LIPID-CONTENT AND TIME-TO-DEATH-DEPENDENT LETHAL BODY BURDENS OF NAPHTHALENE AND 1,2,4-TRICHLOROBENZENE IN FATHEAD MINNOW (PIMEPHALES-PROMELAS)

For naphthalene (NAPH) and 1,2,4-trichlorobenzene (TCBz), lethal body burdens (LBB) of 8 +/- 3.1 mmol/kg wet wt (ww) and 14 +/- 4.5 mmol/kg (ww), respectively, were determined in fathead minnow (Pimephales prom elas), LBBs of both compounds were found to increase with increasing l ipid content and time-to-death of fish within the same aquarium, The c orrelation with time-to-death suggests that besides lipid content at l east one other factor causes intraspecies variation in LBBs, When intr aspecies variation is excluded by comparing mean LBBs from different a quaria and exposure regimes, LBBs still vary with time-to-death. In co ntrast to the situation within one aquarium, between different aquaria and exposure regimes often a decrease in LBB with time-to-death is fo und, The present study and others indicate that LBBs can vary with tim e-to-death, Therefore, a time-independent LBB cannot be assumed. (C) 1 997 Academic Press.