Browsing by Author "Ndimbumi, Joram"

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    Effects of lead exposure on survival, growth and development of forebrain in bufo regularis tadpoles
    (University of Dar es Salaam, 2008) Ndimbumi, Joram
    The effect of lead exposure on survival, growth and development of forebrain in Bufo regular is tadpoles fanuran species) were investigated. Tadpoles were exposed to 1.8, 3.5, 6, 10, and 15mg/l ambient lead for 96 hours. Mortality of tadpoles was recorded and the median lethal concentration (LC50) for lead was 5.1 mgPb/1 (96hrs). Forty eggs of Bufo regularis were exposed to 0.5, 1, 2, 4, 8 and 10 mg/1 of ambient lead in each test container for 7, 14, 21, 28 and 35 days. The bioaccumulation of lead in the body of tadpoles increased concomitantly with an increase in the ambient lead concentrations while the survival decreased with an increase of exposure concentrations and time. Tail malformation and swimming dysfunction were common in tadpoles exposed to 4, 8 and 10 mg/1. The histopathological study of the forebrain revealed poor development of the neural tube and delayed migration of neurons into the cortex of the forebrain. It can therefore be concluded that lead has detrimental effect on survival, growth and development of forebrain in Bufo regularis tadpoles. Hence discharge of waste containing lead in aquatic environment can have detrimental effects on early stages of amphibian development