worried about pesticides in tea?

Yeah, but technically, that is still Taiwan, isn't it?

Well, Lianjiang county is a county near Fuzhou that is partly controlled by Mainland China, and partly controlled by the ROC. The outlying islands anyway, are controlled by the ROC, and that's a tea producing area. In that area, they all speak Fuzhou dialect. It's only about 19 Km to the mainland.

Already done. Also, most people from here don't drink tea from Fujian anymore either. Most of their big revenue comes from illegal smuggling anyway; giving a few million people health problems because of their filthy tea is the least of their worries. Sad to say.

Won't happen. Most Chinese are relatively ignorant that this is even a problem and the Chinese media is making sure that it doesn't look too serious. They are out to make SARS look like the common cold.

Damn, I hate being so negative. What's wrong with me?

Also an excellent point. It's why I only buy from sources IN TAIWAN from Taiwanese people that are into the tea trade. Mainland "GaoShan" tea is just as filthy as TieGuanYin and you can taste it.

I wish I could invite ya'll down to my house in Dongguan to have a blind tasting: some top grade TGY vs. some supermarket grade GaoShan Tea from Taiwan. Your jaws would drop.

Good news is that DDT and many other controlled pesticides aren't actually particularly bad for people in applied amounts. (I'm not sure that there is even a single example of someone dying from ingesting grams of the stuff, which happened not infrequently.) DDT was banned because - being fat-soluble and metabolized only very slowly - it concentrates up the food chain. So top-predator birds had problems with egg shell development. We'd have to eat the cats that fed on the mice that ate the beetles that ate the Pu-erh weevils...

I'm not a medic or biologist, but my impression is that many of the really nasty pesticides like cholinesterase inhibitors have high acute toxicity (e.g. to field workers) but very little chronic risk in lower doses. Kind of the opposite of heavy-metal poisoning, like recent lead problems. FWIW, I don't worry about it, and I do think a lot about food safety.

-DM

Niisonge, I am glad you find something nice to say about Fuzhou. My paternel grandparents and distant relatives are from that region. I have never visited the city itself, as where were from more distant Fuzhou villages.

Since you mention food, could you please tell me what you find nice about it? My grandmother was a good cook, but ever since she passed away, I solely missed Fuzhou cooking. As a boy, she never bothered trained me in the art of cookery.

Agree.

I think in fairness to Anxi, you really have to be talking about the mountainous villages of Xiping, Xianghe and Gande, where the authentic Tieguanyin are grown.

Could you share with us your opinions on how clean and dirty these villages are?

I will be very keen to have their teas tested to remove any doubts.

Julian

Dogma/Mynight

I am with Dogma with this one. I think environmental pollution (road traffic, air, water, lead, fluoride etc) are a more serious threat than pesticides itself.

Tea garden situated in high attitude sloping land tend to use little pesticide anyway. Usually these best parts of tea garden are used to make the really high grades, like the better tasting Tieguanyin Wangs.The price is usually a reflection of the location of the same tea garden.

Just my opinion. I want to test their teas to be sure, anyway.

Julian

Nigel/Ankit

This discussion is getting better and better! I am really excited!

I have been ill the entire weekend, but I just can't help participating.

Nigel, thanks for the correction.

I am particularly concerned about fluoride (and aluminium) because of the focus on past scientific studies, mainly in West China, where people had too much of them from the consumption of compressed tea.

Also the recent case study of a women in US suffering from fluorosis.

I am not an expert, but there have also been concern about fluoride pesticide (if there is such thing, please correct me if I am wrong).

Again, open to correction. I really need to educate myself in this matter much further.

My question is which tea do you test?

Dried tea leaf chemical composition? Brewed tea liquor chemical composition?

I believe dried tea leaves contain less than half of soluble solids?

I have also thought that harmful substances in dried tea leaves are less likely to be soluble.

So brewed tea liquor is better, but much more subjective as preparation method can influence chemical composition.

So I guess standard practice is dried tea leaves, but bearing in mind we are testing for a maximum here, and this is just an INDICATION (probably less) of the amount present in brewed tea liquor?

Any data on the water-solubility of these pollutants will definitely be very relevant.

Probably less soluble than vitamin C, theanine, caffeine and catechins?

Julian

Precisely. I grew up with sprinking DDT between the sheets before getting into bed, and pouring DDT-laced diesel into the fire before cooking outside to keep the bugs away. Not that it isn't an environmental disaster, but it's not a human health disaster. Also, sad to say, it's not as effective as it was when I was a kid because insects have evolved to develop tolerances. Bug generations are very short.

That said, if you want to do testing for DDT, there is an easy titration test that has a high false positive rate, a harder titration test that has a lower false positive rate, and a chromatographic test that requires much less material and is much easier if you have the machine. I assume any professional laboratory today is using the chromatographic method, but if you want to do it at home you can get the reagents to do the older tests.

Yes, but don't forget there are some organometallic pesticides in common use today now, which are indeed the opposite. On the gripping hand, we also have to contend with the fact that the pesticides used in the field are not exactly reagent-grade and come with all kinds of other contaminants in possibly significant amounts.

--scott

Dried tea leaf chemical composition? Brewed tea liquor chemical composition?

both are tested by the lab..

Scott/Dogma

Can you explain what chromatographic is about is layman's terms? How is that different from gas-chromatography which I came across in more recent studies?

Could you elaborate further on the "recent lead problems"? Is that the toy paint thingy? That seems to be a different issue from environmental pollution.

Could you explain what is organometallic pesticides? Is there such thing as fluoride pesticide? How can I read about the different kinds of pesticides available, pros and cons etc?

