Cadmium (Cd) is a heavy metal that poses significant health risks, making it a key focus for the Heavy Metal Tested & Certified (HMTC) program. Due to its toxicity and persistent presence in the environment, cadmium is considered one of the top eight metals to be regulated in consumer products and food. It is a notable public health concern because of its widespread use in industry, its ability to accumulate in the body over time, and its potential for causing severe health issues. Exposure to cadmium, even at low levels, can lead to long-term health effects, including kidney damage, bone diseases, and increased cancer risks.

Overview

Cadmium is a non-essential metal that exists primarily in inorganic forms such as cadmium oxide, chloride or sulfate.^[1] Natural weathering and volcanic activity release these compounds, but industrial activities greatly increase environmental loads. Unlike other metals like zinc or copper, which are essential for various metabolic functions, cadmium has no known role in normal cellular or systemic processes. It is primarily absorbed through inhalation or ingestion and accumulates in the kidneys, liver, and bones.^[2] The body does not have an efficient way of eliminating cadmium, which leads to long-term accumulation, increasing the risk of chronic health problems. The toxic effects of cadmium include kidney damage, particularly renal tubular dysfunction, bone loss or osteomalacia, and increased risks of cancer, especially lung and prostate cancers.^[3][4] The metal’s persistence in the body and its ability to bioaccumulate in various tissues underscore its significance as a public health concern, particularly in individuals exposed to occupational or environmental cadmium sources.^[5]

Major Sources of Cadmium (Cd) Exposure

Cadmium exposure primarily occurs through environmental, dietary, and occupational pathways. The metal widely distributes in the environment, originating from natural sources like soil and water, as well as human activities such as industrial processes and agricultural practices.^[6] People are exposed to cadmium through air pollution, contaminated water, food sources, and workplace settings. The most common sources of dietary exposure include rice, leafy vegetables, and seafood, while occupational exposure is a significant concern for workers in industries like battery manufacturing and metal smelting. Understanding these exposure pathways is essential for managing and reducing cadmium-related health risks.^[7]

Category	Examples of Cadmium Exposure
Environmental	Cadmium is emitted into the air and water from mining, metal smelting, coal combustion, phosphate fertilisers, and waste incineration.^[8] These emissions deposit onto soil and are taken up by crops. Household dust and contaminated drinking water can contribute to exposure, although drinking‑water standards is 0.003 mg/L recommended by WHO, which limits this risk.^[9]
Dietary	Cadmium in soil and water is taken up by crops. Cereals, leafy vegetables, potatoes, pulses and offal are recognised as major dietary sources.^[10] Investigations in Austria showed high average cadmium concentrations in algae (1800 µg/kg), cocoa and cocoa products (179 µg/kg), seafood (136 µg/kg), mushrooms (128 µg/kg), and oilseeds (116 µg/kg).^[11] Fruit, juices, and meat generally contain lower levels. Cocoa powder and chocolate remain notable sources; EU regulations therefore cap cadmium in cocoa powder at 0.6 mg/kg. For smokers, tobacco is a major source because tobacco plants accumulate cadmium; smoking doubles body burdens compared with non‑smokers.^[12]
Occupational	Workers involved in battery manufacture, metal plating, recycling, soldering, or pigment production inhale cadmium‑laden dust and fumes.^[13] Industrial air concentrations may be thousands of times higher than ambient air. Inhalation of cadmium fumes can lead to acute respiratory distress, while chronic occupational exposure produces renal and bone effects.^[14]

Adverse Health Effects

Cadmium toxicity stems from its ability to induce oxidative stress, interfere with calcium metabolism and accumulate in kidney and bone tissues.^[15] Vulnerable populations include infants and young children who may be exposed to cadmium through contaminated products or toys, and whose developing kidneys and bones make them more susceptible to cadmium accumulation.^[16] Pregnant women and individuals with iron deficiency absorb more cadmium because iron deficiency upregulates intestinal cadmium transporters.^[17] Smokers, due to the cadmium content of tobacco, may have urinary cadmium levels double those of non‑smokers. Low‑income groups consuming diets high in rice, shellfish or organ meats are also at risk.

