Response and recovery of fathead minnows (Pimephales promelas) following early life exposure to water and sediment found within agricultural runoff from the Elkhorn River, Nebraska, USA

• Published in: The Science of the total environment Vol. 618; pp. 1371 - 1381
• Main Authors: Ali, Jonathan M., D'Souza, Del L., Schwarz, Kendall, Allmon, Luke G., Singh, Rajeev P., Snow, Daniel D., Bartelt-Hunt, Shannon L., Kolok, Alan S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.03.2018
• Subjects: Gene expression; Herbicides; Larval fish; Pesticides; Sediment toxicity; Herbicides; Larval fish; Sediment toxicity; Gene expression; Pesticides
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.09.259

Agricultural runoff is a non-point source of chemical contaminants that are seasonally detected in surface water and sediments. Agrichemicals found within seasonal runoff can elicit endocrine disrupting effects in organisms as adults, juveniles and larvae. The objectives of this study were (1) to determine if exposure to water, sediment or the water-sediment combination collected from an agricultural runoff event was responsible for changes in endocrine-responsive gene expression and development in fathead minnow larvae, and (2) whether such early life exposure leads to adverse effects as adults. Larvae were exposed during the first month post-hatch to water and sediment collected from the Elkhorn River and then allowed to depurate in filtered water until reaching sexual maturity, exemplifying a best-case recovery scenario. Gas chromatography mass spectrometry (GC/MS) analysis of the water and sediment samples detected 12 pesticides including atrazine, acetochlor, metolachlor and dimethenamid. In minnow larvae, exposure to river water upregulated androgen receptor gene expression whereas exposure to the sediment downregulated estrogen receptor α expression. Adult males previously exposed to both water and sediment were feminized through the induction of an ovipositor structure whereas no impacts were observed in other reproductive or sex characteristic endpoints for either sex based on exposure history. Results from this study indicate that both water and sediments found in agricultural runoff elicit responses from minnow larvae, and larvae can recover following early life exposure under a best-case scenario. [Display omitted] •Fathead minnow larvae were exposed to contaminated water and sediment using a factorial design.•Water and sediments were collect from a seasonally occurring agricultural runoff event.•Pesticide concentrations were discordant between the aqueous and sediment matrices as determined by GC/MS analysis.•Larval fish exposure to water and sediment resulted in matrix-specific effects on endocrine-responsive gene expression.•Fish exhibited recovery following early life exposure to contaminated water and sediment.