Overview
This is the contaminant reference layer. Start here when your question begins with the metal rather than with a food or product. Each metal page is a self-contained account of one element: what it is, how it enters the food and product supply, the toxicology that makes it a concern, the populations most vulnerable to it, and the regulatory limits that govern it.
Pages link outward to the ingredients that carry the metal, the products it ends up in, the regulations that set limits, and the testing methods used to measure it.
What a metal page covers
Every developed metal page carries the same eight sections, so a reader always knows where to look.
The elements tracked most fully are the toxic metals below. Nutrient and trace elements carry briefer reference stubs that expand as the corpus warrants.
Species — read this first
The single most common error in reading heavy-metal data is comparing a total-element measurement to a limit derived for one chemical species. Four elements are maintained as separate species pages because their toxicology and regulation diverge sharply — often by two to three orders of magnitude.
| Element | Species that governs | Compared against | Why they diverge |
|---|---|---|---|
| Arsenic arsenic (As) | Inorganic arsenic — the carcinogenic species | Total arsenic | Total includes far less toxic organoarsenicals. |
| Mercury mercury (Hg) | Methylmercury — neurotoxic, bioaccumulating | Total mercury | Only the methylated fraction biomagnifies up the food chain. |
| Chromium chromium (Cr) | Hexavalent chromium — carcinogenic | Total chromium | Most total chromium is the far less toxic trivalent form. |
| Tin tin (Sn) | Organotins — the organometallic species | Inorganic tin | Organotins and inorganic tin have unrelated toxicological profiles. |
A total-element number cannot be honestly mapped to a species-based limit. Where a source reports only a total, the metal page says so.
Metals at a glance
The toxic metals covered most fully, with the reference point most readers reach for.
| Metal | Why it is a food concern | Shows up most in | Reference limit anchor |
|---|---|---|---|
| Lead lead (Pb) | Neurodevelopmental toxicant; no safe blood level in children | Cereals, root vegetables, spices, chocolate, baby food | FDA Closer to Zero action levels for baby food |
| Cadmium cadmium (Cd) | Kidney and bone toxicant; accumulates over decades | Cocoa, leafy greens, shellfish, rice, sunflower and flax seeds | EU maximum levels by food; JECFA and EFSA reference values |
| Inorganic arsenic inorganic arsenic (iAs) | Carcinogen; the toxic arsenic species | Rice and rice products, some drinking water, seaweed | FDA 100 ppb, infant rice cereal |
| Methylmercury methylmercury (MeHg) | Neurotoxicant; biomagnifies up the aquatic food chain | Predatory fish — tuna, swordfish, shark, king mackerel | FDA 1 ppm action level, fish |
| Nickel nickel (Ni) | Systemic contact allergen; gastrointestinal effects at higher intake | Legumes, oats, soy, cocoa, nuts | EFSA tolerable daily intake; no food maximum level |
| Aluminum aluminum (Al) | Debated neurotoxicity; hyperaccumulates in tea | Tea, herbs and spices, some additives | JECFA provisional tolerable weekly intake |
| Hexavalent chromium hexavalent chromium (Cr-VI) | Carcinogenic chromium species | Some drinking water, supplements | No food maximum level yet set; assessed via water limits |
| Tin tin (Sn) | Gastrointestinal irritant at high dose | Canned foods and beverages in uncoated tinplate | EU 200 mg/kg, canned food other than beverages |
Each row links to the full page, which carries the complete, source-referenced limits table. The anchor above is a navigational summary, not the authoritative value.
Full index
Every element the wiki tracks, grouped by how developed its page is. Counts are corpus pages referencing the element, read from the structured evidence layer on every build; stubs carry no count until a page is developed.