Determination of Total Petroleum Hydrocarbons (TPH) and Heavy Metals in Tilapia (Hemichromis spp.) and Mackerel (Scomber japonicus) in Lagos Markets

Abstract

This paper reports the determination of total petroleum hydrocarbons (TPH) and heavy metals in tilapia (Hemichromis spp.) and mackerel (Scomber japonicus) sourced randomly from some Lagos markets. Control samples were harvested from a fish
farm in the outskirt of Lagos metropolis. TPH in the samples were estimated gravimetrically following standard methods of TPH analysis, while the heavy metals were determined by atomic absorption spectrophotometry. Chromium was not detected, whereas, the mean values for copper, iron, nickel and lead are 0.06 ± 0.05 /mg/g, 0.94 ± 0.18 /mg/g, 4.62 ± 1.63 /mg/g, 1.28 ± 0.42 /mg/g, 0.02 ± 0.01 /mg/g, respectively, for tilapia and 0.13 ± 0.03 /mg/g, 1.65 ± 0.37 /mg/g, ND, 0.49 ± 0.20 /mg/g for mackerel samples, respectively. However, the TPH values are 0.02 ± 0.01 /mg/g and 0.01 ± 0.01 /mg/g for tilapia and
mackerel samples, respectively. Values for the control samples were generally found to be lower for both TPH and heavy metals. These values were, however, compared with the World Health OrganisationÕs permissible limits.

Keywords: Contamination, Total Petroleum Hydrocarbons (TPH), Heavy Metals, Tilapia, Mackerel

Discovery and Innovation Vol. 19 (4) 2007: pp. 276-279