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[SANET-MG] GM Contamination At 21 km and Farther
The article below deals with coexistence ( a term synonymous with the
Borg motto "assimilation). Organic agriculture is facing a three step
process as assimilation proceeds step 1. 1% GM is acceptable on organic
food step 2. GM food is acceptable as organic step 3 GM is the only
acceptable organic food!
ISIS Press Release 27/06/07 http://www.i-sis.org.uk/index.php
GM Contamination At 21 km and Farther
No Co-Existence Possible
Researchers find GM pollen cross-pollinated non-GM plants at 21 km and
predict much worse. Dr. Mae-Wan Ho
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GM contamination rampant
Everyone knows by now that GM contamination of non-GM crops and produce
is inevitable. There have been142 contamination incidents recorded
worldwide since 1997, according to the GM Contamination Register .
This is an underestimate, as not every shipment of non-GM produce has
been tested, and not every incident registered.
Many wary consumers are buying organic to avoid eating GM food. But GM
contamination of organic produce is no longer a rarity.
A recent case of serious contamination involved a shipment of organic
soybeans to a processor in the United States. The processor had the
shipment tested after being tipped off by a buyer. The lab result showed
up a massive GM contamination of 20 percent. The organic certifier was
unable to prosecute the supplier, also in the US, who sent a different
sample for testing. The processor lost $100 000 in the incident, but the
supplier was still selling his crop .
Perhaps in anticipation of widespread contamination of organic produce,
the European Union Council of Agriculture Ministers voted in June 2007
that organic produce could contain up to 0.9 percent GM , despite the
fact that, in March the same year, the European Parliament passed a
directive setting the contamination threshold at 0.1 percent, which
effectively maintained the organic industry’s insistence on “zero
tolerance” of GM contamination.
Current separation distances derisory
The current regulatory regime where GM and non-GM crops are allowed to
grow in adjacent fields separated by tens or hundreds of metres is based
on the assumption that the separation distances are sufficient to reduce
cross-pollination levels to the acceptable minimum.
Pollen flow is not the only means of GM contamination. Other means
involve GM seeds: impurities in the seed stock, volunteers from a
previous crop, seeds dropped during transport, seeds inadvertently mixed
by suppliers and during processing. Seeds persist much longer and can
travel much farther. When the same machinery is used in several fields
for harvesting, cultivation and spraying, seeds will be readily moved
around from one field to another.
But even the extent of cross-pollination is greatly underestimated, as
has been pointed out, pollen can remain airborne for hours and a 25
miles-per-hour wind speed is not unusual , which is why extensive
contamination of certified seed stocks had been detected as far back as
2003 (Transgenic Contamination of Certified Seed Stocks, SiS 19).
Two recent scientific studies have now confirmed that the extent of
cross-pollination has been greatly underestimated.
GM bentgrass pollen spreads 21 km or more
A research team led by scientists at the US Environment Protection
Agency in Corvallis, Oregon, used an atmospheric model of wind blowing
above fields planted with GM bentgrass to look at GM pollen dispersal,
combining modelling with actual analysis of cross pollination with
non-GM plants of the same or related species . The GM bentgrass
carried the glyphosate tolerance trait, which provided a ready
selectable marker for cross-pollination.
During extensive greenhouse and laboratory testing, glyphosate-tolerant
progeny of non-GM test plants were found up to 21 km from the GM fields.
This was consistent with the model of wind direction and speed, which
showed movement of pollen up to 15 km from the GM fields by the first
hour; and maximum travel distances increased to 40 and 50 km after two
and three hours respectively. The three-hour cut off period was based on
previous findings that the viability of the grass pollen dropped to zero
within three hours.
These findings were at odds with previous small-scale experiments,
involving hundreds of GM plants in small plots, which showed pollen
dispersal limited to a few kilometres, basically because the source of
GM pollen was too small. It is like putting a drop of ink in an ocean,
which soon gets diluted.
