CHARACTERISTIZATION, SOURCE IDENTIFICATION AND POTENTIAL HEALTH RISKS OF ATMOSPHERIC PM2.5-BOUND POLYCYCLIC AROMATIC HYDROCARBONS IN AUTO MECHANIC WORKSHOPS AROUND UWELU MOTOR SPARE PARTS MARKET, BENIN CITY

ABSTRACT

This study investigated PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in order to determine the seasonal changes in total PAH concentrations, to estimate carcinogenic risk of exposure and to identify possible sources by using Cluster Analysis and Principal Component Analysis, two statistical tools, and diagnostic Ratios of PAHs. The sampling period was from February to June 2019. Casella Apex-2IS PM2.5 sampler equipped with 37-mm quartz membrane filters were operate data flow rate of 3.5Lmin –1 for 8hours. The concentrations of 16 PAHs were determine through gas chromatography –flame ionization detector. The results revealed the PM2.5 and total PAHs in the two seasons ranged from 2604.16 to 7351.18µg/m3 and 585.86 to 764.07ng/m3 respectively. The highest contributions to the total PAH level were made by Benzo(g,h,i)perylene [289.03 ng/m3 ], Indeno(1,2,3-c,d)pyrene[130.51ng/m3 ], Benzo(a)pyrene[122.63ng/m3] and Dibenz(a,h)anthracene [99.06ng/m3 ] while lower values were recorded for other PAHs like Anthracene[4.40ng/m3 ], Phenanthrene [3.22ng/m3 ], Fluoranthene[1.7ng/m3 ], Pyrene[3.65 ng/m3 ], Chrysene[12.91ng/m3 ], Benzo(a)Anthracene[5.27ng/m3 ], Benzo(k)Fluoranthene[16.77ng/m3 ] and benzo(b)Fluoranthene [72.20ng/m3 ] while BAP-TEQ was 2.73×10 -7 ng/m3