Randy wrote: So why don't we carefully review the scientific (as well as on-the-ground) > evidence to date as to the long-term effects of the strong binding affinity > of neonics on either individual honey bees, honey bee colonies, or other > organisms? But let's not waste the List's time. I suggest that we cite > actual data--not papers in which someone is citing someone else's opinion. > James kindly offered an interesting paper, free access, which you have not commented on. It is a radioactive labelling plus quantitative analysis and something we could discuss beyond Suchail. It is also ten years more recent work. From the abstract: key to understanding their risk is whether the astonishingly low levels found in the nectar and pollen of plants is sufficient to deliver neuroactive levels to their site of action: the bee brain. Here we show that bumblebees (*Bombus terrestris audax*) fed field levels [10 nM, 2.1 ppb (w/w)] of neonicotinoid accumulate between 4 and 10 nM in their brains within 3 days. Acute (minutes) exposure of cultured neurons to 10 nM clothianidin, but not imidacloprid, causes a nicotinic acetylcholine receptor-dependent rapid mitochondrial depolarization. However, a chronic (2 days) exposure to 1 nM imidacloprid leads to a receptor-dependent increased sensitivity to a normally innocuous level of acetylcholine, which now also causes rapid mitochondrial depolarization in neurons. Finally, colonies exposed to this level of imidacloprid show deficits in colony growth and nest condition compared with untreated colonies. These findings provide a mechanistic explanation for the poor navigation and foraging observed in neonicotinoid treated bumblebee colonies. So, if the concentrations over three days are increasing in the brain and not being metabolized then I think this points to their being "irreversibily" bound. Also from the discussion: In this study, we demonstrate the delivery of neuroactive levels of imidacloprid to the brains of bumblebees fed at a field realistic level for 3 days. Brain levels were determined by both the use of a radioactive tracer and LC-MS to confirm, beyond doubt, the existence of active parental compound in the brain. This is likely an underestimate of exposure to active ingredient as the imidacloprid metabolite, olefin, is neuroactive in bees I include that quote because of your recent point about the hydroxy metabolite would still have the radioactive tracer. The authors of this study do not seem to use radioactive tracing as more than an indication of presence. They actually quantify the amounts with LC-MS. I am not surprised that James did not thoroughly read the study. It is not very reader friendly, and I also was not that thorough. But it does seem to have been done fairly meticulously and the doses are definitely field relevant and the sample size is sufficient for statisical analysis. Stan Stan *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html