Risk at a Glance

Inorganic Arsenic in Hijiki Seaweed


Hijiki (scientific name Sargassum fusiforme) is a brownish green seaweed found along the coasts of Japan, Korea and China. Hijiki is dried after harvesting and looks like brownish-black twigs. It is commonly served boiled or braised with rice, added to soup or salad in Japanese and Korean cuisine.

Hijiki naturally absorbs and accumulates high levels of inorganic arsenic, a heavy metal, from seawater. Long-term intake of high levels of inorganic arsenic, may lead to health problems such as cancer and skin lesions.


Dried hijiki seaweed

How does SFA safeguard consumer health?

SFA takes a risk-based approach to ensure food safety, which meets international standards and is guided by science. Arsenic occurs naturally at very  low levels in some foods, such as rice, meat and seafood. It is not possible to completely eliminate arsenic from our food. Therefore, limits on arsenic in food are set based on the internationally accepted principle of “As Low as Reasonably Achievable”. Food which does not comply with SFA’s food safety standards will not be allowed for sale.

What can we do to reduce exposure to inorganic arsenic in hijiki?

While SFA has safeguards in place, food safety is a joint responsibility and consumers have to play their part to ensure food safety. Some tips include:

  • Buy hijiki from established retailers and exercise caution when purchasing food online or bringing food back from overseas trips. 
  • Soak hijiki in warm water for approximately 20 minutes before use. The water should be not be consumed and should be disposed off  thereafter.
  • Consume hijiki in moderation.
  • Eat a balanced diet, containing a wide variety of food.


Hijiki with rice


About the Author

Dr Tan Yong Quan is a Scientist from the Risk Assessment and Communications Department of the National Centre for Food Science. He holds a PhD in Biochemistry from the National University of Singapore and is currently responsible for matters related to genetically-engineered food as well as new food sources and production systems.