The effects of xenobiotics on fish tissues: morphological studies.

Current applications of light and electron microscopy to investigations of changes in various tissues from fish exposed to xenobiotics have been reviewed. Emphasis has been placed on two types of contaminants, petroleum hydrocarbons and chlorobiphenyls, as examples of important xenobiotics found in the marine environment. Although the data are fragmentary because of the small number of studies, they clearly contribute new and valuable information to an understanding of the impact of these contaminants on the olfactory organ, liver, lens, and intestine from several species of fish. The morphological aspects of damage to the olfactory organs of fish exposed to petroleum hydrocarbons included hyperplasia and attenuation of the chemosensory cilia. In the liver of fish exposed to chlorobiphenyls, one of the most evident cellular anomalies was whorls of smooth endoplasmic reticulum. The rough endoplasmic reticulum appeared proliferated and its cisternae were dilated. Changes in th amount of lipid stored in the hepatocytes have been observed in fish exposed to both petroleum hydrocarbons and chlorobiphenyls. Some hydrocarbons affected eye tissues. Structural alterations that occurred during hydration of lens fiber cells and cataract formation were elucidated. A synopsis of the morphological changes in the intestine of fish exposed to petroleum hydrocarbons alone, chlorobiphenyls alone, and the combined contaminants is presented. All three groups of contaminant-exposed fish have subcellular inclusions that are distinctly abnormal. Recommendations for future studies include the need for further characterization of the range of normal tissue structure, comparative studies of additional species, and multiple contaminant exposures.