Meeting Abstract

P3-9  Monday, Jan. 6  Cross-taxa Distinctions in Developmental Effects of Trifluralin Exposure between Representative Toxicological Species for Aquatic Risk Assessment AWKERMAN, JA*; LAVELLE, CM; HENDERSON, WM; HEMMER, BL; LILAVOIS, CR; HARRIS, P; ZIELINSKI, N; HOGLUND, MD; GLINSKI, DA; MACMILLAN, D; FORD, J; SEIM, RF; Gulf Ecology Division, US EPA, Gulf Breeze, FL ; Gulf Ecology Division, US EPA, Gulf Breeze, FL ; Exposure Methods and Management Div, US EPA, Athens, GA ; Gulf Ecology Division, US EPA, Gulf Breeze, FL ; Gulf Ecology Division, US EPA, Gulf Breeze, FL ; Gulf Ecology Division, US EPA, Gulf Breeze, FL ; Gulf Ecology Division, US EPA, Gulf Breeze, FL ; Gulf Ecology Division, US EPA, Gulf Breeze, FL ; Exposure Methods and Management Div, US EPA, Athens, GA ; Research Cores Unit, US EPA, RTP, NC ; Research Cores Unit, US EPA, RTP, NC ; Exposure Methods and Management Div, US EPA, Athens, GA awkerman.jill@epa.gov

Standard ecological risk assessment practices often rely on larval and juvenile fish toxicity data as representative of the amphibian aquatic stage. This study compares developmental endpoints for zebrafish (Danio rerio) and the African clawed frog (Xenopus laevis), two standard test species, exposed to the herbicide trifluralin for 30 and 70 days, respectively. D. rerio were more sensitive in acute toxicity and demonstrated a reduction in growth measurements with increasing trifluralin exposure. Growth measurements in X. laevis at metamorphosis were not correlated with exposure; however, time to metamorphosis was delayed relative to trifluralin concentration. Species-specific gene expression patterns suggest that different biological pathways in D. rerio and X. laevis are perturbed by trifluralin exposure. Non-targeted hepatic metabolomics also identified a subset of metabolites that exhibited a non-monotonic response to trifluralin exposure in X. laevis. Linking differential cellular response with taxonomic distinctions in ecologically relevant endpoints will refine assumptions used in inter-species extrapolation of exposure effects and improve assessment of sublethal impacts on amphibian populations.