Uptake, Disposition, and Persistence of Acrylonitrile in Rainbow Trout

Abstract

The uptake and disposition of [2,3-14C]acrylonitrile-derived 14C were studied in rainbow trout by water exposure. Trout were exposed to [14C]ACN at 5.3 μg/liter and sampled at various times during a 24-hr uptake phase. After transfer to fresh water, fish were sampled to 72 hr for the estimation of elimination rates and the half-life of 14C. Throughout these experiments several fish were also sacrificed for whole-body autoradiography. The uptake of 14C in carcass and viscera began to level off at 24 hr and the apparent bioconcentration factor was low and of the order of 3–4. In the elimination studies, the 14C appeared to persist in both muscle and visceral tissue for a longer time than anticipated based upon its octanol-water partition coefficient (log p = −0.92). The t½ of 14C in muscle in two such experiments was calculated to be 117 and 102 hr. The autoradiographs of whole-body sections of exposed trout also revealed a slow loss of 14C from muscle. Muscle extracts prepared from exposed fish were essentially nondialyzable. When dialyzed muscle extract was analyzed for protein and 14C after SDS-PAGE electrophoresis, most of the 14C was associated with a single protein band with a mobility comparable to standards in the 10,000 Dalton range. These studies indicate that the long half-life of 14C seen in trout muscle may be due to covalent binding of 14C to a protein with a molecular weight of approximately 10,000 Daltons.