Iodide- and electrochemical assisted removal of mercury by Cirsium arvense from gold tailings in the Amansie West District, Ghana.

Mercury (Hg) pollution in Ghana through mining has become a serious environmental challenge. This study investigates the potential of Cirsium arvense to photostabilize Hg using electrokinetic current with or without an iodide solution in gold mine tailings heavily contaminated through mining activities in southern Ghana. An initial Hg concentration of 9.60 mg/kg using cold vapor atomic absorption spectrometry (CVAAS) was determined. The biological absorption coefficient, bioconcentration factor, and translocation factor of Hg have been presented. Cirsium arvense therefore had a higher bioconcentration factor (BCF) of 2.6-5.15 mg/kg, and a transfer factor (TF) of 0.24-0.36 indicating a higher efficiency for phytostabilization. Both the rate and time of extractions of Hg from the tailings by Cirsium arvense are efficiently improved in the combined electric current and iodide treatment. Plant and electric current combined treatment and plant and iodide combined treatment had only 60 and 50% phytostabilization rates, respectively. The combined plant, iodide, and electric current treatment has proven to be superior with about >90% Hg removal rate. Therefore, the combined plant, iodide, and electric current treatment resulted in a higher Hg removal efficiency by Cirsium arvense in a shorter period due to higher solubilization rate and electromigration effects on Hg species.

A comparative study of the pollution status of Sakumo II and Muni lagoons in Ghana.

The pollution status of Sakumo II and Muni Lagoons and Mamahuma and Gbagbla Ankonu feeder streams, which feed Sakumo II along the coast of Ghana, were assessed and compared. As expected of saline waters, pH values of both lagoons fell within a slightly neutral to saline range whilst, the feeder streams were moderately saline. Conductivity distribution also showed saline (>5.0 mS cm(-1)) characteristics of the lagoons, while, the feeder streams are brackish (1.5-5.0 mS cm(-1)). DO concentrations in both lagoons indicated a wide variation. Relatively high BOD and nutrients content of Sakumo II and the feeder streams suggested that, Sakumo II and its feeder streams are moderately to grossly polluted. However, Muni Lagoon was characterized by relatively low BOD and nutrients content suggesting relatively low anthropogenic impact. The ionic dominance patterns for Sakumo II and Muni Lagoons were: Na(+) > Mg(2 + ) > Ca(2 + ) and Cl(-) > HCO(3)(-) > SO(4)(2-), Na(+) > Ca(2 + ) > Mg(2 + ) and Cl(-) > HCO(3)(-) > SO(4)(2-), respectively. Using water quality index (WQI), Sakumo II was found to be grossly polluted and requires mitigation measures, while, Muni Lagoon was of fairly good quality and requires monitoring.

The hydrochemistry of groundwater in the Densu River Basin, Ghana.

Hydrochemical analyses of groundwater samples were used to establish the hydrochemistry of groundwater in the Densu River Basin. The groundwater was weakly acidic, moderately mineralized, fresh to brackish with conductivity ranging from of 96.6 microS cm(-1) in the North to 10,070 microS cm( - 1) in the South. Densu River basin have special economic significance, representing the countries greatest hydrostructure with freshwater. Chemical constituents are generally low in the North and high in the South. The order of relative abundance of major cations in the groundwater is Na+>Ca2+>Mg2+>K+ while that of anions is Cl->HCO3->SO4(2-)>NO3-. Four main chemical water types were delineated in the Basin. These include Ca-Mg-HCO3, Mg-Ca-Cl, Na-Cl, and mixed waters in which neither a particular cation nor anion dominates. Silicate weathering and ion exchange are probably the main processes through which major ions enter the groundwater system. Anthropogenic activities were found to have greatly impacted negatively on the quality of the groundwater.