Metal pollution assessment of surface sediments along a new gas pipeline in the Niger Delta (Nigeria).

Chromium, nickel, copper, zinc and cadmium were determined in sediments of the Niger Delta (Nigeria) in order to discriminate between natural metal sources and anthropogenic ones. Surface sediments were collected at seven sites along a new gas pipeline near Port Harcourt, between the New Calabar River and the Bonny River towards Bonny town. Chemical characterisation is obtained by hydrofluoric-nitric acid digestion procedure, providing the 'total' ('residual') metal contents.