Why this page exists
Each HMTc limit defaults to the strictest maximum a credible government regulator sets for that product–analyte pair, in the product’s native basis. Some foods and ingredients carry a natural heavy-metal background — drawn from soil, water, and how the plant concentrates metals — that runs above those limits. Where that happens, certification is demanding, and for a few products it is out of reach without exceptional sourcing.
This is not a defect to bury. A standard that only sets limits products already meet is not a standard. This page names the hard cases so a brand can self-assess before it applies, and so a reader can see that the program discloses where its own numbers bite.
The figures below come from the published occurrence literature synthesised at the Heavy Metal Index. They characterise the market; they carry no compliance weight and set no limit. A brand’s own product is measured on its own results, not on a distribution.
Rice and rice-derived ingredients — arsenic, and lead
Rice takes up arsenic from soil and water more readily than almost any other staple crop, and most of that arsenic is the toxic inorganic form. It concentrates lead the same way. This makes rice the single hardest ingredient in the infant and child food category.
Products affected: infant rice cereal, rice-based teething biscuits and puffs, rice beverages and rice milk, brown and white rice sold as grain, rice flour, rice noodles, and rice syrup used as a sweetener. A finished product carrying any of these as a major ingredient inherits the challenge.
Against the Infant and Child Foods arsenic limits — inorganic arsenic 20 ppb, total arsenic 50 ppb, both the strictest sovereign infant numbers — the measured rice market clears only a small fraction:
| Product | Analyte | HMTc limit (ppb) | Measured median (ppb) | Studies pooled |
|---|---|---|---|---|
| Infant rice cereal | Inorganic arsenic | 20 | 99 | n = 173 |
| Infant rice cereal | Total arsenic | 50 | 131 | n = 269 |
| Rice teething snacks | Inorganic arsenic | 20 | 156 | n = 21 |
| Rice teething snacks | Lead | 20 | 67 | n = 8 |
Median of the pooled occurrence distribution against the published limit — and the limit is the strictest government maximum for the product, never a percentile of this data (Method v2.0). Where the median sits above the limit, most of the measured market does not clear it. Occurrence figures characterise the market only; they carry no compliance weight and set no limit.
For these products, certification is not a matter of ordinary care in manufacturing. It requires sourcing rice with an unusually low arsenic background — particular growing regions and cultivars, and lot-by-lot verification — or the product cannot carry the mark. This is deliberate. Inorganic arsenic has no established safe intake for infants, and the limit follows the strictest government that regulates it rather than the level the market happens to sit at.
Cereals and grains — aluminium
Grains and cereals carry a high natural aluminium background. Dry infant cereals — rice-based and non-rice alike — commonly run in the tens of thousands of ppb, against an aluminium limit of 500 ppb. On the occurrence literature, few dry cereals clear it.
The aluminium limit is read across from the only aluminium maximum any government sets — an infant-formula standard — because no jurisdiction regulates aluminium in solid food. Applying a formula limit to a dry cereal is a basis question the program is reviewing, and the aluminium figure for dry cereals may change. It is disclosed here as a current challenge, not a settled one.
How to read the challenge
A product landing above a limit on the occurrence distribution is not disqualified — a specific lot may sit well below the market median, and only a brand’s own tested result decides certification. What the distribution shows is where the work is: which ingredients demand exceptional sourcing, and which subcategories a brand should not expect to certify on standard supply.
Every limit named here is published, dated, and traced to its source on the subcategory standards register. Where a limit is under methodological review, that is stated on the page and here.