Health Effect	Evidence and Mechanisms
Renal dysfunction and Kidney Damage	Kidney damage is the hallmark of chronic exposure.^[18] A long‑term cohort study involving Swedish women found that urinary cadmium was associated with tubular toxicity and decreased glomerular filtration rate at exposures previously considered safe.^[19]
Bone demineralisation and fractures	Bone fragility is a key outcome, with the MrOS study revealing that elderly men in the highest quartile of urinary cadmium had 4-8% lower bone mineral density and increased fracture risk compared to those in the lowest quartile.^[20] Mechanistic studies show that cadmium disrupts vitamin D metabolism and osteoblast function, contributing to osteoporosis.^[21][22]
Cardiovascular disease	Cardiovascular and metabolic effects have also been reported; a review summarised epidemiologic evidence that cadmium exposure is associated with hypertension and thickening of the carotid artery, and mechanistic studies showed endothelial dysfunction and atherosclerotic plaque formation^[23]^[24]
Cancer	The risk of cancer is also a concern. The International Agency for Research on Cancer classifies cadmium as a human carcinogen.^[25] A review reported associations with lung, prostate, renal and liver cancers, attributed to interference with DNA repair and activation of oncogenic pathways.^[26] A meta‑analysis of 17 studies found that higher cadmium exposure modestly increased breast cancer risk.^[27]

Consumer Relevance

Cadmium is found in a wide range of consumer products, many of which are part of daily life. Exposure can occur through the consumption of contaminated food, particularly rice, cereals, vegetables, seafood, and baby foods, as well as through the use of products like Ni-Cd batteries, jewelry, and cosmetics. Due to its widespread presence, understanding where cadmium shows up in real-life products is important for reducing exposure, especially for vulnerable populations like infants.

Product Category	Examples and Details
Cereals and Rice	Cadmium is found in cereals because plants absorb it from the soil and transport it to their grains.^[28] This is a concern because cadmium is a toxic heavy metal that accumulates in the human body, potentially causing kidney damage, decreased bone density, and an increased risk of cancer and cardiovascular disease.^[29]
Vegetables & Pulses	Cadmium is found in vegetables (Leafy greens, potatoes, root vegetables) and pulses, often due to its presence in the soil as an environmental contaminant from industrial and agricultural sources.^[30]
Seafood & Offal	Shellfish, liver, and kidneys from animals often contain elevated levels of cadmium, as it accumulates in these animals from the environment.^[31] While these foods can contain higher levels of cadmium, they do not contribute as much to overall dietary exposure because people generally consume them less frequently than other major food sources.
Chocolate & Cocoa	Cadmium in chocolate and cocoa products comes from soil, where cacao trees absorb it.^[32] Dark chocolate contains more cadmium than milk chocolate due to higher cocoa solids. While naturally occurring, long-term exposure to even low levels poses health risks, especially for children, though levels vary by brand and region.
Baby Foods & Formula	Cadmium has been found in some baby foods and infant formulas, with studies showing levels exceeding recommended intake levels in certain products.^[33] Rice-based foods and some formulas, especially soy-based, have shown higher concentrations, raising concerns for stricter guidelines.
Ni-Cadmium (Cd) Batteries, Pigments & Coatings	Cadmium is used in batteries, pigments, and coatings; leakage from batteries and contamination in jewelry and toys may expose consumers.^[34]

Regulatory Snapshot

Various global organizations set guidelines for cadmium (Cd) exposure in food and water. The FDA (USA) limits cadmium in bottled water to 5 µg/L and plans guidance for baby foods.^[35] WHO/JECFA sets a drinking water guideline of 0.003 mg/L and a tolerable monthly intake of 25 µg/kg body weight.^[36] EFSA (Europe) establishes a tolerable weekly intake of 2.5 µg/kg body weight, with potential over-exposure for vegetarians, children, and smokers.^[37] EU Regulation 2023/915 sets maximum cadmium levels in foods, including 0.6 mg/kg for cocoa powder and 3 mg/kg for certain supplements. However, gaps remain in the regulation of cadmium in cosmetics, jewelry, and packaging, with varying international standards.

Implications for the HMTC Program

Cadmium (Cd)’s persistence, ubiquitous presence and cumulative toxicity justify HMTC’s strict certification. By applying the As Low As Reasonably Achievable (ALARA) principle, HMTC verifies that products, especially those marketed to infants and pregnant women, meet cadmium levels far below existing regulatory limits. This proactive stance protects vulnerable consumers, offers transparency to clinicians and public health professionals, and gives brands a competitive advantage ahead of tightening regulations. HMTC testing also reinforces supply-chain accountability, as manufacturers must assess raw ingredients (such as rice, cocoa, and herbs) and packaging for cadmium contamination and implement best practices, including sourcing from low-cadmium regions, soil remediation, and the use of phosphate-free fertilizers. As public awareness grows and international agencies revisit cadmium limits, HMTC certification positions companies as leaders in pediatric safety and environmental stewardship.

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