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Pesticides in Tea And What You Should Know About It

Pesticides, pollution and environmental damage have to be at the very least a background concern for tea drinkers: What do you need to know to make sure that you don’t buy something that puts your health at risk?   

My post can’t provide definitive answers. This is an area where just about any opinion can be found, from scare stories to shrug it all off, and there’s an information overload that is close to impossible to sort out. The evidence suggests that tea is safer than most agricultural products and that you can minimize your own health risks by focusing your choices on mountain-grown teas.

I see three main areas of concern about pesticides and the more general risks from environmental damage: (1) the health reflex, (2) the China association, and (3) tabloid science.

When you add all this up, what can you reliably conclude? Should you be fearful, cautious, indifferent or comfortable? Here’s just one tea drinker’s assessment, based on a fairly exhaustive tracking of news, scientific reports, tea industry position statements, blogs and just about anything else that spots my eye.

How serious is the problem of pesticides?

I am asking the question for my own self-interest so I bring no vested position. Like most people, I am well aware of all the buzz and gloomy news about “poison” in our foods that make you worry that maybe you should worry. Then you worry because you’re not worried and don’t know if you should be.

I am much less concerned now about the short-term personal risks than when I started my investigation; don’t worry. But I am pretty fatalistic about the wider long-term environmental ones. Artisan whole leaf teas, where good management is making a difference, add up to only 15% of the market. The 85% Agribusiness segment lacks economic incentives, coordination and in many instances the growers’ skills, financial resources and access to information and education to do much more than go with the drift. Their focus is this season: cost cutting, volume production, chemicals, mechanization and short-term fixes. They put the long-term at increasing risk.

My personal recommendations are:

  • Understand that “pesticide” does not automatically mean bad or “organic” equate to good. It’s the broader biodynamic management ethos and expertise that determine good and bad. Organic methods are part of this but the organic label is more an expensive certification than a pervasive solution. For example, it does not vouch for lead residues in the soil.
  • Be wary of broad scare stories and shrug-it-all-off ones that rely on science but do not provide research details or evidential support. When you read a striking short piece that provides assertive claims and figures, you just can’t tell how reliable it is.
  • Buy single estate and pedigree teas from mountain regions. Today’s best tea still comes from the places that dominate its historical reputation and craft. There’s a new generation of managers in the elite gardens and estates of Darjeeling, Taiwan, Japan, Nilgiri and parts of China who fully understand that biodynamics is core to their future growth and profits; the buzz word in the trade is “premiumization” and contrasts to commoditization.
  • Avoid generic blends, low end tea bags, anonymous teas from unspecified sources, and lowland mass farming commodity tea. This is not a matter of snobbery and many of these meet the core standards of agricultural quality and safety, but there are just too many gaps in the supply, distribution, and production systems to be sure.

A Natural Pesticide: Caffeine

Tea-n-health” is almost a single word in everyday discussion. Many people drink tea mainly for its perceived health value and most assume that it is good for you. They recognize that tea is a dynamic “bioactive” agent that affects the body’s organisms and tissues. They don’t want bioactive to become biodamaging.

Volume production of cheap food inevitably means pesticides. The humid subtropical climates in which tea grows are nurseries for lots and lots of insects and critters. The estimated crop loss from uncontrolled farming is anywhere from 10% to 55%.

“Pesticide” is too often translated as “poisonous” and at best a necessary evil. But most pesticides are completely safe and there are others that in trace amounts pose no health risks. Many are short-lived and while around 85% are synthetic, there is an increasing adoption of natural ones as part of biodynamic farming.

Among the most effective natural pesticides is the one that seems to have evolved from the bushes themselves: caffeine. This discourages many of the 300 or so main tiny predators that eat away, weaken or contaminate the leaf.

As with antibiotics used in everyday medical treatment, there are broad spectrum pesticides that zap everything and ones that are more targeted. Overuse of pesticides, as with antibiotics, can weaken their effectiveness and be literally overkill.  One of the problems in moving to natural pesticides is that they take much longer than synthetic ones to take effect, 6-9 months versus weeks or even days. The worry is that many giant farms and smallholders that produce low grade tea have underinvested in bush and soil renewal and must rely on chemical boosts.

All their incentives are to cut costs now – and not invest in future quality and environmental sustainability. Smallholders face growing and very, very severe poverty as prices continue to erode. In many countries, they are threatened by takeover of their land, and they are naturally ready to use anything that helps their marginal business, including banned and bootleg pesticides, some of which are associated with neurological damage.

The problems are most acute in markets where consumption is mostly domestic. By and large – somewhat weaselly words for “we think but can’t be sure” – tea imports seem to be at least as safe as fruits and meats. Reliance on exports requires meeting the standards of the import monitoring agencies of the EU, Japan and a few other nations that have tightened regulation and increased sanctions. One of the main reasons to doubt the most extreme scare stories is that there is growing sophistication and security in handling tea imports, partly because tea is such an integral element of everyday life in so many countries.

