Polished rice: arsenic, cadmium, lead

Levels measured in Japanese government surveys and studies

Units are mg/kg (= ppm). Polished rice is brown rice milled to a yield of about 90%. The lead row is not a measurement of polished rice itself but a value estimated from the total diet study’s “rice and processed rice products” group (cooked), so it is not a directly measured average.

Limits (Japan, international, EU)

Good to know

• Inorganic arsenic in domestic polished rice has been falling. The brown rice average went from 0.21 (2012 crop) to 0.13 (2022–24 crops), and polished rice from 0.12 to 0.09 mg/kg. MAFF says that “reduction measures are considered to be working effectively.”
• This is a reference using other countries’ yardsticks. The polished rice average of 0.09 is 60% of the EU’s 0.15, and the maximum of 0.23 is at a level that would exceed it. Because Japan has no standard, it cannot be said that a standard was “exceeded.” MAFF says that more than 99% of the 2022–24 crops were at or below the Codex standard.
• About 70% of Japanese inorganic arsenic intake is from rice (total diet study, 2024: rice group 14.4 μg/day, overall 21.2). The same report compares 0.39 μg/kg/day per body weight with reference values such as the US EPA’s and calls it a “possible high risk,” but Japan’s FSCJ has not set a tolerable intake. The conclusion changes depending on which benchmark you choose.
• Polishing removes the bran layer (about 9% on the outside of the brown rice grain), where inorganic arsenic is high, so polished rice is lower than brown rice. The concentration in polished rice is about 60–70% of brown rice: an average of 63% for the 2017–18 crops, and a median of 75% and an average of 73% for the 2022–24 crops (the material gives no explanation for the reason).
• Cadmium barely falls with polishing, washing, or cooking. Taking brown rice as 100, polished rice averages 95%.
• There is a water-management trade-off between arsenic and cadmium. Draining the paddy after heading reduces arsenic but increases cadmium. In June 2024 MAFF drew up guidelines for reducing both.
• Lead in rice is mostly below the limit of quantification, and no public measurements of polished rice itself were found (for brown rice, 580 of 600 samples were below the limit of quantification, with a maximum of 0.04). MAFF explains that “even when concentrations are low in rice and vegetables, they are eaten in large amounts, so their contribution to intake is large.” No Japanese public survey values were found for inorganic arsenic in rice flour, rice crackers, or nuka-zuke (rice-bran pickles).

Reducing it at home (shown in tests)

• Washing white rice: washing three times with deionized water leaves inorganic arsenic at 71–83% of its pre-washing level (about a 20% reduction). A test of three domestic white rice samples (Naito et al., 2015). Washing barely reduces it in brown rice
• Wash-free rice processing (bran-based method): inorganic arsenic falls by about 10% (MAFF’s guide)
• With the usual Japanese way of cooking (water to rice 1.4–2.0 : 1, cooked with no water left over), inorganic arsenic does not fall (Naito et al., 2015)
• Cooking in plenty of water and discarding it: about a 57% reduction at water to rice 12 : 1 (Carey et al., 2015, six brown and six white rice samples), and a 45% reduction at 6 : 1 (Raab et al., 2009; results for long-grain and basmati rice). The parboiling-and-absorption method gave a 73% reduction in white rice (Menon et al., 2021). Cooking in plenty of water and discarding it also washes out nutrients. The parboiling-and-absorption method was reported to lose the same amount of nutrients as excess water, or less (Menon et al., 2021)
• Cadmium barely changes with washing or cooking (MAFF)

Related explainers

• Arsenic and Cadmium in Brown and White Rice: Is Eating It Every Day OK? Measurements of Japanese Rice and How to Reduce Them
• Can Home Cooking Reduce Heavy Metals? Figures Shown for Hijiki, Rice, Innards, Tap Water, and Canned Food
• Why Do Heavy Metal Standards Differ Between Japan and Other Countries? Japanese, Codex, and EU Standards and Tolerable Intakes Compared
• How Much Heavy Metal Do Japanese People Take In? Fifty Years of Lead, Cadmium, Mercury, and Arsenic Intake

Pages for each metal

• Arsenic
• Cadmium
• Lead

Sources

• MAFF, “Survey of arsenic contained in food” (updated December 2025)
• MAFF, results of the arsenic and cadmium survey of rice from the 2022–24 crops (December 19, 2025)
• MAFF, “Guide to reducing arsenic in rice” (drawn up 2019, revised 2022)
• MAFF, “Domestic standards for cadmium in food”
• MHLW research grant, Total Diet Study, fiscal 2024, sub-study report
• Naito S et al. Food Chem 2015 (milling, washing, and cooking of Japanese rice)（PMID 25172713）
• Carey M et al. PLoS One 2015 (cooking in plenty of water)（PMID 26200355）
• Menon M et al. Sci Total Environ 2021 (parboiling and absorption method)（PMID 33153748）

Last checked 2026.10.03 (against the original government documents and papers, collected and cross-checked in Gemini Notebook).

Also in “Rice, grains and beans”

• Brown rice
• Wheat
• Soybeans