https://www.nature.com/articles/s41598-017-03467-5.pdf

Noa Simon-Delso1, Gilles San Martin 2, Etienne Bruneau1, Christine Delcourt1
& Louis
Hautier2

1Beekeeping Research and Information Centre (CARI), Place Croix du Sud 1,
Bte L7.04.01 1348, Louvain-la-Neuve,
Belgium. 2Walloon Agricultural Research Centre, Life Sciences Department,
Plant Protection and Ecotoxicology Unit,
Rue de Liroux, 2, B-5030, Gembloux, Belgium. Correspondence and requests for
materials should be addressed to 
N.S. (email: [log in to unmask])

Extract

To evaluate the risks of pesticides for pollinators, we must not only
evaluate their toxicity but also
understand how pollinators are exposed to these xenobiotics in the field. We
focused on this last point
and modeled honey bee exposure to pesticides at the landscape level. Pollen
pellet samples (n = 60)
from 40 Belgian apiaries were collected from late July to October 2011 and
underwent palynological and
pesticide residue analyses. Areas of various crops around each apiary were
measured at 4 spatial scales.
The most frequently detected pesticides were the fungicides boscalid (n =
19, 31.7%) and pyrimethanil
(n = 10, 16.7%) and the insecticide dimethoate (n = 10, 16.7%). We were able
to predict exposure
probability for boscalid and dimethoate by using broad indicators of
cropping intensity, but it remained
difficult to identify the precise source of contamination (e.g. specific
crops in which the use of the
pesticide is authorized). For pyrimethanil, we were not able to build any
convincing landscape model
that could explain the contamination. Our results, combined with the late
sampling period, strongly
suggest that pesticides applied to crops unattractive to pollinators, and
therefore considered of no risk
for them, may be sources of exposure through weeds, drift to neighboring
plants, or succeeding crops.

Kind regards,
Ghislain De Roeck,
Belgium.

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