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|Title: ||Characterization, Spatial Variation and Risk Assessment of Heavy Metals and a Metalloid in Surface Soils in Obuasi, Ghana|
|Authors: ||Akoto, Osei|
Nakayama, Shouta M.M.
Marfo, Jemima Tiwaa
|Issue Date: ||2018|
|Publisher: ||Journal of Health & Pollution|
|Citation: ||Journal of Health & Pollution, Vol. 8, No. 19|
|Abstract: ||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
|Description: ||This article is published in Journal of Health & Pollution|
|Appears in Collections:||College of Science|
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