What is natural radioactivity?
Natural radioactivity comes from radioactive elements. Examples are uranium and thorium. These occur naturally in rocks, soil, and water. Radioactive elements continually emit a small amount of radiation.
Different types of rock have different amounts of radioactive elements. This means that some areas have higher levels of radioactivity than others.
Radioactivity and your health
Exposure to high levels of radioactivity can cause cancer and other diseases. But low levels are not harmful. Natural radioactivity has always been in the environment.
Natural radioactivity in our food
Most food has very low levels of radioactivity and is safe to eat.
All foods contain natural radioactivity.
- Plants absorb it from the soil.
- Animals absorb it from plants.
- Fish absorb it from the water.
In 2013, a study found that levels in New Zealand soils were similar to those overseas. These levels are considered safe.
Shellfish has higher levels
Shellfish can contain relatively high levels of radiation. But it’s still only a tiny amount and is not a concern. Even if you eat a lot of shellfish, your exposure through diet will be well within safe levels.
We don’t yet know why shellfish have higher levels of radiation. Researchers have started looking into the reasons.
Surveys show safe levels in our diet
Scientists have found the level of radiation in New Zealand food is similar to the levels in other countries. Both natural radioactivity and radioactivity from human sources were at safe levels.
Since 1960, the Ministry of Health has measured radioactivity in the air, rain, seawater, and milk powder.
Environmental radioactivity monitoring programme – Ministry of Health
Scientific papers
Who to contact
If you have questions, email info@mpi.govt.nz
