Dissipation behavior, residue distribution, and risk assessment of triflumizole and FM-6-1 in greenhouse strawberries and soil

This study aimed to develop a reliable method for the simultaneous analysis of triflumizole (TRIF) and its primary metabolite FM-6-1 (N-4-chloro-2-trifluoromethylphenyl-2-propoxy-acetamidine) in the soil and treated strawberries using solid phase extraction (SPE) coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS). Using this method, TRIF and FM-6-1 degradation in strawberries and the soil under greenhouse conditions were investigated. The field trials showed that t_1/2 of TRIF and total residues (the sum of TRIF and FM-6-1) were 1.6-2.2 days and 2.4-2.9 days in strawberry and 4.3-6.1 days and 5.5-6.9 days in soil, respectively. Terminal total residues were ≤ 0.39 mg/kg in strawberry and ≤ 0.42 mg/kg in soil from 5 to 10 days of harvest. The risk quotient (RQ) of TRIF was below 1.89%, showing that the dietary risk of TRIF in strawberry was low. These findings provide guidance for the use of TRIF on crops and provide reference to establish the maximum residue level (MRL) of TRIF in strawberry.

Acute toxicity of triflumizole to freshwater green algae Chlorella vulgaris

Triflumizole is one of imidazole fungicides that works by inhibiting ergosterol biosynthesis, and is widely used for the control of powdery mildew and scabs on various fruits and crops. Triflumizole residue has been frequently detected in soil and aquatic ecosystems. While many studies have focused on its toxic effect on terrestrial and aquatic animals, little attention has been paid to aquatic algae, the primary producers of aquatic environments. Therefore, we evaluated the acute (96 h) toxicity effects of triflumizole on the freshwater algae Chlorella vulgaris, by examining growth, cell morphology, photosynthesis, and oxidative stress. The results showed that the 96 h median inhibition concentration (96 h-EC₅₀) was 0.82 mg/L (95% confidential interval 0.70-0.98 mg/L).The growth of algal cells was conspicuously inhibited by triflumizole exposure, and the cell surfaces appeared to be shrunkThe chlorophyll content (including Chl-a, Chl-b and T-Chl) dramatically decreased at triflumizole concentrations of 0.2 and 1.0 mg/L. In addition, the transcript abundance of photosynthesis-related genes (psaB, psbC and rbcL) showed obvious decreases in above treatments after 96 h of exposure to triflumizole. Moreover, the algal growth inhibition was accompanied by an increase in intracellular reactive oxygen species and malondialdehyde content, as well as increased activity of antioxidant enzymes such as superoxide dismutase and peroxidase, indicating oxidative stress and lipid peroxidation. Our findings reveal that triflumizole has potential toxicity to the primary producers (freshwater algae) in aquatic ecosystems.

Development of triflumizole ionic liquids containing anions of natural origin for improving the utilization and minimizing the adverse impacts on aquatic ecosystems

Triflumizole, a broad-spectrum systemic fungicide, has been widely used for the management of fungal diseases in plants. However, rapid photolysis and high risk to the aquatic environment limit its application. Ionic liquid (IL) forms of active pharmaceutical ingredients are innovative and promising agents that can optimize the application of the starting chemicals through the selection, or functionalization of the counterions (cation or anion). In this study, triflumizole was paired with various natural organic acids to develop novel ILs for improving the physicochemical properties and reducing the toxicity to fish. The results showed that the obtained ILs had low surface tension and lipophilicity and could protect triflumizole against degradation under UV irradiation as well as exhibit more excellent biological activity against Botrytis cinerea than triflumizole. The IL forms of triflumizole reduced the dosage and frequency of this fungicide, accordingly minimized the negative effect on environment. The IL contained salicylic acid as anion decreased > 4-fold toxicity to adult zebrafish over TFM. The results reported here create new application possibilities for imidazole fungicides and offer some heuristic rules for the design of active pharmaceutical ingredients-ionic liquids.