Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Enugu State, Nigeria



The study determined the concentrations of heavy metals in dry deposition in Enugu Urban, Nigeria. Dry deposition samples are collected using plastic containers mounted on elevation of 3 meters at 9 various locations with 3 sampling stations per location and left for 30 days. The dust samples were collected for 3 consecutive   times from November 2018 to March, 2019 and a total of 27 composite samples were collected for analysis. The samples were treated in accordance with the standard method of analysis and analyzed for Cu, Cr, Ni, Mn, Zn, Pb and Cd using Perkin Elmer Optima 8000 Inductively Coupled Plasma – Optical Emitting Spectrometer (ICP – OES). The result shows the highest mean values of the metals concentrations (mg/kg) as follows; Cu – 146.29 ± 10.23 , Cr – 13.01 ± 0.30 , Ni – 30.35 ± 0.37 , Mn – 179.07 ± 0.83 , Zn – 507.24 ± 2.97 , Pb – 0.43 ± 0.09 , Cd – 2.43 ± 0.21 .  The mean values of the concentrations of the metals decrease in the following order; Zn > Mn > Cu > Ni > Cr > Cd > Pb. The values of potential ecological risk indexes ranges in each sampling period across the locations are as follows: (November/December) 457.31 - 915.12, (January/February) 412.81 – 911.09, (February/March) 260.29 – 933.48. The indication is that Enugu urban atmosphere is continuously being contaminated with toxic metals and it poses a great ecological risk. Regular atmospheric monitoring is very important and effective pollution control measures must be in place and enforced.


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