Prior to the analysis, the soil samples were air-dried in the
laboratory and sieved through the 250 μm mesh before they were
ground using a mortar and pestle. Heavy metal extraction from the
soil samples was undertaken using the sequential extraction
method of Badri (1984). The extraction process was divided into
four fractions namely easily leachable and ion exchange (ELFE),
acid reducible (AR), organic oxidation (OO) and resistant (RR)
fractions. The ELFE fraction normally contained metals that were