Tetracyclines uptake from irrigation water by vegetables: Accumulation and antimicrobial resistance risks

Activation of peroxymonosulfate by Cu0/CuFeO2 composite for tetracycline hydrochloride degradation with free radical and non-radical multi-pathways

The widespread use of tetracycline has made the efficient and environmentally friendly treatment of tetracycline-contaminated wastewater a pressing issue in environmental management. This study synthesized high-purity and uniformly mixed Cu0/CuFeO2 composite materials using a one-step hydrothermal method, aiming to enhance the catalytic activation of peroxymonosulfate (PMS) through the synergistic effect of zero-valent metal and bimetallic compounds. The Cu0/CuFeO2 composite demonstrated exceptional PMS activation performance, achieving 84% tetracycline hydrochloride (TCH) degradation within 1 min and 91% degradation within 20 min. The degradation process involved the synergistic action of •OH, SO4 •-, 1O2, and electron transfer. The degradation intermediates of TCH were identified using high-performance liquid chromatography-mass spectrometry (HPLC-MS), and four potential degradation pathways were proposed. Furthermore, Cu0/CuFeO2 exhibited robust degradation performance across a wide pH range and maintained high efficiency in complex aqueous environments. Even after five cycles, the composite retained 78% of its degradation efficiency, demonstrating excellent stability and reproducibility in the degradation of TCH using the Cu0/CuFeO2/PMS system. PRACTITIONER POINTS: A high-purity and uniformly mixed Cu0/CuFeO2 composite was synthesized. Robust catalytic activity and stability was observed for the synthesized catalyst. Synergistic contributions from •OH, SO4 •-, 1O2, and e- resulted in TCH degradation. Four potential TCH degradation pathways were derived.

A nationwide probabilistic risk assessment and a new insight into source-specific risk apportionment of antibiotics in eight typical river basins in China: Human health risk and ecological risk

China is the largest producer and consumer of antibiotics, a nationwide study on the contamination of antibiotics in China is urgently needed, and source apportionment towards risks associated with antibiotics is now attracting increasing attention. In this study, based on eight antibiotics at 666 sampling sites, spatial variations and probabilistic risks (human health and ecological risk) of antibiotics in eight river basins in China were analyzed. Source-specific health and ecological risk associated with antibiotics in a typical basin was apportioned quantitatively. Results showed that mean antibiotic concentration in Haihe River Basin (HaiRB) and Yellow River Basin (178.25 and 257.36 ng·L-1, respectively) was higher than other basins. In HaiRB, the contribution of livestock and poultry breeding (31.89 %) was the largest of all sources for health risk, whereas pharmaceutical wastewater (35.97 %) was the most dominant source for ecological risk. To determine the most important source for risks associated with antibiotics, the concept of risks-targeted key source was proposed, and a risks-targeted key source apportionment model was developed. Results showed that pharmaceutical wastewater should be prior controlled among all sources. The concept and apportionment model of risks-targeted key source proposed in this study are applicable and referential for related studies.

Versatile laccase-mimicking enzyme for dye decolorization and tetracyclines identification upon a colorimetric array sensor

In this study, the laccase-mimicking enzyme MnO2/Cu-BDC-His was synthesized by a facile procedure, and was applied in tetracycline antibiotics (TCs) identification and dye degradation. The MnO2/Cu-BDC-His nanozymes effectively recognized phenolic hydroxyl groups in TCs and catalyzed the generation of colored oxidation products with different characteristic absorbance peaks at 350 nm, 525 nm and 600 nm. Different TCs mixtures produced different absorbance intensities at the above wavelengths and exhibited cross-color responses. Consequently, a colorimetric array sensor for the simultaneous identification and detection of TCs with wavelength as the sensing element was established. Unlike the traditional "lock-and-key" detection mode, the array sensor enabled simultaneous multi-analyte detection and identification, which achieved the identification and quantification of mixed TCs in the range of 5-200 µM, providing a premise for its application in lake and soil water. Additionally, the MnO2/Cu-BDC-His nanozymes were also applied in colored dyes decolorization. Therefore, MnO2/Cu-BDC-His nanozymes provided a promising application in environmental monitoring.

