remain controversial. Here, we explored the pathways of N2O production in agricultural soils exposed to ciprofloxacin (CIP), and revealed the underlying mechanisms of CIP degradation and the associated microbial metabolisms using 15N-isotope labeling and molecular techniques. CIP exposure significantly increases the total soil N2O production rate. This is attributed to an unexpected shift from heterotrophic and autotrophic nitrification to denitrification and an increased abundance of denitrifiers Methylobacillus members under CIP exposure. The most striking strain M. flagellatus KT is further discovered to harbor N2O-producing genes but lacks a N2O-reducing gene, thereby stimulating denitrification-based N2O production. Moreover, this denitrifying strain is probably capable of utilizing the byproducts of CIP as carbon sources, evidenced by genes associated with CIP resistance and degradation. Molecular docking further shows that CIP is well ordered in the catalytic active site of CotA laccase, thus affirming the potential for this strain to degrade CIP. These findings advance the mechanistic insights into N2O production within terrestrial ecosystems coupled with the organic contaminants degradation.

Assessing Lettuce Exposure to a Multi-Pharmaceutical Mixture in Soil: Insights from LC-ESI-TQ Analysis and the Impact of Biochar on Pharmaceutical Bioavailability

Agricultural practices introduce pharmaceutical (PhAC) residues into the terrestrial environment, potentially endangering agricultural crops and human health. This study aimed to evaluate various aspects related to the presence of pharmaceuticals in the lettuce-soil system, including bioconcentration factors (BCFs), translocation factors (TFs), ecotoxicological effects, the influence of biochar on the PhAC bioavailability, persistence in soil, and associated environmental and health risks. Lettuce (Lactuca sativa L.) was exposed to a mixture of 25 PhACs in two scenarios: initially contaminated soil (ranging from 0 to 10,000 ng·g-1) and soil irrigated with contaminated water (ranging from 0 to 1000 μg·L-1) over a 28-day period. The findings revealed a diverse range of BCFs (0.068-3.7) and TFs (0.032-0.58), indicating the uptake and translocation potential of pharmaceuticals by lettuce. Significant ecotoxicological effects on L. sativa, including weight change and increased mortality, were observed (p < 0.05). Interestingly, biochar did not significantly affect PhAC uptake by L. sativa (p > 0.05), while it significantly influenced the soil degradation kinetics of 12 PhACs (p < 0.05). Additionally, the estimated daily intake of PhACs through the consumption of L. sativa suggested negligible health risks, although concerns arose regarding the potential health risks if other vegetable sources were similarly contaminated with trace residues. Furthermore, this study evaluated the environmental risk associated with the emergence of antimicrobial resistance (AMR) in soil, as medium to high. In conclusion, these findings highlight the multifaceted challenges posed by pharmaceutical contamination in agricultural environments and emphasize the importance of proactive measures to mitigate the associated risks to both environmental and human health.

Contamination status, source analysis and exposure assessments of quinolone antibiotics in the south of Yancheng Coastal Wetland, China

Yancheng coastal wetland, the largest coastal wetland in the west coast of the Pacific Ocean and the margin of the Asian continent, has significant environmental, economic and social effects on local human beings. The extensive contamination and potential risk of quinolone antibiotics (QNs) on local aquaculture and human health are still not clear until now. In this study, 52 surface sediment samples were collected to investigate the contamination status and polluted sources, and evaluate ecological risks of QNs in the south of Yancheng coastal wetland. The total contents of QNs ranged from 0.33 to 21.60 ng/g dw (mean value of 4.51 ng/g dw), following the detection frequencies of QNs ranging from 19.23 to 94.23%. The highest content of QNs occurred around an aquaculture pond dominated by flumequine. The total organic carbon contents of sediment were positively correlated with sarafloxacin and lomefloxacin (p < 0.05), indicating the enhanced absorption of these QNs onto sediments. Partial QNs, such as lomefloxacin, enrofloxacin, sarafloxacin and flumequine, presented the homology features originating from the emission of medical treatment and aquaculture. There was no potential risk of QNs to human beings but a potential risk to aquatic organisms (algae > plant > invertebrate). Totally, the management and protection of Yancheng coastal wetland should be of concern with aquaculture as the important industry.

Veterinary antibiotics differ in phytotoxicity on oilseed rape grown over a wide range of concentrations

Residues of veterinary antibiotics are a worldwide problem of increasing concern due to their persistence and diverse negative effects on organisms, including crops, and limited understanding of their phytotoxicity. Therefore, this study aimed to compare the phytotoxic effects of veterinary antibiotics tetracycline (TC) and ciprofloxacin (CIP) applied in a wide range of concentrations on model plant oilseed rape (Brassica napus). Overall phytotoxicity of 1-500 mg kg-1 of TC and CIP was investigated based on morphological, biochemical, and physiological plant response. Photosystem II (PSII) performance was suppressed by TC even under environmentally relevant concentration (1 mg kg-1), with an increasing effect proportionally to TC concentration in soil. In contrast, CIP was found to be more phytotoxic than TC when applied at high concentrations, inducing a powerful oxidative burst, impairment of photosynthetic performance, collapse of antioxidative protection and sugar metabolism, and in turn, complete growth retardation at 250 and 500 mg kg-1 CIP treatments. Results of our study suggest that TC and CIP pollution do not pose a significant risk to oilseed rapes in many little anthropogenically affected agro-environments where TC or CIP concentrations do not exceed 1 mg kg-1; however, intensive application of manure with high CIP concentrations (more than 50 mg kg-1) might be detrimental to plants and, in turn, lead to diminished agricultural production and a potential risk to human health.

