Periodic table entry for arsenic that include the atomic number, abbreviation and mass
CAS Number: 7440-38-2

Arsenic is found in soil and water in some areas, and in some foods. It occurs naturally and from human activity. Arsenic compounds were used extensively as pesticides and wood preservatives, but these uses have been mostly phased out. There are different forms of arsenic, some of which may cause health problems and others that are not a health concern.

Fact Sheet

Arsenic is found in

  • Some foods, including:
    • Seafood, especially shellfish.  The main form of arsenic in seafood is not considered to be a health concern.
    • Rice and foods with rice-based ingredients, such as some hot and cold cereals, some infant formulas, and rice cakes.  Rice plants can take up arsenic from water or soil.
    • Hijiki seaweed (short, black, noodle-like seaweed).
  • Some drinking water sources, such as in some places in the Central Valley and Southern California. 
  • Some pressure-treated wood used in outdoor structures, such as decks and playground equipment.  Arsenic-treated wood was phased out in 2004.
  • Cigarette smoke.
  • Additive(s) put in some chicken and turkey feed to prevent parasites.
  • Some herbal medicines and other traditional remedies, especially from China and India.
  • Some herbicides in limited use on golf courses, cotton, and at sod-growing facilities.

Possible health concerns of arsenic

Some forms of arsenic:

  • May harm the developing fetus.
  • May harm the nervous system and may affect learning in children.
  • May contribute to cardiovascular disease and may affect lung function.
  • Can increase cancer risk.

Possible ways to reduce exposure to forms of arsenic that may affect health

  • Include plenty of variety in your and your child’s diet.
  • Breastfeed your infant if you can.  Include alternatives to rice-based foods in your infant’s diet.
  • Do not burn older pressure-treated wood (manufactured before 2004) and avoid using it for home projects.
  • Have children wash their hands after they play on or around older wooden playground equipment or decks.  If you own the equipment or deck, apply a sealant or coating every one to two years.
  • If your water comes from a private well, have it tested for arsenic.  (If your water comes from a public water supplier, it is already tested regularly for arsenic.)

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