Apr 20, 2013

concern of lead in tea products - a boring post after an awful week in Boston

Photo taken by Robert Seto on a deserted streets of Boston on Friday (4/19) morning.
This has been a terrible week for Boston! On top of it, yesterday, a grade 7 earthquake broke out in Sichuan province (actually Ya An, the region where Tibetan Hei Cha is produced). On one hand, natural disasters are always so overwhelming and leave a completely helpless feeling to people. On the other hand, in some sense, human disasters caused by human violence feel even more awful than natural disasters.

I'm glad that the week in Boston has a relatively good end, and grateful for the efficient and effective action of the law enforcement. Everybody feels relieved after last night. But on the other hand, we all know that this is so not-over for many others whose lives were permanently damaged at the Boston Marathon bombing...

This is by far not the first time large-scale man-slaughter (involving kids!) has happened. But this time, it makes me feel awful in a whole new way. Part of the awful feeling is from the awareness that we've already got too much violence in this world, yet it happened again, to an event that is supposed to be one of the most inspiring and most peaceful activities in our society.

I have this draft about concern of lead in tea, which I'm afraid is neither interesting nor pleasant. I left it unfinished for a long time. But this week, I guess I won't have the mood to write anything pleasant anyway, and hopefully this lead thing can be a little bit informative for people who do care about lead problems. So I thought I would post it this week.

From time to time, there are questions from tea drinkers about lead contamination in tea. It is a legitimate concern and lead is indeed occasionally found in tea. Recognized sources of lead contamination includes:

* air pollution - this is mainly caused by automobiles and mainly affects plantations near urban areas.

* soil pollution - this is mainly caused by deposition from automobiles and mainly affects plantations by the roadsides.

Considering the first above two factors, high end teas from traditional producing areas have smaller chance of lead contamination. This is because most of the best tea producing areas are in remote mountainous regions relatively short of automobile roads.

* harvest method - buds and younger leaves are more free of contamination. Generally speaking, higher end green teas are composed of mostly buds and younger leaves, compared with lower end green teas. Across tea categories, green teas generally take younger leaves than high end oolong products. Most black teas and many puerh and hei cha products take older leaves than green teas and higher end oolong.

Harvest method and leaf stage is just one factor affecting lead contents in tea. Older leaves of puerh from pristine environments could be totally free of lead, and very young tea buds in heavily polluted areas can be exposed to lead.

* processing - lead contamination from processing equipment. This is supposed to be the easiest to avoid but unfortunately happens sometimes. According to a study published in a Chinese journal, among the 18 factories whose tea products are sampled, the factories focusing on higher grade teas have the lowest lead contents, and the lead content is less after processing compared with before processing. The factories focusing on lower grade teas have the highest lead contents.

According to a Chinese article about lead standard, the Chinese tea inspection standard is 2mg/kg. Japanese standard is 25mg/kg. EU is 5mg/kg. Australia and Canada's is 10mg/kg. (None of them is zero because for various reasons, trace amount of lead is commonly found in air and water.)

Since the above numbers are from a Chinese article published in 2008, I don't know how accurate it is about other countries' standards and if there have been any changes in recent years.

The article with these numbers resulted from an interview with Chen Zongmao, Chinese leading tea scientist and Academician of Chinese Academy of Engineering. He quoted these numbers to emphasize that Chinese lead standards were made in 1988, while the standards of most other countries were made in later years (with a more polluted world). EU standards were made much more strict than before to target on food/tea imports from other countries. Chen Zongmao listed this numbers to urge the government to LIFT Chinese tea lead standard, because he believes it's unfair to Chinese producers. This suggestion from Chen Zongmao, of course, caused great social debate. On the one hand, do people ever want to lift inspection standard, don't we want to always make it stricter and safer??

Chen Zongmao's proposal should be viewed with a context though. What he said was mainly in response to the international trade wars on going during the time. In 2008, EU tightened a series of pesticides inspection standards overnight, with the most rapid change on endosulfan, whose inspection standard was lowered from 30mg/kg to 0.01mg/kg, a 3000 times change overnight. In 2008, many western countries were shocked by the news that so many Chinese food products export to EU failed inspection. But with the context, it's not really surprising that most of those products satisfied all EU requirement one night before, and would fail the 3000 times more strict standards one night after. Not surprisingly, this failure of compliance of EU inspection standards happened to many products from various exporting countries. European and American news media mainly targeted Chinese producers on this. This action of singling out Chinese products is not surprising to me and I wonder if it's surprising to anybody at all :-p

So basically the discussion on lead and many other pesticides standards in China were not just about the environment or health, but about politics and economics as well. This is rather unfortunate. But equally unfortunately, the inspection standards of some importing countries, including EU countries, were not just about the environment or health, but about politics and economics as well.

Since not all tea products are inspected for lead (lead inspection is not required for all international trades), the inspection standards can only serve as references. Generally speaking, it seems to me "high grade tea" and "young leaves" are the most visible standards to consumers. Besides, as for many other quality factors of tea, the quality of the ecosystems where the tea is grown is extremely important. However, information of ecosystems is not always available to consumers, and in today's economy, many "high end" teas are made "high end" based on packaging and advertising.

At last, I also want to point out that the lead concern in tea is not necessarily greater than lead concern in almost everything else, including air and water. In fact, I suspect lead concern in tea is much smaller than lead concern in many other things. In many ways, other food products are more easily contaminated by lead than tea, and many  other food products are for complete consumption, instead of being infused like tea (lead is in its insoluble form in tea products). So generally speaking, lead contamination is a great concern in tea, but it's in everything else as well. The ultimate way to get clean food is to improve the entire ecosystem, and have more progressive gasoline standards (since automobile contamination is one of the major source of lead contamination).

In non-food products, from time to time, lead raises concerns too. For example, according to some consumer group reports, purses of some popular brands have lead significantly above the legal standards. Among the brands mentioned there are purses with typically $200-$500 price tags (such as Tory Burch).

I love purses as much as I love tea... (and I like Tory Burch a lot!) So I hope it's not just the bias toward tea that makes me feel tea is generally perfectly safe (but bias does exist because I suspect I love tea more than purses...)  I feel we are in a more danger and more polluted world nowadays, but I still feel tea is safer than a lot of other things.

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