Comparative phytoremediation potential of Calophyllum inophyllum L., Bixa orellana L. and Schleichera oleosa (lour.) Oken on iron ore tailings

The present study focused on the comparison of three economically important tree species Calophyllum inophyllum L., Bixa orellana L. and Schleichera oleosa (lour.) Oken, regarding their phyto-stabilisation potential in the presence of iron ore tailings (IOT). Results indicated that Calophyllum showed the best growth on IOT as compared to Bixa and Schleichera. A continuous increase in chlorophyll a, b and total chlorophyll was observed in Callophyllum and Bixa, while in Schleichera it was greater in the freshly treated plants but went on decreasing later. The catalase enzyme activity was observed to be greater in the treated plants compared to their controls in all the three plants. Metal accumulation rate was observed to be maximised in Calophyllum; it accumulated maximum amount of lead (Pb) and copper (Cu) while zinc (Zn) and nickel (Ni) accumulation was maximum in Bixa. Interestingly, both Calophyllum and Bixa accumulated similar and greater amounts of chromium (Cr) than Schleichera. The study revealed that Calophyllum has the most potential for phyto-stabilisation than Bixa and Schleichera.