Urban agglomerations as an environmental dimension of antibiotics transmission through the "One Health" lens

The spatiotemporal distributions of antibiotics in different media have been widely reported; however, their occurrence in the environmental dimension of the Chinese urban agglomerations has received less attention, especially in bioaccumulation and health risks of antibiotics through the "One Health" lens. The review presents the current knowledge on the environmental occurrence, bioaccumulation, as well as health exposure risks in urban agglomerations through the "One Health" lens, and identifies current information gaps. The reviewed studies suggested antibiotic concentrations in water and soil were more sensitive to social indicators of urban agglomerations than those in sediment. The ecological risk and resistance risk of antibiotics in water were much higher than those of sediments, and the high-risk phenomenon occurred at a higher frequency in urban agglomerations. Erythromycin-H2O (ETM-H2O), amoxicillin (AMOX) and norfloxacin (NFC) were priority-controlled antibiotics in urban waters. Tetracyclines (TCs) posed medium to high risks to soil organisms in the soil of urban agglomerations. Health risk evaluation based on dietary intake showed that children had the highest dietary intake of antibiotics in urban agglomerations. The health risk of antibiotics was higher in children than in other age groups. Our results also demonstrated that dietary structure might impact health risks associated with target antibiotics in urban agglomerations to some extent.

Chemistry of soil-type dependent soil matrices and its influence on behaviors of pharmaceutical compounds (PCs) in soils

Behaviors of pharmaceutical compounds (PCs) in soil are usually determined by experimental extrapolation of results from separate constitutes to the soil, or from a special soil to other regional soil conditions. However, such extrapolation is problematic due to variations in soil clay mineral and organic matter (OM) compositions with soil types, which dominate the interaction mechanisms of PCs in soil. It is essential to review current literature to enhance our understanding of the soil-type dependent surface chemistry of soil matrices and the environmental behavior of PCs in different soil types. Major types of soils occur globally in parallel to the latitudinal or altitudinal zonation due to regional climate conditions with distinct clay mineral and OM compositions. The soil-type dependent surface chemistry results in variations in retention, distribution, transport, and transformation PCs in soil. The mixture of PCs of different classes usually exhibited enhanced sorption due to the cooperative multilayer sorption on soil constituents, and that of the same class often caused differential adsorption capacity compared to the sorption from single compound due to competitive sorption. PCs preferentially adsorb to a soil component, or to a special soil type, and exhibit notably soil-type dependent sorption affinity, mobility, and dissipation. The soil-dependent surface chemistry of soil is critical to predict the persistence and bioavailability of PCs in soil. In the future, more detailed studies of influence of individual soil factor on the behaviors of PCs and especially the practical field site investigation are required to better understand the sorption, transport, transformation, and ecotoxicology of PCs in typical soil types.

A comprehensive and global evaluation of residual antibiotics in agricultural soils: Accumulation, potential ecological risks, and attenuation strategies

The occurrence of antibiotics in agricultural soils has raised concerns due to their potential risks to ecosystems and human health. However, a comprehensive understanding of antibiotic accumulation, distribution, and potential risks to terrestrial ecosystems on a global scale is still limited. Therefore, in this study, we evaluated the accumulation of antibiotics and their potential risks to soil microorganisms and plants, and highlighted the driving factors of antibiotic accumulation in agricultural soils based on 134 peer-reviewed studies (between 2000 and 2022). The results indicated that 56 types of antibiotics were detected at least once in agricultural soils with concentrations ranging from undetectable to over 7000 µg/kg. Doxycycline, tylosin, sulfamethoxazole, and enrofloxacin, belonging to the tetracyclines, macrolides, sulfonamides, and fluoroquinolones, respectively, were the most accumulated antibiotics in agricultural soil. The accumulation of TCs, SAs, and FQs was found to pose greater risks to soil microorganisms (average at 29.3%, 15.4%, and 21.8%) and plants (42.4%, 26.0%, and 38.7%) than other antibiotics. East China was identified as a hot spot for antibiotic contamination due to high levels of antibiotic concentration and ecological risk to soil microorganisms and plants. Antibiotic accumulation was found to be higher in vegetable fields (245.5 µg/kg) and orchards (212.4 µg/kg) compared to croplands (137.2 µg/kg). Furthermore, direct land application of manure resulted in a greater accumulation of TCs, SAs, and FQs accumulation in soils than compost fertilization. The level of antibiotics decreased with increasing soil pH and organic matter content, attributed to decreasing adsorption and enhancing degradation of antibiotics. In conclusion, this study highlights the need for further research on the impacts of antibiotics on soil ecological function in agricultural fields and their interaction mechanisms. Additionally, a whole-chain approach, consisting of antibiotic consumption reduction, manure management strategies, and remediation technology for soil contaminated with antibiotics, is needed to eliminate the potential environmental risks of antibiotics for sustainable and green agriculture.