The Artisan tradition is responding by strengthening its biodynamic methods, streamlining supply chains, and becoming very selective in its use of pesticides and fertilizers. Japan and Germany have rejected imports from several countries, forcing them to upgrade their growers’ practices.

Agribusiness mass production of low end teas is much more “iffy.” The major brands seem to be both responsible and efficient in managing their own operations and in buying leaf. There doesn’t appear to be much substance in the accusations that their teas are packed with residues from pesticides.

The China Association

“Tea-n-China” is another verbal elision, like tea-n-health. It’s natural to associate “tea” with China, even though half of US tea imports are from Argentine and about 30% more from African growers. China does not exactly have a sterling reputation for food safety. Scandal is the more general label: corruption, contamination, pollution of air, soil and water, and fraud.

Published interviews with many Western tea experts suggest that this Chinese stereotype is incomplete. They point to reasonably effective government tightening of loopholes and aggressive increase in sanctions aimed at protecting China’s export markets, though some doubt these will be much more than window-dressing.

They are generally much more positive about the pedigree mountain teas. Even close to the massively polluted cities and manufacturing regions, the mountain winds and seasonal shifts keep the slopes swept clean.

The elite highland tea growing communities are moving firmly to protect their heritage. Key regions like Wuyi, noted for its rock oolongs, have improved waste management and burning of trash. The Longjing growers of Dragonwell, routinely identified as China’s best tea, are collaborating to protect water supply and quality.  Before a tea can be sold in Guangzhou’s famous market of 3,000 shops, it must be taste-tested in a lab, which also offers free services for growers to send their samples.

The contamination problems seem less one of nation than type of terrain. There are three major general  sources of agricultural harm: heavy metals in the soil, water contamination and pesticides. The metals are a roadside problem, from passing cars. The mountains are not auto-friendly and lack roads and traffic. This discourages heavy use of pesticides simply because it is too expensive to lug the stuff up there.

The climate is also less the playground of bugs and pests than the more humid lowlands. So far, acid rain and the appalling smokestack airborne pollution that is at crisis levels in the big cities of China and India don’t seem to have affected mountain plants but the chain effects of carbon monoxide are uncertain and likely to be pervasive.

Even Darjeeling now has a traffic pollution problem. The tea fields of Assam are often next to oil drilling operations. Korean and Japanese land prices are shrinking the areas available for tea growing and housing and complexes are encroaching on what was only a few years well-protected, pristine and packed with now disappearing biodiversity. Fertilizers and run offs are lowering water quality.  

China is not the main problem for the future of tea. It’s a broader ecological issue.

Tabloid Science 

Would you like a scary Frankencrop alarm analysis of tea? Take your pick…  One that created headlines and has been widely quoted is a report by Greenpeace that “More than half of Chinese tea is tainted with banned pesticides.” Eighteen medium-grade teas from leading companies were tested by “an accredited third-party laboratory.” It found that every single sample contained three or more pesticides, including at   least one that is banned from use. Almost 10% of workers using pesticide applicators suffered pesticide poisoning.

This is striking and disconcerting. Is it true? You just can’t tell. The companies totally deny the validity of the tests and point to the refusal to publish the data or source; the results haven’t been replicated and the teas all meet strict import standards.

Another Greenpeace study states that 60% of Indian tea samples contain pesticide residues above the maximum permitted by the European Union. The Chairman of the India Tea Board dismisses this as “completely baseless.” A famous or infamous US report that names many top brands as pesticide-packed turns out to have been sponsored by an investment firm short-selling – betting on a drop in stock price – of one of these. But the lab analysis has been accepted by some experts as reliable. Again, how can you tell?

The science of tea is astonishingly complex, because the leaf is basically a chemistry lab of over six hundred interacting compounds. The analysis of pesticides gets reported in broad headlines of X% of teas or more than Y% above MRL (maximal residual level) but the base research is at a molecular scale and doesn’t create tidy headlines and figures. The more detailed the study, in general the less scary its conclusions.  

Much of the work includes developing precise measurement tools such as gas chromatography, immunoassay and atomic absorption methods. Here’s a fairly random extract from a study: “… using hyphenation of SPME in a head-space mode with a comprehensive two-dimensional GC coupled with high-speed time-of-flight MS…”

This doesn’t translate easily to even the best of journalism, where headlines need to be big, messages definite and figures understandable. The presentation and interpretation gap is illustrated in reports on a big scare in Japan that has led to the government banning sales from a number of major tea growing regions.

This is a response to the high levels of cesium radiation in tea leaves that is a direct outcome of the nuclear power plant meltdown in 2011. Domestic and foreign demand has plummeted. As one farmer comments “When people are fearful, they are not going to buy your products, no matter how many times they tell you they are safe.”

The farmers are telling them exactly that; the government regulations measure the concentration in the dried leaves, not the final tea product. You would have to drink two hundred bottles of green tea every day for a year before there would be any health risk. But the simple tabloid headline blocks the scientific exegesis.

