Heavy metals in food databaseVegetables, tubers and teaChecked 2026.10.03
Green tea: lead, arsenic, cadmium
In a MAFF survey (fiscal 2019) of 120 samples of domestic green tea (tea leaves), lead was below the limit of quantification (0.10 mg/kg) in 77 samples, and the maximum was 2.4 mg/kg in one sample of bancha. Total arsenic and cadmium were below the limit of quantification in nearly all samples. About 8.8% of the lead in the leaves dissolves into the brewed tea (the infusion), and MAFF concludes that “tea is not a major source of these substances.”
Levels measured in Japanese government surveys and studies
| Metal | Form / state | Mean | Range / max | Samples | Survey |
|---|---|---|---|---|---|
| Lead | Total lead, tea leaves (dried) | Not calculated (more than half were below the limit of quantification; the median is <0.10) | <0.10–2.4 | 120 samples (77 below the limit of quantification) | MAFF, fiscal 2019 (purchased September–October 2019) |
| Arsenic | Total arsenic, tea leaves (dried) | Not calculated (119 samples below the limit of quantification) | <0.01–0.13 | 120 samples | MAFF, fiscal 2019 (purchased September–October 2019) |
| Cadmium | Total cadmium, tea leaves (dried) | Not calculated (119 samples below the limit of quantification) | <0.01–0.11 | 120 samples | MAFF, fiscal 2019 (purchased September–October 2019) |
Units are mg/kg (= ppm), dried tea leaves. The limit of quantification is 0.10 mg/kg for lead, total arsenic, and cadmium (the detection limit is 0.01). Because more than half of the samples were below the limit of quantification, MAFF did not calculate averages.
Limits (Japan, international, EU)
| Set by | Limit | Note |
|---|---|---|
| Japan (Food Sanitation Act) | No standard for lead, arsenic, or cadmium in tea leaves | — |
| Codex (international standards) | Lead in tea and herbal infusions is a candidate for setting a standard (reviewed in 2019) | It has not been confirmed whether this led to a standard |
| EU (Regulation 2023/915) | No entry for tea leaves confirmed | Unconfirmed |
Good to know
- The three samples with lead above 0.30 mg/kg were all bancha, and the maximum of 2.4 is a single bancha sample. For this bancha, the manufacturer changed the source tea leaves and reduced the lead. This one sample was also the only one in which total arsenic (0.13) and cadmium (0.10; MAFF corrected the maximum from 0.10 to 0.11) were quantified.
- The concentration in the tea leaves and the concentration in the tea you drink are different things. MAFF tested both the leaves and the infusion, estimated intake from Japanese tea consumption, and says that intake through tea is markedly lower than from the diet as a whole.
- The infusion leaching test was done on five samples of sencha and five of bancha with high lead concentrations. The material has no measured values for matcha, where the whole leaf is consumed (10 samples in the survey), as it is drunk.
- In green tea, aluminum stands out more than lead. In the same survey, aluminum was detected in all 120 samples, at 246–1,980 mg/kg (average 707). MAFF explains that the tea plant readily takes up aluminum from the soil (it is not a heavy metal, and is given here only for reference).
- In the total diet study (2024), the food group with the largest contribution to lead is the beverages group (group 9), at 22.5%. This group includes drinks other than tea, and the contribution of tea alone is not known. MAFF’s survey conclusion is as stated above.
- For inorganic arsenic, total arsenic, and cadmium in tea leaves, no Japanese public values finer than the limit of quantification (0.10) were found.
Reducing it at home (shown in tests)
- Brewing and drinking: of the lead in the leaves, about 8.8% comes out into the tea (10 g of tea leaves with 450 mL of 90°C water for 60 seconds. A test on five sencha samples with high lead concentrations). For bancha, 10 g of tea leaves with 430 mL of 100°C water for 30 seconds (five samples)
- Total arsenic and cadmium in the infusion were all below the detection limit (0.001 mg/kg). MAFF also gives leaching rates, assuming the infusion of the single highest tea leaf sample was at the detection limit (total arsenic under 32%, cadmium under 39%)
Related explainers
Pages for each metal
Sources
- MAFF, “Results of the fiscal 2019 survey of lead, aluminum, and other contents in green tea” (published November 2020)
- MAFF, “Information on lead in food”
- MHLW research grant, Total Diet Study, fiscal 2024, sub-study report
- MAFF, “Lead standards set by international organizations and other countries”
Last checked 2026.10.03 (against the original government documents and papers, collected and cross-checked in Gemini Notebook).
Heavy metals occur naturally in soil and the sea, and every food contains small amounts. This page lists facts from government surveys, limits and assessments and from published papers; it does not judge any food as good or bad. Where there is official advice — such as on eating fish during pregnancy — follow it.