Bioaccumulation of the pesticide imidacloprid in stream organisms and sublethal effects on salamanders

Global Ecology and Conservation
By: , and 



Neonicotinoids are one of the most widely used classes of insecticides in the world. The neonicotinoid imidacloprid is commonly applied to hemlock (Tsuga spp.) stands in eastern North America to reduce tree mortality from infestations of the invasive hemlock woolly adelgid (HWA; Adelges tsugae). While laboratory and mesocosm studies have determined that imidacloprid can bioaccumulate in anurans and cause sublethal effects, no field studies have investigated whether salamanders or insects in streams adjacent to HWA treatments bioaccumulate imidacloprid or if sublethal effects are detectable in wild salamanders. We assessed relationships between imidacloprid exposure and stream salamander health in West Virginia, USA, using concentration of the stress hormone corticosterone and body condition indices (BCI) as response variables. Of 107 Desmognathus salamanders from 11 sites tested for bioaccumulation, we detected imidacloprid in 47 salamanders. Of 15 benthic macroinvertebrate samples tested, we detected imidacloprid, imidacloprid-urea, and imidacloprid-olefin in 15, 13, and 1 sample, respectively. Based on 115 Desmognathus salamanders sampled at 11 sites for stress hormone responses, corticosterone concentration increased with imidacloprid concentration in stream water. For 802 salamanders sampled at 48 sites, BCI decreased as concentration of imidacloprid in stream water increased, but explanatory power was low. Our study suggests that chronic leaching of imidacloprid from treated hemlock stands into adjacent streams has the potential to negatively affect aquatic organisms and may provide a route of exposure to higher trophic levels.

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Publication type Article
Publication Subtype Journal Article
Title Bioaccumulation of the pesticide imidacloprid in stream organisms and sublethal effects on salamanders
Series title Global Ecology and Conservation
DOI 10.1016/j.gecco.2020.e01292
Volume 24
Year Published 2020
Language English
Publisher Elsevier
Contributing office(s) Coop Res Unit Leetown
Description e01292, 15 p.
First page 1
Last page 15
Country United States
State West Virginia
Other Geospatial Gauley River National Recreational Area, Monongahela National Forest, New River Gorge National River
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