Travis S Schmidt

Imidacloprid in United States Rivers, 2013–2022: Persistent Presence and Emerging Chronic Hazard Imidacloprid, a neonicotinoid insecticide, is used for agricultural and nonagricultural purposes and is toxic to nontarget organisms at low concentrations in aquatic ecosystems. A total of 12,547 water samples were collected from 2013 to 2022 from 77 rivers across the United States (U.S.) and were analyzed to evaluate detections and temporal trends in imidacloprid concentrations. Imidacloprid was detected in 44% of all samples, and the mean concentration, adjusted for nondetect samples, of 24.9 ng/L (median = 11.9 ng/L) was more than twice the chronic benchmark for freshwater invertebrates (10 ng/L). This potential hazard to aquatic life was persistent, with 44% of the sites having a median concentration exceeding the chronic benchmark. Half of the sites (n = 38) had increasing trends, including large river sites along the Mississippi River. The mean increase was 10.6 ng/L over the past decade, while only six sites indicated decreasing trends. The estimated total loading of imidacloprid delivered to the Gulf of America from 2013 to 2022 was 129,489 kg (142.7 U.S. ton). The extensive presence of imidacloprid in U.S. waterways, the high percentage of sites with trends of increasing concentrations, and the prevalence of concentrations exceeding chronic benchmarks suggest widespread persistent risks to ecosystem health.

pubs.acs.org/doi/10.1021/...

Sometimes you set out to ask one question and you end up addressing something different. Here is an example of that where we set out to synthesize US biomonitoring data and pesticide data and ended up asking a biodiversity question. Fun working with this team!

Our research group just published a study in Nature on how fish biodiversity in U.S. rivers and streams has been changing over the past 27 years (1993–2019). The results show sharply diverging trends depending on historic and changing water temperature. 🧵 rdcu.be/eH0l8

Multiple lines of evidence point to pesticides as stressors affecting invertebrate communities in sm... Multistressor studies were performed in five regions of the United States to assess the role of pesticides as stressors affecting invertebrate communi…

New paper!

A causal assessment of pesticide impacts to streams of the United States.