Is there any way to determine which arsenic species is in my water (Arsenic 3 or Arsenic 5)?

  • There is no simple and affordable test commercially available to determine which arsenic species is present so the species of arsenic present is usually unknown. 
  • There is an Arsenic Speciation "Rule of Thumb" developed by the New Jersey Geological and Water Survey and Rutgers University that can be used to determine if Arsenic 3 may be a factor or not.
  • The Arsenic Speciation Rule of Thumb works by answering these two questions:
    • Are the Iron or Manganese concentrations in the untreated well water greater than 50 micrograms/liter (mcg/L)?
    • Is the Dissolved Oxygen concentration in the untreated well water less than 1.0 milligrams/liter (mg/L)?
  • If the answer to each question is "no" it is very unlikely that the water contains a significant concentration of Arsenic 3. 
  • If the answer to either question is "yes" then Arsenic 3 is likely present at a concentration greater than 3 mcg/L and therefore a serious factor in water treatment selection. In this case, a confirmatory Arsenic 3 test by arsenic speciation cartridge or laboratory analysis is recommended before spending extra money on treatment components to convert Arsenic 3 to Arsenic 5.