Toxicology Profile; Arsenic
Basic Chemistry
Introduction
Arsenic is an abundant naturally occurring element with an atomic number of 33 and an atomic weight of 74.92 g. Although strictly a metalloid, arsenic is commonly referred to as a ‘heavy metal’ and can be found within group 4 of the periodic table. It should be noted that most of the other elements within this group have a biological role, but arsenic itself is a toxin (see section 1.x). Some additional chemical properties of elemental arsenic are shown in table_1.
Elementary Arsenic
Elementary arsenic has only one stable isotope 75As, and 33 radioactive isotopes. Generally, the isotopes are relatively short lived with the longest lived radioisotope (73As) having a half-life of 80.3 …show more content…
Figure 1 shows a Pourbaix diagram for inorganic compounds which are likely to exist under different pH and Oxidation states.
Overall, Aresenite is generally found under reducing conditions especially within areas suffering from a high pH such as land contaminated by acid mine drainage. Whereas arsenate is typically the more dominant under oxidizing conditions, and therefore is likely to occur within the upper well ventilated zones of soil. Additionally, in the presence of microorganisms the formation of organic arsenic can occur under a process known as biomethylation [Ref].
2.0) Sources of Arsenic
According to the International Mineral Association, there are over 560 different minerals which contain arsenic as an essential constituent to their crystal lattice. The diverse minerology is due to the fact that arsenic naturally combines with other elements such as oxygen, sodium and sulphur.
Generally, Organic Arsenic forms a similar oxidation state as for inorganic arsenic. Whilst organo-arsenic compounds have had considerable and widespread commercial applications, the American Cancer Association state that Organic Arsenic is not carcinogenic and much less toxic than inorganic
Basic Chemistry
Introduction
Arsenic is an abundant naturally occurring element with an atomic number of 33 and an atomic weight of 74.92 g. Although strictly a metalloid, arsenic is commonly referred to as a ‘heavy metal’ and can be found within group 4 of the periodic table. It should be noted that most of the other elements within this group have a biological role, but arsenic itself is a toxin (see section 1.x). Some additional chemical properties of elemental arsenic are shown in table_1.
Elementary Arsenic
Elementary arsenic has only one stable isotope 75As, and 33 radioactive isotopes. Generally, the isotopes are relatively short lived with the longest lived radioisotope (73As) having a half-life of 80.3 …show more content…
Figure 1 shows a Pourbaix diagram for inorganic compounds which are likely to exist under different pH and Oxidation states.
Overall, Aresenite is generally found under reducing conditions especially within areas suffering from a high pH such as land contaminated by acid mine drainage. Whereas arsenate is typically the more dominant under oxidizing conditions, and therefore is likely to occur within the upper well ventilated zones of soil. Additionally, in the presence of microorganisms the formation of organic arsenic can occur under a process known as biomethylation [Ref].
2.0) Sources of Arsenic
According to the International Mineral Association, there are over 560 different minerals which contain arsenic as an essential constituent to their crystal lattice. The diverse minerology is due to the fact that arsenic naturally combines with other elements such as oxygen, sodium and sulphur.
Generally, Organic Arsenic forms a similar oxidation state as for inorganic arsenic. Whilst organo-arsenic compounds have had considerable and widespread commercial applications, the American Cancer Association state that Organic Arsenic is not carcinogenic and much less toxic than inorganic