Environmental Risk Assessment of Heavy Metals of Road Runoff in Ehimiri Housing Estate Umuahia, Abia State, Nigeria

Abstract

The study focused on the environmental risk evaluation of heavy metals in road runoff as non-point source in Ehimiri housing Estate Umuahia. Absorption Atomic Spectrophotometer was used for the analysis. The major streets selected include Sam Onyeozari street (ERSP1), Ukpai A.Ukpai street (ERSP2), Dick Uduma stree (ERSP3), Justice Atuma Street (ERSP4), Ibe Nwachukwu (ERSP5), Mazi Uwakaeme (ERSP6), and Nwogu street (ERSP7) respectively. A total of twenty one runoff samples, three each from the seven selected roads were collected across three months (May-August, 2014), and analyzed using standard methods. Results shown that heavy metal concentrations originating from the non-point source (NPS) in the selected routes were in the following ranges: Cd(0.01 -0.02 μg/l-1), Cu (10.00-45.00 μg/l-1), Cr(0.05-4.01 μg/l-1), Zn(5.00 -50.00 μg/l-1), and Pb(1.64 -29.01 μg/l-1), which further explained that concentrations were higher in the months of April and May in Aba road and reduced in other routes. An increased in heavy metals were observed during the month of July than the month of May. Statistically, mean variations were observed among heavy metals from road runoff that ranged between: Cd 0.07 μg/l-1, Cr 3.10 μg/l-1, Cu 22.70 μg/l-1, Pb 36.70 μg/l-1 and Zn 51. 40 μg/l1in order of Zn >Pb>Cu> Cr>Cd respectively. The results also indicated that Cd, Cu, Cr, Zn and Pb concentrations in road runoff sampled were above the NESREA and WHO standards for potable water during the month of April being first flush, May being the after first flush and July that proceeds August break that affects man and his environment.