Absorption, transportation, residual distribution of chiral 14C-dufulin in garlics and metabolism of its racemate.

Dufulin is a novel chiral plant antiviral agent. In this study, we investigated the uptake, translocation and accumulation of 14C-dufulin stereoisomers in different tissues of garlic via leaf introduction and root uptake. The behavior of dufulin enantiomers in plants is not stereoselective, and dufulin is more likely to be absorbed by leaves than by roots. The metabolites of 14C-dufulin with high specific activity in garlic were qualitatively and quantitatively analyzed by HPLC-QTOF-MS, and the metabolic pathway involved was elucidated. In the leaf and bulb, dufulin underwent phase I and phase II metabolism and produced four metabolites. The ratios and concentrations of these four metabolites in the bulb, but not in the leaf, met the residue criterion. Overall, our results provide relatively accurate predictions for the risk assessment of dufulin, which will help guide its rational use and ensure its ecological safety and human health.

Carbon-14 labeled transformation of atrazine in soils: Comparison of superabsorbent hydrogel coating and technical material.

Atrazine exhibits adverse effects on diverse organisms in both terrestrial and aquatic environments, even though it effectively targets specific organisms. This study employed superabsorbent hydrogels to coat 14C-atrazine coupled with a four-compartment model to determine the fate of this herbicide in three oxic soils over a 100-day incubation period. Mineralization of atrazine was limited in all soils, with rates remaining below 3.5 %. The encapsulation treatment reduced mineralization of atrazine in soil A and soil B. Bound residues ranged from 26.1 to 43.6 % at 100 d. The encapsulation treatment enhanced the degradation of atrazine and reduced the content of deethylatrazine in soil A, but significantly increased the content of deisopropylatrazine in soil A and hydroxyatrazine in soil C. Using the obtained data, we also constructed a four-compartment model to clarify the relationships among the parent compound, degradation products, bound residues, and mineralization. This model accurately fits the fate of atrazine in the present work. Additionally, the correlation study suggested that both soil parameters and superabsorbent hydrogels played significant roles in influencing atrazine transformation. These findings serve as a reference for evaluating the environmental impact of superabsorbent hydrogels in atrazine pollution reduction and offer a foundational model approach for a comprehensive understanding of organic pollutants.

Impact of superabsorbent hydrogels on microbial community and atrazine fate in soils by 14C-labeling techniques.

The accumulation of atrazine in soils can create environmental challenges, potentially posing risks to human health. Superabsorbent hydrogel (SH)-based formulations offer an eco-friendly approach to accelerate herbicide degradation. However, the impact of SHs on soil microbial community structure, and thus on the fate of atrazine, remains uncertain. In this study, a radioactive tracer was employed to investigate the influence of SHs on microbial communities and atrazine transformation in soils. The results revealed that the mineralization of atrazine in active soils was considerably greater than that in sterilized soils. Atrazine degradation proceeded rapidly under SH treatment, indicating the potential of SH to accelerate atrazine degradation. Furthermore, SH addition did not alter the atrazine degradation pathway in soils, which included dealkylation, dechlorination and hydroxylation. The relative abundance of dominant microbial population was influenced by the presence of SHs in the soil. Additionally, SH application led to an increased relative abundance of Lysobacter, suggesting its potential involvement in atrazine degradation. These findings reveal the significance of soil microorganisms and SH in atrazine degradation, offering crucial insights for the development of effective strategies for atrazine remediation and environmental sustainability.

Charged polystyrene microplastics inhibit uptake and transformation of 14C-triclosan in hydroponics-cabbage system.

