Swimming speed in 96 hpf zebrafish larvae after exposure to POP and PFOS at two different concentrations (10× and 70× higher than human serum level) between 48 to 96 hpf. In order to expose the zebrafish for gene expression analyses, concentrations were adjusted to 10× and 70× human serum level as the highest dose at which there was no significant effect on swimming speed (HNSS) or the lowest dose that consistently and significantly increased the swimming speed (LISS), respectively. Data presented as mean ± SD. An asterisk indicates a significant difference between the exposure group and the solvent control (LME, * = p < 0.017, ** = p < 0.0017, *** = p < 0.0001).