How much heavy metals (lead, arsenic, cadmium, mercury) exposure is too much?
Heavy metals are naturally occurring toxic elements like lead, arsenic, cadmium, and mercury that can contaminate food, water, and everyday products. They build up in the body over time, and for lead there is no known safe level of exposure.
Renee · Founder & Lead Researcher, R3
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The claim: If it is organic or natural, it does not have heavy metals.
The reality: Heavy metals come from soil, air, and water, so organic crops and organic cotton can absorb them too. The 2024 Berkeley tampon study actually found more arsenic in the organic products than the conventional ones.
Heavy metals are a small group of dense, naturally occurring elements that are toxic to people even at low doses. The four that come up most in product safety are lead, arsenic, cadmium, and mercury. They are not added on purpose. They get into products because they are already in soil, water, and air, so they travel up through crops, cotton, and manufacturing into the things you buy.
The reason researchers and regulators treat them as a class is that they share an unwelcome trait: your body has no good way to get rid of them. They accumulate in bone, kidney, and other tissue over years. That is why exposure that looks tiny on any single day can still matter, and why the people most at risk are the ones with the most years ahead of them or the most rapid development happening right now: babies, young children, and pregnant women.
Lead. The most studied and the most unforgiving. The CDC states plainly that no safe blood lead level in children has been identified, and even low levels are linked to lower IQ, attention problems, and developmental delays. The CDC uses a blood lead reference value of 3.5 micrograms per deciliter to flag children with more lead than most, but stresses it is a screening tool, not a safe threshold.
Arsenic. A known human carcinogen in its inorganic form. The EPA sets the legal limit for arsenic in public drinking water at 10 parts per billion, while openly setting the health goal at zero, because the cancer risk does not drop to nothing at the legal limit. Arsenic concentrates in rice and rice-based foods, which is why it shows up in conversations about baby cereal.
Cadmium. Linked to kidney damage and bone weakening with long-term exposure, and classified as a carcinogen. It turns up in some leafy greens, root vegetables, and chocolate, and in pigments and batteries.
Mercury. Best known from fish, where it appears as methylmercury and can harm a developing brain. It is also why pregnant women are told to limit high-mercury fish like swordfish and king mackerel.
The exposure most parents already know about is food. The FDA's Closer to Zero plan exists specifically because arsenic, cadmium, lead, and mercury were found across baby and toddler foods, and the agency has begun setting action levels (final lead guidance for processed baby food came in January 2025). Infant formula and children's vitamins and supplements are screened for the same reason.
Water is the second route. If your home draws from a private well or an older system, arsenic and lead are worth testing for, and a certified water filter rated for those specific contaminants is the practical fix.
The newer and more surprising finding is menstrual products. A 2024 University of California, Berkeley study published in Environment International tested 30 tampons across 14 brands and found measurable lead in 100 percent of them, with arsenic actually higher in the organic products. The unsettling part is regulatory: as the National Center for Health Research points out, there are no regulatory limits for metals in menstrual products at all, even though vaginal tissue absorbs chemicals more readily than skin elsewhere on the body. This is exactly why R3 ranks tampons on whether a brand publishes independent heavy-metal lab results, not on the word organic.
It is tempting to assume that trace amounts are harmless. For most single exposures, the dose really is small. The problem is summation. You are not exposed to lead only from one source, you are exposed from food plus water plus dust plus, now, the occasional consumer product, every day, for years. Regulators think in terms of total cumulative exposure, and so should you. The goal is not zero from any one product (that is rarely achievable), it is keeping the running total as low as is reasonable, with extra care during pregnancy and early childhood.
You cannot test your groceries at home, so the practical levers are about choosing better-screened products and reducing the biggest contributors.
Heavy metals are not a reason to panic, but they are a reason to pay attention to which brands prove what is inside, especially for the products your kids eat, drink, and wear closest to their bodies.
