Heavy Metals in Tea: Why We Test Every Batch (Lab Results) (Preview)

Green tea is one of the most studied beverages on earth — linked in research to polyphenols, catechins, and potential benefits for metabolism, heart health, and more. After water, tea is the most consumed drink in the world.

But have you ever wondered what else might be in the leaves — especially if you drink matcha whole, not just an infusion?

Tea plants are bioaccumulators: they draw minerals (and contaminants) from soil into the leaf. That is why origin, harvest, organic certification, and independent testing matter as much as grade or colour.

At Purematcha, safety is our number one priority. We test at source in Japan and again through independent Australian laboratories — and we publish the results.

At a glance

How toxic is your tea?

Green tea’s health halo only holds if the leaf itself is clean.

Factors that affect contamination risk:

• Soil and air quality at the farm (industrial regions vs clean mountain terroir)
• Harvest timing — older leaves on lower-grade tea have longer to accumulate contaminants
• Processing and packaging — including microplastics in some tea bags
• Country of origin — studies have found higher pesticide residues in some mass-market teas from heavily industrialised regions compared with Japanese production

A 2012 Greenpeace China investigation (reported in the Financial Times) found pesticides in all tested Chinese tea samples — 14 of 18 with compounds potentially harmful at consumed levels. That is why who you buy from and what they publish matters.

What Purematcha tests for

We screen for the four heavy metals most relevant to tea safety:

Tests are run to method TP/394 (Agrifood Technology) or NT2_46 (NMI). Results are compared against Australian food safety guidelines.

EISAI Organic Ceremonial Pure Matcha Powder

Our flagship ceremonial matcha — independently lab tested in Australia.

View product

Lab results summary (mg/kg)

All results below are well below safety guidelines or not detected. Expand any product for the full breakdown, or scroll to laboratory certificates for the original PDF reports.

ND = not detected at method limit. Values in mg/kg.

Results by product

Laboratory certificates

Independent Agrifood Technology certificates are embedded below — the same PDF reports published on our original safety page. Each report may cover multiple products tested in the same batch.

NMI report RN1/400876 (Yamabuki Nadeshiko, Nishi, Gokou — August 2023) is summarised in the product results above.

How to choose safer, higher-quality tea

• Buy organic-certified tea — JAS / Australian organic standards reduce pesticide exposure
• Know the origin — country, region, and ideally the farm or co-op
• Choose brands that test and publish — transparency beats marketing claims
• Prefer early-harvest, higher-grade leaf — less time in soil to accumulate contaminants
• Check packaging — avoid tea bags with plastic mesh if that concerns you

Japanese teas from reputable farms — especially organic, first-flush matcha — consistently test cleaner than many mass-market alternatives. That is the lane we operate in, and why we keep testing.