Physiological Effects of Mining Contaminants on Algae with Special Reference to Heavy Metal Toxicity

The process of mining affects all the components of environment and ecology. resulting in different types of pollution problems like soil, surface and ground water pollution. Acid Mine Drainage (AMD) and mine spoil dumps may contain an elevated amount of Heavy metals. Physiological effect of heavy metal toxicity on algal species like Chlorella vulgaris, Scenedesmusbijugatus, Oscillatoriaamphibia and Lyngbyamajuscula isolated from mine waters of Mansar, Kandri,Beldongari and Gumgaon Manganese mines of MOIL, Nagpur Region were investigated. Results obtained showed significant concentrations of heavy metals in mine spoil and mine water. Observed Mn and Fe concentrations were very high (215.2 to 224.3 and 47.9 to 52.5 mg kg−1, respectively in mine spoil followed by Cu, Zn, Cr, Pb and Cd concentrations. Similarly, mine waters of all sampling sites showed elevated concentrations of manganese (1.645 to 1.745 mg/l), iron (0.950 to 1.124 mg/l) followed by copper (0.029 to 0.032 mg/l) and zinc (0.011 to 0.013 mg/l) while concentrations of cadmium, chromium and lead remained below detecting limit and hence they were selected for toxicity tests. Most of the tested algal species were reported with maximum inhibitory level and TIC to iron and manganese than zinc and copper. Among all algal species cyanophycean member Oscillatoriaamphibia was reported with maximum inhibitory concentration for Mn( 2.5 mg/l), Fe (2.4 mg/l), Cu (1.0 mg/l) and Zn (1.7 mg/l) and Lyngbyamajuscula with Mn ( 2.2 mg/l), Fe (2.3 mg/l), Cu (0.9 mg/l) and Zn (1.4 mg/l) whereas chlorophycean member Chlorella vulgaris was reported with minimum inhibitory concentrations. Tolerance Index Concentration values also revealed more tolerance to iron and manganese and least to copper and zinc. Among cyanophycean members, Oscillatoriaamphibia was reported with more TIC to zinc (0.784 mg/l) while Lyngbyamajuscula with more TIC to iron (1.811 mg/l) followed by manganese (1.574mg/l) and copper (0.665 mg/l). The chlorophycean member, Scenedesmusbijugatuswas reported with more TIC to iron (1.543 mg/l) followed by manganese (1.268 mg/l) and copper (0.227 mg/l) whereas Chlorella vulgaris with more TIC to zinc (0.271 mg/l).Overall, all the algal species were affected by heavy metal toxicity and their observed tolerance to the heavy metals especially to higher concentrations of Mn and Fe might be due to adaptation contaminated mine water in the vicinity of mines.