Browsing by Author "Akoto, O."
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Item Accumulation of Heavy Metals and Metalloid in Foodstuffs from Agricultural Soils around Tarkwa Area in Ghana, and Associated Human Health Risks(International Journal of Environmental Research and Public Health, 2015-07) Bortey-Sam, N.; Nakayama, S.M.M.; Akoto, O.; Ikenaka, Y.; Fobil, J.N.; Baidoo, E.; Mizukawa, H.; Ishizuka, M.This study was carried out to assess the extent of heavy metals and metalloid accumulation from agricultural soils to foodstuffs (viz, M. esculenta (cassava) and Musa paradisiaca (plantain)) around thirteen neighboring communities within Tarkwa, Ghana; and to estimate the human health risk associated with consumption of these foodstuffs. Concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn were measured with an inductively coupled plasma-mass spectrometer and mercury analysis was done using a mercury analyzer. From the results, 30% of cassava samples collected, contained higher concentrations of Pb when compared to Codex Alimentarius Commission standard values. Bioconcentration factor indicated that Ni had higher capacity of absorption into food crops from soil than the other heavy metals. For both children and adults, the target hazard quotient (THQ) of Pb in cassava in communities such as Techiman, Wangarakrom, Samahu, and Tebe (only children) were greater than 1, which is defined as an acceptable risk value. This indicated that residents could be exposed to significant health risks associated with cassava consumption.Item Isolation and characterization of dipeptide derivative and phytosterol from Capparis tomentosa Lam(Scientific Research and Essays, 2008-08) Akoto, O.; Oppong, I.V.; Addae-Mensah, I.; Waibel, R.; Achenbach, H.In this study, chemical investigation of the constituents of the roots of Capparis tomentosa was carried out. C. tomentosa is a medicinal plant used extensively for the treatment of various diseases. It is also known to be poisonous. The crude petroleum ether extract of the roots of this plant was subjected to column chromatography for separation. Progress of separation was monitored by thin layer chromatography. The isolated compounds were recrystallized for further purification. The structures of these compounds were elucidated by comparison of their spectroscopic data from IR, 1HNMR, 13CNMR and MS analysis with that of authentic samples. The isolated compounds were identified as 24-ethylcholestan-5-en-3-ol a phytosterol and a dipeptide derivative, N-benzoylphenylalanylaninol acetate. This is the first time these compounds have been isolated from this plant. © 2008 Academic Journals.Item Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana(Environmental Science and Pollution Research, 2012-06) Adu-Kumi, S.; Kareš, R.; Literák, J.; Borůvková, J.; Yeboah, P.O.; Carboo, D.; Akoto, O.; Darko, G.; Osae, S.; Klánová, J.Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p′- and p,p′-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m-3 (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p′-DDT/p,p′-DDE ratio suggested recent inputs of fresh technical DDT. © 2012 Springer-Verlag.