Yahya Al Naggar

Organophosphorus insecticides in honey, pollen and bees (Apis mellifera L.) and their potential hazard to bee colonies in Egypt

There is no clear single factor to date that explains colony loss in bees, but one factor proposed is the wide-spread application of agrochemicals. Concentrations of 14 organophosphorous insecticides (OPs) in honey bees (Apis mellifera) and hive matrices (honey and pollen) were measured to assess their hazard to honey bees. Samples were collected during spring and summer of 2013, from 5 provinces in the middle delta of Egypt. LC/MS-MS was used to identify and quantify individual OPs by use of a modified Quick Easy Cheap Effective Rugged Safe (QuEChERS) method. Pesticides were detected more frequently in samples collected during summer. Pollen contained the greatest concentrations of OPs. Profenofos, chlorpyrifos, malation and diazinon were the most frequently detected OPs. In contrast, ethoprop, phorate, coumaphos and chlorpyrifos-oxon were not detected. A toxic units approach, with lethality as the endpoint was used in an additive model to assess the cumulative potential for adverse effects posed by OPs. Hazard quotients (HQs) in honey and pollen ranged from 0.01-0.05 during spring and from 0.02-0.08 during summer, respectively. HQs based on lethality due to direct exposure of adult worker bees to OPs during spring and summer ranged from 0.04 to 0.1 for best and worst case respectively. It is concluded that direct exposure and/or dietary exposure to OPs in honey and pollen pose little threat due to lethality of bees in Egypt.

Concentrations of neonicotinoid insecticides in honey, pollen and honey bees (Apis mellifera L.) in central Saskatchewan, Canada.

Neonicotinoid insecticides (NIs) and their transformation products were detected in honey, pollen and honey bees, (Apis mellifera) from hives located within 30 km of the City of Saskatoon, Saskatchewan, Canada. Clothianidin and thiamethoxam were the most frequently detected NIs, found in 68 and 75% of honey samples at mean concentrations of 8.2 and 17.2 ng g(-1) wet mass, (wm), respectively. Clothianidin was also found in >50% of samples of bees and pollen. Concentrations of clothianidin in bees exceed the LD50 in 2 of 28 samples, while for other NIs concentrations were typically 10-100-fold less than the oral LD50. Imidaclorpid was detected in ∼30% of samples of honey, but only 5% of pollen and concentrations were <LOD in bees. Transformation products of Imidaclorpid, imidaclorpid-Olefin and imidacloprid-5-Hydroxy were detected with greater frequency and at greater mean concentrations indicating a need for more focus on potential effects of these transformation products than the untransformed, active ingredient NIs. Results of an assessment of the potential dietary uptake of NIs from honey and pollen by bees over winter, during which worker bees live longer than in summer, suggested that, in some hives, consumption of honey and pollen during over-wintering might have adverse effects on bees.

Metals in agricultural soils and plants in Egypt

Since analysis of both soil and plants are useful to assess contamination of a geographic area, concentrations of five representative metals: copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), and iron (Fe) in soil and associated plants were measured by atomic absorption spectroscopy. Samples were collected from four different Egyptian regions (El-mehala El-kobra, Kafr El-Sheikh, Kafr El-zayat, and Al-fayoum) during spring and summer 2010. Concentrations of the selected metals in agricultural soils were significantly different among locations and seasons. Concentrations of Cd and Fe in soils at the four locations exceeded the maximum allowable concentrations for Cd (8 mg/kg, dry mass (dm)) and Fe (1000 mg/kg, dm). Accumulation was different for clover and cotton. Clover blossoms grown in soil from Kafr El-zayat contained the greatest concentrations of Cu, Zn, Pb, and Fe. Cotton flowers from El-mehala El-kobra accumulated the highest levels of Cd. Concentrations of Cd and Pb in both clover and cotton flowers from the four locations exceeded maximum allowable concentrations (3 mg/kg, dm) for both Cd and Pb. Using such agricultural soils for cultivation of edible crops for consumption may result in chronic hazards to human health.

