Polycyclic aromatic hydrocarbons levels in   Nta-Wogba Stream water in Port Harcourt, Rivers State, Nigeria

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants which are associated with carcinogens. Their presence in the environment has been linked to cancer. Assessment of polycyclic aromatic hydrocarbons in water of Nta-Wogba stream were studied, in which three (3) samples of water from the Nta-Wogba stream were sampled. The water samples were extracted using a liquid – liquid extraction technique into dichloromethane and dehydrated with sodium sulfate anhydrous. The results obtained showed that total PAHs concentration in the water at the various stations were 23.33, 23.67and 24.74mg/L in June and 25.22, 24.58 and 31.09mg/L in October. The source diagnosis of the levels and nature of occurrence of PAHs in the stream using the different hypothetic ratios showed that the sources of PAHs were both petrogenic and pyrogenic. However, the values obtained from the diagnostic ratio indicated that pyrogenic sources were the dominant source of the PAHs within the Nta-Wogba stream. The ring size analysis carried out showed that 2-3 ring PAHs were sparingly detected while 5-6 ring PAHs were generally detected. This was attributed to the high volatility and instability of the low ringed PAHs. These can pose serious health risk since 5-6 ring PAHs have been associated with cancer-causing and mutagenic potentials.