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Accumulation of Metals and Polychlorinated Biphenyls (PCBs) in Soils around Electric Transformers in the Central Region of Ghana

Bentum J. K., Dodoo, D. K. and Kwakye P. K

Twenty six hot spots of PCBs pollution in the central Region of Ghana were investigated. Soil samples were collected from around twenty six transformers in the central region. The soil samples were extracted with hexaneacetone mixture (1:1 v/v) for 16 hours and the extract cleaned up with concentrated sulphuric acid (1+1), 5% (w/v) aqueous potassium permanganate and copper granules. The extract was eluate with hexane: dichloromethane (97:3 v/v), concentrated to 1 ml, transferred into a pre cleaned 2 ml vial with acetate ethyl resins and acetate ethyl added to the vial to make the total volume 2 ml. This was analyzed for PC Bsusing GC – ECD. The soils were digested withHNO3 and HClO4 acid, and analyzed for metals by Varian 235 AAS. The mean concentration of the ΣPCB (8.17 ± 2.96 μg/kg) was much lower than the 25 mg/kg recommended level. The ΣPCB ranged between 1.32 and 12.94 μg/kg. The mean concentration (in mg/kg) of the metals were Zn (94.70 ±123.87) >Pb (26.68± 37.27) > Cu (21.63±20.51) > Al (0.70± 0.38) > Fe (0.06±0.03)> Ag (0.06±0.20). The variations in the levels of the metals were in the order Ag >Pb> Zn >Cu >Al > Fe. Very few site were found to be contaminated with metals, but the level of metal contamination was very low. There was no significant correlation between the PCBs and any of the metals. However, significant relations were observer among some metals. Correlations between the metals agreed with the results obtained by PCA. The sources of the PCBs and metal were anthropogenic.