Distribution and Role of Green Algae in Acid Mine Drainage at Sarcheshmeh Copper Mine

Sarcheshmeh Copper Mine, one of the well known porphyry copper deposits, is located in 55 km south of Rafsanjan, south-eastern Iran. Metalliferrous deposit mining, prepare proper conditions for oxidation of sulphide minerals and acid mine drainage will be produced easily by chemical reactions between metal sulphides and water, with the presence of air. Investigations on impact of waste dumps on producing acid mine drainage at Sarcheshmeh copper mine shows decreased pH up to 3-5.5 in acid drainages with the presence of some dissolved toxic and heavy metals higher than permitted standard limits (WHO). In such degraded water and improper environment for aquatic life, just some of microorganisms are able to survive. At Sarcheshmeh copper mine in some of acidic drainages which maintain high dissolved elements, an acid tolerant alga recognized. The genus of this filamentous green alga is Ulothrix and species is Ulothrix gigas without antimicrobial and antifungal properties. The alga is observed in the drainages with high dissolved solids (TDS≈1800mg/l). It seems pH values, type of dissolved elements and secondary minerals formed on the substrate, are important factors in distribution of Ulothrix. This research shows the most prolific and densely populated communities occur in effluent with the pH 3- 4.5. The colloidal conditions and presence of suspended Iron and Aluminium prevent growth or reproduction of them. Sampling and chemical analysis of algae show elevated absorption of heavy metals. Therefore the presence of this alga is a factor to remove heavy metals from acid mine drainage naturally and improve the water quality.