# Arsenic: A Review on a Great Health Issue Worldwide
## 9 Arsenic Phytoremediation  
Heavy metals (Cd, Cr, Hg, Pb, Ni, Co), metalloids (As, Si, Se), and organic pollutants (methyl mercury (CH\({}_{3}\))Hg\({}^{+}\), dimethyl mercury (CH\({}_{3}\))\({}_{2}\)Hg) accumulation in soil and groundwater has been rapidly increased because of various natural processes and anthropogenic activities. Most organic pollutants are biodegradable. Heavy metal and metalloid show greater environmental persistence because they are non-biodegradable and have the possibility to enter the food chain through drinking water, vegetables, and fruits with serious effects on health in humans. Therefore, the removal of these elements had been a challenging task for the scientific community. In the past, many expensive physical, chemical, and biochemical approaches have been used for the removal of arsenic from soil determining the alteration of soil properties and disturbing the soil microflora. Phytoremediation is an eco-friendly, green, cheap, and safer technology that makes use of plants to remove toxic and radioactive metals and organic pollutants (pesticides, herbicides, fertilizers, and detergents) from the environment [92,93]. The results obtained by [PERSON] et al. (2018) [94] at the Botanical Garten (University of the Punjab, Lahore) revealed that _Eucalyptus Lam_, _Terminalia arjuna L._, and _Salix letrasperma_ L. can be used for arsenic phytoremediation. Six months old seedling were planted in plastic pots containing loamy soil and treated with diverse doses of arsenic (0.5, 1.0, 2.0, 4.0 mg/L) for 18 months. Arsenic accumulated in all parts of the seedlings with maximum in roots of _Eucalyptus Lam_. (37.25 mg/kg), _Salix tetrasperma_ L. (35.76 mg/kg), and _Terminalia arjuna_ L. (24.13 mg/kg) in the pots with an arsenic concentration of 4.0 mg/L. Among these three species that can grow in the fields contaminated with arsenic, _Eucalyptus Lam_ is considered an excellent candidate for phytorefraction and phytoremediation as it accumulates maximum level of arsenic in all parts of the plant tissues in the order roots > shoot > leaves. In 2006, [PERSON] and [PERSON] (2006) [95] studied the capability of eight _Pteris cretica_ L. and sixteen _Pteris vittata_ L. to accumulate arsenic in an area near arsenic mine in Hunan Province of South China. Regarding the arsenic uptake, three factors were determined by the authors: its concentration in fronds, the bioaccumulation factor (BF: ratio of arsenic in fronds to soil), and the arsenic translocation factor (TF: ratio of arsenic in fronds to roots). The results obtained by the authors showed that the arsenic concentration in the fronds of _Pteris cretica_ L. were between 3 and 704 mg/kg, the BF factor were 0.06-7.43, and the TF were 0.17-3.98; on the contrary, the values determined in _Pteris vittata_ L. were 149-694 mg/kg, 1.34-6.62, and 1.00-2.61 respectively. Between these two ferns, _Pteris cretica_ L. showed to be the best candidate for arsenic phytoremediation of contaminated area near arsenic mine. Can \begin{table}
\begin{tabular}{c c} \hline \hline
**Structure** & **Name** \\ \hline HS & OH & BAL (British Anti-Lewisite; 2,3-dimercapto propanol, dimercaprol) \\ SH & & DMPS (2,3-dimercapto-1-propanesulfonic acid) \\ HS & & DMSA (dimercaptouscinic acid) \\ SH & & DMPA \\ H & & (N-(2,3-dimercaptopropyyl)-phthalamidic acid) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Structures of chelating agents. [PERSON] and its collaborators (2020) [96] used the fern _Pteris vittata_ L. in symbiosis with Arbuscular Mycorrhizal Fungi (AMF) to extract arsenic from an industrial site in northwestern Italy contaminated also with other heavy metals due to metallurgic activities. Two series of experiments were performed by the authors. In the first one, which lasted two years, AMF-colonized _Pteris vittata_ L. ferns were grown under controlled conditions in pots containing soil coming from the contaminated metallurgic area. In this experiment, an excellent arsenic accumulation in fronds was observed.