Quantification of neonicotinoid residues in soils and dust drift in conservation reserve program fields in Illinois, USA

Neonicotinoids, a new class of systematic insecticides, are commonly used as seed coat treatment for crop protection. In the United States, neonicotinoid-treated seeds are planted on most corn acres and over half of the soybean acres. Neonicotinoids are also registered to use on other major field crops, such as cotton and wheat. Increasing attention has been paid to the extensive use of neonicotinoids, considering that empirical evidence has shown that neonicotinoids can affect bee longevity and behavior. Furthermore, dust drift from neonicotinoid-treated seeds has been implicated in acute bee mortality. As has been documented in the literature, dust drift can disperse over a considerable distance from farm sites and settle into surrounding habitats. A number of studies have reported the detection of neonicotinoid residues in the non-target environment. In recent years, the U.S. Conservation Reserve Program (CRP) has been converting retired croplands into conservation habitats designed to restored pollinators through an initiative called Conservation Practice 42 (CP-42) Pollinator Habitat Establishment. However, little is known about the exposure risks of neonicotinoids to pollinators foraging at CP-42 habitats in agricultural landscapes. Potentially subjecting to dust drift, CP-42 habitats may be receiving a constant input of airborne neonicotinoids throughout the planting season. Furthermore, legacy neonicotinoid residues may persist in the soil of CP-42 habitats. In the study, soil and dust samples were collected from multiple CP-42 habitats located in east-central Illinois to survey for the presence of neonicotinoid residues. The field surveys were conducted in the spring planting season of 2019 and 2020. The objectives of the study were 1) to examine temporal variations of neonicotinoid concentrations in soil and airborne dust samples and 2) to determine the influence of airborne neonicotinoid inputs on surface soil contamination. Our data indicate that the levels of neonicotinoid residues in soil and dust drift are variable over time and space. However, surface soil neonicotinoid concentrations did not change significantly over time. Although the influence of airborne neonicotinoid inputs on surface soil contamination was small, individual deposition events were observed containing a high dose of neonicotinoids for bees. Measures should be taken to protect pollinators in agroecosystems and mitigate dust drift.U of I OnlyAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD syste