INTRODUCTION: Since the outbreak of COVID-19, microplastics (MPs) and triclosan in pharmaceuticals and personal care products (PPCPs) are markedly rising. MPs and triclosan are co-present in the environment, but their interactions and subsequent implications on the fate of triclosan in plants are not well understood. OBJECTIVE: This study aimed to investigate effects of charged polystyrene microplastics (PS-MPs) on the fate of triclosan in cabbage plants under a hydroponic system. METHODS: 14C-labeling method and liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (LC-QTOF-MS) analysis were applied to clarify the bioaccumulation, distribution, and metabolism of triclosan in hydroponics-cabbage system. The distribution of differentially charged PS-MPs in cabbage was investigated by confocal laser scanning microscopy and scanning electron microscopy. RESULTS: The results showed that MPs had a significant impact on bioaccumulation and metabolism of triclosan in hydroponics-cabbage system. PS-COO-, PS, and PS-NH3+ MPs decreased the bioaccumulation of triclosan in cabbage by 69.1 %, 81.5 %, and 87.7 %, respectively, in comparison with the non-MP treatment (control). PS-MPs also reduced the translocation of triclosan from the roots to the shoots in cabbage, with a reduction rate of 15.6 %, 28.3 %, and 65.8 % for PS-COO-, PS, and PS-NH3+, respectively. In addition, PS-NH3+ profoundly inhibited the triclosan metabolism pathways such as sulfonation, nitration, and nitrosation in the hydroponics-cabbage system. The above findings might be linked to strong adsorption between PS-NH3+ and triclosan, and PS-NH3+ may also potentially inhibit the growth of cabbage. Specially, the amount of triclosan adsorbed on PS-NH3+ was significantly greater than that on PS and PS-COO-. The cabbage biomass was reduced by 76.9 % in PS-NH3+ groups, in comparison with the control. CONCLUSION: The uptake and transformation of triclosan in hydroponics-cabbage system were significantly inhibited by charged PS-MPs, especially PS-NH3+. This provides new insights into the fate of triclosan and other PPCPs coexisted with microplastics for potential risk assessments.

Effects of reduced graphene oxide nanomaterials on transformation of 14C-triclosan in soils.

Increasing use and release of graphene nanomaterials and pharmaceutical and personal care products (PPCPs) in soil environment have polluted the environment and posed high ecological risks. However, little is understood about the interactive effects and mechanism of graphene on the behaviors of PPCPs in soil. In the present study, the effects of reduced graphene oxide nanomaterials (RGO) on the fate of triclosan in two typical soils (S1: silty loam; S2: silty clay loam) were investigated with 14C-triclosan, high-resolution mass spectrometry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations, and microbial community structure analysis. The results showed that RGO prolonged the half-life of triclosan by 23.6-51.3 %, but delayed the formation of transformed products such as methyl triclosan and dechlorinated dimer of triclosan in the two typical soils. Mineralization of triclosan to 14CO2 was inhibited by 48.2-79.3 % in 500 mg kg-1 RGO in comparison with that in the control, whereas the bound residue was 54.2-56.4 % greater than the control. RGO also reduced the relative abundances of triclosan-degrading bacteria (Pseudomonas and Sphingomonas) in soils. Compared to silty loam, RGO more effectively inhibited triclosan degradation in silty clay loam. Furthermore, the DFT calculations suggested a strong association of the adsorption of triclosan on RGO with the van der Waals forces and π-π interactions. These results revealed that RGO inhibited the transformation of 14C-triclosan in soil through strong adsorption and triclosan-degrading bacteria inhibition in soils. Therefore, the presence of RGO may potentially enhance persistence of triclosan in soil. Overall, our study provides valuable insights into the risk assessment of triclosan in the presence of GNs in soil environment.

Effects of charged polystyrene microplastics on the bioavailability of dufulin in tomato plant.

