Arsenites Toxic effect

Arsenic uptake in rabbit intestine is inhibited by phosphate, casein, and various metal-chelating agents (USEPA 1980). Mice and rabbits are significantly protected against sodium arsenite intoxication by (V-(2,3-dimercaptopropyl)phthalamidic acid (Stine et al. 1984). Conversely, the toxic effects of arsenite are potentiated by excess dithiols, cadmium, and lead, as evidenced by reduced food efficiency and disrupted blood chemistry in rodents (Pershagen and Vahter 1979). 

Vega, L. et al., Helper T cell subpopulations from women are more susceptible to the toxic effect of sodium arsenite in vitro, Toxicology, 199, 121, 2004. 

It is of historical interest that Fowler s solution, which contains 1% potassium arsenite, was widely used as a medicine for many conditions from the eighteenth century through the mid-twentieth century. Organic arsenicals were the first pharmaceutical antimicrobials and were widely used for the first half of the twentieth century until supplanted by sulfonamides and other more effective and less toxic agents. 

The presence of suitable reductants (or oxidants) is essential. These effects are examined here for As(III)/As(V) and Cr(III)/ Cr(VI). The redox states of trace elements affect their solubility (e.g., Cr(III)/Cr(VI)) and their affinity for binding to solid phases (e.g., arsenite and arsenate). Biological effects (e.g., uptake and toxicity) are also dependent on the redox state. 

Payne, K.B. and Abdel-Fattah, T.M. (2005) Adsorption of arsenate and arsenite by iron-treated activated carbon and zeolites effects of pH, temperature, and ionic strength. Journal of Environmental Science and Health, Part A Toxic/Hazardous Substances and Environmental Engineering, 40(4), 723-49. 

Another very important role that metal oxides such as Mn(III/IV) play in soils and sediments is the oxidation of inorganic cations. These reactions can be both advantageous and deleterious to environmental quality. On the positive side, oxidation of toxic arsenite [As(III)] to arsenate [As(V)] ny Mn(III/IV) oxides has been demonstrated (Oscarson et al., 1980). On the negative side, Mn(III/IV) oxides can effect oxidation of Cr(III) and Pu(III) to Cr(VI) and Pu(VI). These latter forms are very mobile in soils consequently, they can be toxic pollutants in the underlying aquatic environment (Amacher and Baker, 1982). 

---