TOXIC STRESS OF LEAD ON CLARIAS GARIEPINUS (AFRICAN CATFISH) FINGERLINGS

ABSTRACT

Toxicity testing of chemicals on animals has been used for a long time to detect the potential hazards posed by chemicals to man. Bioassay technique has been the cornerstone of programmes on environmental health and chemical safety (Ward and Parrish, 1982). Lead is a potentially toxic chemical that may be directly ingested by man or indirectly through aquatic animals like fish and shellfish .The effects of lead on man include mental retardation, learning dysfuntion, and loss of coordination (Goodman and Gilman, 1992). Though the effect of lead toxicity is well elucidated in man (Klaassen, 1992), there is paucity of information on its effects on fish, which are eaten by man. This work is therefore aimed at assessing the toxic stress of lead on fish using a static bioassay technique (Reish and Oshida, 1987). The fish Clarias gariepinus is a hardy fish and highly valued in Nigeria .It would therefore be of interest to study the quantity of lead that can be accumulated within its tissues; which would then give an indication of how much lead is indirectly consumed by man.