What is reagent-grade in layman's terms?

Sorry for the bother. I don't really intend to take up too much of your time. But if you can point me in the right direction, I will much appreciate it.

Thank you.

Julian

Thank you.

Okay, if you take a paper sheet and you put a drop of something in it, and you put the bottom of the sheet in a solvent, the various constituents of that drop will move up the paper by capillary actions, and lighter molecules will move up more.

Today we have automated machines... you drop a liquid in, and the machine spits out a graph of composition vs. molecular weight. Fancier systems will also spit out level vs. valence vs. molecular weight by applying charge to the sample as well and separating it that way. A semi-skilled technician can do the testing and it only takes an analytic chemist to read the results, which means you can do lots of tests fast.

It's an organic molecule with a metal in it. I don't know where you would get good information on available pesticides because they change so much, but I'd start with a good college library.

I don't know of any pesticides containing fluorine but I'm no expert in the subject. Fluorine for the most part is a lot more expensive than chlorine which is often an effective subsitute. Pesticides are engineered for low cost and low reactivity.

If you buy a bottle of 50% ethanol from a chemical supplier, it will contain 50% alcohol and 50% water and very little else, and most of the other items will be listed on the data sheet that comes with it. You can order with all sorts of different purity requirements... if you need it to have no detectable iron, you can order one grade, if you need it to have no detectable chlorine, you can order another. "Chemically pure" reagent grade is about the lowest laboratory grade you'll see but it's still very pure compared with vodka over the counter.

A lot of "practical grade" chemicals are much lower than vodka grade, because they're used in applications where they don't need to be very pure. If you look at the assay on a fertilizer grade ammonium nitrate, you'll see it's only about 95% ammonium nitrate and the rest is junk and God only knows what. But for fertilizer, that's fine.

Call your local extension service and ask for a reference to a local pesticide chemist.

--scott

Good advice but sadly Julian, who is located in the UK, will find it hard to follow. We no longer have an Extension Service as would be recognisable by US citizens nor even a Ministry of Agriculture - this was replaced by DEFRA (Department for Environment, Food and Rural Affairs) and the extension experts were disbanded long ago. Most of the practical information quoted by DEFRA is culled from USDA sources!

However, to keep this on-topic aI searched the DEFRA site for "tea growing" and the first hit is a DEFRA Newsletter mentioning Tregothnan, the new commercial tea farm in Cornwall where weather is very similar to that of Darjeeling. I have tasted this tea and was surprized to find it very similar in taste. The article continues that it's possible that climate change could extend tea growing to other areas, particularly with springtime frost growing less common in southern England - and since its publication I have seen reference to Taylors of Harrogate planting tea in Yorkshire.

Nigel at Teacraft

Scott et all

Thanks for your reply. I really appreciate it.

============Further Questions ============

Just out of curiosity, why is organometallic pesticides harm the drinkers and not the workers?

It is interesting you compare pesticides to vodha, or spirit. Does that tell me anything about the hot water solubility of this pesticide?

===PSD === I have found this article in the UK Pesticide Safety Directorate (PSD)

As you can see, EU currently have MAXIMUM ALLOWABLE LIMITS for 30 pesticides residuals, with another 40 under discussion.

Not to mention other environmental pollutants.

It kind of struck me that low cost testing doesn't really exist, at least for now, and the only logical place for comprehensive testing is in the larger tea gardens, where it is subject to manipulation.

:((

=================My tentative conclusion ================= The more I look into this issue, the less I am convinced pollution and pesticides are an issue, especially if you are drinking a high grade.

First, a lot of tea quality is in the taste, so anyone can do their DIY testing.

Second, as pointed to me earlier by Chagonwala, we drink only a few grams of tea leaves each day. Only less than half is soluble in water.

Now compared this to the other foods you eat. Another 300 grams or more? Do your vegetables and fruits and meats grow in high mountain? Are they TRULY organic? They don't dissolve in water, do they? Have they any history of health scare? Do they kill bacteria and virus and reduce cancer risk?

Julian

Nigel, you must be kidding! Maybe we can collaborate and plant some teas in Sussex? :) I was very tempted earlier to put my money in an English Wine company...

Lots of them do harm the workers, especially when excessively applied. A lot of pesticides that are no longer legal for use in the US because of safety concerns are still extensively used in other countries.

Well, ethanol is a thing you can get in a lot of forms. It makes it a convenient reference point.

Sure.

Yes, precisely. The thing is, we drink a lot of tea which is farmed in developing countries under poorly-controlled conditions, and we don't consume many other products like that. On the other hand, if I were living in mainland China today, tea would be the last thing I would ever worry about.

--scott

I don't have numbers for this at my fingertips - does anybody within the sound of my "voice"? - but the idea that people in developed countries don't consume much food grown under lax controls in less-developed countries seems, well, something I wouldn't be able to prove. Chinese-grown garlic and ginger is definitely sold here in New York. And there's lots of Mexican produce - how much? - that, in reality, is how well controlled in the fields and and how well inspected thereafter?

/Lew

Tea is an agricultural product. If you die it will be from some bacteria you didn't kill without boiling water not because of accumulation of pollutants or pesticides in your body. For those who find their tea contaminated I'll take it off your hands for FREE. You pay for shipping.

Jim

PS DDT was causing bird eggs to crack prematurely. Drink too much water at once you'll die from drowning. Eat all the lead paint you want as an adult. The FDA is responsible for all agricultural and seafood imports into this country. I'll guarantee there is more hazardess artificial preservatives in your refrigerator than your tea.

Scott Dorsey wrote: