Evaluation of Highly Detectable Pesticides Sprayed in Brassica napus L.: Degradation Behavior and Risk Assessment for Honeybees

Abstract

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.

Sulfoxaflor Residues in Pollen and Nectar of Cotton Applied through Drip Irrigation and Their Potential Exposure to Apis mellifera L.

“…Because bees were mainly exposed to sulfoxaflor by pollen and nectar when sulfoxaflor was applied via drip irrigation [44]. Firstly, we assessed the contact exposure of sulfoxaflor on honey bees by the flower hazard quotient (FHQ do ) [29], and the results showed that all FHQ do values were lower than 0.1, indicating that sulfoxaflor residues in pollen and nectar were safe to honey bees ( Table 4; Table 5) [29]. Honey bees generally have different types, such as worker larvae, nurses, and forager.…”

“…To understand the risk of sulfoxaflor posed to A. mellifera, the risk assessment was estimated according to the flower hazard quotient (FHQ do ) value [29]. The FHQ do value was calculated from the predicted exposure concentration (PEC) in pollen and nectar multiplied by the maximum contact level (MCL)] and the acute contact LD 50 for adult bees.…”

“…The FHQ do value was calculated from the predicted exposure concentration (PEC) in pollen and nectar multiplied by the maximum contact level (MCL)] and the acute contact LD 50 for adult bees. According to the reference, the maximum contact level of honey bees was 1 g of contaminated flowers per day [29,30]. The contact LD 50 was 0.585 µg a.i.…”

“…The contact exposure of sulfoxaflor to honey bees in 2016 and 2017 was estimated by the flower hazard quotient (FHQ do ) [29]. The results showed that FHQ do values were lower than 0.1 for the two doses of sulfoxaflor applied either before or during flowering ( Table 4; Table 5).…”

Special Issue “Chemical Speciation of Organic and Inorganic Components of Environmental and Biological Interest in Natural Fluids: Behaviour, Interaction and Sequestration”

“…The Special Issue had satisfactory feedback from researchers, with contributions having cross-field character and being of interest for different industrial, pharmaceutical, chemical, and biological fields [7][8][9][10][11][12][13][14][15][16][17].…”