Change of tetracycline speciation and its impacts on tetracycline removal efficiency in vermicomposting with epigeic and endogeic earthworms

Synthesis of Three-Dimensional β-In2S3 Nanoflowers with a Tunable Surface Area for Boosted Photocatalytic Degradation of Tetracycline and Rhodamine B

Three-dimensional (3D) β-In2S3 nanoflowers with a tunable surface area were successfully synthesized by a simple hydrothermal method. Their growth mechanism, observed through transmission electron microscopy (TEM) and scanning electron microscopy (SEM), revealed the formation of In2S3 flowers by the assembly of 2D In2S3 nanosheets. This unique 3D structure enhances optical absorption and tailors the band gap, as evidenced by UV-vis DRS and photoluminescence (PL) analyses. XRD and Raman spectroscopy confirm the β-phase of the synthesized In2S3 nanoflowers. The tunable surface area of the samples was confirmed by Brunauer-Emmett-Teller (BET) analysis. As a result, the prepared material exhibits an enhanced degradation efficiency to tetracycline (TC) and Rhodamine B (RhB), reaching up to 85.4 and 99.4% after 240 and 60 min under irradiation by low-power household LED (60 W), respectively, which has not been reported yet. Radical trapping experiments indicated that O2•- was the primary reactive species responsible for the photocatalytic degradation of RhB and TC molecules in the β-In2S3 system. The excellent photocatalytic properties and high structural stability of β-In2S3 make it a promising material for degrading antibiotics and persistent textile pollutants.

Country-level antibiotic risk assessment in the multiple environmental matrices based on decennial data

The overuse of antibiotics has led to widespread environmental detection. However, country-level antibiotic risks from a global perspective remain unclear, highlighting a crucial need for antibiotic management worldwide. This study elucidated a global assessment of antibiotic detection frequencies and concentrations across various countries, compared detection levels of antibiotic classifications across compartments in representative countries, and conducted a risk assessment based on predicted no-effect concentrations (PNECs) for antibiotic resistance and minimum inhibitory concentrations (MICs) relevant to microbial nitrogen cycling. A decennial dataset comprising 431,441 records for 137 antibiotics across eight environmental compartments in 45 countries was analyzed. Results showed that Kenya (199 %) had the highest cumulative detection frequencies of four aqueous media. Wastewater from WWTPs (mean: 19.7 ng/L) and animal manure (mean: 2.6 μg/kg) exhibited the highest levels in aqueous and solid media, respectively. From sources to receptors, the highest antibiotic detections and concentrations were found in wastewater from WWTP, where quinolones dominated in France and the USA, and sulfonamides in Kenya (175-357 detections, median: 137-580 ng/L). Similarly, in surface water, sulfonamides were significant in Kenya and Vietnam, quinolones in Kenya (290-2049 detections, median: 32-70 ng/L). From the perspective of cumulative risk, Malaysia, China, and Canada are ranked the top three for both PNECs risk (81 %-191 %) and MICs risk (211 %-236 %). Whether for PNECs or MICs, sulfonamides are the most exceedance-prone antibiotic class across countries and also the highest-risk antibiotic class (median: 33 %). According to the total risk results from different countries, Malaysia (402 %) has the highest risk, followed by Canada (317 %) and China (315 %). The highest antibiotic risks were observed in Asia (medium SDG score), followed by Europe and the Americas (high SDG score), and Africa (low SDG score).

Influence Mechanism of Vermicompost with Different Maturity on Atrazine Catabolism and Bacterial Community

Atrazine causes serious contamination of agricultural soils and groundwater. This study investigated the influence mechanism of sterilized soil (CKs), unsterilized soil (CKn), sterilized soil amended with 45 (SsV1), 60 (SsV2), 75 (SsV3) days of vermicompost (the maturity days of vermicompost), and unsterilized soil amended with 45 (SnV1), 60 (SnV2), 75 (SnV3) days of vermicompost on atrazine catabolism. The atrazine degradation experiment lasted for 40 days. The results showed that the atrazine degradation rates for CKs, CKn, SsV1, SsV2, SsV3, SnV1, SnV2, and SnV3 were 24%, 56.9%, 62.8%, 66.1%, 65.9%, 87.5%, 92.9%, and 92.3%, respectively. Indigenous microorganisms capable of degrading atrazine were present in unsterilized soil, and the addition of vermicompost enhanced atrazine degradation. The humic acid content of SnV2 was the highest, at 4.11 g/kg, which was 71.97% higher than that of CKn. The addition of the vermicompost enhanced the production of hydroxyatrazine, deethylatrazine, and deisopropylatrazine. Vermicompost increased the abundance of atrazine-degrading bacteria (Mycobacterium, Devosia, etc.), and introduced new atrazine-degrading bacteria (Mesorhizobium, Demequina). The above results showed that the best degradation of atrazine was achieved with 60 days of vermicompost addition. This study provides a new, efficient, economical, and environmentally friendly strategy for the remediation of atrazine-contaminated soil.

Mesoporous TiO2@g-C3N4 Nanostructure-Enhanced Photocatalytic Degradation of Tetracycline Under Full-Spectrum Sunlight

TiO2 has broad prospects in reducing the safety risks posed by emerging pollutants in water environments. However, the high recombination rate of photogenerated carriers limits the activity and photon utilization efficiency of TiO2. In this study, mesoporous TiO2 (m-TiO2) and ultra-thin g-C3N4 nanosheets were composited using a hydrothermal method, with the m-TiO2 tightly and uniformly wrapped by g-C3N4. The chemical structure, elemental composition, and optical properties of the heterojunction were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS). The activity of the m-TiO2@g-C3N4 was evaluated by the degradation of tetracycline hydrochloride (TCH). Results showed that the heterojunction exhibited significantly enhanced reactivity compared to pure m-TiO2 and g-C3N4, with kinetic rates of TCH being 1.48 and 6.84 times that of pure m-TiO2 and g-C3N4, respectively. The TCH degradation kinetic rate varied from 0.194 min-1 to 0.026 min-1 and then decreased to 0.015 min-1 on the scale of the bandgap and the number of absorbed photons in m-TiO2@g-C3N4. Concurrently, a 10wt% doping amount of g-C3N4 significantly increased the reaction rate of photogenerated carriers in the system compared to the recombination rate, corresponding to excellent photon efficiency. Reproducibility was evaluated, and a possible degradation mechanism is proposed. This study opens new perspectives for the optimization of catalyst preparation processes aimed at enhancing photon efficiency.

Dynamic distribution of tetracycline and its degradation products in different organs of the geophagous earthworm Metaphire guillelmi

Tetracycline (TC) residues in the environment are harmful to plants and animals; earthworms play an important role in detoxicating tetracycline in the soil. However, the response of different systems of the geophagous earthworm to TC and its degradation products is still not understood well. To understand this problem, Metaphire guillelmi were exposed to the soil contaminated by 100 mg kg-1 tetracycline for 21 days. Liquid chromatography was used to detect the tetracycline concentration and its degradation products in different organs of earthworms on the 1st, 7th, and 21st day. Structural equation model (SEM) was used to determine the cumulative interaction of TC among different systems of earthworm. The results showed that the degradation ability of TC of digestive organs (98.29-99.77 %) was stronger than that of reproductive organs (87.46-98.64 %). The main metabolic pathway of TC in earthworms might be direct dehydration. Anhydrotetracycline was the main degradation product in earthworm organs and could last long in production organs. For lipid soluble pollutants, such as TC, the digestive system of earthworms might be the main pathway for absorbing pollutants from the soil. Furthermore, earthworms can expedite the degradation of organic pollutants. Meanwhile, they also need to absorb more nutrients like nitrogen and phosphorus, to counteract the impact of pollutants on their antioxidant system and reproductive organs. Our study improves our understanding of the degradation and detoxification mechanism of earthworms to TC, and provides useful information for further assessment of the soil eco-risk.

The influence of vermicompost on atrazine microbial degradation performance and pathway in black soil, Northeast China

The atrazine (ATR) is extensively used in dryland crops like corn and sorghum in black soil region of Northeast China, posing ecological risks due to toxic metabolites. Vermicompost are known for soil organic pollution remediation but their role in pesticide degradation in black soil remains understudied. The influence of vermicompost on the microbial degradation pathway of atrazine was assessed in this study. Although vermicompost didn't significantly boost atrazine removal, they notably aided in primary metabolite degradation, hydroxyatrazine (HYA), deisopropylatrazine (DIA), and deethylatrazine (DEA), reducing their content by 38.67 %. They also altered the soil microbial community structure, favoring atrazine-degrading bacteria like Proteobacteria, Firmicutes, and Actinobacteria. Five secondary degradation products were identified in vermicompost treatments. Atrazine degradation occurred via dechlorination, dealkylation, and deamination pathways mainly by Nocardioidacea, Streptomycetaceae, Bacillaceae, Sphingomonadaceae, Comamonadaceae and Nitrososphaeraceae. pH and available nitrogen (AN) influenced microbial community structure and atrazine degradation, correlating with vermicompost application rates. Future black soil remediation should optimize application rates based on atrazine content and soil properties.

