Multigenerational,
Indirect Exposure to Pyrethroids
Demonstrates Potential Compensatory Response and Reduced Toxicity
at Higher Salinity in Estuarine Fish
posted on 2024-01-25, 01:06authored bySara J. Hutton, Samreen Siddiqui, Emily I. Pedersen, Christopher Y. Markgraf, Amelie Segarra, Michelle L. Hladik, Richard E. Connon, Susanne M. Brander
Estuarine environments
are critical to fish species and
serve as
nurseries for developing embryos and larvae. They also undergo daily
fluctuations in salinity and act as filters for pollutants. Additionally,
global climate change (GCC) is altering salinity regimes within estuarine
systems through changes in precipitation and sea level rise. GCC is
also likely to lead to an increased use of insecticides to prevent
pests from damaging agricultural crops as their habitats and mating
seasons change from increased temperatures. This underscores the importance
of understanding how insecticide toxicity to fish changes under different
salinity conditions. In this study, larval Inland Silversides (Menidia beryllina) were exposed to bifenthrin (1.1
ng/L), cyfluthrin (0.9 ng/L), or cyhalothrin (0.7 ng/L) at either
6 or 10 practical salinity units (PSU) for 96 h during hatching, with
a subset assessed for end points relevant to neurotoxicity and endocrine
disruption by testing behavior, gene expression of a select suite
of genes, reproduction, and growth. At both salinities, directly exposed
F0 larvae were hypoactive relative to the F0 controls; however, the
indirectly exposed F1 larvae were hyperactive relative to the F1 control.
This could be evidence of a compensatory response to environmentally
relevant concentrations of pyrethroids in fish. Effects on development,
gene expression, and growth were also observed. Overall, exposure
to pyrethroids at 10 PSU resulted in fewer behavioral and endocrine
disruptive effects relative to those observed in organisms at 6 PSU.