Assessment of the Bioaccumulation of TPH and Heavy Metals in Tissue of Selected Fishes’ Species Caught from Stream near a Petroleum Processing Plant

Abstract

This article investigated the bioaccumulation of total petroleum hydrocarbon (TPH) and selected heavy metals in the tissue of selected fishes’ species from a stream near a petroleum processing plant in Rivers State, Nigeria. The concentration of TPH and Ni, Mn, Fe, Zn, Pb, Cr and Co in the fish species’ tissue were measured using standard methods. The TPH concentrations in the fish species were generally high (1.97 to 52.84 mg/kg), greater than the European Union threshold limit of 2μg/kg. Gobius sp and Periophthalmus sp recorded the highest TPH content: 52.84 mg/kg and 28.07mg/kg levelsrespectively. Tilapia sp and Sardinella sp recorded the least and highest concentration of Manganese (0.61 mg/kg and 5.90 mg/kg respectively). The levels of Fe content in the fish tissue were higher than all other metals: 8.27 mg/kg in Gobiussp to 129.7 mg/kg in Sardinella sp. Zn: 4.39 mg/kg in Mugilidae to 11.84 mg/kg in Gobius sp while Co:<0.02 mg/kg in Tilapia sp and 1.51mg/kg in Calinectis sp. The concentrations of Cd:0.24 mg/kg in Pomadasys sp to 0.56 mg/kg in Gobius sp. These values are relatively high because of the metal’s high toxic response factor of 30. The levels of Pb:<0.03 mg/kg in Tilapia sp and Carangidae to 2.69 mg/kg in Calinectis sp. Gobius sp recorded the highest level (3.36 mg/kg) of Ni. The concentrations of Co, Cd, Pb, and Ni in consumable fish are of great concern because of their high toxic response factors. These results implied that the petroleum processing activities (legal and illegal) are negatively impacting aquatic habitats/ food chains. This calls for caution in the consumption of the fish from this area, the audit of the legal petroleum processing facilities and stoppage of the illegal operations.