Neonicotinoid insecticides are of concern in the environment, but little is known about their overall occurrence. Neonicotinoids are commonly used in both agricultural and urban settings, but most current research has focused on their fate near the point of application. These compounds are water soluble (log Kow <1) and have aqueous half-lives on the order of months, so they have the potential for offsite transport. More information on their occurrence in water is needed to  understand better the possible environmental effects of these insecticides. Water samples were collected from two different climatic, geographical, and land use regions in the United States (Georgia and Iowa) and analyzed for six neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam). Two streams in Georgia, one draining a predominantly urban area and the other integrating a mixture of land uses (urban, forested, limited agriculture), were sampled bi-monthly for one year. Imidacloprid was detected in both streams and in all seasons except for late fall, with the urban stream having more frequent detections and higher concentrations. The Iowa locations consisted of select streams in agricultural areas (e.g., corn and soybeans) that were sampled in spring (May) and summer (July) during runoff conditions. The spring samples had detections of neonicotinoids associated with seed treatments (clothianidin, imidacloprid, thiamethoxam) while the summer samples also had detections of one associated with aerial applications (acetamiprid). The frequencies of detection and concentrations were generally higher in the spring compared to the summer samples. An additional set of samples was collected at a wastwater-impacted Iowa stream during winter low flow conditions (stream flow approximately 99% effluent at this time). Results document fairly conservative transport of chlothianidin and imidacloprid over an 8 km reach. Concentrations during such winter conditions indicate these compounds can persist long after initial application and are also present in wastewater.

Occurrence of neonicotinoid insecticides in water in two US regions

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.