Additive guides · Product label guide
Heavy metals in food: arsenic, lead, cadmium and mercury, and where they come from.
Updated
How arsenic, lead, cadmium and mercury get into food, what the FDA and WHO say about each, which foods the agencies mention, and practical steps. A sourced overview; the catalog has no contaminant test data.
Quick answer
Arsenic, lead, cadmium and mercury are called toxic elements or heavy metals. They are in the soil, water and air where food is grown, raised or processed, sometimes naturally and often at higher levels because of past industrial use and pollution. The FDA prioritizes them because they can harm brain development from the womb through early childhood. The FDA says detecting one in a test does not necessarily mean a food should be avoided and advises a varied diet. This site reads ingredient labels and has no heavy-metal measurements.
- The four metals
- Arsenic, lead, cadmium, mercury
- Mainly affects
- Developing brains (FDA)
- FDA advice
- Eat a varied diet
- Catalog test data
- None
01 · A closer look
How heavy metals get into food.
The FDA says these elements can be present in food because they are in the soil, water or air where it is grown, raised or processed. They may occur naturally, but are often at higher levels because of past industrial uses and pollution. The FDA’s concern is greatest for infants and children, older adults and people with chronic conditions, and especially for neurological development in children.
| Metal | How it reaches food | What the source says |
|---|---|---|
| Arsenic | Soil and irrigation water; rice, cereals, fish, shellfish, meat, poultry, dairy | WHO: inorganic arsenic is highly toxic; organic forms in seafood are less harmful |
| Lead | Contaminated dust, soil, water and food; lead plumbing in water | WHO: no level of exposure known to be without harmful effects; FDA finalized baby food action levels in Jan 2025 |
| Cadmium | Soil, higher near some phosphate fertilizer use and industrial sources; seaweed and chocolate tested | FDA: builds up in kidneys over time; bone and kidney effects are the most sensitive outcomes |
| Mercury | Methylmercury in fish and shellfish | FDA and EPA advise choosing lower-mercury seafood for pregnancy, breastfeeding and children ages 1 to 11 |
02 · A closer look
Arsenic.
The WHO says arsenic is highly toxic in its inorganic form and that long-term exposure from drinking water and food can cause cancer and skin lesions, with studies also linking exposure to impaired cognitive development. See the rice guide for the FDA’s infant rice cereal limit.
WHO: arsenic fact sheet (Dec 7, 2022)03 · A closer look
Lead.
The WHO says no level of lead exposure is known to be without harmful effects, that young children absorb more of an ingested dose than adults, and that contaminated food is one route alongside dust, soil and water. The FDA notes the same and that testing results that detect lead do not necessarily mean the food should be avoided.
WHO: lead poisoning and health fact sheet (June 10, 2026)04 · A closer look
Cadmium.
The FDA says cadmium is eliminated slowly, so long-term low-level exposure can build up in the kidneys and liver, and that chocolate is a minor source of cadmium exposure internationally. It has tested foods such as seaweed and chocolate, and notes pottery with cadmium-based pigments can leach into food.
FDA: cadmium in food and foodwares (content current as of Mar 5, 2024)05 · A closer look
Mercury.
In the US the most common exposure is methylmercury in seafood. The FDA says nearly all fish and shellfish contain trace amounts, most types do not reach levels that cause health effects in adults, and young children and fetuses are more vulnerable. Its fish advice chart lists lower-mercury choices that still provide nutrients.
FDA: mercury in food (content current as of Mar 5, 2024)06 · A closer look
What to do with this.
The FDA’s consumer advice is to eat a variety of nutrient-dense foods across vegetables, fruits, grains, dairy and protein foods, which supports nutrition and limits exposure from any one food. For babies, see the baby food guide. CleanFoodScore cannot tell you which products contain fewer metals because it records ingredients, not laboratory results.
Primary sources
Sources
- FDA: environmental contaminants in food (content current as of Apr 29, 2026) fda.gov
- FDA: lead in food and foodwares (content current as of Jan 6, 2025) fda.gov
- FDA: cadmium in food and foodwares (content current as of Mar 5, 2024) fda.gov
- FDA: mercury in food (content current as of Mar 5, 2024) fda.gov
- WHO: arsenic fact sheet (Dec 7, 2022) who.int
- WHO: lead poisoning and health fact sheet (June 10, 2026) who.int