Amal Seif

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.

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 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.

Effect of some botanical oils on the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae)

Six botanical oils of clove, Tugenia aromatica, anise, Pimpinella anisum, chamomile, Matricaria recutita, cumin, Cuminum cyminum, basil, Ocimum basilicum and lupine, Lupinus albus were tested to determine their insecticidal properties against Sitophilus granarius on wheat grains. Considering the percentage of mortality, the toxicity of oils increased gradually with increasing concentrations. Anise oil had the lowest LC50 followed by clove ˂ basil ˂ chamomile ˂ cumin ˂ lupine. Mortality rates of adult weevils was high at the initial time up to 6 weeks post exposure to grains pre-treated with the tested botanical oils at LC50 Level. Thereafter, the activity gradually decreased over time. Both LC50 and LC99 of anise oil prevented weevilsÂ’ oviposition on treated wheat grains. At both LC50 and LC99 values, no adults emerged from eggs laid on grains pretreated with clove and chamomile. At LC50, very few adults emerged from eggs laid on grains pretreated with cumin, lupine and basil in comparison with the control. In addition, the effects of these oils on water absorption and seed germination of treated wheat grains stored for up to 18 weeks was studied. In general, either LC50 or LC99 values of tested oils showed negligible reduction in water swelling capacity (WSC) of treated wheat seeds at the initial time or even after long time of storage. The results also showed negligible decrease in germination of wheat grains treated with tested oils at LC50 and LC99 levels even 18 weeks post-treatment. This study suggests that the use of these botanical oils, especially anise oil, may be effective to protect wheat seeds from stored grain pests in storage.