Health risk and groundwater contamination by the polycyclic aromatic hydrocarbons in wells and boreholes around the Okinni Osogbo service station, Osun State, Nigeria

Abstract

This study investigated the levels and potential toxicity of polyaromatic hydrocarbons (PAHs) in underground water near a gas station within the Okinni locality, Osun State, Nigeria. Water samples from six locations were analysed with gas chromatography–mass spectrometry. Low-molecular-weight PAHs, naphthalene, acenaphthene and acenaphthylene were undetected. However, 3-ring PAHs (fluorene, phenanthrene and anthracene) were found across most sites, exceedingthe maximum contamination level of 0.0002 µg/mL set by the United States Environmental Protection Agency and the World Health Organization (0-0.005 µg/mL). High molecular weight PAHs also surpassed the Canadian Council of Ministers of the Environment's water quality guideline threshold (1.5 × 10−5–5.8 × 10−3 µg/mL). The health risk revealed average toxicity values ranging from 2.6 × 10−4 to 1.8 × 10−3 for adults and 6.06 × 10−4 to 4.18 × 10−3 for children, indicating potential carcinogenic health risks. Given that the values exceeded acceptable limits (1.0 × 10-6). There is an urgent need for attention from relevant authorities to protect public health. The risks would be largely subject to ingestion frequency, duration, and individual vulnerability, emphasizing the need for prompt action to safeguard the health of the populace. The findings suggest a possible unacceptable health risk from exposure to PAHs.