Arsenic distribution in the dissolved, colloidal and particulate size fraction of experimental solutions rich in dissolved organic matter and ferric iron

Strong chemical evidence for high Fe(II)-colloids and low As-bearing colloids (200nm–10kDa) contents in groundwater and flooded paddy fields in Bangladesh: A size fractionation approach

“…The results observed here under anoxic conditions are quite different from those obtained for synthetic systems under oxic conditions with As, dissolved organic matter and Fe(III) where relationships between these components (depending on Fe/C ratios) and the amount of As-bearing colloids have been demonstrated (Bauer and Blodau, 2009). This is likely due to the fact that, under oxic conditions, Fe is mostly insoluble and, therefore, has more potential to control the As speciation.…”

“…Arsenic mobility has been shown to be particularly controlled by interaction with Fe oxyhydroxide-colloids because of their strong ability to adsorb As at circum neutral pH (Dixit and Hering, 2003). However, interactions of As with Fe mineral phases may be indirectly and strongly modified by the presence of PO 4 , silica, Mn or organic matter that can act upon the Fe (oxyhydr)-oxides) formation and structure (Rose et al, 1996;Doelsch et al, 2003;Wolthoorn et al, 2004), and fixation of As on/in Fe minerals (Davis et al, 2001;Liu et al, 2001;Thoral et al, 2005;Sahai et al, 2007;Ciardelli et al, 2008;Bauer and Blodau, 2009).…”

Recent applications of vibrational mid-Infrared (IR) spectroscopy for studying soil components: a review

“…This signal probably corresponds to the As-O stretching vibration, suggesting that the 856 cm -1 peak involved not only Fe-O vibrations but also the symmetric (As-O-Fe) vibration (Jing, et al, 2003;Reza, et al, 2012). The presence of other divalent and trivalent cations such as Ca 2+ , Mn 2+/4+ , Mg 2+ , and Al 3+ can favour the ternary complexes formation of As with other metal-HS complexes, as has been shown in previous studies (Bauer and Blodau, 2009;Wang and Mulligan, 2009). Alternately, As can bind to HS via the presence of carbonyl, phenol hydroxy, hydroxyl, methoxyl groups, and other functional groups on the benzene rings and the aliphatic side chains.…”

Metal and Metalloid Speciation in Aquatic Environments: Concepts, Techniques and Applications

“…34 Tonello e associados também usaram DGT e UF para fracionar Al e Cu em águas ricas em matéria orgânica e afirmaram que o emprego das duas técnicas fornecem informações complementares, o que foi reforçado por Liu et al 35,43 Bauer et al investigaram a distribuição do As em diversas frações de soluções ricas em Fe, matéria orgânica e As(V). 57 Basicamente o estudo reforçou o papel da matéria orgânica e do Fe na mobilidade do As em sistemas aquáticos. 57 Estudos com DGT em ambientes ricos em matéria orgânica também foram conduzidos em rios amazônicos no Brasil para medição dos metais Al, Cd, Co, Cu, Mn, Ni e Zn livres e lábeis.…”

“…57 Basicamente o estudo reforçou o papel da matéria orgânica e do Fe na mobilidade do As em sistemas aquáticos. 57 Estudos com DGT em ambientes ricos em matéria orgânica também foram conduzidos em rios amazônicos no Brasil para medição dos metais Al, Cd, Co, Cu, Mn, Ni e Zn livres e lábeis. 58 Os coeficientes de difusão aparente dos metais analisados foram determinados em laboratório a partir das amostras coletadas em campo e comparados com os coeficientes teóricos.…”