Monosodium methyl arsonate

Monosodium methyl arsenate (MSMA) is an arsenic-based herbicide. It is an organo-arsenate; less toxic than the inorganic form of arsenates. However, the EPA states that all forms of arsenic are a serious risk to human health and the United States' Agency for Toxic Substances and Disease Registry ranked arsenic as number 1 in its 2001 Priority List of Hazardous Substances at Superfund sites.[1]

Monosodium methyl arsonate
Skeletal formula of monosodium methyl arsenate
Ball-and-stick model of the monosodium methyl arsenate molecule
Names
IUPAC name
Sodium hydrogen methylarsonate
Other names
Monosodium methyl arsenate; sodium methylarsonate; monosodium methane arsonate; methyl arsonic acid monosodium salt; EPA Pesticide Chemical Code 013803
Identifiers
3D model (JSmol)
Abbreviations MSMA
ChemSpider
ECHA InfoCard 100.016.815 Edit this at Wikidata
UNII
  • InChI=1S/CH5AsO3.Na/c1-2(3,4)5;/h1H3,(H2,3,4,5);/q;+1/p-1 ☒N
    Key: JITOKQVGRJSHHA-UHFFFAOYSA-M ☒N
  • InChI=1/CH5AsO3.Na/c1-2(3,4)5;/h1H3,(H2,3,4,5);/q;+1/p-1
    Key: JITOKQVGRJSHHA-REWHXWOFAY
  • C[As](=O)(O)[O-].[Na+]
Properties
CH4AsNaO3
Molar mass 161.95 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Arsenic is classified as a Group-A carcinogen.[1] The EPA states that:[2]

Arsenate (AsV) is the oxidized form and occurs in well-aerated soils, whereas in chemically-reduced soil environments, arsenite (AsIII) is the prevalent As form. Although arsenite is more toxic than arsenate, arsenate can also have deleterious effects on humans, plants, and microorganisms. Arsenic-contaminated soils pose serious risk to human health. The EPA also states that, while contaminated soil poses a serious risk to health, arsenic frequently mobilizes from soils and other sources, ending up in water where it is even more of a toxicity issue.

Trade names include:

  • Target 6 Plus
  • Target 6.6
  • MSMA 6 Plus
  • MSMA 6.6

References

edit
Specific
  1. 1 2 Dibyendu, Sarkar; Datta, Rupali (2007). "Biogeochemistry of Arsenic in Contaminated Soils of Superfund Sites". EPA. United States Environmental Protection Agency. Archived from the original on February 26, 2018. Retrieved 25 February 2018.
  2. Carelton, James (2007). "Final Report: Biogeochemistry of Arsenic in Contaminated Soils of Superfund Sites". EPA. United States Environmental Protection Agency. Archived from the original on February 26, 2018. Retrieved 25 February 2018.