In the present experiment, GM bent grass was planted in 162 hectares, at
about 2.8 million seeds per hectare. This provided realistically high
pollen concentration for the estimation of pollen dispersal. The maximum
potential spread of 21 km observed was an underestimate because pollen
trapping plants were not set much further than the distance observed.
According to the model, GM contamination could be as far as 75 km
downwind of the GM field.
Realistic modelling shows highly variable and unpredictable GM pollen
spread, but most studies underestimate the real extent
In a similar theoretical study, researchers at Exeter University in the
United Kingdom used records of wind direction and speed from 27 weather
stations across Europe to predict pollen dispersal and wind-borne
cross-pollination in maize, oilseed rape, sugar beet and rice . Their
results showed that cross pollination rates vary greatly according to
the relative orientation of the GM and non-GM fields, and substantially
from year to year. The main determining factor is wind direction, which
accounts for most of the variation, 75 percent in the case of maize in
For maize and rice, cross-pollination rates are relatively high only if
the non-GM field is downwind of the GM field with respect to the
prevailing winds over the short pollination period. In contrast,
contamination rates vary least with field orientation in crops with
relatively long flowering periods, such as oilseed rape and sugar beet,
because the distribution of wind directions becomes more even as the
flowering period lengthens.
“Consequently, even replicated field trials may inaccurately estimate
typical levels of cross-pollination, and therefore distort our
perception of the separation distances required to achieve sub-threshold
adventitious GM presence.”
The best one could do is to predict the likely range in levels of
cross-pollination based on limited data typically available from field
trials, and to introduce time delays between the peak-flowering periods
in adjacent fields to reduce cross-pollination to a specific level.
What the model actually says is that a contamination rate measured in
any single experiment without knowing the prevailing winds is
unreliable, because the wind changes direction from day to day and year
to year. The model gives the mean maximum and minimum relative rates
based on prevailing conditions, not the absolute rates. For example,
suppose that a rate of 0.001 percent contamination was measured in a
single field trial and the necessary meteorological records were not
available. For the UK, the mean maximum and minimum relative
cross-pollination rates for maize were estimated by the model to be 7
and 0.0005 respectively, in the case of maize grown in fields of
dimension 500 x 200m, separated by 1 000 m. The maximum possible rate is
given by the ratio of the maximum and minimum rates multiplied by the
measures rate, i.e., 7/0.0005 x 0.001 = 14 percent, which is quite
substantial. If the prevailing weather and wind conditions were known,
then the estimate improves considerably. Suppose that the maize trial
was carried out in Leeds in 1998, and the relative orientation of the GM
and non-GM fields was 100o, and according to the prevailing wind
conditions, the minimum relative rate was 0.5 while the maximum relative
rate was 9.5, then a measured value of 0.001 percent would give a
maximum possible rate of 9.5/0.5 x 0.001 = 0.019 percent, substantially
less than the previous estimate. The moral in the example is that wind
speed and direction should be measured during future field trials. No
such data currently exist.
The researchers stress that their analysis is conservative, because if a
very large quantity of pollen is released in strong gusts of wind, then
cross-pollination rates will be even more extreme.
For oilseed rape, sugar beet and rice, contamination rates could be
reduced by 50 percent when the lag between the times of peak flowering
of the GM and non-GM fields is 13 days and by 90 percent when the lag is
24 days. For maize, similar reductions require lags of only 4 and 8 days
respectively because of the shorter flowering period.
Maize, sugar beet and rice are almost entirely cross-pollinated by wind,
whereas oilseed rape is cross-pollinated by both wind and insects.
Stop planting GM crops right now
It is clear that transgene contamination is inevitable and unavoidable
if GM crops are planted. We must make the choice to stop planting GM
crops right now, not only to avoid the massive economic losses involved
in transgene contamination incidents, but also on the basis of the now
irrefutable evidence that GM crops are neither safe not sustainable [6,
7] (Scientists for a GM Free Europe, No to GMOs, No To GM Science)
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