ABSTRACT
Investigations were carried out for heavy metals composition of ambient air using a special instrument designed for this purpose. The lack of portable air sampler is a major obstacle to air pollution studies in Nigeria of recent. As a remedy to this, a simplified air sampler was designed and fabricated at the Water Resources and Environmental Engineering Department. Varied designs of this sampler were constructed and deployed for assessing the air quality of some selected heavy metals in some commercial areas in Kaduna metropolis such as Chechenia Market, Ahmadu Bello Way, Old and New Panteka. The instrument was mounted in strategic locations free from interference by humans and other natural factors. In accordance with standard methods, the trapped samples were washed in de-ionized water, diluted and digested and analyzed by Atomic Absorption Spectrometer (AAS) for the heavy metals zinc (Zn) lead (Pb) and iron (Fe). From the results Chechenia Market recorded mean values of Zn=1.55, Pb=0.00 and Fe=1.65 mg/l, Old Panteka recorded mean values of Zn= 0.13, Pb=0.00, Fe=4.29 mg/l and New Panteka recorded mean values of Zn=3.05, Pb=0.02, Fe=2.37 mg/l. These results were compared with national and international standards of National Environmental Standards and Regulations Enforcement Agency (NESREA) (2009) and the World Health Organization (WHO) (2011).Pb showed low mean values in the rainy season while the mean values obtained in the dry season were high. Zn and Fe maintained a fairly constant mean value though the values for Fe were high above recommended values of NESREA (2009)/WHO (2011).The results showed that Zn and Fe were above the permissible limits while Pb was within the permissible limit.The presence of these heavy metals in these areas maybe from numerous on-going human activities such as smelting of metals, vehicle exhaust, wearing of brake pads, tire abrasion, road dust and burning of refuse, among others. This investigation has highlighted that these heavy metals fractions exist in the air around these parts of Kaduna metropolis and they could be detrimental to human health. Further studies are recommended to determine the risks posed by these fractions and develop technological and management options for their reduction. Phasing out any remaining use of heavy metal additives should be encouraged.