Microplastics (MPs) and pesticides commonly exist in the environment, yet the interactions between them and their subsequent impacts on plants remain poorly understood. Thus, this study aimed to investigate the impacts of differently charged polystyrene (PS) MPs, including PS-COO-, PS and PS-NH3+ MPs, on the fate of 14C-labelled new antiviral pesticide Dufulin (DFL) in a hydroponic tomato system. The results showed that MPs greatly reduced the growth of tomato plants, with suppression of 18.4-30.2%. Compared to the control group, PS-COO-, PS and PS-NH3+ MPs also reduced the bioaccumulation of DFL in whole tomato plants by 40.3%, 34.5%, and 26.1%, respectively. Furthermore, MPs influenced the translocation of DFL in plant tissues, and the values decreased at the rates of 38.7%, 26.5% and 15.7% for PS-COO-, PS and PS-NH3+, respectively. Interestingly, compared to the control group, PS-COO- exhibited a profound inhibitory effect on DFL concentrations in tomatoes, potentially resulting in a lower dietary risk in the hydroponic tomato system. This may be due to the strong adsorption between PS-COO- and DFL, and PS-COO- may also inhibit the growth of tomato plants. Overall, our study could provide valuable insights into the risk assessment of DFL in the presence of MPs in plant systems.

Waterborne Tebuconazole Exposure Induces Male-Biased Sex Differentiation in Zebrafish (Danio rerio) Larvae via Aromatase Inhibition.

Tebuconazole is a widely used fungicide for various crops that targets sterol 14-α-demethylase (CYP51) in fungi. However, attention has shifted to aromatase (CYP19) due to limited research indicating its reproductive impact on aquatic organisms. Herein, zebrafish were exposed to 0.5 mg/L tebuconazole at different developmental stages. The proportion of males increased significantly after long-term exposure during the sex differentiation phase (0-60, 5-60, and 19-60 days postfertilization (dpf)). Testosterone levels increased and 17ß-estradiol and cyp19a1a expression levels decreased during the 5-60 dpf exposure, while the sex ratio was equally distributed on coexposure with 50 ng/L 17ß-estradiol. Chemically activated luciferase gene expression bioassays determined that the male-biased sex differentiation was not caused by tebuconazole directly binding to sex hormone receptors. Protein expression and phosphorylation levels were specifically altered in the vascular endothelial growth factor signaling pathway despite excluding the possibility of tebuconazole directly interacting with kinases. Aromatase was selected for potential target analysis. Molecular docking and aromatase activity assays demonstrated the interactions between tebuconazole and aromatase, highlighting that tebuconazole poses a threat to fish populations by inducing a gender imbalance.

Adaptive Aromaticity in 18e Metallapentalenes.

Complexes with aromaticity in both the lowest singlet state (S0) and the lowest triplet state (T1) (denoted as adaptive aromaticity) are rare because according to Hückel's and Baird's rules, a species could be aromatic in either the S0 or T1 state in most cases. Thus, it is particularly challenging to design species with adaptive aromaticity. Previous reports on adaptive aromaticity were mainly focused on 16e metallapentalenes. Here, we demonstrate that 18e metallapentalenes could possess adaptive aromaticity supported by a set of aromaticity indices when the nitrido and imido ligands are introduced via density functional theory calculations. Further investigation suggests that the metal-carbon bond strength plays an important role in the S0 state aromaticity and the T1 state aromaticity could be attributed to spin electron localization. All these findings could be useful for the development of metallaaromatic chemistry.

Multi-dimensional visualization of ingestion, biological effects and interactions of microplastics and a representative POP in edible jellyfish.

