Atmospheric Pollution Assessment from a Mountainous Environment in Southern Ghana: Case Study of Abetifi

ABSTRACT 

In the pursuit to improve man’s livelihood, human activities which include emission of heavy metals from various industries and sectors, as well as the past use of chemicals such as pesticides, polychlorinated biphenyls and flame retardants have often mobilized and redistributed natural substances and anthropogenic pollutants into the atmosphere, predisposing it to relatively high concentrations of such pollutants even in pristine areas in the environment. This study assessed the level of atmospheric pollution, contributing sources and human health exposure risk of persistent organic pollutants (POPs) along with selected heavy metals with focus on Abetifi, one of the highest altitude environments in Ghana. Passive sampling with polyurethane foam (PUF) as adsorbent was employed. Samplers were deployed every 84 days for two years. A total of 65 polyurethane foams were deployed and twelve (12) groups of analytes were considered together with their various isomers. High resolution gas chromatographic technique coupled with high resolution mass spectrometry (HRGC-HRMS) and electron capture detectors (ECD) were used in the analysis of the POPs. Besides, high performance liquid chromatography (HPLC) coupled with MS was employed in analysing the perfluorinated compounds (PFCs) while the heavy metals were analysed using Atomic Absorption Spectrometer (AAS). Principal Component Analysis (PCA) and UNMIX model were used to group pollution source contribution of all analytes (POPs and heavy metals) in this study. Diagnostic isomer and other predictive ratios were also employed for source apportionment of various individual analyte groups. Results revealed that polychlorinated dibenzo-furans gave with the least total mean concentration (0.074 pg/m3 ) for the sampling period and polybrominated biphenyls gave the highest (55 pg/m3 ). The pesticide group gave values in the order of DRINs 2 (53 pg/m3 ) > DDT (41 pg/m3 ) > HCHs(28 pg/m3 ). Data for perflourinated compounds (PFCs) in the atmosphere at Abetifi was recorded with a maximum total concentration (Σ8) of 15 pg/m3 . The human exposure level to dioxin-like chemicals in the air at the study location was 0.0067 pg TEQ/kg bw per day. The atmospheric pollution source observed at Abetifi was a mixed one consisting of agricultural, vehicular and from burning of biomass. Agricultural source was basically as a result of re-volatilization from polluted sinks (a secondary pollution source).