engleski

Surface water characterization of three rivers in the Pb/Zn mining region of north-eastern Macedonia

The mine waste was recognized as one of the most serious threats for freshwater ecosystems, and it still represents one of the biggest environmental concerns in Macedonia. The aim of our investigation was to obtain in-depth understanding of the mining influence on freshwater systems, from the water contamination to the effects on aquatic organisms. In this paper we have assessed the impact of active Pb/Zn mines Zletovo and Toranica on water quality of three rivers in north-eastern Macedonia (Bregalnica, Zletovska and Kriva), based on the data collected in spring and autumn of 2012. The Bregalnica River, near Shtip, was characterized mainly by weak contamination with As, Ba, Fe, Mo, Ti, U, V, nitrate and phosphate, and critical faecal pollution, which alltogether could be connected to agricultural activities, whereas the impact of the mines was not observed. Contrary, both Zletovska and Kriva rivers revealed a clear impact of Pb/Zn mines on water quality. In the Zletovska River, increased concentrations of Cd, Co, Cs, Cu, Li, Mn, Ni, Rb, Sn, Sr, Tl, Zn, sulphates and chlorides were found, especially in autumn (e.g. Cd: 2.0 µg L-1 ; Mn: 2.5 mg L-1 ; Zn: 1.5 mg L-1). In the Kriva River, increased Cd (0.270 µg L-1) and Pb (1.85 µg L-1) concentrations were found only in spring, possibly due to sediment resuspension during higher water discharge. The selected sampling sites on Bregalnica, Zletovska and Kriva rivers were confirmed as the appropriate locations for further studies of mining waste impact on the freshwater ecosystems, the first one as non-impacted site, and the other two as possible areas of increased exposure of aquatic organisms to metals.

bacterial counts; metals; mining; rivers; surface water quality

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