Earthworms and lactic acid bacteria (LAB) cooperate to promote the biodegradation of tetracycline residues in livestock manure

Tetracycline is an antibiotic with extensive veterinary use in the livestock industry. However, their widespread application poses risks to soil health as residue in livestock feces, and their removal is crucial for sustainable soil-ecosystem development. Physical and chemical approaches to extract tetracycline may have adverse effects on soil ecosystems, but no studies have thus far examined the potential for biological methods, such as collective degradation action of soil fauna. Thus, this study aimed to investigate the synergistic effects of lactic acid bacteria (LAB) and earthworms (Eisenia fetida) on biodegradation of tetracycline residues in sheep manure. We assessed earthworm biomass, tetracycline residue, and bacterial communities in both earthworm intestines and vermicompost. Earthworm biomass and tetracycline degradation efficiency increased significantly with LAB addition, with a degradation rate of up to 80.16%. This increase may be attributable to LAB acting as electron donors to spur tetracycline degradation. Additionally, we noted that tetracycline presence significantly influenced bacterial communities in earthworm intestines and vermicompost, elevating the abundance of potential pathogenic bacteria (e.g., Flavobacterium, Gammaproteobacteria, and Enterobacteriaceae). This finding suggests that heightened environmental stress from antibiotics could actually facilitate the growth of less prevalent bacteria, including potential pathogens. In conclusion, our study provides evidence supporting the effectiveness of LAB and earthworms in degrading tetracycline residues. In particular, LAB appears to mitigate stress from tetracycline exposure in earthworms, thus increasing their vermicomposting efficacy. Our work has important implications for soil management, with the potential to enhance pollution clean-up rates while minimizing negative side-effects to soil microbial communities.

Oxidation of antibiotic micropollutants in various water resources through integration of Bi2WO6 and g-C3N4

Recently, the hazardous effects of antibiotic micropollutants on the environment and human health have become a major concern. To address this challenge, semiconductor-based photocatalysis has emerged as a promising solution for environmental remediation. Our study has developed Bi2WO6/g-C3N4 (BWCN) photocatalyst with unique characteristics such as reactive surface sites, enhanced charge transfer efficiency, and accelerated separation of photogenerated electron-hole pairs. BWCN was utilized for the oxidation of tetracycline antibiotic (TCA) in different water sources. It displayed remarkable TCA removal efficiencies in the following order: surface water (99.8%) > sewage water (88.2%) > hospital water (80.7%). Further, reusability tests demonstrated sustained performance of BWCN after three cycles with removal efficiencies of 87.3, 71.2 and 65.9% in surface water, sewage, and hospital water, respectively. A proposed photocatalytic mechanism was delineated, focusing on the interaction between reactive radicals and TCA molecules. Besides, the transformation products generated during the photodegradation of TCA were determined, along with the discussion on the potential risk assessment of antibiotic pollutants. This study introduces an approach for utilizing BWCN photocatalyst, with promising applications in the treatment of TCA from various wastewater sources.

Removal of tetracycline by ultraviolet/sodium percarbonate (UV/SPC)advanced oxidation process in water

Tetracycline (TC) was widely used and frequently detected in various water bodies, where the presence of TC posed a significant threat to the health of aquatic organisms. Furthermore, antibiotics were hardly degraded by biological treatment. Thus, in order to enhance the removal of TC, we proposed the use of a novel ultraviolet/sodium percarbonate (UV/SPC) advanced oxidation process and initiated an in-depth study. The study investigated the influence of oxidant dosage, initial pH, UV intensity, and TC concentration on the removal of TC. The results demonstrated that the UV/SPC system efficiently removed TC, with removal efficiency increasing as the SPC concentration increased. Within the pH range of 3-11, TC degradation exhibited minimal variation, indicating the UV/SPC system's strong adaptability to pH variations. The research on the impact of the water matrix on TC removal revealed that HCO3- had an inhibitory effect on TC degradation, while NO3- promoted TC degradation. Additionally, the presence of free radical species (·OH, ·CO3-, ·O2-) were detected and rate constants for the secondary reactions (k·OH,TC = 6.3 × 109 L mol-1·s-1, k·CO3-,TC = 3.4 × 108 L mol-1·s-1) were calculated, indicating that ·OH exhibited a stronger oxidative performance compared to ·CO3-. This study did not only present a novel strategy via UV/SPC to remove TC but also uncovered the unique role of ·CO3- for contaminant removal.

