Characterized Organic Pollutants and Their Health Effects in Sampled Groundwater Around Ilorin Metropolis

Abstract

The study was aimed at determining the possible volatile organic compounds present in groundwater from hand-dug wells within and around filling stations across Ilorin metropolis as well as to ascertain the possible sources of the contaminants and their health effects. Water samples were obtained from twenty-six (26) wells that were found within the scope of stations above the age of 15 years and functioning with underground storage tank capacities of over 33,000 L each for different petroleum products stored above the water level. Laboratory analysis to determine volatile organic compounds and their concentrations were carried out using the gas chromatography- mass spectrophotometer (GC-MS) after prior extraction of hydrocarbon from the water samples by the Liquid-Liquid Extraction (LLE) method. The result revealed a total of fifty-three (53) VOCs across samples where nonanal, dodecane, methyl palmitate, heptanophenone, 13, hexyloxacyclotridec – 10 – en – 2 – one, cyclohexane, octyl, decahydro- 4, 4, 8, 9, 10 – pentamethyl naphthalene, (z) – 3 – heptene, were the most frequently occurring compounds, which could be traced to anthropogenic activities involving the use of paints, detergents, stain removers, leaking underground storage tanks, piped networks containing petroleum products as the possible sources of release into the environmental media. Related health impacts from exposure to these contaminants includes brain damage, cancer, tumours, anaemia, central and peripheral nervous system breakdown, liver, bones, autism, Skin, eye, and nose irritation, headache, dizziness, narcosis, and death at high levels of exposure. The study concluded that groundwater sources at close proximity to filling stations are susceptible to contamination through activities in the stations and such water resource should be treated before consumption and use to avoid negative health effects.