Determination of tetracycline residues in potatoes and soil by LC-MS/MS: Method development, validation, and risk assessment

A method utilizing liquid-liquid extraction (LLE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated according to the Commission Implementing Regulation (CIR) EU 2021/808 for quantifying four tetracyclines (TCs) in potatoes and soil. The method demonstrated recovery values ranging from 70 to 121% and precision (repeatability and within-laboratory reproducibility), with coefficient of variation (CV) values below 18% for all TCs in both matrices. The limits of quantification (LOQs) for the TCs ranged from 0.90 to 1.87 μg/kg in potatoes and from 0.68 to 1.25 μg/kg in soil. The decision limit (CCα) and detection capability (CCβ) ranged from 10.4 to 12.3 μg/kg and 11.9 to 14.3 μg/kg, respectively. Analysis of 538 potato and soil samples from Egyptian farms revealed a 13.2% occurrence of TC residues, with a higher frequency in soil (19.33%) than in potatoes (7.06%). Target hazard quotient (THQ) values indicated that TC residues in potatoes do not pose a health risk to Egyptian consumers.

Tetracycline antibiotics in agricultural soil: Dissipation kinetics, transformation pathways, and structure-related toxicity

Tetracyclines (TCs) are the most common antibiotics in agricultural soil, due to their widespread usage and strong persistence. Biotic and abiotic degradation of TCs may generate toxic transformation products (TPs), further threatening soil ecological safety. Despite the increasing attention on the environmental behavior of TCs, a systematic review on the dissipation of TCs, evolution of TPs, and structure-toxicity relationship of TCs in agricultural soil remains lacking. This review aimed to provide a comprehensive overview of the environmental fate of TCs in agricultural soil. We first introduced the development history and structural features of different generations of TCs. Then, we comparatively evaluated the dissipation kinetics, transportation pathways, and ecological impacts of three representative TCs, namely tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC), in agricultural soil. The results showed that the dissipation kinetics of TCs generally followed the first-order kinetic model, with the median dissipation half-lives ranging from 20.0 to 38.8 days. Among the three TCs, OTC displayed the lowest dissipation rates due to its structural stability. The typical degradation pathways of TCs in soil included epimerization/isomerization, demethylation, and dehydration. Isomerization and dehydration reactions may lead to the formation of more toxic TPs, while demethylation was accompanied by the alteration of the minimal pharmacophore of TCs thus potentially reducing the toxicity. Toxicological experiments are urgently needed in future to comprehensively evaluate the ecological risks of TCs in agricultural soil.

Monitoring of trace oxytetracycline using a porphyrin-MOF layer-based electrochemical aptasensor

A two-dimensional porphyrin-MOF nanolayer was developed to construct an electrochemical aptasensor for monitoring oxytetracycline from 0.01 pg mL-1 to 0.1 ng mL-1. This aptasensor exhibited high sensitivity, outstanding selectivity, good stability, fine reproducibility, and quantitative detection ability in real samples.

Divergent effects of azithromycin on purple corn (Zea mays L.) cultivation: Impact on biomass and antioxidant compounds

The present study assessed the impact of using irrigation water contaminated with Azithromycin (AZM) residues on the biomass and antioxidant compounds of purple corn; for this purpose, the plants were cultivated under ambient conditions, and the substrate used consisted of soil free from AZM residues, mixed with compost in a ratio of 1:1 (v/v). The experiment was completely randomized with four replications, with treatments of 0, 1, 10, and 100 μg/L of AZM. The results indicate that the presence of AZM in irrigation water at doses of 1 and 10 μg/L increases the weight of dry aboveground biomass, while at an amount of 100 μg/L, it decreases. Likewise, this study reveals that by increasing the concentration of AZM from 1 to 10 μg/L, total polyphenols and monomeric anthocyanins double, in contrast, with an increase to 100 μg/L, these decrease by 44 and 53%, respectively. It has been demonstrated that purple corn exposed to the antibiotic AZM at low doses has a notable antioxidant function in terms of DPPH and ORAC. The content of flavonols, phenolic acids, and flavanols increases by 57, 28, and 83%, respectively, when the AZM concentration is from 1 to 10 μg/L. However, with an increase to 100 μg/L, these compounds decrease by 17, 40, and 42%, respectively. On the other hand, stem length, root length, and dry weight of root biomass are not significantly affected by the presence of AZM in irrigation water.

Carbon Monoxide as a Potential Therapeutic Agent: A Molecular Analysis of Its Safety Profiles

Carbon monoxide (CO) is endogenously produced in mammals, with blood concentrations in the high micromolar range in the hemoglobin-bound form. Further, CO has shown therapeutic effects in various animal models. Despite its reputation as a poisonous gas at high concentrations, we show that CO should have a wide enough safety margin for therapeutic applications. The analysis considers a large number of factors including levels of endogenous CO, its safety margin in comparison to commonly encountered biomolecules or drugs, anticipated enhanced safety profiles when delivered via a noninhalation mode, and the large amount of safety data from human clinical trials. It should be emphasized that having a wide enough safety margin for therapeutic use does not mean that it is benign or safe to the general public, even at low doses. We defer the latter to public health experts. Importantly, this Perspective is written for drug discovery professionals and not the general public.