Olivier Lambert

Widespread Occurrence of Chemical Residues in Beehive Matrices from Apiaries Located in Different Landscapes of Western France

Background The honey bee, Apis mellifera, is frequently used as a sentinel to monitor environmental pollution. In parallel, general weakening and unprecedented colony losses have been reported in Europe and the USA, and many factors are suspected to play a central role in these problems, including infection by pathogens, nutritional stress and pesticide poisoning. Honey bee, honey and pollen samples collected from eighteen apiaries of western France from four different landscape contexts during four different periods in 2008 and in 2009 were analyzed to evaluate the presence of pesticides and veterinary drug residues. Methodology/Findings A multi-residue analysis of 80 compounds was performed using a modified QuEChERS method, followed by GC-ToF and LC−MS/MS. The analysis revealed that 95.7%, 72.3% and 58.6% of the honey, honey bee and pollen samples, respectively, were contaminated by at least one compound. The frequency of detection was higher in the honey samples (n = 28) than in the pollen (n = 23) or honey bee (n = 20) samples, but the highest concentrations were found in pollen. Although most compounds were rarely found, some of the contaminants reached high concentrations that might lead to adverse effects on bee health. The three most frequent residues were the widely used fungicide carbendazim and two acaricides, amitraz and coumaphos, that are used by beekeepers to control Varroa destructor. Apiaries in rural-cultivated landscapes were more contaminated than those in other landscape contexts, but the differences were not significant. The contamination of the different matrices was shown to be higher in early spring than in all other periods. Conclusions/Significance Honey bees, honeys and pollens are appropriate sentinels for monitoring pesticide and veterinary drug environmental pollution. This study revealed the widespread occurrence of multiple residues in beehive matrices and suggests a potential issue with the effects of these residues alone or in combination on honey bee health.

Bees, honey and pollen as sentinels for lead environmental contamination.

Three beehive matrices, sampled in eighteen apiaries from West France, were analysed for the presence of lead (Pb). Samples were collected during four different periods in both 2008 and 2009. Honey was the matrix the least contaminated by Pb (min = 0.004 μg g(-1); max = 0.378 μg g(-1); mean = 0.047 μg g(-1); sd = 0.057). The contamination of bees (min = 0.001 μg g(-1); max = 1.869 μg g(-1); mean = 0.223 μg g(-1); sd = 0.217) and pollen (min = 0.004 μg g(-1); max = 0.798 μg g(-1); mean = 0.240 μg g(-1); sd = 0.200) showed similar levels and temporal variations but bees seemed to be more sensitive bringing out the peaks of Pb contamination. Apiaries in urban and hedgerow landscapes appeared more contaminated than apiaries in cultivated and island landscapes. Sampling period had a significant effect on Pb contamination with higher Pb concentrations determined in dry seasons.

Polycyclic aromatic hydrocarbons: Bees, honey and pollen as sentinels for environmental chemical contaminants

Three beehive matrices, sampled in six different apiaries from West France, were analyzed for the presence of four polycyclic aromatic hydrocarbons (PAH4: benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene and chrysene). Samples were collected during four different periods in both 2008 and 2009. Honey samples showed the lowest levels of PAH4 contamination (min=0.03 μg kg(-1); max=5.80 μg kg(-1); mean=0.82 μg kg(-1); Sd=1.17). Bee samples exhibited higher levels of PAH4 contamination (min=0.32 μg kg(-1); max=73.83 μg kg(-1); mean=7.03 μg kg(-1); Sd=17.83) with a great dispersion of the concentrations due to four main events of high concentrations. Pollen samples showed only one major episode with the highest PAH4 concentration found (min=0.33 μg kg(-1); max=129.41 μg kg(-1); mean=7.10 μg kg(-1); Sd=22.28). The PAH4 concentrations found were significantly influenced by the landscape context for all beehive samples.

Synthesis of three-arm star block copolymers

We describe the synthesis and characterization of three-arm star block copolymers based on polystyrene, poly(ethylene oxide), poly(ϵ-caprolactone), poly(methyl methacrylate), poly(tert-butyl methacrylate) and poly(L-lactide) blocks. The copolymers were obtained by a route consisting of two successive initiation steps on functional macroinitiator. Some results on micellization and crystallization are given. They indicate an increase in the miscibility of different incompatible blocks.

Adsorption of triarm starblock copolymers based on polystyrene, poly(ethylene oxide) and poly(ϵ-caprolactone) at the solid-solution interface

Abstract Triarm starblock copolymers of ABC type and AB diblock copolymers, where A, B and C are respectively poly(ethylene oxide) (PEO), polystyrene (PS) and poly(ϵ-caprolactone) (PCL) blocks, having molecular weights in the range 24 700–260 000, were prepared by anionic polymerization in tetrahydrofuran. The copolymer adsorption onto titanium dioxide particles in toluene was studied in the concentration range 0.1–30 g dm −3 . The proton NMR experimental results indicate that the copolymers were adsorbed by titanium dioxide via the PEO block. For the diblock copolymer the measured maximum adsorbed amount Γ and the surface density σ were larger than those observed for the corresponding star copolymer. For star copolymers having the same number of repeat units of PS and PEO blocks ( N PS and N PEO ) Γ and σ were found to increase with decreasing size of PCL block N PCL . Furthermore, the estimated average spacing Σ between the adsorbed chains was found to increase with N PCL , indicating that in the adsorbing layer the PCL arms were close together and stretched.