Pesticides
Tea, especially green tea,
tends to be accused by some institutions as polluted with pesticides
and, therefore, as being unhealthy.
Especially consumer watch
groups tend to interpret the test results in uncorrect ways. The
pollutants are caused by the use of pesticides.
What are pesticides?
Generally speaking, all plant protection products are pesticides if they are produced artificially!
The plant protection products can be categorised in 3 groups:
Herbicides: weed control
Insecticides: pest control
Fungicides: combat fungal infestation and leaf diseases
With respect to tea, insecticides are almost always referred to.
Generally speaking, all three groups, including the heavy metals,
should be investigated. Pesticides are used worldwide in all areas of
the agriculture today. The chemical industry produces several hundred
presticides. Many of these substances are already forbidden in many
countries. However, many of these substances remain in the soil for a
long period of time and are very persistent in that they still affect
the plants after several years. Of course, in many so-called Third
World countries, a large number of questionable or even poisonous
pesticides are still used if the importing countries do not exert
pressure against this.
Examinations, tests and regulations
Based
on the much more sensible methods of analysis which can be used today,
it is possible to find even the smallest residues of pesticides on the
plants. Tea is generally analysed with respect to a certain number of
possible pesticides. Hereby, a certain maximum amount per pesticide is
determined by the EU. These residue amounts are definitely binding and
regulated by the the RHmV in Germany.
The amounts of the pesticides
which are present are only written down if a certain maximum amount is
surpassed. Apart from this, the amounts are declared as "smaller than"
or "n.n." (not traceable).
These analyses also often provide the ground for misinterpretations.
Especially journalists like to publish and interpret these analyses. It
is then often the journalists and not the experts who arrogate to
appraise and judge the teas using their own, arbitrary measurements.
Particularly the setting of subjective judgement criteria, such as
slightly polluted or questionable, is hereby especially confusing.
Traces of pesticides or heavy metals are nowadays unfortunately
everywhere, i.e. in every foodstuff. Subsequently, the label
"pesticide-free" is wrong and confusing.
When
interpreting the analytic data of the residue analyses, some details
have to be taken into account: the results of the residue analyses vary
quite a lot due to
– the very small amounts which are to be identified and quantified,
– the type of the material which was analysed, which is often very inhomogenous
– the differing quality standards of the laboratories. According to the
statement of a laboratory, fluctuations of up to 60% (+/-) are
definitely possible!
Due to this, the
foodstuff examination office declared the range of variaton at 50% +/-.
This means that a trespassing of the peak amount is only given if the
entire range of variation lies above the peak amount and also does not
touch it.
Additionally, it has to be
noted that only about 2-15% of the pesticide residues, which can be
found in the tea leaf, are solved and can be found in the infusion. The
largest proportion remains unsolved in the leaf. Hence, a pesticide
pollution of tea has to be rated differently than in other foodstuff
which is consumed in its entirety.
Unfortunately,
and paradoxically, the accepted amounts are higher for some foodstuff
which is consumed in its entirety than for tea.
For example, up
to 2,0 mg/kg of Lindan may be contained in leaf salad. With respect to
tea, the maximum amount allowed for Lindan is 0,2 mg/kg. If you then
consider that only about 2-15% of the residue on the leaf is solved in
the tea, it is almost neglectable to even talk about.
In
the important tea producing countries which also have a large per
capita amount of tea consumption (such as Japan), strict rules are also
in place according to the cleanliness and purity of the product.
However, in these countries, the basis of the analysis is always the
Eluat, that is, the infusion of the tea, which much more represents the
reality.
A brief description of the residues on tea.
chloride pesticides
are acutely poisonous and even small doses lead to long-term damage and
cancer. The most frequently used chloride pesticide is DDT. The
smallest amounts of this are deposited in fat tissue and need years to
be broken down. Hence, the use of pesticides is highly problematic and
has been forbidden by many tea cultivating countries for years.
Therefore, the pesticide residue analysis is only of limited relevance
to tea nowadays and it is more important in how far the soil is still
polluted with the pesticides which were used years ago.
Some more widely known chloride pesticides are, for example, DDT, isodrin, endirn, triallat.
cyanogene pesticides
A group of pesticides which appears frequently and which has a highly
toxical effect on the human organism. They, however, have not been
playing any major role in tea cultivation for many years.
phosphorous pesticides
This is a group of highly toxical, but biologically degradable
substances such as ethion. They are broken down quickly in the soil
and, therefore, are only of a short relevance, e.g.: carbophenothion,
chlorthion, diazion, ethion, phosalon
heavy metals
Especially copper combinations cause a stir with respect to residues in
tea. Copper salt is highly toxic and also responsible for long-time
damages in the liver. Generally, however, heavy metals are only
detectable in tea in very small doses. Their effect on the human
organism is almost non-existant.
KbA – controlled organic cultivation
The
label kbA refers to the cultivation methods which are controlled, and
not to the possible residues on the product. That means, a product with
a “ kbA“ label may contain residues of pesticides and heavy metals.
What is meant by controlled organic cultivation?
Controlled
organic cultivation of natural plant families, the support of organic
plant protection products. Synthetic spray and fertilizing substances
are forbidden under kbA.
The conversion from conventional cultivation to organic agriculture can be achieved in three years.
After the so-called first inspection where all fields are analysed with
respect to the soil, plants and harvests, the so-called "zero year"
begins. During this year, the cultivation may not be called organic,
even though all the rules which apply to organic cultivation have to be
followed. This is a difficult phase for the tea cultivator, because the
costs are significantly higher even though the prices may not be
adapted to this new situation.
The phase of
the “Cultivation with respect to the switch to controlled organic
agriculture" lasts from the beginning of the second year until the end
of the third year. During this period, the product may already be
labeled: produced with respect to the switch to controlled organic
cultivation".
After the successful
finalisation of the three-year conversion, the products may now be
called "from controlled organic cultivation".
Without
doubt, the chemical industry is, of course, interested to sell
pesticides to the agricultural industry worldwide. On the other hand,
the ambitions to replace these substances have increased within the
last few years. New tendencies in conventional cultivation are, for
example, the use of a new generation of pesticides, such as the
fenfalerates. These belong to the so-called pyrethroids which are
substances which are extracted from descendents of African carnicerous
plants. These substances are organically degradable and can be consumed
by humans. In more and more tea gardens and plantations these methods
are used extensively and allow strict organic cultivation. For example,
straw and bast mats are laid out against vermins and insecticides are
exchanged or natural insect eaters such as frogs or lizards.
*These fields must be filled in.