Residue, distribution and degradation of neonicotinoids and their metabolites in chrysanthemum plants and cultivated soils

Abstract

In this study, the residue, distribution, adsorption and degradation of neonicotinoids were systematically evaluated in chrysanthemum planting sites. There were low residues of neonicotinoids in plants (<19.35 μg kg−1) and cultivated soils (<11.45 μg kg−1) without use of neonicotinoids in the past three years, but high residues were found in other chrysanthemum plants (304.66–582.15 μg kg−1) and soils (126.44–275.45 μg kg−1). Leaf and soil were more likely to accumulate neonicotinoids. The residues of imidacloprid and its metabolites in plants and soils showed positive correlations. Additionally, neonicotinoids were weakly adsorbed by soil (KOC = 249–509 L kg−1), and the degradation half-lives were 20–36 days. High residues of imidacloprid in soils had serious ecological risk to the organisms in the planting regions. It reminds us to pay more attention to neonicotinoids residues in the plants and the growing environment, which is of great significance for ensuring human dietary safety and reducing environmental risks.