Effects of treatments with Apivar® and Thymovar® on V. destructor populations, virus infections and indoor winter survival of Canadian honey bee (Apis mellifera L.) colonies

Efficacies of two miticides, Apivar® and Thymovar®, were evaluated as a fall treatment against V. destructor. The effect of treatment with miticides was further evaluated by monitoring both viral load and rate of indoor overwintering survival of colonies of European honey bees (Apis mellifera L.) in the vicinity of Saskatoon, Saskatchewan, Canada. Forty-five colonies were randomly assigned to three treatment groups with 15 hives per group: Group 1; 2 strips of Thymovar® (thymol); Group 2; 2 strips of Apivar® (Amitraz); and Group 3; no treatment (control). Significant decreases in the rates of colony infestation (Mites per hundred bees, MPHB) by V. destructor were observed (p < 0.05) between colonies of bees treated with Apivar® in October 2013 when compared to control colonies. Efficacy of Apivar® and Thymovar® against V. destructor after treatment for 22 days were 76.5 and 26.7%, respectively. After 22 days, concentrations of the two miticides in bees were 15.4 ng amitraz/g wet mass (wm) and 64,800 ng thymol/g wm. There were no significant differences (p > 0.05) in the percentage of colonies infected by deformed wing virus (DWV) and Israeli acute paralysis virus (IAPV) either before or after treatment with Apivar® or Thymovar® in October 2013 and 7 months post treatment in April 2014. Only the Apivar® treatment group showed IAPV infections in April 2014. The group treated with Apivar® exhibited a better overwintering rate of survival (93%), than hives treated with Thymovar® (67%). These results suggest volatile miticides like Thymovar® should be avoided in geographical areas with colder fall temperatures.

Effects of environmentally-relevant mixtures of four common organophosphorus insecticides on the honey bee (Apis mellifera L.)

We assessed whether exposure to environmentally-relevant mixtures of four organophosphorus insecticides (OPs) exerted adverse effects on honey bees. Adult and worker bees were orally exposed for five days under laboratory conditions to mixtures of four insecticides, diazinon, malathion, profenofos and chlorpyrifos at two concentrations. Concentration in the mixtures tested were equivalent to the median and 95th centile concentrations of the OPs in honey, as reported in the literature. Effects on survival, behavior, activity of acetylcholinesterase (AChE), and expression of genes important in detoxification of xenobiotics and immune response were examined. Survival of worker bees was not affected by exposure to median or 95th centile concentrations of the OPs. Activity of AChE was significantly greater in worker bees exposed to the 95th centile concentration mixture of OPs compared to the median concentration mixture. Expression of genes involved in detoxification of xenobiotics was not affected by treatment, but the abundance of transcripts of the antimicrobial peptide hymenoptaecin was significantly greater in worker honey bees exposed to the median concentration mixture. Results suggest that short-term exposure to environmentally relevant concentrations of a mixture of OPs do not adversely affect worker honey bees.

Neonicotinoid insecticides in pollen, honey and adult bees in colonies of the European honey bee (Apis mellifera L.) in Egypt

Honeybee losses have been attributed to multiple stressors and factors including the neonicotinoid insecticides (NIs). Much of the study of hive contamination has been focused upon temperate regions such as Europe, Canada and the United States. This study looks for the first time at honey, pollen and bees collected from across the Nile Delta in Egypt in both the spring and summer planting season of 2013. There is limited information upon the frequency of use of NIs in Egypt but the ratio of positive identification and concentrations of NIs are comparable to other regions. Metabolites of NIs were also monitored but given the low detection frequency, no link between matrices was possible in the study. Using a simple hazard assessment based upon published LD50 values for individual neonicotinoids upon the foraging and brood workers it was found that there was a potential risk to brood workers if the lowest reported LD50 was compared to the sum of the maximum NI concentrations. For non-lethal exposure there was significant risk at the worst case to brood bees but actual exposure effects are dependant upon the genetics and conditions of the Egyptian honeybee subspecies that remain to be determined.

