Brown rice: arsenic, cadmium, lead

Levels measured in Japanese government surveys and studies

Units are mg/kg (= ppm). The brown rice is the shipping grade (after drying and adjustment). A range such as “0.00–0.02” runs from the mean with samples below the limit of quantification (0.02) counted as 0 to the mean with them counted at the limit of quantification. The limit of quantification for cadmium in the 2009–10 crops was 0.04, so its detection power differs from that of the 2022–24 crops (0.01).

Limits (Japan, international, EU)

Good to know

• Brown rice is a food with more inorganic arsenic than polished rice. Polishing removes the bran layer (about 9% on the outside of the brown rice grain) and leaves about 60–70% (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).
• MAFF says that brown rice is richer than white rice in vitamins B1 and E, iron, and dietary fiber, and that eating brown rice or nuka-zuke (rice-bran pickles) as part of a balanced diet poses no health problem from arsenic. The FSCJ’s assessment is likewise “no problem with a balanced diet.” On the other hand, there are also international assessments that say there may be a concern even at average intakes (JECFA 2025, EFSA 2024), so views are not unified.
• This is a reference using other countries’ yardsticks. In the 2022–24 brown rice, the maximum of 0.37 is at a level that would exceed both Codex (0.35) and the EU (0.25). Five samples (0.6%) exceeded 0.3. The share above 0.2 fell from 19.7% in the 2017–19 crops to 7.4% in the 2022–24 crops. Because Japan has no standard for inorganic arsenic, this does not mean a legal violation.
• There is a report that rice bran itself contains about 1 mg/kg of inorganic arsenic, 10–20 times a normal grain (Sun et al., 2008; 0.61–1.9 in five rice bran soluble products). No Japanese public survey values were found for rice bran or nuka-zuke.
• MAFF summarizes that cadmium barely falls when brown rice is milled to white rice (an average of 95%, about a 5% reduction), and that rice bran is higher than brown rice. No sample exceeded the standard of 0.4 in either the 2022–24 crops or the 2009–10 crops (for the 1997–98 crops, 96 of 37,250 samples, or 0.3%).
• 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.

Reducing it at home (shown in tests)

• Brown rice barely falls with washing (MAFF’s guide)
• Milling: at a milling ratio of 91%, inorganic arsenic falls by an average of 51% (10 samples, 38–61%); at 89%, by 53%; at 80%, by 60%. Half-milled rice (milling ratio 95%) reduces it by about half as much as normal milling (12–25%) (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). Recirculating percolation reduced brown rice by 69 ± 10% (13 samples). The parboiling-and-absorption method reduced brown rice by 54% (Menon et al., 2021)
• Nutrient loss from the cooking method was reported to be smaller for brown rice than for white rice (Menon et al., 2021). With the usual Japanese way of cooking (cooked with no water left over), inorganic arsenic does not fall
• 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

Pages for each metal

• Arsenic
• Cadmium
• Lead

Sources

• MAFF, “Survey of arsenic contained in food” (updated December 2025)
• MAFF, “Q&A on arsenic”
• MAFF, results of the arsenic and cadmium survey of rice from the 2022–24 crops (December 19, 2025)
• MAFF, “Survey of cadmium in domestic agricultural products (fiscal 2009–14)”
• MAFF, “Guide to reducing arsenic in rice” (drawn up 2019, revised 2022)
• 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”

• Polished rice
• Wheat
• Soybeans