# Arsenic: A Review on a Great Health Issue Worldwide  
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1 Dipartimento di Farmacia e Scienze della Salutte e della Nutrizione, Universita della Calabria, 87036 Cosenza, Italy; [EMAIL_ADDRESS] (G.G. ); [EMAIL_ADDRESS] (G.L. ); [EMAIL_ADDRESS] (M.S.S.) [PERSON]  
1 Dipartimento di Farmacia e Scienze della Salutte e della Nutrizione, Universita della Calabria, 87036 Cosenza, Italy; [EMAIL_ADDRESS] (G.G. ); [EMAIL_ADDRESS] (G.L. ); [EMAIL_ADDRESS] (M.S.S.) [PERSON]  
2 Dipartimento di Farmacia-Scienze del Farmaco, Universita degli Studi di Bari \"A. Moro\", 70125 Bari, Italy; [EMAIL_ADDRESS]  
[PERSON]  
1 Dipartimento di Farmacia e Scienze della Salutte e della Nutrizione, Universita della Calabria, 87036 Cosenza, Italy; [EMAIL_ADDRESS] (G.G. ); [EMAIL_ADDRESS] (G.L. ); [EMAIL_ADDRESS] (M.S.S.) Footnote 1: email: {}  
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from the development of cancer, inducing epigenetic changes, to skin diseases [5]. Since it is not a mutagen, the mechanism by which it causes changes in gene expression and disease pathogenesis has not been clearly defined [6]; however, its anti-cancer activities against various human neoplastic diseases have been extensively studied. On the other hand, arsenic trioxide is one of the first-line chemotherapeutic drugs for acute promyelocytic leukemia [7]. Natural sources of human exposure to arsenic are represented by volcanic ash, weathering of minerals and ores. Arsenic is present in the smelter dust from copper, gold, and lead smelters, and is recovered principally from copper refinement dust, and mineralized groundwater. Inhalation of atmospheric gases and dusts represents an additional way of exposure. Arsenic trioxide is used in the industries of pesticides, treated wood products, herbicides, and insecticides. It may be also found in food, water, soil, and air. Arsenic is generally absorbed by all plants, and is concentrated especially in leafy vegetables, rice, apple and grape juice, and seafood. The United States Environmental Protection Agency states that all forms of arsenic are a serious risk to human health. Arsenic has been classified as a Group-A carcinogen. Several studies documented the tissue-specific accumulation of arsenic in the hepatopancreas, cephalothorax, viscera, inhalant and ex-halant siphon, digestive glands and mantle in shellfish, mollusks, and crustaceans [8; 9; 10; 11]. Anthropogenic and submarine volcanic activities (IARC, International Agency for Research on Cancer 2012) increase the risk by shellfish ingestion of inorganic forms of arsenic (As\({}^{3+}\) and As\({}^{5+}\)) and organic form of arsenic (methylarsonic and dimethylarsonic acids, and arsenobetaine) [12]. Seafood often contains high concentrations of arsenic (approximately 10-100 mg/kg dry weight). In seaweeds, arsenic occurs predominantly as ribose derivatives known as arsenosugars. Although it is clear that arsenosugars are not acutely toxic, there is a chance of arsenosugars to show slight chronic toxicity [13]. Fish and shellfish contain higher arsenic concentrations than other food [11] and terrestrial animals in the form of arsenobetaine [14]. Arsenobetaine is neither metabolized nor accumulated in human beings; thus, it may be considered non-toxic [15; 16]. Although arsenobetaine is the prevalent arsenic compound present in shellfish, many researchers presented risk results to human health with the shellfish consumption [17; 18; 19]. Several removal technologies have been used for removing arsenic [20]. Several technologies have been used for removing arsenic from the water and environment using, including adsorption technique [21], porous ceramic (Fe/TiPC) beads with photocatalytic performances [22], nanofiltration membranes [23], coagulation with ferric chloride and chitosan [24], and new materials such as graphite oxides and carbon nanotubes [20]. Trivalent arsenic is more difficult to remove than pentavalent arsenic.