Due to their ubiquity and potential risks, microplastics (MPs) and nanoplastics (NPs) are concerning environmental issues. Yet there are still significant knowledge gaps in understanding the tissue-specific accumulation and dynamic change of MPs and NPs in the aquatic organism and how these micro/nano-scale emerging contaminants interact with other environmental pollutants such as persistent organic pollutants (POPs). Here, in vivo imaging systems (IVIS), radioisotope tracing, and histological staining were innovatively used to reveal the fate and toxicity of fluorescently-labeled MPs/NPs and 14C-labeled 2,4,4'-trichlorobiphenyl (PCB28) in edible jellyfish Rhopilema esculentum. These contaminants' ingestion, biological effects, and interactions were visualized at cellular, tissue, and whole-body multidimensional levels. Both MPs and NPs were shown to be preferentially accumulated in the mouthlets of oral arms, and most ingested MPs/NPs were present in the extracellular environment instead of being internalized into the mesoglea. Moreover, the presence of MPs or NPs in the seawater significantly inhibited the bioaccumulation of PCB28 in the jellyfish tissue, thus alleviating physiological alteration, gastric damage, and apoptosis caused by PCB28. This study provides a multi-dimensional visualization strategy to display the distribution and biological effects of typical pollutants in marine organisms and offers new insights for understanding the impacts of MPs/NPs and POPs on marine ecosystems.

Environmental fate and metabolism of the systemic triazolinthione fungicide prothioconazole in different aerobic soils.

As a best-selling triazolinthione fungicide, prothioconazole (PTZ) has been widely used worldwide and has aroused concern about its environmental effect. This study used phenyl-UL-14C-labeled PTZ and an improved fate model to investigate the fate and metabolism of this fungicide in aerobic soil. During 120 d of incubation, PTZ rapidly transformed into metabolites and bound residues, with a half-life (DT50) of less than 1 d. After 120 d, approximately 45-55% of PTZ formed bound residues, and the extractable metabolite residues were gradually degraded over time. Approximately 19%, 44% and 27% of phenyl-UL-14C-PTZ was mineralized in red soil, fluvo-aquic soil and cinnamon soil, respectively, but only approximately 3% was mineralized in black soil. Five metabolites were identified and confirmed, and a possible metabolic pathway for phenyl-UL-14C-PTZ in soil was proposed. Based on the correlation analysis between soil properties and model rate constants, soil properties exerted important effects on PTZ transformation. These results will provide basic data for environmental risk assessments and removal of the PTZ pollutant and suggest that the soil type should be considered in the selection and application of pesticides.

Nonenantioselective environmental behavior of a chiral antiviral pesticide dufulin in aerobic soils.

Dufulin is a promising chiral antiviral agent, but little is known about its fate in soils. In this study, the fate of dufulin enantiomers in aerobic soils was investigated using radioisotope tracing techniques. The result of the four-compartment model showed no significant differences in dissipation, generation of bound residues (BR) and mineralization between S-dufulin and R-dufulin during incubation. Dufulin dissipated most quickly in cinnamon soils, followed by fluvo-aquic and black soils and the half-lives of dufulin in these soils obtained by the modified model were 4.92-5.23, 32.39-33.32 and 60.80-61.34 d, respectively. After 120 d incubation, the percentage of radioactivity of BR increased to 18.2-38.4 % in the three soils. Dufulin formed most bound residues in the black soil, least in the cinnamon soil, and BRs rapidly formed in the cinnamon soil during the early culture period. In these three soils, the cumulative mineralization of 14CO2 ranged from 25.0 to 26.7 %, 42.1 to 43.4 % and 33.8 to 34.4 %, respectively, which indicated that the environmental fate of dufulin was primarily influenced by soil characteristics. The study of microbial community structure revealed that the phyla Ascomycota, Proteobacteria and genus Mortierella might be related to the degradation of dufulin. These findings provide a reference for assessing the environmental impact and ecological safety of dufulin application.

Fate characteristics of the chiral pesticide dufulin in flooded anaerobic soils and its interaction with soil microorganisms.

