Distribution and elimination of naphthalene and 2-methylnaphthalene in rainbow trout during short- and long-term exposures

Abstract

The accumulation and elimination of 14C in rainbow trout tissues following short- and long-term exposures to aqueous 14C-naphthalene or 14C-2-methylnaphthalene were studied. After exposure for eight hr to 0.005 mg/L or 0.023 mg/L of 14C-naphthalene most tissues of fingerling rainbow trout studied contained 14C at 20 to 100 times the water levels while fat and bile contained 14C at several hundred times water levels. The half-lives for elimination of 14C from all tissues except fat were less than 24 hr. Exposure of fingerling rainbow trout to 14C-naphthalene or 14C-2-methylnaphthalene for four weeks in a continuous-flow delivery system resulted in maximum tissue levels of these chemicals of from 40 to 300 times the water concentration. Maximum bile 14C levels were 13,000 and 23,500 times the water concentration for 14C-naphthalene and 14C-2-methylnaphthalene exposure, respectively. Elimination of 14C accumulated from 14C-naphthalene in this long-term exposure was much slower than after short-term exposures, while elimination of 14C accumulated from 14C-2-methylnaphthalene was biphasic. The presence of parent compounds and metabolites in acetone extracts of muscles was determined by TLC. The data suggest that the biphasic release of 14C from muscle of trout exposed to 14C-2-methylnaphthalene may be due to differential elimination of parent compound and metabolites.