Concentration of Vehicular and Generators Soot in Lafia Metropolis, Nasarawa State, Nigeria

The concentrations of Pb, Cd, Cr, Al and Fe in Heavy Duty Trucks (HDT), Power Generating Plants (PGP), Motor Vehicles (MV) and Small Generator (SG) Soot derived from the College of Agriculture, Bukan Sidi and Mararaba Akunza in Lafia City, Nigeria, were assessed for the level of contamination using Atomic Absorption Spectrophotometer (AAS). The results indicated that the ranges of heavy metal concentrations in soot (mg/kg) were: Pb (0.0911±0.001 to 0.069±0.008) for the HDTs, (0.775±0.008 to 0.002±0.000) for the PGPs, (0.456±0.000 to 0.091±0.000) for the MVs and (0.837±0.000 to 0.027±0.000) for the SGs. The concentrations of Cd and Cr in the HDTs and PGPs were below the detection limits of the AAS. More so, Cd and Cr in MVs were below the detection limits of the AAS except for one of the MVs which gave a highly objectionable Cr concentration of 4.336±0.004 above WHO permissible limits for emissions into air and water. Al concentrations across the soot samples ranges from (0.126±0.002 to 0.093±0.001) for HDT, (0.170±0.001 to 0.097±0.000) for PGPs, (0.150±0.000 to 0.057±0.001) for MVs; and (1.348±0.000 to 0.518±0.000) for SGs. Iron concentrations ranges from (65.885±0.006 to 27.834±0.009) for HDTs, (62.663±0.004 to 11.422±0.019) for PGPs, (52.448±0.003 to 2.418±0.001) for MV, and (129.433±0.008 to 9.129±0.002) for the SGs. The results revealed that the concentration of Pb, Al and Fe in the HDTs, PGPs, MVs and SGs are above the WHO permissible limits for emissions into air and water. Cd, Cr, Al and Fe concentrations were higher in concentrations in SGs. The presence of heavy metals in the sampled soot portends their transfer to the food chain, especially as crop and vegetable cultivation in and around Lafia city.