ELEMENTAL CHARACTERIZATION OF PM2.5 AND TORAL SUSPENDED PARTICULATE (TSP) IN AUTO-MECHANIC WORSHOPS AROUND UWELU MOTOR SPARE PARTS MARKET, BENIN CITY.

ABSTRACT

Particulate matter (PM) are basically released into the environment through anthropogenic activities such as combustion processes which includes vehicular emissions, combustion of fossil fuel, metal smelting, which significantly pollutes the environment, thereby having negative effects on man and its environment. Particulate matter comprises of different particles size, ranging from ultrafine particles to total suspended particulates and various composition, the major components are the organic and the inorganic (metals) and these are the once that have cause for health concern. Metals have divers of adverse effects on the environment and on the human body In this study, PM2.5 and TSP were collected during the dry and wet season using APEX2IS Casella standard pump coupled with conical inhalable sampler (CIS) head at a flow rate 3.5L/min for a sampling period of 8 hours per day. The weight of the sample collected were determined gravimetrically and analyzed for heavy metal concentration in PM2.5 and TSP using Atomic Absorption Spectroscopy (AAS) method. The results obtained were subjected to Statistical analysis such as principal component analysis (PCA) for source identification, cluster analysis and correlation matrix. PM2.5 concentration obtained ranged from 2604.16 - 7351.18 µg/m3 , while TSP levels obtained ranged from 10758.91 - 16458.34 µg/m3 . The highest concentrations for both PM2.5 and TSP were obtained in February and the least concentrations in June. The heavy metals analysis showed that the highest value of lead (1.08 and 2.78 µg/m3 ) and cadmium (0.73 and 1.36 µg/m3 ) for PM2.5 and TSP respectively in all sampling sites had values which exceeded those of the regulatory limits (0.5 µg/m3 for lead) and (0.005 µg/m3 for cadmium), while other like chromium, zinc, nickel, cadmium, iron, arsenic and manganese were below the regulatory limits. The PCA result identified vehicular emission, as a major source of emission into the environment. Correlation matrix revealed strong positive correlation among some metals, others negative correlation and some were not correlated. The concentration of PM2.5 recorded in this study were higher than safe limit stated by regulatory bodies (WHO, FEPA, FMNEW).