Dufulin (DFL), a plant antiviral agent synthesized in China, has been widely used to control viral diseases in rice, tobacco, tomato, and other crops. However, its fate in flooded anaerobic soils, which is essential for environmental risk assessment, remains unknown. Using the 14C tracer technique, the fate of 14C-labeled DFL isomers in flooded anaerobic soils was systematically investigated in this study. Over the 100-day incubation, a small part of 14C-DFL enantiomer was mineralized to 14CO2 (< 10.44 %) or entered the surface water phase (< 6.69 %), with most of the 14C (> 80.40 %) remaining in the subsoil. The residues in all tested soils were gradually converted from extractable residues (ERs) to nonextractable residues (NERs). At the end of incubation, the fraction of 14C-NERs reached 5.38-23.77 %. The half-life (t1/2) of the DFL parent in soil is relatively long under submerged anaerobic conditions, especially in Fluvo-aquic soil, up to 277.26-315.07 days, which exceeds the risk threshold recommended by the Stockholm Convention (< 180 days). Soil type and microbial activity influenced the fate of DFL in flooded soils and microbial analysis showed that 2.0 mg kg-1 DFL had no obvious impact on soil bacterial richness and function. Pseudomonas spp. was estimated to be a potentially efficient degrading genus for DFL. No enantioselective behaviors were detected in this study. This research provides a theoretical basis for evaluating the environmental impact and ecological safety of DFL application.

Insights into the Fate of the Novel Pesticide Vanisulfane from Animal Manure in Plant-Soil Systems: Assisted by Carbon-14 Labeling.

Pesticide use can result in plant residues, which can be ingested by livestock consuming plant-derived feed and appear in manure. When this manure is applied as a fertilizer, pesticides can contaminate plant-soil systems. Few studies have focused on pesticide infiltration from applying pesticide-contaminated manure to land. In this study, the fate of pesticide vanisulfane from chicken manure was studied in radish-soil and cabbage-soil systems assisted by carbon-14 labeling. Vanisulfane and its metabolites mostly appeared as bound residues (BRs) after introduction, and BR release was found at 35 d. Notably, manure contaminated with vanisulfane and its metabolites exhibited higher plant accumulation and phytotoxicity than manure contaminated with only the parent. Four metabolites were identified, and germination toxicity assays illustrated that a metabolite with an aldehyde structure induced phytotoxicity. This study provides valuable information on pesticide contamination from manure and emphasizes the importance of considering pesticide metabolites when assessing environmental risks.

Understanding the metabolism of the novel plant antiviral agent dufulin by different positional 14C labeling in cherry radishes.

Dufulin is a new type of plant antiviral agent. However, its metabolism in plants, which is very important for environmental risk assessment, is still unclear. In this study, we used 14C markers at different positions and high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (HPLC-QTOF-MS) to qualitatively and quantitatively analyze dufulin metabolites in cherry radish. By combining ion pairs with unique abundance ratios, we clarified the metabolite structures, inferred the metabolic pathway of dufulin, and clarified the criteria for residues. The extractable residue of dufulin from cherry radish stem and leaf tissues was above 98 % and that in the succulent root was above 87 %. In the stem and leaf tissues and succulent root, dufulin underwent both phase I and phase II metabolism, and four metabolites were produced, including a conjugate of glucose malonate and hydroxylated dufulin, which was confirmed by comparison with a standard. However, the proportions and concentrations of the four metabolites did not meet the residue criteria, so only the dufulin precursor compound was included as a residue. This study provides reliable data for evaluating the impacts of dufulin on the environment and human health and for objectively examining the safety of dufulin.

Accumulation and biotransformation of the novel vanillin-derived pesticide, vanisulfane, in laying hens after dietary exposure.

Vanisulfane is a novel plant antiviral agent with promising prospects to prevent and control viral crop diseases. However, human health risk assessment after vanisulfane exposure from animal-derived food products remains limited. To gain insight into the accumulation and biotransformation of vanisulfane in livestock, laying hens were dietary exposed to 14C-vanisulfane. Although more than 80 % of the applied dose was observed in the excreta, vanisulfane and its metabolites accumulated in tissues, especially the liver and kidney, and was found to be transferred to eggs. A total of eight metabolites associated with both phase I and phase II metabolism were identified via 14C tracing and LC-QTOF-MS. Phase I metabolism included oxidation, hydroxylation, dechlorination and demethylation, and phase II metabolism was associated with sulfonic acid and glucuronide conjugation. The high percentages of metabolites in laying hens' tissues and organs, illustrated the active biotransformation of vanisulfane in vivo, which suggests that the marker residues of vanisulfane should consider its major metabolites. A digestive model was also used to determine the digestive fate of vanisulfane. This study improves our understanding of vanisulfane accumulation and biotransformation in laying hens, which will be helpful for risk assessments of foods derived from animals exposed to pesticides.

