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Heavy metal loading and its impact on Villorita cyprinoides (Hanley) along the estuaries of south west coast of India (TH 097)

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Relation http://eprints.cmfri.org.in/7151/
 
Title Heavy metal loading and its impact on Villorita cyprinoides (Hanley) along the estuaries of south west coast of India (TH 097)
 
Creator Priyalekshmi, A
 
Subject Theses
Marine Pollution
Clam
 
Description Bivalves which are filter feeders are found to be the best ones suited
for pollution monitoring because of their abiltiy to concentrate
pollutants to several orders of magnitude. For the present study, black clam,
Villorita cyprilloides was selected owing to its euryhaline and hardy nature.
A fortnightly study conducted at the four stations (station I, 2, 3 &
5) and a seasonal (Pre-monsoon, Monsoon & Post-monsoon) study conducted
at the other four stations (station 4, 6, 7 & 8) revealed a postmonsoon
maxima and a pre-monsoon minima for copper in the whole soft
tissue and digestive gland of clams. Cadmium and lead values were comparatively
low. However, metals in the sediment did not show any seasonal
variation in accumulation. Acute toxicity and bioaccumulation studies
(using copper and lead) showed that copper was more toxic to the clams
than lead. Digestive glands showed highest value for copper whereas gills
showed highest value for lead. A linear relationship between time and
concentration was observed in the accumulation of the two metals in the
tissues studied. Histology of the digestive glands and gills of copper and
lead exposed clams showed severe degeneration and destruction of the
epithelial cells. The planimetric study conducted also revealed destruction of
epithelial cells which was indicated by a significantly lower MET(Mean
Epithelial Thickness) values for copper exposed clams. There was
Significant incrcasc in MLR & MLRlMET values of copper exposed clams.
Though samc results were obtained for lead exposed clams the values did
not show any statistical difference. Fine structure of the digestive glands
of copper and lead exposed clams revealed proliferation of SER, Iysomes,
destruction of digestive cells, a labile nuclear membrane and breakage at
the basal lamina.
 
Date 2001
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Language en
 
Identifier http://eprints.cmfri.org.in/7151/1/TH-97_Pri.pdf
Priyalekshmi, A (2001) Heavy metal loading and its impact on Villorita cyprinoides (Hanley) along the estuaries of south west coast of India (TH 097). Doctoral thesis, Central Institute of Fisheries Education, Versova.