A multi-residue method for the determination of 54 pesticide residues in pollens has been developed and validated. The proposed method was applied to the analysis of 48 crude pollen samples collected from eight provinces of China. The recovery of analytes ranged from 60% to 136% with relative standard deviations (RSDs) below 30%. Of the 54 targeted compounds, 19 pesticides were detected. The major detection rates of each compound were 77.1% for carbendazim, 58.3% for fenpropathrin, 56.3% for chlorpyrifos, 50.0% for fluvalinate, 31.3% for chlorbenzuron, and 29.2% for triadimefon in crude pollen samples. The maximum values of each pesticide were 4516 ng/g for carbendazim, 162.8 ng/g for fenpropathrin, 176.6 ng/g for chlorpyrifos, 316.2 ng/g for fluvalinate, 437.2 ng/g for chlorbenzuron, 79.00 ng/g for triadimefon, and so on. This study provides basis for the research on the risks to honeybee health.

The residue dynamics and risk assessment of prochloraz and its metabolite 2,4,6-trichlorophenol (2,4,6-TCP) in apple under different treatment concentrations were investigated using a GC-ECD method. The derivatization percent of prochloraz to 2,4,6-TCP was stable and complete. The recoveries of prochloraz and 2,4,6-TCP were 82.9%–114.4%, and the coefficients of variation (CV) were 0.7%–8.6% for the whole fruit, apple pulp, and apple peel samples. Under the application of 2 °C 2.0 g/L, 2 °C 1.0 g/L, 20 °C 2.0 g/L, and 20 °C 1.0 g/L treatment, the half-life for the degradation of prochloraz was 57.8–86.6 d in the whole fruit and apple peel, and the prochloraz concentration in the apple pulp increased gradually until a peak (0.72 mg·kg⁻¹) was reached. The concentration of 2,4,6-TCP was below 0.1 mg·kg⁻¹ in four treatment conditions and not detected (<LOD) in apple pulp. Finally, based on the detection of market samples in Hefei (China), we believe that the residual level of prochloraz in apples meets the requirements of the Chinese standards.

Honeybees are major pollinators of agricultural crops and many other plants in natural ecosystems alike. In recent years, managed honeybee colonies have decreased rapidly. The application of pesticides is hypothesized to be an important route leading to colony loss. Herein, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used to determine eight highly detectable pesticides (carbendazim, prochloraz, pyrimethanil, fenpropathrin, chlorpyrifos, imidacloprid, thiamethoxam, and acetamiprid) in rape flowers. A field experiment was conducted at the recommended dose to evaluate the contact exposure risk posed to honeybees for 0–14 days after treatment. The initial residue deposits of neonicotinoids and fungicides among these compounds were 0.4–1.3 mg/kg and 11.7–32.3 mg/kg, respectively, and 6.4 mg/kg for fenpropathrin and 4.2 mg/kg for chlorpyrifos. The risk was quantified using the flower hazard quotient (FHQ) value. According to the data, we considered imidacloprid, thiamethoxam, chlorpyrifos, fenpropathrin, and prochloraz to pose an unacceptable risk to honeybees after spraying in fields, while fungicides (carbendazim and pyrimethanil) and acetamiprid posed moderate or acceptable risks to honeybees. Therefore, acetamiprid can be used instead of imidacloprid and thiamethoxam to protect rape from some insects in agriculture, and the application of prochloraz should be reduced.

To clarify the residue formation of prothioconazole and its main metabolite in wheat plants, the uptake, translocation, and metabolism of prothioconazole in wheat roots and leaves were investigated by nutrient solution culture and the spraying method. The results showed that prothioconazole and its metabolites showed a trend of increasing and then decreasing in wheat plants under two treatment methods, and the concentration of prothioconazole and its metabolites was higher in the high-concentration group (5000 μg/mL) than in the low-concentration group (1000 μg/mL). The transferability from stem to leaf was stronger than that from root to stem. In the nutrient solution culture, prothioconazole and its metabolites were mainly enriched in wheat roots. The concentration of prothioconazole in wheat roots increases with the increase in prothioconazole concentration and was significantly higher than the prothioconazole concentration on stems and leaves. In wheat leaves in the spraying method, prothioconazole and its metabolites were conducted from leaves to stems and roots up to the nutrient solution. Prothioconazole-desthio was detectable in wheat nutrient solution, while prothioconazole was not detected. Analysis of actual samples of 9 wheat grains and 28 flours showed that the residues of prothioconazole and its metabolites met the maximum residue limit (0.1 mg/mL) set in China and by the Codex Alimentarius Commission. The results will provide a theoretical basis for the scientific use of prothioconazole and food security assurance.

Estimating the influence of bioaccessibility of pesticide residues in fruits and vegetables on dietary exposure is a challenge for human health risk assessment. This study investigated the bioaccessibility of pesticide residues in cherry tomatoes and contributing factors (digestion time, pH, solid/liquid ratio, and dietary nutrition) using an in vitro test simulating the human gastrointestinal tract. pH had the largest effect on triazolone precipitation in the simulated gastric intestinal juice, which had a significant impact on the bioaccessibility. The bioaccessibility of triazolone in the intestinal stage was slightly higher than that in the stomach stage, owing to bile salts and pancreatic enzymes present in the intestinal juice. The bioaccessibility of triazolone did not change significantly with digestion time. In the gastric stage, there was a logarithmic relationship between the bioaccessibility and solid/liquid ratio (R² = 0.9941). The addition of oil significantly changed the bioaccessibility in the gastrointestinal stage. Protein and dietary fiber only affected bioaccessibility in the stomach stage. Dietary nutrition can reduce the release of pesticides from fruits and vegetables into the stomach, sharply reducing the bioaccessibility, and the dietary exposure of pesticide residues in fruits and vegetables can be properly evaluated.