Ambient Air Measurement of Benzene, Toluene and Xylene Within a Nigerian Petroleum Products Depot and Its Host Environment Using Carbon Adsorption and GC-FID Techniques
Health effects of benzene, toluene and xylene emissions from a Nigerian Petroleum Products depot make stringent adherence to maximum allowable concentration very important. The storage facilities and distribution network and other installations of petroleum products depot are significant sources of benzene, toluene and xylene therefore ambient air of the depot requires observation and assessment. The ambient air concentrations of BTX were been measured within Pipelines and Product Marketing Company, Mosimi Depot and its immediate environment. Air samples were collected on granular activated charcoal through low volume air sampler and extracted with carbon disulphide (CS2) by desorption process.The extracted solutions were subjected to Flame Ionization Detection analysis in a gas chromatograph (Model: HP 6890) using a capillary column HP 5MS with length, inner diameter and particle size set at 30 m × 0.25 mm × 0.25 μm. The gas chromatograph was powered with chemstation RevA09.01  software to determine the concentrations of each of the identified VOCs species. The concentrations of benzene, toluene, p xylene, m xylene and o xylene ranged between 0.0104 - 0.0711, 0.0019 - 0.0998, 0.0010 - 0.0022, 0.0014 - 0.0026 and 0.0006 0.0019 mg/m3 respectively. The mean values were 0.0277, 0.0389, 0.0013, 0.0019 and 0.00010 mg/m3, respectively. On the average, the observed concentrations did not exceed the tolerance (air concentrations) limits set for Nigeria environment by the National Environmental Standards and Regulations Enforcement Agency (NESREA).