Effects of contaminated sediment on the epidermis of mummichog, Fundulus heteroclitus

Secretion of mucus by epidermal goblet cells protects fish against many bio logical, physical, and chemical insults encountered in the environment. Thi s study monitored changes in hemoglobin concentration in epidermal mucus an d in the density, diameter, and mucus quality of epidermal goblet cells in the mummichog, Fundulus heteroclitus, following exposure to creosote-contam inated sediment from the Elizabeth River, Virginia, USA. Fish were exposed for 13 d in flow-through aquaria to either uncontaminated (US) or contamina ted (CS) sediments and were sampled periodically. The condition index was l ower and the mortality rate and the occurrence of epidermal lesions were hi gher in CS-exposed fish than in US-exposed fish. Hemoglobin contents in epi dermal mucus from the former group were significantly higher than from the latter. Significant reductions in both size and density of goblet cells in CS-exposed fish suggested a mucus secretion rate exceeding its production r ate. Significant changes in mucin types between treatments did not occur un til day 13 and are not believed to be directly related to the creosote pres ent in the contaminated sediment. These results all indicate that exposure to creosote-contaminated sediment had a profound and deleterious effect on fish health.