Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
This original research article systematically evaluated rice grain cadmium concentrations across the global market supply chain to map contamination risks relevant to heavy metal certification programs. A total of 2,270 polished (white) rice samples were collected from retailers spanning 32 countries on six continents. The study sought to establish baseline cadmium levels in commercially available rice, identify geographic variations, and assess compliance with European Union (EU) cadmium standards for rice and infant foods. The global context of rice cadmium was explored, with special attention given to regions historically understudied for heavy metals in rice, such as Africa, the Indian subcontinent, and parts of Southeast Asia. The study leveraged unified laboratory protocols and quality controls, ensuring robust cross-regional comparison that can inform food safety standards and supply-chain risk management for the Heavy Metal Tested and Certified (HTMC) program.
Who was studied?
The population under study comprised rice samples acquired from markets and retailers, representing the rice consumed by the general population in 32 countries. The sampling was intentionally broad to reflect the diversity of global rice production and consumption, including major rice-producing countries (such as China, India, Bangladesh, Brazil, and the United States) and regions less commonly scrutinized for heavy metal content (notably East and West Africa and parts of South America). While the study did not sample individuals directly, it was designed to reflect real-world consumer exposure by targeting locally produced, polished rice from commercial supply chains. Subpopulations of specific interest included infants and young children, given their heightened vulnerability and the stricter EU cadmium standard for infant foods.
Most important findings
| Critical Points | Details |
|---|---|
| Geographic variation in cadmium concentration is significant | 5% of the global rice supply exceeded the EU polished rice standard (200 µg/kg). For the stricter infant food standard (40 µg/kg), 25% of rice samples globally were not suitable for baby food use. In China, 17% exceeded the 200 µg/kg limit. |
| Compliance with regulatory standards varies widely | 5% of global rice supply exceeded the EU polished rice standard (200 µg/kg). For the stricter infant food standard (40 µg/kg), 25% of rice samples globally were not suitable for baby food use. In China, 17% exceeded the 200 µg/kg limit. |
| Regional risks are heightened by consumption rates | High cadmium concentrations observed in regions with high rice consumption (e.g., Bangladesh and Southeast China) pose amplified exposure risks, even if absolute concentrations are sometimes lower than in other areas. |
| No clear relationship between cadmium and arsenic in rice | Some regions (notably East Africa: Malawi, Tanzania) are low in both; others (e.g., China) are high in both, but no overall correlation was found, emphasizing the need for dual contaminant assessment. |
| Implications for infant foods and food safety | Many rice sources, including in the EU, failed to meet the stricter infant food cadmium standard, underscoring the necessity for extensive testing before rice is used in baby foods or products aimed at sensitive populations. |
| Methodological rigor strengthens findings | Use of standardized QA/QC protocols and a unified dataset enabled robust cross-country comparisons, overcoming the inconsistencies seen in literature-based compilations. |
| East African rice as a model for low-contaminant sourcing | Only rice from Malawi and Tanzania consistently exhibited low levels of both cadmium and inorganic arsenic, making these regions key candidates for sourcing safe rice, especially for vulnerable populations. |
Key implications
This study demonstrates that cadmium contamination in global rice supply chains varies greatly, with significant regulatory exceedances in key regions, especially China and the Indian subcontinent. For heavy metal certification programs, regular, region-specific testing is vital, and sourcing from regions like East Africa may minimize consumer heavy metal exposure, particularly for infants and children.
Citation
Shi Z, Carey M, Meharg C, Williams PN, Signes-Pastor AJ, Triwardhani EA, Pandiangan FI, Campbell K, Elliott C, Marwa EM, Jiujin X, Gomes Farias J, Nicoloso FT, De Silva PMCS, Lu Y, Norton G, Adomako E, Green AJ, Moreno-Jiménez E, Zhu Y, Carbonell-Barrachina ÁA, Haris PI, Lawgali YF, Sommella A, Pigna M, Brabet C, Montet D, Njira K, Watts MJ, Hossain M, Islam MR, Tapia Y, Oporto C, Meharg AA. Rice grain cadmium concentrations in the global supply-chain. Exposure and Health. 2020;12:869–876. doi:10.1007/s12403-020-00349-6
Cadmium is a persistent heavy metal that accumulates in kidneys and bones. Dietary sources include cereals, cocoa, shellfish and vegetables, while smokers and industrial workers receive higher exposures. Studies link cadmium to kidney dysfunction, bone fractures and cancer.
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
