29 Oct 2025

A Multigenerational Exposure of the Zebrafish (Danio rerio) to PFOS

Abstract: The ecological risk of PFOS in extended chronic and multigenerational exposures was quantified through survival, growth, reproduction, and vitellogenin (egg yolk protein precursor) responses as well as PFOS bioconcentration in zebrafish (Danio rerio). Fish were exposed to environmentally relevant PFOS concentrations through 180 days postfertilization (dpf) in the parental (P) and first filial (F1) generations and 16 dpf in the second filial (F2) generation. Survival decreased significantly in P and F2 generation exposures, but not F1, at the highest PFOS treatment. Significant adverse effects on body weight and length occurred predominantly at highest exposure treatment. Finally, PFOS had no significant effects on P or F1 egg production and survival or whole-body vitellogenin levels in P or F1 male fish. The present investigation indicated a threshold for ecologically relevant adverse effects in zebrafish at 119 μg/L (standard deviation [S.D.] 23 μg/L, n = 10) for survival and 87 μg/L (S.D. 48 μg/L, n = 19) for all statistically significant negative effects observed. Importantly, males had significantly increased PFOS accumulation and bioconcentration factors versus females in both P and F1 generations. PFOS transfer to eggs was not a depuration pathway. Finally, a toxicokinetic model was developed to reliably predict PFOS whole-body burdens.

1 Aug 2024

Detection and Decay of Different Classes of Environmental RNA (eRNA) from Zebrafish (Danio rerio)

Purpose: This technical note contributes to the growing body of knowledge about macroscopic eukaryotic environmental RNA (eRNA) by exploring detection and decay for several different zebrafish (Danio rerio) eRNAs in a mesocosm setting. The study addressed four basic hypotheses: (1) D. rerio would deposit detectable levels of eRNA into water, (2) different classes of eRNA would be detected, (3) different eRNA sequences (for example, loci) would degrade at different rates, and (4) abiotic and biotic factors would influence rates of degradation. For the last hypothesis, we tracked eRNA concentration decay under treatments with different water temperatures and levels of microbiological activity, two factors known to significantly influence environmental DNA (eDNA) decay (Barnes et al. 2014; Lance et al. 2017; Nielsen et al. 2007; Strickler et al. 2015).