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ABSTRACT: Leachates from solid wastes have been implicated in the pollution of the environment including surface
and groundwater contamination which ultimately affect human health. Raw leachates were obtained
from three open dumpsites: a University campus (CSL), an urban market place (UML), and a domestic
dumpsite (OSL), and were evaluated for their possible genotoxic effects on the root tip cells of Allium
cepa L. The leachates were examined for the presence of heavy metals using standard methods. The
onion bulbs were cultivated in 1%, 2.5%, 5% and 20% of each leachate sample, and after 48 hours, one
root tip from each bulb was harvested and processed for cytological observation using the aceto-orcein
squash technique. After 72 hours, mean root lengths of the Allium cepa were obtained. The results
revealed that compared to the control, treatment with the leachates resulted in significant (p<0.05)
concentration-dependent onion root growth inhibition with EC50 values of 3.2%, 4.5%, and 5.7% for
CSL, UML and OSL respectively. The leachates were characterized by various chromosomal
aberrations and reduction in the number of dividing cells. The physical and chemical properties showed
that the leachates were acidic and contained toxic chemicals. CSL was most toxic, while OSL was least
toxic. The results obtained suggest that the toxic chemicals present in these leachates pose a threat to
the environment and human health if left unchecked.
Continental J. Environmental Sciences. 01/2011; 5:6-12.
