Digestion dynamics of acetamiprid during royal jelly formation and exposure risk assessment to honeybee larva based on processing factor.

Previous studies to the exposure effects of acetamiprid on honeybees were based on the analysis of bee pollen and honey sacs from field trials or of beebread and honey in the hive, which overestimate or underestimate the risk of exposure to pesticide residues. It was believed that the processing factor (PF) is an important variable to determine the final pesticide residue during royal jelly formation and the actual risk to honeybee larva. Hence, a QuEChERS method to determine acetamiprid contents in honeybee samples was established in this study. Then, the PFs for acetamiprid in beebread fermentation, honey brewing, and royal jelly formation were determined to be 0.85, 0.76, and 0.16, respectively. The PF for royal jelly formation was 0.04 when acetamiprid was detected in beebread alone, and it was 0.12 when acetamiprid was only detected in honey. Finally, the predicted exposure concentration of acetamiprid in royal jelly was calculated to be 2.05 µg/kg using the PF without significant difference with the 90th percentile value (3.64 µg/kg) in the actual sample. However, the value was 16.62 µg/kg without considering the PF. This study establishes a methodology for the correct evaluation of the risk to bee larva of acetamiprid residues in bee pollen and honey sac contents and the residual levels in royal jelly.

Perfluorooctane sulfonate and perfluorooctanoic acid inhibit progesterone-responsive capacitation through cAMP/PKA signaling pathway and induce DNA damage in human sperm.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are two persistent organic pollutants harmful to human health. They induce negative effects on male reproduction by influencing male hormones, spermatogenesis, and sperm quality. However, their effects and mechanisms on human sperm capacitation and fertilization remain unclear. Here, human sperm were incubated with different concentrations of PFOS or PFOA with progesterone during capacitation. Both PFOS and PFOA inhibited human sperm hyperactivation, sperm acrosome reaction, and protein tyrosine phosphorylation levels. PFOS and PFOA decreased intracellular Ca2+ concentration in the presence of progesterone, and subsequently decreased cAMP level, and PKA activity. PFOS and PFOA increased reactive oxygen species production and sperm DNA fragmentation during the only 3 h capacitation incubation. Conclusively, PFOA and PFOS may inhibit human sperm capacitation via the Ca2+-mediated cAMP/PKA signaling pathway in the presence of progesterone, and induce sperm DNA damage through increased oxidative stress, which is not conducive to fertilization.

Toxic effects of detected pyrethroid pesticides on honeybee (Apis mellifera ligustica Spin and Apis cerana cerana Fabricius).

To obtain the presence of environmental contaminants in honeybee and compare the toxicity of the detected pesticides to Apis mellifera ligustica Spin and Apis cerana cerana Fabricius. In this work, 214 honeybee samples were collected to simultaneous monitoring 66 pesticides between 2016 and 2017 in China. A modified QuEChERS extraction method coupled with multi-residue analytical methods by Ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and Gas chromatography-mass spectrum (GC-MS). Among, four pyrethroid pesticides were selected to test and compare the acute oral toxicities of two honeybees. And the survival risk of beta-cypermethrin was analyzed to them. Using this method, 21 compounds were detected, including 3 neonicotinoids, 5 pyrethroids, 5 organophosphorus and 8 others. Importantly, detected frequencies of pyrethroid pesticides were accounted for 53.3%. Among, acute toxicity values (LD50) of four pyrethroid pesticides to the A.m. ligustica were higher than of that the A.c. cerana. When they were exposed to the same concentration of beta-cypermethrin (0.2906 mg/L), the survival rate of the A.m. ligustica (40.0%) was higher than the A.c. cerana (18.9%). Our work is valuable to analyze multiple pesticide residues of honeybees and evaluate the survival risk of two honeybee species, which also provides a basis for the risk assessment.

Analysis of honey bee exposure to multiple pesticide residues in the hive environment.

Since the loss of honeybees in hives could have a greater impact on colony health than those of their foraging bees, it is imperative to know beehives' pesticide exposure via oral ingestion of contaminated in-hive matrices. Here, a 4-year monitoring survey of 64 pesticide residues in pollen, nectar and related beehive matrices (beebread and honey) from China's main honey producing areas was carried out using a modified version of the QuEChERS multi-residue method. The results showed that 93.6% of pollen, 81.5% of nectar, 96.6% of beebread, and 49.3% of honey containing at least one target pesticide were detected either at or above the method detection limits (MDLs), respectively, with up to 19 pesticides found per sample. Carbendazim was the most frequently detected pesticide (present in >85% of the samples), and pyrethroids were also abundant (median concentration = 134.3-279.0 µg/kg). The transfer of pesticides from the environment into the beehive was shown, but the pesticide transference ratio may be affected by complex factors. Although the overall risk to colony health from pesticides appears to be at an acceptable level, the hazard quotient/hazard index (HQ/HI) value revealed that pyrethroids were clearly the most influential contributor, accounting for up to 45% of HI. Collectively, these empirical findings provide further insights into the extent of contamination caused by agricultural pesticide use on honeybee colonies.