Superabsorbent hydrogel as a formulation to promote mineralization and accelerate degradation of acetochlor in soils.

The excessive use of herbicides had caused serious environmental pollution and ecological problems. Therefore, it is imperative to explore an effective method to reduce herbicide residues and pollution. In the present study, we used superabsorbent hydrogels coated 14C-acetochlor (SH-ACE) to investigate its behavior in different soils under oxic conditions. After 100 days, the mineralization by SH-ACE was increased by 2.3%, 2.5% and 3.3% in the red clay soils, fluvio-marine yellow loamy soils and coastal saline soils, respectively, compared to the control group. This result indicated that the SH-ACE treatment resulted in more complete degradation and detoxification of acetochlor. In addition, the dissipation rates of acetochlor were significantly faster in the SH-ACE treatment, which reduced the persistence of acetochlor. The probable degradation pathways of acetochlor involved dechlorination, hydroxylation, deethoxymethylation, and the formation of thioacetic acid derivatives in the two treatments, but the contents of transformation products were completely different. These findings suggest that the SH-ACE treatment has a significant effect to accelerate the degradation of acetochlor. When developing green pesticides, we emphasize that superabsorbent hydrogel coating treatment should be considered as a promising method for ecological safety in the environment.

Reduced graphene oxide accelerates the dissipation of 14C-Triclosan in paddy soil via adsorption interactions.

Reduced graphene oxide (RGO) is one of common carbon nanomaterials, which is widely used in various fields. Triclosan is an antimicrobial agent added in pharmaceuticals and personal care products. Extensive release of RGO and triclosan has posed potential risks to humans and the environment. The impact of RGO on the fate of triclosan in paddy soil is poorly known. 14C-Triclosan was employed in the present study to determine its distribution, degradation and mineralization in paddy soil mixed with RGO. Compared with the control, RGO (500 mg kg-1) significantly inhibited the mineralization of 14C-triclosan, and reduced its extractability by 6.5%. The bound residues of triclosan in RGO-contaminated soil (100 and 500 mg kg-1) were 2.9-13.3% greater than that of the control at 112 d. RGO also accelerated the dissipation of triclosan, and its degradation products in both treatments and controls were tentatively identified via 14C-labeling method and LC-Q-TOF-MS analysis. The concentrations of the major metabolites (methyl-triclosan and dechlorinated dimer) were inversely related with the concentrations of RGO. RGO at 50 mg kg-1 or lower had a negligible effect on the degradation of triclosan in paddy soil. Triclosan was strongly adsorbed onto RGO-contaminated soil, which may play a vital role in the fate of triclosan in RGO-contaminated paddy soil. Interestingly, RGO had little effect on triclosan-degrading bacteria via soil microbial community analysis. This study helps understand the effects of RGO on the transformation of triclosan in paddy soil, which is of significance to evaluate the environmental risk of triclosan in RGO-contaminated soil.

Uptake and metabolism of 14C-triclosan in celery under hydroponic system.

