Toxic Potential of Carcinogenic Polycyclic Aromatic Hydrocarbons (cPAHs) and Heavy Metal in Crude Oil from Gokana Area, Rivers State, Nigeria

Abstract

This article is focused on ascertaining the toxic potentials of heavy metals and the levels of PAHs and cPAHs in crude oil samples from Gokana area and using the data to determine the carcinogenicity (toxicity) of the cPAHs in the crude oil. All the cPAHs namely; benzo (a) pyrene, benzo (a) Anthracene, benzo (b) Fluoranthene, chrysene, benzo (k) fluoranthene, dibenzo (a, h) perylene and indeno (1,2,3-cd) pyrene were detected at various concentration in mg/l as 1597.88, 46.97, 4219.99, 1498.04, 1220.41,831.82 and 1106.20 respectively. The total concentration of cPAHs is 10,474.34 mg/l which represent 41.83% of the total PAHs (tPAHs) in the crude oil sample. Using BaP as baseline standard (0.0007 mg/l) to correlate the (toxicity) carcinogenicity of the cPAHs, we found out that the crude oil sample is many thousands of folds significantly and exceedingly (toxic) carcinogenic. The order of concentration of heavy metal (Fe > Ni > Cr > Cu > Cd = Pb = Zn) in the crude oil sample did not reflect their actual toxic potential as only nickel and chromium exceeded the maximum effluents limits. Considerable caution should be applied in exploration, exposure and distribution of the crude oil through protected and well maintained pipelines to avoid the possible release of PAHs as well as nickel and chromium toxicity to soil, water and inhabitants of Gokana area.

Keywords: carcinogenicity, toxicity, crude oil, heavy metal, cPAHs