Menstrual products have no regulatory limits for metals, and a 2024 study found lead in 100% of tampons tested. R3 ranks tampons on whether a brand publishes independent heavy-metal lab results, because in a category with no rules, published testing is the only proof you can trust.
Lead: no safe level identified by the CDC; linked to lower IQ, learning and attention problems, and developmental delays in children. Arsenic: a known human carcinogen (inorganic form); the EPA health goal is zero. Cadmium: kidney damage, weakened bones, classified carcinogen. Mercury: harms the developing brain. All four accumulate in the body over time, so risk is cumulative and highest for fetuses, infants, and young children.
The FDA runs the Closer to Zero plan to set action levels for lead, arsenic, cadmium, and mercury in foods for babies and young children, issuing final lead guidance for processed baby food in January 2025. The EPA caps arsenic in public drinking water at 10 ppb (health goal: zero) and lead at an action level of 15 ppb. Critical gap: there are no regulatory limits for heavy metals in menstrual products, and supplements are loosely regulated, so in those categories independent third-party testing is the only real safeguard.
How to reduce exposure
Vary your child's grains beyond rice, test well or old-home water and filter specifically for lead and arsenic, and favor brands that publish real third-party testing. Reduce the largest single contributors rather than chasing zero from every product.
Who is most at risk
When to seek medical attention
If you are concerned about a child's exposure, ask your pediatrician about a blood lead test, especially for children in older homes or with known exposure. Acute symptoms or high test results require medical care.
Common product triggers
Look for these
Watch out for
What this does NOT cover
This page covers the four metals most relevant to consumer product safety. It does not cover occupational exposure, acute poisoning, or chelation treatment, which require a medical professional.
How to verify
Look for a published lab report (PDF or web page) that names the testing lab and gives concentrations for each metal. For water, use an EPA-certified lab test of your specific tap. For food, the FDA's Closer to Zero pages list current action levels.
Timeline
2001
EPA arsenic standard
EPA lowers the drinking water arsenic limit to 10 ppb, with a health goal of zero.
2021
Closer to Zero
FDA launches its plan to drive toxic elements in baby food toward zero.
2021
CDC reference value
CDC lowers its blood lead reference value for children to 3.5 µg/dL.
2024
Metals in tampons
UC Berkeley study finds lead in 100% of 30 tampons tested, arsenic higher in organic.
2025
FDA lead guidance
FDA issues final action levels for lead in processed baby food.
What to look for instead
What this means for your family
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Heavy metals are toxic elements like lead, arsenic, cadmium, and mercury that occur naturally in soil and water and end up in food, water, and products. They are dangerous because the body cannot easily remove them, so they build up over years. Lead has no known safe level, and arsenic is a known carcinogen. Children and pregnant women are most at risk.
Rice and rice-based foods concentrate arsenic, which is why rice cereal comes up in baby-food discussions. Cadmium appears in some leafy greens, root vegetables, and chocolate, and mercury is highest in large fish like swordfish and king mackerel. The FDA's Closer to Zero plan targets these in foods for babies and young children.
Not necessarily. Heavy metals come from soil, air, and water, so organic crops and organic cotton can absorb them too. The 2024 Berkeley study on tampons actually found higher arsenic in the organic products. Organic tells you how something was grown, not what a lab would find in the finished product.
Yes. A 2024 University of California, Berkeley study published in Environment International found measurable lead in 100% of the 30 tampons it tested, across 14 brands. There are no regulatory limits for metals in menstrual products, so R3 ranks tampons on whether a brand publishes independent heavy-metal lab results.
Vary your child's grains beyond rice, test your water if you have a well or old pipes and use a filter certified for lead and arsenic, and favor brands that publish real third-party testing. Focus on the biggest contributors rather than trying to eliminate every trace, and apply extra care during pregnancy and early childhood.
No. The CDC states that no safe blood lead level in children has been identified, and even low levels are linked to developmental and behavioral problems. The CDC's reference value of 3.5 micrograms per deciliter is a screening tool to flag children with more lead than most, not a safe threshold.
