Histopathological and Physiological Responses of Fundulus heteroclitus to Naphthalene Exposure

Abstract

Mummichogs, Fundulus heteroclitus, were exposed to naphthalene concentrations ranging from 30 to 0.002 mg/L over time periods ranging from 1 to 15 d. Histopathology of exposed animals was evaluated. Major effects were found in the brain, liver, and pancreas down to 0.2 mg/L for a 15-d exposure. The results of these experiments indicate that the toxicity of naphthalene in this fish is due primarily to its effect on blood components. There was also evidence of neurosensory damage at exposures as low as 0.02 mg/L for 15 d. In addition, serum glucose, protein, and cortisol were measured in animals exposed to low levels of naphthalene for 15 d. All were significantly elevated, indicating metabolic stress at exposures as low as 0.02 mg/L. 14C-naphthalene uptake was measured at two concentrations of naphthalene. Naphthalene was found to accumulate in significant amounts in organs most susceptible to pathology. The distribution of naphthalene was found to be independent of its water concentration in all organs tested except the spleen. Key words: toxicity, naphthalene, teleosts, histopathology, uptake, Fundulus, mummichog