Metal · Heavy metal contaminant

Cadmium

Cadmium is a heavy metal that appears in pigments, some ceramics, and occasionally as a contaminant in cocoa, leafy greens, and rice. It accumulates in the kidneys over decades.

What it is

Cadmium is a soft, bluish metal used in batteries, pigments, and some metal plating.

It is also a common environmental contaminant that plants take up from soil and water.

Why it matters

Long-term cadmium exposure damages the kidneys and bones; the World Health Organization classifies it as a Group 1 human carcinogen.

The main dietary sources are cocoa (especially dark chocolate), leafy greens, and some root vegetables grown in contaminated soil.

In consumer goods, brightly coloured ceramics, low-quality jewellery, and painted glassware are the notable concerns.

Common uses

  • Batteries (NiCd)
  • Pigments in older ceramics and paints
  • Trace contaminant in fertilisers and soil

Safety considerations

  • Avoid using decorated or imported ceramic ware with worn or crazed glazes for food.
  • Rotate cocoa/dark chocolate sources rather than relying on a single origin.
  • For bakeware, choose brands that publish third-party heavy metal testing.

Where you meet it in the home

  • Kitchen — imported ceramics, painted glassware, some bakeware
  • Food — dark chocolate, leafy greens, rice (trace)

Related categories

Related essays

Frequently asked questions

Should I stop eating dark chocolate?

No — but rotating brands and origins reduces cumulative exposure, and independent testing (Consumer Reports has published relevant data) is worth reviewing.

Is cadmium in bakeware a real risk?

It is uncommon in reputable modern bakeware. It's a concern mostly for imported or handmade painted glassware and ceramics.

Editorial references

  • World Health Organization — Cadmium fact sheet
  • IARC Monograph — Cadmium (Group 1)

Last updated 2026-07-18.