Bioaccumulation of metals from nickel smelter waste in P and F1 generation of exposed animals. Part III. Morphological responses.

Inhalation exposure experiments were conducted on a group of female adult Chinchilla rabbits placed in a field biomonitoring station located downwind from dumped nickel refinery wastes. Their F1 generation offsprings were exposed prenatally and 6 weeks postnatally. After termination of exposure, both P and F1 generation rabbits were sacrificed, their organs removed and subjected to a histologic examination using light and electron microscopy techniques. The histological responses were most marked in P generation female rabbits, namely hypertrophy of the muscle layer of pulmonary artery walls and foci of atelactasis. Electron microscopic examinations of the myocardium of chamber-exposed rats revealed evidence of muscle fibre lesions at sites of intercalary discs and changes in mitochondrial structure as a result of accumulated Ni, Cr and/or other metals. Histologically remarkable was interstitial accumulation of an unidentified electron-dense crystalloid substance situated near blood capillaries and between myofibrils and collagenous fibres; this substance is believed to be a result of metal-protein interaction. The rats injected intravenously with a suspension of metal waste displayed mitochondrial lesions analogous to those observed after inhalation exposure, but no presence of the electron-dence substance could be noted. It is concluded that chronic exposure to metal waste may give rise to cardiovascular lesions.