Should Your Salt Contain Heavy Metals and Microplastics?

Short answer: No.

Yet this lab analysis shows that some popular salts do, and in amounts that could matter for your health.

Why This Matters

Salt isn’t just seasoning - it’s something most of us eat every single day. Even tiny amounts of contaminants can build up over time. Two main concerns emerged in our study:

• Heavy Metals (Lead, Arsenic, Aluminum): These can accumulate in the body, affecting the brain, heart, and kidneys. Lead is especially harmful for children and pregnant women, impacting development even at low doses. Arsenic is a known carcinogen. Aluminum is linked to neurological effects when exposures get high.
• Microplastics: Tiny plastic fragments from packaging and pollution. While the science is young, early data suggests they may cause inflammation, disrupt hormones, and carry toxic chemicals into the body. No amount has yet been declared “safe.”

What We Found

We tested 7 salts for heavy metals and microplastics.

Heavy Metals (per ~1 tsp / 5 g serving)

• Celtic Sea Salt: 2.3 µg lead, 0.6 µg arsenic, 1.3 mg aluminum
• Redmond Real Salt: 0.66 µg lead, 0.08 µg arsenic, 0.75 mg aluminum
• Baja Gold: 0.55 µg lead, 0.06 µg arsenic, 0.07 mg aluminum
• Morton, Maldon, Jacobsen, Diamond Crystal: No heavy metals detected

For context: California prop 65 guidelines limit lead to 0.5ug per serving, many of these salts are significantly over that level with just 1 tsp. The FDA’s daily “limit” for lead in children is just 2.2 µg. That means a child eating ~1 tsp/day of Celtic salt could already be over the FDA limit.

Microplastics (particles per gram of salt)

• Maldon Sea Salt: 0.081 particles/g → ~0.4 particles per teaspoon
• Jacobsen Salt: 0.034 particles/g → ~0.17 particles per teaspoon
• Celtic Sea Salt, Morton, Redmond Real Salt, Baja Gold, Diamond Crystal: Not detected

Compared to other sources of microplastics like tea bags, plastic water bottles and seafood, these numbers are quite low and unlikely to represent a significant contribution to total microplastics load. Target these other sources first to reduce your microplastic load.

Quick Comparison Chart

Which Salts Were Completely Clean?

Two salts in our testing showed no detectable heavy metals or microplastics:

• Morton Iodized Sea Salt & Diamond Crystal

Why Excess Lead, Aluminum, and Arsenic Matter

Lead

Even in very small doses, lead is a neurotoxin. It disrupts brain development in children, lowers IQ, and contributes to learning and behavioral issues. In adults, it’s linked to hypertension, kidney dysfunction, and cardiovascular disease. The body stores lead in bones, meaning exposure can build silently over time. In our salt tests: Celtic contained ~2.3 µg per teaspoon, that is enough to exceed the FDA’s daily “safe” limit for children if eaten regularly. Redmond and Baja Gold were lower but still measurable.

8Other common food sources of lead:

• Root vegetables (carrots, sweet potatoes, beets - from soil exposure)
• Leafy greens (spinach, kale)
• Spices and imported teas
• Drinking water (from old plumbing)

Combined with contaminated salt, these dietary sources can push daily exposure above safety benchmarks.

Aluminum

Aluminum is not considered an essential nutrient; in fact, excess intake has been associated with neurotoxicity and potential links to Alzheimer’s disease, though the science is ongoing. It can also accumulate in bones and the central nervous system.

In our salt tests: Celtic (~1.3 mg/tsp) and Redmond (~0.75 mg/tsp) had the highest levels, likely from natural mineral content or processing with anti-caking agents.

Other common food sources of aluminum:

• Processed cheese
• Baking powders
• Some teas
• Packaged baked goods (where aluminum-based leavening agents are used)
• Medications/antacids (major source for some people)

Salt can add to this “background load,” which makes choosing low-aluminum salt an easy win.

Arsenic

Arsenic is a Group 1 carcinogen, with links to cancers of the skin, bladder, and lungs. Chronic low-level exposure may also cause skin lesions, immune suppression, and cardiovascular effects

In our salt tests: Celtic (~0.6 µg/tsp), Baja Gold (~0.06 µg/tsp), and Redmond (~0.08 µg/tsp) contained detectable amounts. These are well below the Codex maximum level for salt, but salt is only one contributor.

Other common food sources of arsenic:

• Rice and rice-based products (highest source for many people)
• Fruit juices (apple, grape)
• Seafood (especially shellfish)
• Drinking water in some regions

When combined with these foods, even small amounts in salt add to total body burden.

The Combined Effect

Heavy metals don’t act in isolation, they accumulate. A child eating a bowl of rice (arsenic), a few carrots (lead), and seasoned food with Celtic salt (lead + aluminum + arsenic) could exceed multiple safety benchmarks in a single day. Adults may tolerate higher totals, but chronic intake is linked to long-term disease risk.

What This Means for You

1. Check the source: Not all salts are created equal. Artisanal and unrefined salts may contain trace contaminants.
2. Lead exposure: Children are most sensitive. Even 1 tsp/day of Celtic Sea Salt could exceed FDA’s daily lead benchmark for kids.
3. Aluminum: Salts with anti-caking agents or mineral-rich sources may contribute more aluminum. Though levels found are below official weekly limits, many people prefer to minimize exposure.
4. Microplastics: Science is still catching up, but even tiny counts are worth watching. Our food system should be plastic-free.
5. Safe bets: Choose salts that tested “clean” in our study (like Morton Iodized or Diamond Crystal) or had “Not Detected” across key contaminants.

ABNRF's Take

We don’t say “fear salt” - we say “know your salt.” We believe in radical transparency. Salt is foundational to human health and we deserve to know what’s in it.

• Not all salts are equal.
• Transparency matters.
• We’ll continue publishing independent lab results so YOU can make informed choices.

We'll continue:

• Testing salts and other staple foods
• Publishing full lab reports for the public
• Advocating for clean, nutrient-rich food without hidden contaminants

See the full lab reports here:

Heavy Metal Analysis

Microplastic Analysis

*Questions or comments? Contact our team.