Rainbow trout were exposed for 72 h to (14C)anthracene alone and (14C)anthracene in an oil shale retort water. Tissue levels of (14C)anthracene were analyzed at 24, 48 and 72 h to determine non-steady-state bioconcentration factors (BCFs), and uptake and depuration rates were calculated from anthracene disappearance in exposure waters and metabolite appearance in depuration waters. Uptake rates (14.6 to 16.9/h) were similar to previously reported values; however, depuration rates (0.00158 to 0.00188/h) were very low. Consequently, measured non-steady-state BCFs after 72 h (9,000 to 9,200) for anthracene were higher than expected, probably because fish were not fed and had low excretion rates. Measured and estimated anthracene BCFs were lower in retort water exposures than in single-compound exposures because of slower uptake and faster depuration. (Copyright (c) 1985 SETAC.)