Temporal pattern in levels of the neonicotinoid insecticide, imidacloprid, in an urban stream.

Temporal pattern in levels of the neonicotinoid insecticide, imidacloprid, in an urban stream. Chemosphere. 2019 May;223:83-90 Authors: Batikian CM, Lu A, Watanabe K, Pitt J, Gersberg RM Abstract Imidacloprid is a widely used insecticide with high runoff potential posing a significant threat to aquatic ecosystems. In order to determine the spatial and temporal concentrations of imidacloprid in Forester Creek, a tributary to the San Diego River, surface water samples were collected from two sites under wet-weather and dry-weather conditions. Solid phase extraction and liquid chromatography tandem mass spectrometry were utilized to quantify imidacloprid levels in all samples. Imidacloprid was detected with 100% frequency in surface water samples from Forester Creek with a median concentration of 16.9 ng/L (range: 3.8-96.8 ng/L). Over 60% of samples exceeded U.S. EPA's chronic exposure benchmark (10 ng/L). Temporal analysis displayed significantly higher levels in wet-weather than dry-weather (median 45.6 ng/L vs. 8.2 ng/L (p < 0.05)), demonstrating the influence of wet-weather runoff on stream quality. Imidacloprid generally followed a first flush pattern with the highest levels observed on the rising portion of the hydrograph as compared to the remainder of the storm, further indicating that the build-up and wash off from land surfaces during storms is a major source of imidacloprid into urban surface waters. To our k...
Source: Chemosphere - Category: Chemistry Authors: Tags: Chemosphere Source Type: research