Assessment of heavy metals pollution in sediments and surface water of River Benue, Makurdi, Nigeria

Abstract

Levels of heavy metals were determined in the surface (1-6cm) and body core (45-50cm) sediments, as well as the overlying water of River Benue within the industrialized areas of Makurdi, Nigeria in order to assess the extent of anthropogenic influences. Samples were analyzed for their concentrations of these metals, using the atomic absorption spectrophotometer (AAS). The results of heavy metals show that the average contents of Fe (5.3%), Cr (70 ppm), Cd (0.4ppm) and Co (40ppm) in surface sediments are only slightly higher than corresponding contents in body core sediments; Fe (5.1%), Cr (66ppm), Cd (0.35ppm) and Co (37ppm). These chronic levels suggest similar geochemical control, which is most probably lithogenic. Conversely, the average contents of Mn (1910ppm), Cu (71ppm), Pb (26ppm) and Zn (340ppm) in surface sediments are much higher than corresponding contents in body core sediments; Mn (400ppm), Cu (30ppm), Pb (17ppm) and Zn (96ppm) respectively. These heavy metals are probably enhanced in surface sediments by anthropogenic activities. Results obtained from water analyses, are within the WHO 1991 maximum permissible level for most heavy metals in drinking water except for Mn (0.06-2.00ppm) and Pb (0.02-0.10ppm) close to point sources of pollution.

Keywords: Heavy metals; Surface water; Sediments; River Benue

Journal of Applied Science, Engineering and Technology Volume9,: 1-10