Neonicotinoid insecticide residues in soil dust and associated parent soil in fields with a history of seed treatment use on crops in southwestern Ontario

Abstract

Using neonicotinoid insecticides as seed treatments is a common practice in field crop production. Exposure of nontarget organisms to neonicotinoids present in various environmental matrices is debated. In the present study, concentrations of neonicotinoid residues were measured in the top 5 cm of soil and overlying soil surface dust before planting in 25 commercial fields with a history of neonicotinoid seed treatment use in southwestern Ontario in 2013 and 2014 using liquid chromatography-electrospray ionization tandem mass spectrometry. The mean total concentrations were 3.05 ng/g and 47.84 ng/g in 2013 and 5.59 ng/g and 71.17 ng/g in 2014 for parent soil and soil surface dust, respectively. When surface and parent soil residues were compared the mean concentration in surface dust was 15.6-fold and 12.7-fold higher than that in parent soil in 2013 and 2014, respectively. Pooled over years, the surface dust to parent soil ratio was 13.7, with mean concentrations of 4.36 ng/g and 59.86 ng/g for parent soil and surface dust, respectively. The present study's results will contribute important knowledge about the role these residues may play in the overall risk assessment currently under way for the source, transport, and impact of neonicotinoid insecticide residues in a maize ecosystem.

Meta-analysis reveals that seed-applied neonicotinoids and pyrethroids have similar negative effects on abundance of arthropod natural enemies

“…The relative importance of the various exposure pathways in the field is unclear, but we did see a non-significant trend for soil-dwelling taxa to be more strongly affected than foliar-dwelling taxa. Typically ∼90% of seed-applied neonicotinoids remain in soil, rather than entering the growing crop plant (Goulson, 2013), and recent findings reveal a layer of elevated residues on the soil surface where many species are active (Limay-Rios et al, 2016). Soil exposures, therefore, appear to be an important area for future research, particularly because previous research has leaned toward foliar-dwelling taxa.…”

The Environmental Risks of neonicotinoid pesticides: a review of the evidence post-2013

“…Neonicotinoids not previously applied in the previous three years (predominantly imidacloprid) were detected in 14 of the 18 fields. Limay-Rios et al (2015) analysed soil samples collected in the springs of 2013 and 2014 from 25 agricultural fields in Ontario, Canada before crops were sown and found average concentrations of 3.45 ng/g of clothianidin and 0.91 ng/g thiamethoxam, with total average neonicotinoid concentration of 4.36 ng/g, similar to the findings of Jones et al (2014). Botías et al (2015) analysed soil samples from seven winter-sown oilseed rape and five winter-sown wheat fields collected in summer 2013, 10 months after the crops were sown.…”

Acute toxicity of 6 neonicotinoid insecticides to freshwater invertebrates

“…Transport of neonicotinoids to aquatic environments is typically driven by precipitation events (Hladik and Kolpin 2016;Struger et al 2017), snowmelt (Main et al 2016), and contaminated dust (Limay-Rios et al 2016). Median neonicotinoid surface water concentrations are on the order of ng L À1 , with peak concentrations rising to low mg L À1 .…”