Determination and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface and ground waters from Ifite Ogwari, Anambra State, Nigeria

Abstract

ABSTRACT Levels of Polycyclic Aromatic Hydrocarbons in surface and underground water sources from Ifite Ogwari, Ayamelum Local Government Area of Anambra State were investigated. Ecological and human health exposure risks were assessed following US EPA methods. The surface water sources are Isiachala, Iyiutu, Ube, Ahala Tabasi, Nabaloku, Atammele, Ogbu streams, and Omambala river. Underground water sources include Igbazine, Double, Ogba, Onowulugbe, Orator, and Commodore hand-dug wells. The water samples were collected using precleaned 500 cm3 glass bottles and were analysed for the presence of 16 US EPAPAHs using Gas Chromatography – Flame Ionisation Detector (GC- FID). The validated method showed that regression (R2) for all the PAHs ranged between 0.9622 and 0.9983. Limits of detection (LOD) ranged from 0.0033 to 0.1236 µg L−1 and limits of quantification (LOQ) from 0.0109 to 0.4115 µg L−1. Precision CV values ranged from 5.12 to 18.24%, and recovery values of the analytes in water varied between 83.94 and 99.99%. Naphthalene and chrysene were present in all the water samples while pyrene was absent in all except in Iyiutu. All the PAHs analysed were detected in Isiachala and Iyiutu except pyrene which was absent in Isiachala. All the samples contained at least three PAHs with concentrations ranging from 1.003 ng/µl of benzo[a] pyrene in Tabasi to 128.652 ng/µl of chrysene in Iyiutu. Ecological risk shows that the value was above US EPA background value. Human health risk assessment depicts that hazard index and total cancer risk ranges from 9.63E-05 to 1.93E-02. This study has shown that the inhabitants of Ifite Ogwari will experience adverse health and cancer illnesses over some time and therefore, a holistic approach by researchers and government agencies is needed to mitigate the ecological and health risk effects.