Adult Honeybees and Beeswax as Indicators of Trace Elements Pollution in a Vulnerable Environment: Distribution among Different Apicultural Compartments.

Bees in search of diet sources intensively fly within a radius of up to 3 km, encountering nectar, pollen, and water sources which are potentially contaminated. Consequently, their products can provide valuable information about potential pollution. In the current study, 27 macro and trace elements, including the most hazardous ones, were measured in bees, honey, wax, pollen, and larvae, obtained from seven explicitly industrial areas in eastern regions of Slovakia, using a validated ICP-MS method. All the analysed elements were detected at least in one matrix. The detected concentrations of toxic elements, such as Hg, Pb, and Cd were in some cases higher in wax and bee samples, compared with honey, larvae, and pollen. In particular, Pb and Hg maximum concentrations were detected in the wax samples from Posa (3193 µg/kg) and Strázske_A (90 µg/kg). In addition, adult bees accumulated more elements than larvae, while wax and adult bees seemed more suitable for monitoring macro and trace elements in the surrounding environment. Statistical analysis emphasizing bees and wax correlated Cd with the Strázske area, possibly attributed to the intensified industrial activity in this region.

The adverse effects of synthetic acaricide tau-fluvalinate (tech.) on winter adult honey bees.

Currently several pyrethroids (e.g., flumethrin and tau-fluvalinate) are used in apiculture worldwide as acaricides/miticides. The long half-lives of pyrethroids in synthetic acaricides applied to hive matrices, may adversely affect the health of bee colony. The potentially adverse effects of synthetic acaricide/miticide tau-fluvalinate (tech.) on winter honeybees were assessed in this study (OECD 245 2017). No dose-dependent mortality in in vitro reared winter honeybees was observed after chronic oral 10-day exposure to syrup (50% w/v) spiked with a maximum concentration of 750 µg a.i./kg diet and its 1/10 concentration. The No Observed Effect Concentration is ≥ 750 µg a.i./kg diet. Tau-fluvalinate testing for the sublethal effects on bee immune system showed up-regulated gene expression encoding abaecin, lysozyme, and defensin in both tested groups, however the expression of hymenoptaecin gene was reduced. Moreover, tau-fluvalinate significantly induced levels of DNA damage in exposed bees, which can result in adverse genotoxic effect.