Your Daily Poison - Pesticide Action Network UK

Gaps in testing
different studies are significantly variable and
the ten-fold uncertainty factor between species
is barely adequate in the case of some
pesticides, for example, chlorpyrifos. In the
case of diuron, there is a ten-fold variability
within studies. For lambda-cyhalothrin, there
can be a three or four-fold variability up to a
30-fold variability, depending on which study is
selected.
There is currently no regulatory mechanism to
ensure that human dose-effect data held by
the National Poisons Information Service (and
equivalent organisations internationally) from
human poisonings, are fed into the pesticides
approval process, although PAN UK welcomes
new initiatives of ECVAM, which recognises
the critical importance of human data: ‘ …
Validation – the proof that a test accurately
predicts a specific effect in humans – is the
biggest challenge for alternative methods …
One of the 40 or so tests now going through
validation is the new cytotoxicity test to help
replace the animal lethal dose (LD50) test. It
was the first validation study to involve both US
and European groups from the start. It is also
the first to use data from the records at
national poison centres. The predictions of the
in vitro test provided a better match than the
rat LD50 test when compared with the toxicity
information on 42 chemicals listed has having
poisoned people.’ 48
There are serious ethical concerns about
laboratory animal testing, and the inefficiency
and wastefulness of the current system is
referred to in the Prague Declaration: ‘It is
regrettable that commercial pressures and
property rights often stand in the way of
making publicly available the data gathered by
New concern has been expressed recently about shortcomings in the testing regime in
relation to the supposedly non-active ingredients in pesticide formulations. According
to French scientist Gilles-Eric Seralini 49 :
‘Scientific problems do exist in the registration of pesticides today, when chronic
toxicity tests are conducted with the active ingredient alone – which is generally the
case. First of all, chemists from companies may work hard for several years to find the
formulation which best amplified the effects of the active ingredient. This formulation
will allow penetration and stability and/or bioaccumulation of the active ingredients
within plant, fungi or insect cells, for instance, to reach the best toxicity. If there are
any side effects in other animal or human cells, these will be also amplified by
adjuvants, and thus not measured in chronic toxicity tests with the active ingredient
alone. The active compound absorption by skin is generally calculated in the presence
of formulated adjuvants, but this is clearly a short-term study and not sufficient to
detect, for example, endocrine disruption or carcinogenesis, possibly promoted in vivo
by the described synergy. This should even necessitate further care in the use of
formulated products such as glyphosate-based herbicides on tolerant, edible plants.’
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industrial companies for the purposes of
hazard identification. We propose that the
relevant data from animal testing should be
made publicly available whenever possible.
This would avoid costly duplication of
experiments, and take account of ethical
issues ensuring that the best use can be made
of animal data for the development of
alternative tests.’
Secret practice: human pesticide testing
Over the last year there has been considerable
high level debate initiated in the US about this
issue. There is pressure on the agrochemical
industry globally to conduct these studies ‘to
reduce uncertainty’ because there is increasing
demand for more sophisticated safety
assessment. In the US, since 1996, the Food
Quality Protection Act requires the
Environmental Protection Agency to add an
additional uncertainty factor of between 2 and
10 to account for the special susceptibility of
infants and children to toxic substances, unless
there are data to the contrary. PAN North
America has now launched a campaign with
Earthjustice and the Natural Resources
Defense Council challenging the practice 50 .
Human pesticide testing is unregulated in the
UK. For historical reasons it is exempt from
new stringent regulation imposed on
experimental trials of medicinal
pharmaceuticals. However, there is
considerable public concern. The
internationally accepted legal instrument
controlling human pesticide testing is the
Declaration of Helsinki 1964, which introduced
an ethical framework to be applied to all
biomedical research on human beings, to
prevent the reoccurrence of the evils of Nazi
experimentation. Current 51 human pesticide
testing is conducted in complete secrecy within
the private sector, and the lack of scientific and
ethical scrutiny to which trials of
pharmaceutical drugs are subject is a matter of
concern.
Your daily poison