Heavy metal speciation and potential impact of rice milling operation on metals concentration on soils around kilema rice milling industry Lafia, Nasarawa state, Nigeria

This study assesses the impact of some heavy metals on soils around the rice milling factory using indices such as geo-accumulation index and contamination factor while metal mobility was assessed using mobility factor. The results reveal that the dominant metal concentration were in the order: Fe > Pb > Co > Ni while Cd and Cr were below detection limit. The potential mobility of the metals within the soil was in the order: Co > Ni > Fe > Pb. The Geo-accumulation index of all the heavy metals determined showed that the test and control soils were strongly contaminated with Pb and its relative potential mobility was 36% and 51% respectively. The mobility of metals was less pronounced in the test soil due to high organic matter content of 5.38% in soil around the milling industry usually generated as waste during rice processing compared to the 0.54% organic matter content in the control soil.