Arsenic form Sources Comments References Sodium Arsenate Pesticides and wood    [27] DMA (also known as cacodylic acid) have been widely used as pesticides and herbicides Preservatives   [28,29] Arsenopyrite Rocks, Soils, Minerals, mines   [15,49]   Ground water Arsenite, arsenate [30] Arsenobetaine, Arsenocholine, tetramethylarsonium salts   Organic forms (methyl and dimethyl arsenic compounds) [31] Arsenosugars Coal-fired power generation    [32]   Plants, burning vegetation and also due to eruption of volcano   [33] Fe- reducing bacteria are linked to the mobilization of As in aquifer of the river delta in Bangladesh. Tube-wells >1 mg L-1 Bengal Delta region (encompassing Bangladesh and West Bengal) [34] Metal-reducing bacteria Arsenobetaine Marine animal   [35] [(CH3)3As+CH2COOH] dimethylarsinic acid  Soil   [36] arsenobetain MMA, DMA, TMAO Plants   [37-39] Arsenic III, DMA, MMA, MA As-cysteine, As2S3 and As2O5     [40,41] arsenate, arsenite, MMA and DMA Soil, rice   [42] Asbet, Aschol, arsenosugars, arsenolipids Sea foods No harm by intake [43,44] As(III), DMA,MMA, As(V) Urine wine club soda   [45] Legume–rhizobium Sunflower   [46] Symbiosis (Helianthus annuus L.), jack bean (Canavalia ensiformis L.), velvet bean (Stizolobium aterrimum L.), castor bean (Ricinus communis L.   [4,47]

Table 1: Sources and forms of arsenic.