Of more general interest:
Widespread Use and Frequent Detection of
Neonicotinoid Insecticides in Wetlands of Canada's
Prairie Pothole Region
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092821;j
sessionid=B4A9ACB10ACCCE8248D29FFF6211B8FC
or
http://tinyurl.com/ltt46bo
Abstract
Neonicotinoids currently dominate the insecticide market as seed treatments
on Canada's major Prairie crops (e.g., canola). The potential impact to
ecologically significant wetlands in this dominantly agro-environment has
largely been overlooked while the distribution of use, incidence and level
of contamination remains unreported. We modelled the spatial distribution of
neonicotinoid use across the three Prairie Provinces in combination with
temporal assessments of water and sediment concentrations in wetlands to
measure four active ingredients (clothianidin, thiamethoxam, imidacloprid
and acetamiprid). From 2009 to 2012, neonicotinoid use was increasing; by
2012, applications covered an estimated ~11 million hectares (44% of Prairie
cropland) with >216,000 kg of active ingredients. Thiamethoxam, followed by
clothianidin, were the dominant seed treatments by mass and area. Areas of
high neonicotinoid use were identified as high density canola or soybean
production. Water sampled four times from 136 wetlands (spring, summer, fall
2012 and spring 2013) across four rural municipalities in Saskatchewan
similarly revealed clothianidin and thiamethoxam in the majority of samples.
In spring 2012 prior to seeding, 36% of wetlands contained at least one
neonicotinoid. Detections increased to 62% in summer 2012, declined to 16%
in fall, and increased to 91% the following spring 2013 after ice-off. Peak
concentrations were recorded during summer 2012 for both thiamethoxam
(range: <LOQ - 1490 ng/L, canola) and clothianidin (range: <LOQ - 3110 ng/L,
canola). Sediment samples collected during the same period rarely (6%)
contained neonicotinoid concentrations (which did not exceed 20 ng/L).
Wetlands situated in barley, canola and oat fields consistently contained
higher mean concentrations of neonicotinoids than in grasslands, but no
individual crop singularly influenced overall detections or concentrations.
Distribution maps indicate neonicotinoid use is increasing and becoming more
widespread with concerns for environmental loading, while frequently
detected neonicotinoid concentrations in Prairie wetlands suggest high
persistence and transport into wetlands.
Widespread Use and Frequent Detection of Neonicotinoid Insecticides in
Wetlands of Canada's Prairie Pothole Region
Anson R. Main John V. Headley, Kerry M. Peru, Nicole L. Michel, Allan J.
Cessna, Christy A. Morrissey
Published: March 26, 2014 - DOI: 10.1371/journal.pone.0092821
Kind regards,
Ghislain De Roeck,
Belgium.
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