Soybeans have been inserted with a gene
from a bacterium which makes them resistant to the herbicide glyphosate and
hence dubbed Roundup Ready Soybeans (RRS). Glyphosate is the world's
top-selling broad-spectrum herbicide and is sold by Monsanto under the trade
name, Roundup. The herbicide kills all green plants by blocking the pathway for
nutrients. The newly inserted gene re-opens the pathway, enabling the altered
plant to resist the herbicide. Farmers will be able to spray their crops with
Roundup, killing the weeds but leaving the crop unaffected.
The genetically engineered beans-although currently only 2%
of the total-will be mixed with conventional supplies and used extensively
throughout the food chain. Soya is believed to go into two-thirds of all
processed foodstuffs making it almost impossible to avoid even if it were
clearly labelled. The prospect of being denied any choice over whether food
contains this latest genetically engineered ingredient has outraged consumer
organisations who are calling for the immediate segregation of the two soya
supplies so that consumers can exercise choice(1).
The debate over RRS has so far focused on the denial of
consumer choice but there are a number of underlying issues which deserve
attention. RRS are the first products of a genetically engineered crop which is
traded internationally. The regulations on marketing will therefore set a
precedent for subsequent commodity crops such as genetically engineered corn
that produces its own insecticide or genetically engineered herbicide resistant
oilseed rape.
Monsanto has insisted that the new soya cannot be segregated
because it is indistinguishable from other soybeans. There are however, several
reasons for questioning this assertion. What, for example, would have happened
if the company had failed in its application to market its product in Europe?
Then it would have been illegal to export genetically engineered soya to the EU
and the new crop would have been segregated at source or else the entire US
soybean harvest would be at risk of being excluded from European markets.
This has already happened with respect to AgrEvo's
genetically engineered oilseed rape, another 'indistinguishable' commodity
crop, currently grown in the US. It does not have marketing approval in the EU
and Japan and the new crop is being segregated so that the conventional
varieties can still be exported to both destinations. Segregation is, therefore,
both feasible and sometimes necessary to comply with different regulatory
requirements around the world.
Monsanto requires its contracted US growers to segregate some
of their harvested beans from this year's crop to provide seed for next
year's planting. So, the company itself is insisting on segregation while
publicly denying the technical feasibility to food producers, retailers and
consumers alike.
If the principles of segregation and tractability are
breached by this very first example of a herbicide resistant crop it will be
much harder to argue for them in subsequent genetically modified crops. Failure
to establish these vital principles will also send a signal to large
multi-national companies that they will indeed be able to 'foist'
genetically engineered food products onto world markets irrespective of consumer
wishes and without labelling.
The introduction of the soybean heralds the arrival of other
herbicide-resistant crops (HRCs). RRS is the first herbicide-resistant crop to
be fully commercialised but over half of all genetically engineered crops
currently being tested have been modified to tolerate applications of
proprietary herbicides.
Monsanto claims that the use of herbicide-resistant soybeans
will reduce applications of pre-emergent herbicides and encourage growers to
switch to post-emergent, broad-spectrum and more environmentally-friendly
chemicals such as glyphosate.
This claim the HRCs will reduce application rates for
herbicides has not been substantiated by Monsanto or indeed any other company.
HRCs tend to be based on broad-spectrum chemicals which, in the case of
glyphosate, could mean that a single dose to control grasses and broad-leaf
plants could replace repeated applications of several pre-emergent chemicals in
any single crop(2). But given that glyphosate degrades rapidly in the
environment, weeds germinating after an initial spraying would have to be
controlled by subsequent spraying. It is therefore difficult to assess the
impact of HRCs on rates of herbicide usage. However, the development of HRCs
could encourage growers to switch from pre-emergent, narrow spectrum to
post-emergent, broad-spectrum chemicals.
It is important to remember that whilst glyphosate does
indeed have a more environmentally-acceptable profile than some other herbicides
there is no guarantee that HRCs will be developed only for herbicides considered
safe or environmentally-friendly. Moreover the claim that glyphosate is more
environmentally friendly belies the evidence of toxic effects on humans and the
environment as well as some indirect evidence of environmental damage and
resistance in target weed species(3).
Development of glyphosate resistance in weeds species could
be a serious risk. Tests on annual ryegrass from a farm in Victoria, Australia,
showed that 20% of the plants survived glyphosate applied at 4.8 l/ha. Some 70%
survived at the commercial rate of 0.6-0.8 l/ha. The farm had applied glyphosate
in a continuous cropping programme for over 10 years. Anecdotal evidence from
users in the UK suggests that similar signs of resistance in annual ryegrass and
knotgrass have existed for some time(4). Monsanto, along with other
manufacturers, are already developing other glyphosate resistant crops such as
corn, cotton, potatoes, sugar beet and tomatoes(5).
Monsanto claims that the processed RRS products are perfectly
safe for human consumption. And most of the world's regulatory authorities
share their view. But the safety assessment by these authorities are based on an
analysis of beans which had not been exposed to repeated applications of
Roundup. It may well be that some Roundup residues will remain in the plant.
There appear to be no plans specifically to monitor residues in the soya
products.
Whilst the arrival of the soybeans in Europe has sparked the
initial controversy, an appreciation of the underlying issues and the wider
environmental implications of HRCs are only just beginning to be realised.