Tissue distribution of 14C-labeled residues of aminocarb in brown bullhead (Ictalurus nebulosus Le Sueur) following acute exposure.

Young brown bullhead (Ictalurus nebulosus) were exposed to aminocarb (4-dimethylamino-3-methylphenyl N-methylcarbamate) at lethal and sublethal concentrations and the tissue distribution of total unspecified residues was examined. The concentration of residues in each tissue increased with the concentration of exposure. The liver and stomach/intestine accumulated the largest concentrations of residues of all the tissues studied except for the abdominal fat deposit, which could not be evaluated at all exposure concentrations. These two tissues also displayed a steady increase in the proportion of the total body burden of aminocarb residues during 4 days of exposure to 0.092 mg aminocarb/liter. The proportion of residues in the carcass at this level of exposure decreased steadily over this same period, but was more similar to that found during exposure at the two lethal concentrations (92.7 and 159.3 mg/liter) as opposed to that found at the intermediate, nonlethal exposure level of 41.1 mg/liter. For all tissues examined, the concentration of residues at the end of 4 days of exposure to 0.092 mg/liter was significantly lower than the peak concentration reached during the exposure period, and clearance of residues was found to be relatively rapid.