Biomonitoring of atmospheric trace element deposition around an industrial town in Ghana

Parmelia sulcata lichen species have been used to study the atmospheric deposition of heavy metals and other toxic elements around an industrial area in Ghana. Natural soil samples were collected at all the sampling points and analysed in order to investigate surface accumulation of the heavy metals. The sampling points used for the study were: Afienya, Doryemu Cemetery and Doryemu River. The surface accumulation of the heavy metals would be used to examine the correlation of the elements in the lichen and soil samples in order to separate contributions from atmospheric deposition and from that of soil minerals. Thermal neutron activation analysis techniques employing a 30 kW tank-in-pool research reactor operating at a thermal neutron flux of 5×1011 s−1 cm−2 was used to determine Al, Cr, Mn, Fe, Ti, Th and V in both the lichen and soil samples. The level of contamination was quantified using the enrichment factor approach. This approach was adopted in order to ascertain whether these elements are enriched in the soil or in the atmosphere. The sampling points were enriched in the atmosphere with Cr, Mn, Fe, Ti, Th and V in the decreasing order of Afienya, Doryemu Cemetery and Doryemu River.