Human dietary intake and hazard characterization for residues of neonicotinoides and organophosphorus pesticides in Egyptian honey

ABSTRACT In two recently published reports, hazards posed by dietary exposure to organophosphate and neonicotinoid plant protection products on the European honey bee (Apis mellifera L.) in Egypt were investigated. Using concentrations reported in those studies, an assessment of hazards posed by these two classes of insecticides to humans due to consumption of Egyptian honey from the Nile Delta during both spring and summer was performed. Twenty-eight compounds including metabolites were assessed for exposure of adult Egyptians based on the best- and worst-case scenarios. Even for the worst-case scenario, exposure to these two classes of pesticides in honey was 15-fold less than hazard index value of 1.0 for adverse effects on humans. Based upon this analysis, people exposed to these insecticides through consumption of honey products would be unlikely to exhibit adverse health outcomes.

Chemical characterization and antioxidant properties of Canadian propolis

Propolis is a multifunctional material collected and used by honey bees in the construction and maintenance of their hives. It has been used in folk medicine for centuries. Concentrations of major constituents and antioxidant characteristics of ethanolic extracts of three samples of propolis (EEPs) collected from different geographical locations in Canada (Saskatchewan, Ontario and British Columbia) were determined. Twenty-one compounds were identified in each EEP, of which 18 were polyphenols. Semi-quantitative measurements showed that benzyl caffeate, pinocembrin, sakuranetin and pinobanksin-3-acetate were most abundant in propolis from Ontario. Total phenolic content of EEPs were quantified by using the Folin–Ciocalteu reagent which ranged between 410.81 and 429.61 mg GAE/g EEP. Free radical scavenging activities of propolis were confirmed by use of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and by using Nrf2 Luciferase reporter cell lines. The three EEPs exhibited strong scavenging of free radicals, and protective activity against oxidative stress caused by exposure to H2O2 in this in vitro system. These results support the use of propolis from these regions of Canada as a source of natural antioxidants.

Cellular alterations in midgut cells of honey bee workers (Apis millefera L.) exposed to sublethal concentrations of CdO or PbO nanoparticles or their binary mixture

Beside many beneficial applications in industry, agriculture and medicine, nanoparticles (NPs) released into the environment might cause adverse effects. In the present study, effects of exposure to sublethal concentrations of PbO and CdO NPs, either separately or in combination on honey bee (A. mellifera) workers were assessed. Honey bee workers were fed sugar syrup contained (20% of LC50) of CdO (0.01 mg ml-1) and PbO (0.65 mg ml-1) NPs either separately or combined for nine days under laboratory conditions. Control bees were fed 1.5 M sucrose syrup without NPs. Effects on histological and cellular structure of mid gut cells were investigated using light and electron microscope. Percentages of incidence of apoptosis or/and necrosis in mid gut cells were also quantified by use of flow cytometry. Rapture of the peritrophic membrane (PM) was among the most observed histopathological alteration in bees fed sugar syrup contained CdO NPs separately or combined with PbO NPs. Common cytological alterations observed in epithelial cells were irregular distribution or/and condensation of nuclear chromatin, mitochondrial swelling and lysis, and rough endoplasmic reticulum (rER) dilation, fragmentation, and vesiculation and were quite similar in all treated groups compared to control. The greatest incidence (%) of necrosis was observed in bees fed the diet that contained CdO NPs alone. The greatest % of both apoptosis and necrosis was observed in bees fed sugar syrup spiked with sublethal concentrations of both metal oxide NPs. Joint action of the binary mixture of Cd and Pb oxide NPs on honey bees was concluded to be antagonistic. Collectively, exposure of honey bees to these metal oxide NPs even at sublethal concentrations will adversely affect viability of the colony and further studies are still required to determine the effects of these metal oxide NPs on behavior and pollination ecology of honeybees.