Determination of polynuclear aromatic hydrocarbons (PAHs) in selected water bodies in the Niger Delta

Several water bodies in the Niger Delta region of Nigeria where extensive crude oil production activities take place were analyzed for the presence of 16 US EPA priority polynuclear aromatic hydrocarbons (PAHs) namely: naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(ghi)perylene dibenz(a,h)anthracene and indeno(1,2,3-cd)pyrene. The concentrations ranged from as low as 1.95 ug/L for relatively clean stream with practically no crude oil activity to 10.9 ug/L for the most polluted. The analysis was carried out using GC/MS. The quantitation was done by means of internal standardization using four isotopically labeled internal standards namely acenaphthene-d10, chrysene-d12, phenanthrene-d10 and perylene-d12. High molecular mass PAHs such as benzo(ghi)perylene, dibenz(a,h)anthracene and indeno(1,2,3-cd)pyrene were mostly absent confirming low water solubility of these compounds and carcinogenic PAHs were general lower in concentration than the non carcinogenic ones.