Phytoremediation of Iron Contaminated Soil by Centella asiatica

The leached iron in the soil in addition to anthropogenic activities has posed a great threat to soil ecosystem. The phytoremediation technology is used to treat the contaminated soil containing higher amount of iron (Fe). In this study, Centella asiatica has been used to remediate the iron contaminated soil. The accumulation of iron and removal efficiency of iron by Centella asiatica was carried out in this research. Iron (II) Sulphate (FeSO4) solution was directly added to the soil in each experimental pot at five different iron concentration levels from 0, 50, 100, 150 and 200 mg Fe/kg soil with five replicates for each treatment. The Centella asiatica in different levels of iron treatments were observed for their growth and harvested after 65 days. Iron accumulations in three different parts of Centella asiatica (leaf, stem and root) were analyzed accordingly, through Atomic Absorption Spectrophotometer (AAS) using dry ashing analytical method. Factorial experiment with a Completely Randomized Design (CRD) was used for data analysis and Duncan's test was used for mean and variance comparisons. The results revealed that Centella asiatica have the high ability to uptake and accumulate higher iron concentrations into the aerial parts significantly (p<0.05; r=0.977). Different iron concentrations levels of soil treatments had significant effect on the total iron accumulations in Centella asiatica (p<0.05). Through this study, Centella asiatica been proven as a hyperaccumulator plant species which efficiently accumulate iron metal in higher concentration at harvestable parts of the plant (p<0.05; 1=0.977). The root showed the higher accumulation of iron compared to the leaf (p<0.05) and the lowest iron accumulation was detected in stem (p<0.05). The Pearson correlation coefficient between leaf and root showed the higher significant and correlated (p<0.01; 1=0.785) compare to the leaf and stem (p<0.01; r=0.780) and the lowest correlation was between stem and root (p<0.01; r=0.585). The higher the accumulation in roots will subsequently cause the higher accumulation in leaves but not necessary triggering higher iron accumulations in stems. The efficiency of iron removal from contaminated soil been justified by evaluating through Bioconcentration Factor (BCF) and Translocation Factor (TF). Centella asiatica have bioconcentration factor more than one and translocation factor less than one which highly recommended for phytostabilization mechanism even though it was capable to perform phytoextraction of iron from soil medium effectively. Therefore, Centella asiatica have characteristics of metal hyperaccumulating plant species which able to be used for phytoremediation of iron (Fe) contaminated soil and help to reduce the iron contamination in crops, water sources and will regulate the nutrient cycles of the soil medium.