US EPA

4834245 

Journal Article 

Distribution and chemical speciation of molybdenum in river and pond sediments affected by mining activity in Erdenet City, Mongolia 

Solongo, T; Fukushi, K; Altansukh, O; Takahashi, Y; Akehi, I; Baasansuren, G; Ariuntungalag, Y; Enkhjin, O; Davaajargal, B; Davaadorj, D; Hasebe, N 

2018 

1 

Minerals
ISSN: 2075-163X 

8 

7 

288 

English 

10.3390/min8070288 

WOS:000440860400026 

Rivers and ponds near the Erdenet mine, one of the world's largest copper-molybdenum mines, exhibit high concentrations of molybdenum (Mo). This study evaluates the distribution and chemical speciation of Mo in surface sediments from ponds and rivers in Erdenet city to elucidate the mobility and solubility of Mo in the surface aquatic environments in the area. The waters and sediments were collected in two shallow ponds connected to the tailing pond and from three rivers flowing through Erdenet city. The distribution and chemical speciation of Mo in the sediments were examined using five-step sequential extraction and X-ray absorption fine structure (XAFS) analyses. The XAFS spectra of the sediments showed that large amounts of Mo in the sediments are molybdate or polymeric molybdate, weakly adsorbed onto ferrihydrite. Sequential extraction consistently showed a large amount of Mo distributed in the labile fractions. Results suggest that the surface sediments from ponds and rivers play a role as secondary contamination sources of Mo rather than as sinks of Mo in the area. 

Erdenet mine; molybdenum; sediment; chemical speciation; XAFS; sequential extraction