14. What forms of arsenic are found in New Jersey well water?

  • In New Jersey well water there are two common forms of arsenic that need to be removed by water treatment, Arsenic 3 and Arsenic 5.
  • Arsenic 3 is much more difficut to remove from well water than Arsenic 5 because Arsenic 3 has a neutral charge.
    • 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, though there is a rule of thumb which can help (See FAQ #15).
  • The New Jersey Geological and Water Survey estimates that 20% of New Jersey wells with arsenic above the Maximum Contaminant Limit (MCL) of 5 micrograms/liter (mcg/L) have significant concentrations of Arsenic 3.