My own view is that just about all the reporting on the scientific studies of tea is suspect. They naturally tend to the scare end of the alarm/don’t worry spectrum. Headlines are not enough. I am reasonably well-trained in research methods and have a fair grasp of statistics and experimental design. I could not confidently vouch for the reliability of more than ten percent of the tabloid science articles I read. Equally, I doubt if I really understand much more than that in the solid scientific reports I read: I need a headline.

That is not to discount the scare stories; they may lack needed detail but can be useful alerts. But the Greenpeace studies just don’t pass the core tests of scientific research; no respected journal would accept them for publication. The issues of pollution, contamination ad safety rest on the details of science. Tabloids obscure those details.

Conclusion: Choose tea like you buy hot dogs

My assessment here is offered as a careful briefing rather than a confident dogma. Personally, I feel more comfortable buying tea than hot dogs. My simple way of making my choice in both instances is to avoid entirely the products that either don’t state what they contain or signal lowest quality control; “selected black tea” is equivalent to “processed meat” and “a blend of green tea flavored with” to “contains meat byproducts.” If the label and description don’t convince me that this is natural in its ingredients, offered through a reliable brand and supply chain and backed by a seller of high reputation, I pass.

There is no reason for buy mediocre tea in bags and blends. There are so many whole leaf ones that cost the same and taste better. The odds are highly in favor of their being safe, too. Conversely, if a tea is certified as organic, is made by Artisan methods and provides full information on its source, season and origin, it is likely to taste better as well as be better.  

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  • Peter GW Keen
    Peter Keen has been a professor at leading universities across the world, including Harvard, MIT and Stanford in the US and in Singapore, The
    Netherlands, Mexico and UK. He is the author of over thirty books on the links between business innovation and technology.
    Peter was born in Singapore, brought up in England and now lives in Virginia in the US.

    Peter loves tea and loves writing. His latest book, Tea Tips: A Guide to Finding and Enjoying Tea was published in February 2017.
  • All Posts from Peter GW Keen


    • Swatantra Kumar Sethi says

      Hi Peter,
      I enjoyed your article thoroughly which reflects my own concerns about ubiquitous pesticides in Tea.

      I wish you had given an off-the-shelf type solution to treat Tea at home to eliminate pesticides etc. to great extent if not entirely.

      Occasionally I prefer to wash Tea leaves before making while my wife looks on in disbeleif. Before making Tea I like to shake the Tea leaves in half a cup of hot water for 20 counts & throw the liquid, rinse again for few seconds & throw the liquid again. Then the Tea is finally made after brewing as usual. This I picked up from net.

      How about it?


  1. Peter GW Keen
    peter says

    Hi Christopher….

    Point well taken. This is a problem I don’t know how to solve. The length, format, and readership breadth of online blogs don’t make footnoting, biblio and citations easy to position — I looked at over 200 published items for this brief piece. I try to doublecheck sources but many of them are unreferenced or multi-reprints. Any ideas will be welcome. It does worry me. I tend in my books and research papers to overcite. For the moment, I’m keeping the text fully clean and uncluttered but that’s more a convenience than a satisfactory answer.


    • J.D. says

      Peter, if it’s not feasible to put them on the same page, link to a second page or put them all with active links on a document that can be downloaded (you could host it on Google Docs or something similar). This will minimize the space it takes up while still allowing readers to look things up for themselves.

      Speaking personally, I don’t know you. I don’t know anything about you or your site. As far as I can tell, this is the first time I’ve been here. So, you haven’t established any trust with me. You could be a brilliant researcher or a self-important ignoramus and I really wouldn’t know. What tells me which one you are your citations. The citations are one of the *first* places I go when reading an article. (Seriously.) I skip around, look for some valid points, then follow a link to a supporting source. I take a read and then, based on the credibility of that source, I decide whether to continue reading or not. Without that, your article is just opinion. You could say whatever you want and putting the burden on the reader to find supporting evidence…well, why would you do that? Why would I want to go to a site that makes it more work for me when I can go to another one that doesn’t just make claims but supports them as well?

      As I said, this is my first time here. But, right now, I’m leaving your site not really believing you, feeling like reading your articles will make more work for me, and preferring to go to other sites in the future instead. Is that a feeling you want to impart in your readers? You said that you researched many sources in writing this article. It’s not hard to add those links to a list. You don’t even have to make the citations into links. You could just put a plain text number: [1] then provide a numbered list at the end of the article, or one of the other options that I mentioned. It’s a small amount of extra work to have readers leave here confident of your site as a source of information, rather than looking for other sites instead.

  2. Another avenue that would be interesting to explore: the water solubility of the specific pesticides used on tea. This value varies per chemical. It is a relevant factor here, for tea is typically water brewed and filtered rather than eaten.

    But it may require much good luck to find out the specific pesticides used.

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  8. Heather says

    Thank you for writing this article. I appreciate your insights.

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