title: Neonicotinoid insecticide residues in surface water and soil associated with commercial maize (corn) fields in southwestern Ontario.
abstract: Neonicotinoid insecticides have come under scrutiny for their potential unintended effects on non-target organisms, particularly pollinators in agro-ecosystems. As part of a larger study of neonicotinoid residues associated with maize (corn) production, 76 water samples within or around the perimeter of 18 commercial maize fields and neighbouring apiaries were collected in 5 maize-producing counties of southwestern Ontario. Residues of clothianidin (mean = 2.28, max. = 43.60 ng/mL) and thiamethoxam (mean = 1.12, max. = 16.50 ng/mL) were detected in 100 and 98.7% of the water samples tested, respectively. The concentration of total neonicotinoid residues in water within maize fields increased six-fold during the first five weeks after planting, and returned to pre-plant levels seven weeks after planting. However, concentrations in water sampled from outside the fields were similar throughout the sampling period. Soil samples from the top 5 cm of the soil profile were also collected in these fields before and immediately following planting. The mean total neonicotinoid residue was 4.02 (range 0.07 to 20.30) ng/g, for samples taken before planting, and 9.94 (range 0.53 to 38.98) ng/g, for those taken immediately after planting. Two soil samples collected from within an conservation area contained detectable (0.03 and 0.11 ng/g) concentrations of clothianidin. Of three drifted snow samples taken, the drift stratum containing the most wind-scoured soil had 0.16 and 0.20 ng/mL mainly clothianidin in the melted snow. The concentration was at the limit of detection (0.02 ng/mL) taken across the entire vertical profile. With the exception of one sample, water samples tested had concentrations below those reported to have acute, chronic or sublethal effects to honey bees. Our results suggest that neonicotinoids may move off-target by wind erosion of contaminated soil. These results are informative to risk assessment models for other non-target species in maize agro-ecosytems.
authors.affiliation: Department of Plant Agriculture, University of Guelph, Ridgetown Campus, Ridgetown, ON, Canada.
authors.forename: Arthur
authors.initials: A
authors.lastname: Schaafsma
authors.affiliation: Department of Plant Agriculture, University of Guelph, Ridgetown Campus, Ridgetown, ON, Canada.
authors.forename: Victor
authors.initials: V
authors.lastname: Limay-Rios
authors.affiliation: Ontario Ministry of Agriculture Food and Rural Affairs, Ridgetown, ON, Canada.
authors.forename: Tracey
authors.initials: T
authors.lastname: Baute
authors.affiliation: Department of Plant Agriculture, University of Guelph, Ridgetown Campus, Ridgetown, ON, Canada.
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Smith
authors.affiliation: Department of Plant Agriculture, University of Guelph, Ridgetown Campus, Ridgetown, ON, Canada.
authors.forename: Yingen
authors.initials: Y
authors.lastname: Xue
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005618:Fresh Water / Q000737:chemistry*; D006146:Guanidines / Q000032:analysis / Q000302:isolation & purification; D007306:Insecticides / Q000032:analysis* / Q000302:isolation & purification; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000032:analysis / Q000302:isolation & purification; D009864:Ontario; D010078:Oxazines / Q000032:analysis / Q000302:isolation & purification; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000302:isolation & purification; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry; D000077922:Thiamethoxam; D013844:Thiazoles / Q000032:analysis / Q000302:isolation & purification; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification; D003313:Zea mays / Q000254:growth & development
chemical_list: D006146:Guanidines; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D012987:Soil; D012989:Soil Pollutants; D013844:Thiazoles; D014874:Water Pollutants, Chemical; C480342:clothianidin; D000077922:Thiamethoxam