Impact of microplastics on nicosulfuron accumulation and bacteria community in soil-earthworms system

Microplastics (MPs) widely co-occur with various pollutants in soils. However, the data related to the impacts of MPs on terrestrial animal and microbial properties in pesticide-contaminated soils are few. In this study, the influence of MPs (0.01%, 0.1%, and 1%) on nicosulfuron concentrations in soil (10 µg/g) and earthworms were investigated, moreover, microbial community structure and diversity in soil and earthworm gut were also measured. After 30 days, the concentration of nicosulfuron in soil decreased to 1.27 µg/g, moreover, the residual concentration of nicosulfuron in soil (1%MPs and nicosulfuron) was only 44.8% of that in the single nicosulfuron treatment group. The accumulation of nicosulfuron in earthworms (1%MPs and nicosulfuron) was 7.37 µg/g, which was 1.82 times of that in the single nicosulfuron treatment group. In addition, 1% MPs decreased the richness and diversity of the soil and gut bacterial community in earthworms as well as altered microbial community composition, leading to the enrichment of specific microbial community. Our findings imply that MPs may change the migration of pesticides to terrestrial animal and as well as microbial diversity in earthworms and soil.

Tetracycline adsorption/desorption by raw and activated Tunisian clays

Clay-based adsorbents have applications in environmental remediation, particularly in the removal of emerging pollutants such as antibiotics. Taking that into account, we studied the adsorption/desorption process of tetracycline (TC) using three raw and acid- or base-activated clays (AM, HJ1 and HJ2) collected, respectively, from Aleg (Mazzouna), El Haria (Jebess, Maknessy), and Chouabine (Jebess, Maknessy) formations, located in the Maknessy-Mazzouna basin, center-western of Tunisia. The main physicochemical properties of the clays were determined using standard procedures, where the studied clays presented a basic pH (8.39-9.08) and a high electrical conductivity (446-495 dS m-1). Their organic matter contents were also high (14-20%), as well as the values of the effective cation exchange capacity (80.65-97.45 cmolckg-1). In the exchange complex, the predominant cations were Na and Ca, in the case of clays HJ1 and AM, while Mg and Ca were dominant in the HJ2 clay. The sorption experimental setup consisted in performing batch tests, using 0.5 g of each clay sample, adding the selected TC concentrations, then carrying out quantification of the antibiotic by means of HPL-UV equipment. Raw clays showed high adsorption potential for TC (close to 100%) and very low desorption (generally less than 5%). This high adsorption capacity was also present in the clays after being activated with acid or base, allowing them to adsorb TC in a rather irreversible way for a wide range of pH (3.3-10) and electrical conductivity values (3.03-495 dS m-1). Adsorption experimental data were studied as regards their fitting to the Freundlich, Langmuir, Linear and Sips isotherms, being the Sips model the most appropriate to explain the adsorption of TC in these clays (natural or activated). These results could help to improve the overall knowledge on the application of new low-cost methods, using clay based adsorbents, to reduce risks due to emerging pollutants (and specifically TC) affecting the environment.

Contamination distribution and non-biological removal pathways of typical tetracycline antibiotics in the environment: A review

While the occurrence and removal technologies of tetracyclines in the environment have been reported, a comprehensive systematic summary and analysis remain limited, especially for new generations compounds such as doxycycline. In this review, the latest information regarding the distribution of various tetracyclines in different countries over the past seven years (2017-2023) reveals a notable absence of research reports in North America and Oceania. With China as the representative country, the investigation indicates that the maximum concentrations of TCs exceed 5 µg/L. The maximum concentration of tetracyclines in feces (26.22 µg/L) can reach one order of magnitude higher than that in other media. Furthermore, advanced oxidation technologies, such as Fenton processes, electrochemical oxidation, photolysis, ozonation, etc., were also examined, and the median degradation rate achieved 91.9-97.67%. Reactions such as methylation, demethylation, hydroxylation, dehydration, ring cleavage, and oxidation were observed during degradation. The most common intermediate product was identified as m/z = 461 (C22H25N2O9). This review indicates that future efforts should emphasize understanding the occurrence and fate of new-generation tetracyclines in the environment.