Evaluation of some heavy metals concentration in municipal waste dumpsites in the Niger Delta Region, Nigeria

Abstract

A study was conducted in Delta State, a major Niger Delta region of Nigeria. The aim was to evaluate some heavy metals concentration in municipal wastes dumpsites that are presently used for intensive horticultural crops production. The heavy metals studied were; Iron (Fe); Lead (Pb); Mercury (Hg); Cromium (Cr); Nickel (Ni); and Cadmium (Cd). A semi- detailed
survey at the scale of 1:25,000 was employed in the study, and five permanent dumpsites randomly located in Warri, Ughelli, Sapele, Agbor and Asaba were used. A total number of 30 composite waste samples were collected, processed and digested using Diethylenetriaminepenta-acetic acid (DTPA) extracting solution. The results of the study showed that the
values of the heavy metals evaluated ranged from 83.92-- 100.03.mgkg-1 for (Fe); 0.02--0.07 mgkg-1 for (Pb); 1.41--7.71 mgkg-1, for (Cr), 0.08-1.06 mgkg-1 for (Cd), 0.20- 13.19 mgkg-1 for (Ni), and 0.01-- 13.65 mgkg-1 for (Pb), respectively. Apart from lead (Pb), in which the mean concentration value was greater than the FAO-WHO permissible standard of 1.5 mgkg-1 in Warri, Ughelli, Sapele and Agbor dumpsites, the values obtained for other heavy metals were within the maximum tolerable levels. However, there is need to be cautious since crops grown on soils amended with urban wastes can immobilize heavy metals which could find their ways into human being through food chain processes. Hence, the reason for
regular monitoring of the quality and concentration of heavy metals in waste dumpsites used for horticultural purposes because of health reasons.

Keywords: Evaluation, heavy metals urban waste dumpsites.