RESUMO
Instrumental neutron activation analysis using the single-comparator method has been used for the multielement determination of essential elements in two main types of Pito brewed locally in Ghana. The precision and accuracy of the analytical method was validated and found to be within 10%. In all, eight different brands of Pito depending on the type of cereal crop used in brewing were analyzed for 13 different elements (Al, As, Ba, Cl, Co, Cu, Fe, K, Mg, Mn, Na, Si, and Zn). It was observed that all brands were particularly enriched in nutrient elements Cl, Mg, and K. The rest were generally found in varying concentrations. As these elements are bioavailable in natural form, perhaps in combination with organic constituents, they are likely to be easily digested and assimilated by the human body. Arsenic, a toxic element, was found in insignificant amounts suggesting that it was within safe limits.
RESUMO
The concentrations of airborne particulate matter (PM) in Navrongo, a town in the Sahel Savannah Zone of Ghana, have been measured and the major sources have been identified. This area is prone to frequent particulate pollution episodes due to Harmattan dust and biomass burning, mostly from annual bushfires. The contribution of combustion emissions, particularly from biomass and fossil fuel, to ambient air particulate loadings was assessed. Sampling was conducted from February 2009 to February 2010 in Navrongo. Two Gent samplers were equipped to collect PM10 in two size fractions, coarse (PM10-2.5) and fine (PM2.5). Coarse particles are collected on a coated, 8-microm-pore Nuclepore filter. Fine particle samples were sampled with 47-mm-diameter Nuclepore and quartz filters. Elemental carbon (EC) and organic carbon (OC) concentrations were determined from the quartz filters using thermal optical reflectance (IMPROVE/TOR) methods. Elements were measured on the fine-particle Nuclepore filters using energy-dispersive x-ray fluorescence. The average PM2.5 mass concentration obtained at Navrongo was 32.3 microg/m. High carbonaceous concentrations were obtained from November to March, the period of Harmattan dust and severe bush fires. Total carbon was found to contribute approximately 40% of the PM2.5 particulate mass. Positive matrix factorization (PMF) suggested six major sources contributing to the PM2.5 mass. They are two stroke engines, gasoline emissions, soil dust, diesel emissions, biomass burning, and resuspended soil dust. Biomass combustion (16.0%) was identified as second most important source next to soil dust at Navrongo.
