Vincent Kodzo Nartey

Heavy Metals in Sediments of the Gold Mining Impacted Pra River Basin, Ghana, West Africa

Total concentrations of Hg, Al, Fe, As, Pb, Cu, Cr, Ni, Mn, Co, V, and Zn were determined in surface sediments collected from 21 locations within the gold mining impacted Pra River basin in southwestern Ghana. Samples were collected during both the rainy and dry seasons. We hypothesized that in the rural southwestern portion of Ghana, the lack of industrial activities makes artisanal gold mining (AGM) by Hg amalgamation the main source of water resource contamination with heavy metals. Therefore, metals showing concentration trends similar to that of Hg in the studied system are likely impacted by AGM. We found that total-Hg (THg) concentrations in riverine sediments are rather low as compared to other aquatic systems that are impacted by similar mining activities. Measured THg concentrations ranged from 0.018 to 2.917 mg/kg in samples collected in the rainy season and from about 0.01 to 0.043 mg/kg in those collected during the dry season. However, the determination of the enrichment factor (EF) calculated using shale data as reference background values showed signs of severe contamination in most of the sampled sites. In the dry season, THg concentrations correlated positively and significantly to the concentrations of As (r = 0.864, p < 0.01), Cu (r = 0.691, p < 0.05), and Ni (r = 0.579, p < 0.05). Based on our previously stated hypothesis, this could then be an indication of the impact of AGM on ambient levels of these 3 elements. However, the determined concentrations of Cu, and Ni co-varied significantly with Al, suggesting that natural sources do account for the observed levels. Accordingly, both AGM and metal inputs from weathered natural deposits are likely co-responsible for the observed levels of Cu and Ni. In contrast, the lack of correlation between As and Al tends to suggest an impact of AGM on As levels. Overall, our data suggest that besides Hg and to some extent As, the impact of AGM on ambient levels of investigated metals in the gold mining impacted Pra River remains negligible. Finally, the increase in metal concentrations from the dry to the rainy season underlines the impact of changes in hydrologic conditions on levels and fate of metals in this tropical aquatic system.

Analysis of leachates from solid waste dumpsites: a tool for predicting the quality of composts derived from landfills

Leachate and soil samples were collected near five solid waste dump sites in the Accra metropolitan area of Ghana over a period of six months. The leachate samples were analysed for heavy metals, coliform bacteria and helminth eggs while the soil samples were analysed for only helminth eggs. Heavy metals analysed included Cd, Pb, Zn, Mn, and Cu. It has been observed that the leachates contain high levels of these heavy metals and pathogens. The high heavy metal levels make the solid wastes suitable for composting only after sorting since this would remove materials which serve as sources of these heavy metals. With the high faecal and total coliform levels, choice of composting temperature and period of intensive decomposition and curing, would be key in getting rid of the pathogens.

Essential and non-essential trace elements among working populations in Ghana

BACKGROUND Lead battery repair workers (LBRW) and electronic repair workers (ERW) may be exposed to inorganic components during work. This study aimed at determining essential and non-essential trace elements in male LBRW, ERW, referents and a group of female petty traders (FPT) in Kumasi (Ghana), taking into account iron status and inflammation. METHODS Altogether 64 LBRW, 64 ERW, 65 referents and 26 FPT were investigated in this cross-sectional study. Urine, whole blood and serum were collected for determination of trace elements. C-reactive protein and ferritin were determined in serum. RESULTS The LBRW had higher blood concentrations of manganese (B-Mn) and lead (B-Pb) and antimony in urine (U-Sb), and lower concentrations of cobalt in blood (B-Co). Being ERW was associated with higher concentrations of blood cadmium (B-Cd), urinary tin (U-Sn) and serum chromium (S-Cr). Concentrations of selenium (B-Se), Co and mercury (B-Hg) in whole blood and iodine in urine (U-I) were relatively high. Marginal iron status appeared to be a determinant for elevated concentrations of Co in particular, but also Mn and Cd in blood. Systemic inflammation was associated with the concentrations of copper and Se. The concentrations of Hg in whole blood were highly associated with Se and arsenic (As) in whole blood, indicating fish consumption as a common source of intake of these elements. However, Hg in whole blood was only slightly associated with Se in serum. CONCLUSIONS The ERW had elevated concentrations of B-Cd, S-Cr, and U-Sn, while B-Mn, B-Pb, and U-Sb concentrations were higher among the LBRW. Iron status and inflammation had substantial impact on some element concentration. This population had high concentrations of B-Se, B-Hg and B-Co and U-I.