Browsing by Author "Baidoo, Elvis"

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    Characterization, Spatial Variation and Risk Assessment of Heavy Metals and a Metalloid in Surface Soils in Obuasi, Ghana
    (Black Smith Institute, 2018-08) Akoto, Osei; Bortey-Sam, Nesta; Nakayama, Shouta M.M.; Ikenaka, Yoshinori; Baidoo, Elvis; et. al
    Soil contamination with heavy metals and metalloids has become an increasingly important issue in recent years. Objectives. The present study examines possible contamination of the environment with metals from gold mining activities in Obuasi, Ghana. Methods. Soil samples were collected from commercial and residential areas and tailing dams in Obuasi in order to investigate the extent of lead (Pb), cadmium (Cd), mercury (Hg), copper (Cu), zinc (Zn), cobalt (Co), chromium (Cr), nickel (Ni) and arsenic (As) pollution, create thematic maps showing the extent of heavy metals pollution, identify the sources of pollution, and to assess risks to humans and the surrounding ecological system. Results. Mean concentrations of metals from the study were found in the order of As > Cu > Zn > Cr > Ni > Pb > Co > Hg > Cd. The results showed that all communities were severely polluted with As, and distribution maps highlighted two hot spots at the sulfite treatment plant and Pompura treatment plant tailings dams. Additionally, the levels of Pb, Cu and Zn were elevated around the city center where vehicular traffic is very dense. Principal component analysis indicated that mining activities may have significantly contributed to metal levels in Obuasi soils. The potential ecological risk (RI) indicated that soils in 41% of the communities pose very high risks to the surrounding ecological system, 50% pose considerable risk, and 9% pose a moderate risk. Arsenic and Hg contributed 73 and 15% of the RI, respectively. The average hazard quotient due to soil As exposure was 2.51 ± 1.23 and ingestion of soils in 95% of the communities in the study area could pose non-carcinogenic health risks to children. Moreover, the average cancer risk for children from the communities was 1.13 × 10-3. Based on the United States Environmental Protection Agency (USEPA) recommendation for cancer risk of 10-6 to 10-4, the cancer risk for children (> 10-3) was higher in 45% of the studied communities. Conclusions. The central part of the study area is polluted with Pb, Zn and Cu, and As pollution is severe in all of the studied communities. The RI from all study sites revealed very high risk to the ecological system, including mammals. There could be non-cancer and cancer risks to Obuasi residents due to ingestion of As-contaminated soils, and children are particularly vulnerable. Competing Interests. The author declares no competing financial interests
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    Contamination Levels and Sources of Heavy Metals and a Metalloid in Surface Soils in the Kumasi Metropolis, Ghana
    (Black Smith Institute, 2017-09) Akoto, Osei; Bortey-Sam, Nesta; Ikenaka, Yoshinori; Nakayama, Shouta M.M.; Baidoo, Elvis; et. al
    Environmental contamination with heavy metals and metalloids due to industrial, smelting and mining activities have become common in large and growing cities. Kumasi is one of the most industrialized cities in Ghana and experiences metal pollution due to recent and past activities. Although metals are naturally abundant in the area, their accumulation in soils could potentially lead to adverse effects on local ecosystems. Objectives. The aims of this study were to determine the distribution, enrichment, geo-accumulation and sources of metals in Kumasi soils and to estimate the contamination factor (CF) and pollution load index (PLI) of these metals in soils. Methods. Concentrations of eight heavy metals and a metalloid were determined in 112 soil samples randomly collected from 31 sampling sites in the area. In addition, 5 soil samples were collected from a pristine site (Kwame Nkrumah University of Science and Technology Botanical Gardens) for data comparison, to determine the local background values for metal concentrations and to evaluate the extent of metal pollution in the study area. Results. Heavy metals such as zinc (Zn), lead (Pb), cadmium (Cd) and chromium (Cr) were enriched in 65, 32, 58 and 93% of the sampling sites, respectively, and geo-accumulation indexes for Cr, Zn, Cd, mercury (Hg) and Pb showed moderate to extreme contamination in 100, 97, 77, 65 and 45% of the sampling sites, respectively. Principal component and cluster analyses revealed that industrial activities including mining were the major sources of metals in Kumasi soils with high metal input in the community of Suame. Distribution maps revealed hotspots of Cd, nickel (Ni), arsenic (As), cobalt (Co), copper (Cu) and Pb in Suame. The highest CFs for Cu, Cd, Ni, As, Co and Pb highlighted anthropogenic inputs in Suame, while Hg was highest in Mbrom, Zn in Suntreso, and Cr in Aboabo. Conclusions. The PLI of metals revealed Suame as the most polluted study site, while Anomangye and Bomso were the least polluted. Competing Interests. The authors declare no competing financial interests.
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    Human health risks from metals and metalloid via consumption of food animals near Gold Mines in Tarkwa, Ghana: Estimation of the daily intakes and target hazard quotients (THQs)
    (Academic Press, 2015-01-01) Bortey-Sam, Nesta; Nakayama, Shouta M.M.; Ikenaka, Yoshinori; Akoto, Osei; Baidoo, Elvis; et. al
    Heavy metal and metalloid contamination in food resulting from mining is of major concern due to the potential risk involved. Food consumption is the most likely route for human exposure to metals. This study was therefore to estimate the daily intake and health risk (based on target hazard quotients, THQ) from metals via consumption of free-range chicken, goat and sheep near gold mines in Tarkwa, Ghana. The concentrations of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb were measured with an inductively coupled plasma33 mass spectrometer and Hg analysis was done using the mercury analyzer. The mean concentrations of metals ranged from nd–542 mg/kg wet weight. Principal component analysis of the results showed a clear separation between chicken, grouped on one side, and the ruminants clustered on another side in both offal and muscle. Interestingly, As, Cd, Hg, Mn and Pb made one cluster in the offal of chicken. Chicken muscle also showed similar distribution with As, Hg and Pb clustered together. The daily intake of As (μg/kg body weight/day) were in the following ranges; [0.002 (kidneys of goat and sheep)–0.19 (chicken gizzard)], Cd [0.003 (chicken muscle)–0.55 (chicken liver)], Hg [0.002 (goat muscle)–0.29 (chicken liver)], Pb [0.01 (muscles and kidneys of goat and sheep)–0.96 (chicken gizzard)] and Mn [0.13 (goat kidney)–8.92 (sheep liver)]. From the results, daily intake of As, Cd, Hg, Pb and Mn in these food animals were low compared to the provisional tolerable daily intake guidelines. The THQs although less than one, indicated that contributions of chicken gizzard and liver to toxic metal exposure in adults and especially children could be significant.