Synthesis and Structural Characterization of a Ubiquitous Transformation Product (BTS 40348) of Fungicide Prochloraz

Prediction of Potential Risk for Ten Azole and Benzimidazole Fungicides with the Aryl Hydrocarbon Receptor Agonistic Activity to Aquatic Ecosystems

Azole and benzimidazole fungicides are widely used agrochemicals to prevent and treat fungal growth and are frequently detected in aquatic environments. Here, we aimed to assess the aquatic ecological risks of ten currently used azole and benzimidazole fungicides, which with the aryl hydrocarbon receptor (AhR) agonistic activity, and their transformation products (TPs). We obtained over 400 types of aerobic TPs for ten fungicides. Some fungicides and their TPs (approximately 26.7%) exhibited the potential AhR agonistic activity and toxicity to different aquatic species. Meanwhile, some compounds with the chlorine element and benzene ring structure exhibited environmental persistence and mobile ability. Several of them were frequently detected in aquatic environments, posing potential risks to aquatic ecosystems. These harmful fungicides and their TPs should be given attention. This study provides important insight into the aquatic ecological risks caused by azole and benzimidazole fungicides, which can provide theoretical guidance for their pollution control.

Dissipation and Distribution of Prochloraz in Bananas and a Risk Assessment of Its Dietary Intake

BACKGROUND

As a systematic fungicide, prochloraz is often used to control banana freckle disease, and it is significant to assess the safety and risk of prochloraz.

METHODS

The dissipation kinetics and distribution of prochloraz in bananas were measured by high-performance liquid chromatography (HPLC).

RESULTS

The results showed that the fortified recoveries in bananas were 83.01-99.12%, and the relative standard deviations (RSDs) were 2.45-7.84%. The half-life of prochloraz in banana peel (3.93-5.60 d) was significantly lower than it was in whole banana (8.25-10.80 d) and banana pulp (10.35-12.84 d). The terminal residue of prochloraz in banana fruits was below the maximum residue level (MRL, China) at pre-harvest intervals (PHI) of 21 d. Moreover, the residue of prochloraz in banana peel was always 1.06-7.71 times greater than it was in banana pulp. The dietary risk assessment results indicated that the prochloraz residue in bananas at PHI of 21 d was safe for representative populations. (4) Conclusions: We found that a 26.7% prochloraz emulsion oil in water (EW) diluted 1000-fold and sprayed three times under field conditions was safe and reliable, providing a reference for the safe application of prochloraz in bananas.

Azole and strobilurin fungicides in source, treated, and tap water from Wuhan, central China: Assessment of human exposure potential

Fungicides are widely used in agriculture worldwide. However, data on the occurrence of fungicides in drinking water are scarce. This study aimed to determine the occurrence of 12 selected fungicides in drinking water, the removal efficiency of conventional water treatment processes for fungicides, and the risk of fungicide exposure. In this study, source water (February and July), treated water (February and July), and tap water samples (February, April, July, and October) were collected from Wuhan, central China, in 2019. Seven of the twelve selected fungicides were 100% detected in the three types of water samples; tricyclazole was found with the highest concentrations in the source water phase (median: 15.2 ng/L; range: 4.21-67.9 ng/L). The concentrations of the 12 selected fungicides remaining in the treated water samples (median proportion of the remaining content: 77.5%) revealed that most of the target analytes may not be removed efficiently by conventional water treatment processes, though they could be removed efficiently by advanced treatment. Higher concentrations of the fungicides were observed in samples collected in July (median: 38.7 ng/L; range: 12.5-85.8 ng/L), followed by those in October (median: 21.8 ng/L; range: 10.2-58.8 ng/L), February (median: 9.82 ng/L; range: 5.63-93.3 ng/L), and April (median: 7.13 ng/L; range: 6.23-91.1 ng/L). The health risk assessment implied that estimated daily intake of these fungicides through tap water ingestion might pose a low risk to consumers, though risk associated with infant exposure to the fungicides requires further attention. This study provides baseline data on the occurrence, removal efficiencies, and seasonal variations of the selected fungicides in tap water from central China.

Identity, Synthesis, and Cytotoxicity of Forchlorfenuron Metabolites in Kiwifruit

Forchlorfenuron (CPPU) is a plant growth regulator widely used in kiwifruit production. Although research on the toxicological and environmental effects of CPPU is well-established, the nature and toxicological properties of its metabolites are much less well-known. Using high resolution mass spectrometry and nuclear magnetic resonance, the CPPU previously unidentified metabolites in Xuxiang and Jinyan kiwifruit were identified as N-(2-chloro-4-pyridinyl)-N'-(2-hydroxy-4-methoxyphenyl)-urea (metabolite 1) and N-phenyl-N'-4-pyridinylurea (metabolite 2, CAS: 1932-35-0). Their structures were confirmed by synthesis (metabolite 1) and by comparison with a commercial standard (metabolite 2). Quantitative studies demonstrate that CPPU and its metabolites are mainly retained in the kiwifruit peel, while the content is dependent on the nature of the peel surface, with the smoother peel of Jinyan kiwifruit retaining smaller amounts of the compound. Cell viability experiments in Caco2 and Lo2 cells show that the metabolites may have a lower cytotoxicity compared to the parent compound CPPU.