HEAVY METAL TOXICITY AROUND A CLOSED BARITE MINE IN TARNITA-ROMANIA

• Published in: International Multidisciplinary Scientific GeoConference : SGEM Vol. 2; pp. 525 - 532
• Main Authors: Drochioiu, Gabi, Surleva, Andriana, Ilieva, Daria, Tudorachi, Lucia, Necula, Radu
• Format: Conference Proceeding
• Language: English
• Published: Sofia Surveying Geology & Mining Ecology Management (SGEM) 01.01.2016
• Subjects: Acidic oxides; Acidic soils; Acidity; Arsenic; Barite; Capacity; Chemical analysis; Contamination; Copper; Decontamination; Detoxification; Ecosystems; Environmental impact; Geochemistry; Germination; Heavy metal content; Heavy metals; Iron; Iron oxides; Lead; Magnesium; Metal ions; Mining; Nitrates; Oxides; Phase distribution; Pollution; Polyethylene; Ponds; Procedures; Rivers; Sediment pollution; Soil; Soil conditions; Soil contamination; Soil pollution; Soil water; Toxicity; Uptake; Water purification; Water treatment; Zinc; Romania
• ISSN: 1314-2704

The sterile dump material and drainage waters around closed mines are uncontrolled sources of contamination for surrounding soil and waters. The environmental fate of the sterile dumps is scarcely monitored and detoxification measures are usually just partially efficient. Here, a study regarding the current state of the sterile dump and surrounding soil and water nearby the closed barite ore processing plant in Tarnita-Suceava, Romania, is presented. The heavy metal content in soil, water and plants was determined by ICP-OES. The efficiency of water and magnesium nitrate as soil decontamination agents was also studied. A number of chemical analysis and germinations tests were applied in attempt to estimate the ability of soil to sustain the plants growing, the efficiency of decontamination procedures and the heavy metal uptake by plants. Total content of heavy metals, exchangeable metals, acidity and carbon and nitrogen was estimated. A modified sequential extraction method was used to determine the geochemical phase distribution of heavy metals in three samples of Tarnita soil. The total content of toxic elements of sterile dump was three times higher than that in the surrounding soil samples. Cu, Zn and Pb were the most abundant heavy metals. The highest heavy metal content was found in the fractions associated with iron oxides. Although, metal ions fixed on iron oxides have limited mobility, the acidic soil conditions (pH 2.3) may cause their displacement to more mobile fractions, thus increasing their availability. The soil with the best characteristics among the studied ones was highly toxic, with a very unstable capacity to support germination. The soils were treated with water and magnesium nitrate solution to remove the most mobile fraction of heavy metals. The results from germination tests and heavy metal uptake by plants showed that Mg(NO3)2 is an efficient decontamination agent.