Histological and Hematological Responses of an Estuarine Teleost to Cadmium

Pathological changes attributable to cadmium poisoning were observed in the intestinal tract, the kidney, and the gills of Fundulus heteroclitus after exposure to 50 ppm of the metal. Microscopic examination revealed pathological changes of the intestinal tract as early as 1 hr after exposure, in the kidney after 12 hr, and in the gill filaments and respiratory lamellae after 20 hr. These manifestations of cadmium poisoning bear resemblance to the pathological changes that have been demonstrated clinically and experimentally in mammals.The examination of circulating blood elements revealed rapid and striking changes among cells of the eosinophil lineage. The abundance of eosinophils increased steadily to a level approximately 45% above the usual amount. Indications of the cellular increase occurred as an early rise 4 hr after exposure.A reduction in the relative numbers of mature eosinophils was evident in imprints of head kidney tissue. Nuclear anomalies were associated with the thrombocytes of specimens after 8 hr exposure; however, these changes were not noticeable at either earlier or later time periods.