10 ppb in nectar seems high but in pollen possible, probably due to flying dust on flowers next to the field during plantation of imid protected seeds.

See Neonicotinoids in bees (2012) : a review on concentrations, side-effects and risk assessment from Tjeerd Blacquiere, Guy Smagghe, Cornelis A. M. van Gestel, Veerle Mommaerts 
The average imidacloprid residue levels in positive pollen samples ranged between 0.9 and 3.1 µg/kg, while levels in honey and beeswax were generally lower.
But in : Mullin CA, Frazier M, Frazier JL, Ashcraft S, Simonds R, et al. (2010) High Levels of Miticides and Agrochemicals in North American Apiaries : Implications for Honey Bee Health. PLoS ONE 5(3): e9754. doi:10.1371/journal.pone.0009754
Imidacloprid is found in 2 samples of wax out of 208 samples at 13.6 and 2.4 ppb. In 10 samples of pollen out of 350 samples imidacloprid is found at max 206 ppb min 6.2 ppb, median 20.5 ppb. In bee no detection out of 140 samples.

Georges France

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