Evaluation of some heavy metals loading in dust fall of three universities motor parks in Western Nigeria

Abstract

The high density of vehicles that run to and fro University campus to town has become of great concern for assessment of health status of the ambient air around the Universities motor parks. Moreover, some of the University’s parks are unpaved while the paved ones are old and unmaintained. Dust fall samples in parks of Universities of Ilorin, Ibadan and Kwara State University were collected for five months spanning from 1st November 2014 to 31st March, 2015 using open bucket sampler based on ASTM D 1739 of 1998 (2010). A 0.1 g of dust sample was digested with 20 ml of HNO₃, HClO₄ and HF in ratio of (3:2:1) respectively and heavy metals (Mn, Cu, Zn, Cd, Pb, and Ni) were analysed using atomic absorption spectrophotometer (Buck Scientific model 210 VGP). Results of heavy metal concentrations showed decrease in the following order: 1479.75, 1255.68, 241.50, 128.00, 85.25, and 9.63 mg/kg for Mn, Zn, Pb, Ni, Cu and Cd respectively for University of Ibadan. The decreased in concentrations of heavy metals obtained for University of Ilorin motor park dust-fall were found to be 1145.75, 797.75, 219.63, 133.51, 58.25 and 23.13 mg/kg for Mn, Zn, Pb, Ni, Cu and Cd respectively. For Kwara State University, decrease in the following order: 778.5, 323.88, 259.38, 101.38, 34.38, and 4.63 mg/kg for Mn, Zn, Pb, Ni, Cu and Cd respectively were obtained. Generally for the three sites used, the heavy metal concentrations decreased in the following order: Mn>Zn>Pb>Ni>Cu>Cd. This implies that dust-fall in the parks are heavily loaded with some heavy metals that are of concentrations above Romania standard threshold limit for Cd and Pb while concentration values obtained for Ni are higher than US- EPA values (75 mg/kg). The regulatory agent or management should ensure that the roads are paved and there should be intermittent wetting of the roads with water.

Keywords: Dust Fall; Heavy Metals; University Motor Parks