Responses induced by long-term toxic effects of heavy metals on fish tissues concerned with digestion, absorption, and excretion.
The present study relates to the bioassay as well as the responsiveness induced by long-term exposure to sublethal concentrations of soft acceptor heavy metals, lead (Pb, IV A) and cadmium (Cd, II B), in various fish tissues viz., stomach/intestinal bulb, intestine, liver, pancreas, and kidney of Mystus vittatus (Bloch) and Labeo rohita (Hamilton) belonging to 2 different trophic strata. Responses, however, have been recorded by histopathological and histochemical studies on the aforesaid tissues concerned mainly with digestion, absorption, and excretion. Histopathological observations depict the vacuolation, degranulation, exocytosis of the various cells including their nuclear damage. Erosion of the top plate of intestinal villi, enlargement of epithelial cells, shrinkage of glomeruli, destruction or disruption of the nephric tubular cells, etc. have also been registered. Histochemical investigations emphasize on the change in the intensity of staining reactions of biologically active macromolecules particularly amino acids of the protein component and glycogen among the carbohydrate component as well as acid, neutral and/or mixed mucopolysaccharides of the cells concerned. Toxic effects of the afore-mentioned heavy metals at the tissue level have been discussed.
Datta
D
D
Zoology Department, Burdwan University, West Bengal, India.
Sinha
G M
GM
D000818:Animals; D001681:Biological Assay; D002104:Cadmium / Q000009:adverse effects*; D004781:Environmental Exposure; D005399:Fishes / Q000033:anatomy & histology*; D005618:Fresh Water; D006651:Histocytochemistry; D007422:Intestines / Q000187:drug effects; D007668:Kidney / Q000187:drug effects; D007854:Lead / Q000009:adverse effects*; D008099:Liver / Q000187:drug effects; D010179:Pancreas / Q000187:drug effects; D012007:Rectum / Q000187:drug effects; D013270:Stomach / Q000187:drug effects; D014877:Water Pollution, Chemical / Q000009:adverse effects*
D002104:Cadmium; D007854:Lead