EVALUATION OF SURFACE WATER QUALITY IN THE BĂIȚA MINING AREA

The concentrations of heavy metals and the spatial distribution of Na, Ca, Cu, Zn, Ni, Co, Mg, Fe, Mn, Pb, and Cd in the waters of the Băița area were studied to assess the quality class of surface waters and identify pollution sources. The study area is located along the Băița River and its tributary, Valea Roșie, which are influenced by the Câmpurele mining gallery and mining waste dumps, used for extracting common metal ore deposits. Sampling points were selected along the adjacent path of mine water discharge from mining operations. The metal content in the analyzed surface water was compared with the standard limits for surface waters, in accordance with the five quality classes established by Normative 161/2006. The concentrations of heavy metals in the mine water samples discharged from mining pollution sources were compared with the permissible pollutant loading limits for wastewater discharge into natural receptors, as per NTPA-001/2002 regulations. The spatial distribution of heavy metal concentrations highlights mining activities as the primary source of pollution in the Băița River. The concentrations of Cu, Zn, Ni, Co, Mg, Fe, Mn, Pb, and Cd exceed the specific limits for quality classes I and II of surface waters. Excessive levels of Fe (ranging from 30 mg/L to 105 mg/L) and Mn (ranging from 11 mg/L to 28 mg/L) were recorded in the tributary (Valea Roșie) of the Băița River, associated with mine water discharge, as well as water from the mining waste dump. The exceedance of maximum allowable concentrations for Ni, Co, Pb, Cu, Cd, and Zn in the Băița River and its main tributary, Valea Roșie, leads to the classification of surface water into lower quality classes III and V. Meanwhile, sodium and calcium concentrations fall within the permissible limits for quality class I. The single-factor pollution index reflects surface water pollution levels ranging from light to severe pollution.