As triclosan is used extensively as an antimicrobial agent, it inevitably enters agroecosystems, when sewage and treated wastewater are applied to agricultural fields. As a result, triclosan can be accumulated into crops and vegetables. Currently, limited information is available on the metabolism of triclosan in vegetables. In this study, the fate of 14C-triclosan in celery under a hydroponic system was investigated in a 30-day laboratory test. Most (97.7 %) of the 14C-triclosan accumulated in celery. The bioconcentration factors of triclosan were up to 3140 L kg-1 at day 30. The concentration of 14C-triclosan in roots (17.8 mg kg-1) was 57- and 127-fold higher than that in stems (0.31 mg kg-1) and leaves (0.14 mg kg-1), respectively, at day 30, suggesting a higher accumulation of triclosan in celery roots and negligible transport to stems and leaves. Moreover, triclosan, as well as its eight metabolites, was detected and identified in celery tissues and the growth medium using 14C-labelling and LC-Q-TOF-MS analysis methods. Phase I metabolites in the growth medium were from hydroxylation, dechlorination, nitration, and nitrosylation. Phase II metabolism was the major pathway in celery tissues. Monosaccharide, disaccharide, and sulfate conjugates of triclosan were putatively identified. The results represent an important step toward a better evaluation of the behavior of triclosan in vegetables, with notable implications for environmental and human risk assessments of triclosan.

Fate of chlorpyrifos bound residues in paddy soils: Release, transformation, and phytoavailability.

Chlorpyrifos (CPF) is a widely used organophosphorus insecticide that tends to form bound residues (BRs) in soils. However, the stability and biological activity of CPF-BRs remain to be explored. Facilitated by carbon-14 tracing, this study obtained CPF-BRs initially formed in two typical paddy soils (14C-CPF-BRin), and further investigated their release, transformation and phytoavailability using duckweed (Lemna minor) as a model aquatic organism. Most 14C-CPF-BRin in soils were composed of the parent CPF and its metabolite 3,5,6-trichloro-2-pyridinol (2-OH-TCP), which was mainly formed through reversible entrapment by soil fulvic acids and humin (>80%). At 36 d, 66.67-80.90% of the 14C-CPF-BRin was released, of which only 2-OH-TCP could be released into the water and absorbed by the duckweed, with bioconcentration factors ranging from 247.99 to 324.68 L kg-1. The subsequent metabolism of released 14C-CPF-BRin in duckweed included phase I metabolism from 2-OH-TCP to 4-OH-TCP and phase II metabolism of conjugation of TCP with plant endogenous amino acids. The study suggested that CPF bound residues have high bioavailability in paddy field environments. Given that many pesticides and non-pesticide chemicals share structures analogous to CPF, the findings have important implications for better understanding the environmental and human health risks of man-made chemicals.

Uptake and accumulation of erythromycin in leafy vegetables and induced phytotoxicity and dietary risks.

Erythromycin (ERY), a widely used macrolide antibiotic, is omnipresent in soil and aquatic environments, which may potentially contaminate food crops but remains to be explored. Two leafy vegetables, pakchoi (Brassica rapa subsp. chinensis) and water spinach (Ipomoea aquatica Forsk.), were grown in laboratory-constructed soil or hydroponic systems to investigate the dynamic accumulation of ERY in edible plants. Results indicate 14C-ERY could be absorbed by water spinach and pakchoi in both systems. Autoradiographic imaging and concentration data of plant tissues suggested that ERY had limited translocation from roots to shoots in these two vegetables. The accumulation level of ERY was similar between the two vegetables in the soil system; but in the hydroponic system, pakchoi had a higher ERY accumulation than water spinach, with the bioconcentration factor of 2.74-25.98 and 3.65-11.67 L kg-1, respectively. The ERY intake via vegetable consumption was 0.01-2.17 ng kg-1 day-1, which was much lower than the maximum acceptable daily intake (700 ng kg-1 day-1), indicating negligible risks of consuming vegetables with roots exposed to ERY at environmentally relevant levels. In addition, ERY was found to cause growth inhibition and oxidative stress to pakchoi, even at low concentrations (7 and 22 µg L-1). This work contributes to a better understanding of plant uptake and translocation of ERY in soils and water, and has important implications for the reasonable evaluation of the implied risks of ERY to vegetables and human health.