The contamination of the aquatic ecosystem with heavy metals arising from the discharge of
electronic waste (e-waste) or seepage of leachate from open waste dumpsites is on the increase. The impact of e-waste
leachate on the micronucleus (MN) of
Tilapia guineensis
and the levels of heavy metals ( Pb, Cd, Cr, As, Hg, Al and
Ba) in the sediments, water, leachate and aquatic fauna (
Tilapia guineensis,
Callinectes amnicola
and Cardiosoma armatum
) found in and around e-waste dumpsites in Lagos and Osun States was studied. The levels of heavy metals
were determined using PyeUnicam model 969 Atomic Absorption Spectrophotometry and Inductive Coupling Plasma
Atomic Absorption Spectrophotometry (ICP-AAS).The heavy metal concentrations decreased in the order: Pb ˃ Cd ˃
Cr ˃ Hg ˃ Al ˃Ba ˃As in the samples. The level of Cd in fish muscle from Lagos (1.4mg/kg) exceeded the Environment
Canada threshold effect level (EC TEL, 2006) recommended for sea food (1.0mg/kg). The calculated bioconcentration
factor (BCF) for fish gills (1.4 and1.0) and fish muscles. (3.6 and 1.2) from Lagos and Osun States respectively as well
as the bioaccumulation factor (BAF) for crabs (1.78 and 1.36) are strong indications of the ability of the organisms to
bioaccumulate the heavy metals. The MN assay showed an initial increase in the frequency of mionccronuclei on the 7
th
day which gradually decreased on the 14
th and 21
st day. The result of this study reveals the toxic impacts of e-waste
contamination on ecological and human health in a developing economy.
