Bifenthrin in the tropical sugarcane ecosystem: persistence and environmental risk assessment

Bifenthrin induces cell death in bovine mammary epithelial cells via ROS generation, calcium ion homeostasis disruption, and MAPK signaling cascade alteration

Bifenthrin is one of the widely used synthetic pyrethroid insecticides, employed for various purposes worldwide. As lipophilic pyrethroids can easily bind to soil particles, which is why their residues are detected in various environments. Consequently, the toxicity of bifenthrin to non-target organisms can be regarded as an environmental concern. The toxic effects of bifenthrin have been studied in various animal models and cell lines; however, its toxic effects on cattle remain unclear. In particular, gaining insights into the toxic effects of bifenthrin on the mammary lactation system is crucial for the dairy industry. Therefore, we proceeded to investigate the toxic effects of bifenthrin on the bovine mammary epithelial cells (MAC-T cells). We established that bifenthrin inhibited cell proliferation and triggered apoptosis in MAC-T cells. Additionally, bifenthrin induced mitochondrial dysfunction and altered inflammatory gene expression by disrupting mitochondrial membrane potential (MMP) and generating excessive reactive oxygen species (ROS). We also demonstrated that bifenthrin disrupted both cytosolic and mitochondrial calcium ion homeostasis. Furthermore, bifenthrin altered mitogen-activated protein kinase (MAPK) signaling cascades and downregulated casein-related genes. Collectively, we confirmed the multiple toxic effects of bifenthrin on MAC-T cells, which could potentially reduce milk yield and quality.

Microbial detoxification of bifenthrin insecticide by selected fungal strains and optimizing conditions using response surface methodology for agricultural sustainability

Bifenthrin is a type I broad spectrum pyrethroid insecticide widely employed in urban and agricultural settings with little knowledge about its biodegradation. Bifenthrin was subjected to a 35 days incubation period in which it was degraded by five fungal strains named as Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Penicillium chrysogenum, and Lasiodiplodia theobromae. Penicillium chrysogenum was found to be extremely effective in degrading bifenthrin up to 85%. Furthermore, response surface methodology (RSM) with Box-Behnken design is applied to optimize the degradation conditions with varying pH, temperature (°C), and incubation time (days). The p value < 0.05 in the response surface design and analysis of variance showed the significance of the reaction parameters. The ideal conditions for Penicillium chrysogenum to break down bifenthrin (10 mgL-1) were found to be 30 °C, pH 7, and a 24 days incubation period. In eutrophic conditions and a glucose-rich media, this fungus co-metabolized bifenthrin. By hydrolytically cleaving the carboxyl ester bond, the Penicillium chrysogenum breaks down bifenthrin, as shown by the chromatogram of four metabolites from GCMS. The biodegradation of bifenthrin by strain Penicillium chrysogenum and its use in agronomic situations are now well understood as per the findings of this study.

Effect of bifenthrin application at different maturity stages on its dissipation and residues in kumquat (Citrus japonica) and dietary intake risk assessment

Bifenthrin is a pyrethroid pesticide widely used on kumquats, but the residues in the peel and pulp after bifenthrin application at different maturity stages of kumquats have not been evaluated. This study developed a simple and rapid high-performance liquid chromatography (HPLC) method for the quantitative analysis of bifenthrin residues in whole fruit, kumquat peel, kumquat pulp, and soil. The results showed that regardless of whether bifenthrin was applied one or three times during the near-mature period, the half-lives of the fruit peel and fruit pulp were longer than those in the immature period. Kumquat fruit residues decreased with time at both maturity levels. The residues of bifenthrin in near-mature fruit exceeded the MRL in Guangxi and Fujian 14 days after the three applications of bifenthrin, suggesting that this issue should be focused on in kumquat production and supervision. However, for bifenthrin application in either the near-mature or the immature fruit period, the calculated risks for chronic dietary intake of kumquat were well below 100%. The data demonstrate that the chronic dietary intake risk of bifenthrin through kumquat consumption is low and within acceptable limits. These results provide a reference and risk assessment data for the safe and rational use of bifenthrin insecticides.

Residual levels and dietary risk assessment of bifenthrin and dinotefuran and its major metabolites in open wheat field conditions

To evaluate the residual levels of bifenthrin and dinotefuran, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) and high-performance liquid chromatography-tandem mass spectrometry method for simultaneous detection of bifenthrin and dinotefuran and its major metabolites in wheat was developed and validated. Dietary risk assessments were further performed based on the relevant residual data from 12 wheat fields, toxicology data and dietary patterns. In wheat grain and straw, the recoveries of all analytes ranged from 77 to 102% with the relative standard deviation <9.7% and the limit of quantitation 0.05 mg kg^-1 . The highest terminal residue of bifenthrin in wheat grain was 0.069 mg kg^-1 and dinotefuran was 0.34 mg kg^-1 . Residual concentrations of bifenthrin and dinotefuran decreased to <0.05 and 0.15 mg kg^-1 at 21 days (pre-harvest interval), respectively. The chronic risk quotient ranged from 6.4 to 62.7% and the acute risk quotient varied from 0.38 to 17.73%. The chronic and acute dietary risks caused by the terminal residues of the two insecticides were negligible for Chinese populations. The recommended pre-harvest interval was proposed to ensure safe wheat consumption. These data could provide a scientific reference to establish the Chinese maximum residue limit of dinotefuran in wheat.

Clothianidin in the Tropical Sugarcane Ecosystem: Soil Persistence and Environmental Risk Assessment Under Different Organic Manuring

Clothianidin is drenched at planting to manage the termites of sugarcane. The application of organic manures at planting is also in vogue to conserve the soil moisture in the tropical ecosystem. Hence, the persistence behaviour of clothianidin was studied in the sandy clay loam soil of tropical sugarcane ecosystem under different organic manuring. The clothianidin residues persisted up to 90th DAT and reached below the limit of quantification (LOQ = 0.005 µg/g) on 105th DAT both in the manurial and non-manurial soils. The half-lives of clothianidin were in the range of 22.4-24.8 days in the manurial soils as against 21 days in the non-manurial soil, indicating the insignificant positive impact of organic manures on the soil persistence of clothianidin. The clothianidin residues in the soil were predicted to pose unacceptable to medium level of risk to earthworms during the course of its dissipation in the tropical sugarcane environment.