New Study by Dr. Lu on Neonic Residues in Pollen & Honey
Friday, July 31, 2015
Previous studies conducted by Dr. Chensheng Lu have tried unsuccessfully to establish linkage between neonicotinoids and honey bee colony decline and his most recent publication is no exception. Reviews of his earlier studies found significant flaws in the experimental design. Although some questions remain regarding the methodology used in this latest study, our main concern is with its interpretation of the results and its attempt to draw conclusions that cannot be supported by the data.
A quick review of the data shows that the majority of samples collected had only small amounts of neonicotinoid residues in pollen and honey (less than one part per billion), which are well below levels* that could cause harm to honey bee colonies. Despite this, the paper claims – without any evidence – that these low exposures are somehow related to Colony Collapse Disorder (CCD), a symptom that most bee experts agree has not been seen in U.S. colonies in many years.
Earlier this year, results from a far more comprehensive three-year study
conducted by the University of Maryland, the U.S. Environmental Protection Agency and the U.S. Department of Agriculture confirmed what other field research has already shown – that field-relevant exposures of neonicotinoids, including the levels measured in this latest study by Lu et al., have negligible effects on honey bee health.
*Technical support: Previous studies conducted under Good Laboratory Practice regulations for product registration have established no effect concentrations of >20 ppb for honey bee colonies subjected to long-term dietary exposure to neonicotinoids. A recent study with imidacloprid conducted in accordance with a new EPA-approved protocol determined the no-effect concentration to be 25 ppb. Field-relevant concentrations that bees might be exposed to in agricultural settings are generally below 10 ppb (Blacquierre et al. 2012; Godfray et al. 2014) and there is no consistent evidence that exposure levels below 10 ppb represent a risk to the survival of honey bee colonies (Cresswell et al. 2012; Godfray et al. 2014; Dively et al. 2015). The new study by Lu et al. found that residues levels in pollen and nectar collected by honey bees in Massachusetts averaged 0.7 ppb in pollen and 0.6 ppb in honey, with most samples of both honey and pollen containing residues below 0.1 ppb. It can therefore be concluded, that the exposure levels documented by Lu et al. pose no significant risk to honey bee colonies. Statements to the effect that the results of this study are cause for concern for honey bees have no scientific basis.
Blacquierre T, G Smagghe, C van Gestel and V Mommaerts. 2012. Neonicotinoids in bees: a review on concentrations, side effects and risk assessment. Ecotoxicology DOI 10.1007/s10646-012-0863-x.
Cresswell J, N Desneux and D vanEngelsdorp. 2012. Dietary traces of neonicotinoid pesticides as a cause of population declines in honey bees: an evaluation by Hill’s epidemiological criteria. Pest Manag Sci 68:819-827.
Dively G, M Embry, A Kamel, D Hawthorne, J Pettis. 2015. Assessment of chronic sublethal effects of imidacloprid on honey bee colony health. PloS ONE 10(3): e0118748.
Godfray H, T Blacquierre, L Field, R Hails, G Petrokofsky, S Potts, N Raine, A Vanbergen and A McLean. 2014. A restatement of the natural science evidence base concerning neonicotinoid insecticides and insect pollinators. Proc. R. Soc. B 281:20140558.
Lu, C, C-H Chang, L Tao and M Chen. 2015. Distributions of neonicotinoid insecticides in the Commonwealth of Massachusetts: a temporal and spatial variation analysis for pollen and honey samples. Environ Chem http://dx.doi.org/10/1071/EN15064.