Abstract:
Tree bark samples collected from a major roadway in Akure during the dry and wet seasons were analyzed to determine the concentration of Polycyclic Aromatic Hydrocarbons (PAHs) components which are often the targets in environmental check. Also soil samples on the same road were collected both morning and evening to test for the presence of Heavy metals in the road.
Identification and quantification of the PAHs components was accomplished using an Agilent 7890 Gas Chromatograph 5975 Mass selective Detector (GC-MS) after Ultrasonic extraction of the sample and clean up of the extract. The Heavy metals present in the soil samples were also quantified using Atomic Absorption Spectrometry after being digested with nitric acid, hypochloric acid and hydrofluoric acid.
The concentration of the total PAHs components such as NAP, ANY, ANA, FLU, PHE, FLT,
ANT, PYR e.t.c detected in the samples ranges from 0.02 to 0.35 in the dry season while it ranges from 0.01 to 0.54 in the wet season. Also the heavy metals such as Cd, Cu, Mn, Fe, Ni, Zn, Pb and Cr ranges from 0.00 mg/kg to 6.70 mg/kg in the morning samples and 0.00 mg/kg to 8.23 mg/kg
in the evening samples.
The study was carried out to examine pollution rate and health risk assessment of PAHs in tree (Azahirachta indica, Therminalia mantaly, Anacardium occidentae, Mangifera indica and Sterculia apetala) and the Health risk index of the metals is < 1, this is an indication that the sources of the metals were mainly from anthropogenic sources which could be traced to vehicular emissions and fossil fuel burning. Planting of herbs and edible trees along the roadside should be discouraged and also, continuous monitoring and further studies of the area are recommended to ascertain long term effects.
