## 5 Results and Discussion
### Wastewater Treatment
#### 5.2.4 Translocation Factor of Heavy Metals  
Table 2 shows the TF of aluminum and iron, reflecting the ability of _I. aquatica_ to extract heavy metals from roots to shoots. Results revealed that TF \(<\) 1 for _I. aquatica_, indicating that heavy metals are accumulated in the roots. For Al accumulation, the highest TF was observed on the fourth day of treatment, which was 0.54, and the lowest TF was observed on the final day of treatment, which was 0.09. For Fe accumulation, the highest TF of 0.61 was observed on the sixth day of treatment, and the lowest TF of 0.09 was observed on the eighth day. Table 2 also shows the TF of aluminum and iron, reflecting the ability of _C. asiatica_ to extract heavy metals from roots to shoots. Results indicated for Al, TF \(>\) 1, and the highest TF of 55 is observed on the sixth day of treatment. The lowest TF of 0.16 was observed on the 10 th day of treatment. For Fe accumulation, TF \(<\) 1 was observed for _C. asiatica_, implying that heavy metals are accumulated in the roots or other parts of the plant. The highest TF of 3.11 was observed on the second day of treatment, and the lowest TF of 0.37 was observed on the eighth day. The results showed that there were significant differences in iron translocation factors in the stems by _Ipomoea aquatica_ compared to leaves. For _Centella asiatica_, a significant value was obtained for the amount of iron in the leaves and stems. For aluminum, _Ipomoea aquatica_ recorded a significant value for metal translocation from roots to leaves and from roots to stems. However, no significant value was recorded for the aluminum by _Centella asiatica_. Basically, most of the heavy metals accumulate in plant roots because the surface area of root hairs is greater than those of stems and leaves for the absorption of heavy metals [14]. Besides, roots are the first part of a plant that absorb heavy metals from soil or a waterbody before their distribution to the other parts. In addition, compared to stems and leaves, roots are the only covered part, and they are in contact with the growth medium. Hence, roots demonstrate more potential to absorb nutrients and pollutants due to their plant physiology. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Translocation Factor/Day (TF)**} \\ \hline  & \multicolumn{6}{c}{_Ipomoea aquatica_} \\ \hline Day & 2 & 4 & 6 & 8 & 10 & MIN \\ Aluminum & 0.34 & 0.54 & 0.47 & 0.08 & (0.09) & 0.27 \\ Iron & 0.05 & 0.17 & 0.61 & 0.09 & 0.21 & 0.19 \\ \hline  & \multicolumn{6}{c}{_Centella asiatica_} \\ \hline Day & 2 & 4 & 6 & 8 & 10 & MIN \\ Aluminum & 2.14 & 3.28 & 54.94 & 0.33 & 0.16 & 11.97 \\ Iron & 3.11 & 0.99 & 0.38 & 0.37 & 0.39 & 1.05 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Translocation factor for _Ipomoea aquatica_ and _Centella asiatica_ from root to leave (R/L). [PERSON] et al. [3] found that the _Scirpus grossus_ accumulated Al and Fe from mining wastewater, implying the potential of _Scirpus grossus_ as a hyperaccumulator in the phytoremediation of Al and Fe. [PERSON] et al. [44] have reported bioconcentration factor (BCF) \(<\) 1 for _C. asiatica_. However, TF \(>\) 1 was observed for the accumulation of Pb, Cu, and Zn, indicating that even though _C. asiatica_ is not a potential hyper accumulator or a phytostabilization agent, this species is tolerant to Pb, Cu, and Zn. A BCF range from 0.01 to 0.10 for Zn and Pb revealed that _C. asiatica_ is a weak accumulator for these metals. Based on the study conducted by [PERSON] et al. [45], the highest ratio of lead (Pb) concentration reflects the accumulation from roots to stems, while the lowest ratio reflects accumulation from roots to leaves. The study determined the concentrations of Pb and Cd accumulated in _I. aquatica_ at Laguna de Bay Filipina. Results indicated that the Pb concentration of the plant section follows the order of roots \(\geq\) vertical stems \(\geq\) horizontal stems \(\geq\) leaves. The ratio is 0.82 stems/roots and 0.36 leaves/roots.