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Comparative behavioral ecotoxicology of Inland Silverside larvae exposed to pyrethroids across a salinity gradient

October 17, 2022

Pyrethroids, a class of commonly used insecticides, are frequently detected in aquatic environments, including estuaries. The influence that salinity has on organism physiology and the partitioning of hydrophobic chemicals, such as pyrethroids, has driven interest in how toxicity changes in saltwater compared to freshwater. Early life exposures in fish to pyrethroids cause toxicity at environmentally relevant concentrations, which can alter behavior. Behavior is a highly sensitive endpoint that influences overall organism fitness and can be used to detect toxicity of environmentally relevant concentrations of aquatic pollutants. Inland Silversides (Menidia beryllina), a commonly used euryhaline model fish species, were exposed from 5 days post fertilization (~1-day pre-hatch) for 96 h to six pyrethroids: bifenthrin, cyfluthrin, cyhalothrin, cypermethrin, esfenvalerate and permethrin. Exposures were conducted at three salinities relevant to brackish, estuarine habitat (0.5, 2, and 6 PSU) and across 3 concentrations, either 0.1, 1, 10, and/or 100 ng/L, plus a control. After exposure, Inland Silversides underwent a behavioral assay in which larval fish were subjected to a dark and light cycle stimuli to determine behavioral toxicity. Assessment of total distanced moved and thigmotaxis (wall hugging), used to measure hyper/hypoactivity and anxiety like behavior, respectively, demonstrate that even at the lowest concentration of 0.1 ng/L pyrethroids can induce behavioral changes at all salinities. We found that toxicity decreased as salinity increased for all pyrethroids except permethrin. Additionally, we found evidence to suggest that the relationship between log KOW and thigmotaxis is altered between the lower and highest salinities.

Citation Information

Publication Year 2022
Title Comparative behavioral ecotoxicology of Inland Silverside larvae exposed to pyrethroids across a salinity gradient
DOI 10.1016/j.scitotenv.2022.159398
Authors Sara Hutton, Samreen Siddiqui, Emily Pedersen, Christopher Markgraf, Amelie Segarra, Michelle Hladik, Richard E Connon, Susanne M. Brander
Publication Type Article
Publication Subtype Journal Article
Series Title Science of the Total Environment
Index ID 70237762
Record Source USGS Publications Warehouse
USGS Organization California Water Science Center