The Farm-Scale Evaluations of Genetically Modified Herbicide Tolerant
Crops
Paper for February 2001 AEBC Meeting
A Paper by the Biotechnology Safety Unit, Department of the Environment,
Transport and the Regions
The farm-scale evaluations are a three year programme of ecological studies
into the effects on the abundance and diversity of farmland wildlife,
associated with genetically modified herbicide tolerant (GMHT) crops managed
with their companion herbicide as compared with equivalent non-GM crops.
The farm-scale evaluations were announced in autumn 1998 as part of the
Government's initiative to strengthen and co-ordinate the assessment and
control of GM crops. This comprised:
- A voluntary agreement between Government and the industry body, SCIMAC,
- for a programme of farm-scale evaluations of GMHT crops; and
- no general unrestricted cultivation of GM crops in the UK until
the farm-scale evaluations are complete;
- The setting up of a subgroup of the Advisory Committee on Releases
to the Environment (ACRE) to consider the wider biodiversity implications
of the introduction into agriculture of GM crops and make recommendations
on how such impacts should be assessed and controlled;
- Review of the controls on pesticides with respect to their use on
GM crops.
These actions were taken in response to concerns originally raised by
ACRE and at the National Biotechnology Conference in 1997 and subsequently
by English Nature and concerned non-Governmental Organisations (NGO).
The crops in the FSE either have or are very close to obtaining approval
for general cultivation throughout EU under Directive 90/220 on the release
of genetically modified organisms into the environment. The GM crops are
oil seed rape and maize tolerant to the broad-spectrum herbicide glufosinate
ammonium, Libertyâ, and sugar and fodder beet tolerant to glyphosate,
Roundupâ.
The European Regulatory Authorities and their scientific advisers had
assessed the risks to the environment and human health for compliance
with the requirements of the directive but questions remained about the
impact of the new herbicide regime on the abundance and diversity of farmland
wildlife. The farm-scale evaluations were therefore set up to address
this specific remaining area of uncertainty.
The Government acted to ensure that these crops would not be introduced
into commercial agriculture until it was satisfied that this would not
give rise to an unacceptable impact on the environment.
Mr Meacher's statement in 1998 and the specification for the research
contract make clear that the farm-scale evaluations are investigating
the effects of the management of the crops with the relevant herbicide
not GM crops themselves. However, the Government is taking the opportunity
to monitor the growing crops and our understanding of pollen flow. In
the maize and rape fields the dispersal of pollen and resulting cross-pollination
events in the non-GM half of the field and nearby sexually compatible
crops is being monitored and in the case of rape, cross-pollination with
wild relatives is monitored.
Other concerns have been raised about the safety of GM crops such as
the stability of genetic modification, horizontal gene transfer, antibiotic
resistance markers, viral vector promoters. As they have arisen, these
issues have been referred to ACRE for advice. In 1999 ACRE published a
comprehensive review of the risk assessment for the first herbicide oilseed
rape to receive EU approval (from PGS now Aventis). They are currently
reviewing the dossier and concerns raised about the GMHT maize which already
has EU-wide (Part C) approval (Aventis T25 maize). They have also given
specific advice on the safety of the 35S promoter and horizontal gene
transfer.
Decisions and procedures at the end of the FSE
The field work on the spring sown crops is due to end in autumn 2002
and that on the autumn sown rape in summer 2003. The results of the ecological
studies will be collated and analysed by the research consortium against
the null hypothesis that there are no significant differences between
the biodiversity associated with the management of the particular GMHT
crop and the comparable non-GM crop at the farm scale. The hypothesis
will be tested separately for each indicator. The data will reveal whether
or not there are any statistically significant differences in the abundance
and diversity of the indicator species between the two cropping regimes.
The results and statistical analysis will be presented for scrutiny by
the independent Scientific Steering Committee overseeing the evaluations.
When they are content the work will be published in peer reviewed scientific
journals. The raw data will also be made available for study.
Ministers are likely to wish to refer the results to ACRE and the Advisory
Committee on Pesticides (who have to approve the herbicide for use with
the crops involved) for advice. ACRE might then conduct a public consultation
exercise as part of its evaluation of the results. Both advisory committees
will then advise Ministers, the National Assembly in respect of Wales
and the Scottish Executive for Scotland. In the light of this advice Ministers
would then make a joint decision on the future commercialisation of each
of the GMHT crops involved in the FSEs. This would also depend on whether
decisions had been taken by member states on consent under Part C of directive
90/220 and the other approvals necessary for commercial growing, such
as seed listing, were in place.
Separation Distances
The GMHT crops in the farm-scale evaluations have been assessed for their
impact on the environment and safety for human health through the Directive
90/220 process. The Advisory Committee on Novel Foods and Processes and
the Advisory Committee on Animal Feeds have advised, through ACRE, that
the crops in the FSE do not pose a risk to health if eaten by humans or
animals. Similarly, any seeds or plants arising from cross-pollination
with conventional crops do not pose a risk to health if eaten. ACRE has
advised that the presence of these GM plants in fields does not pose a
risk to the environment. Therefore, there is no need on safety grounds
for separation distances between the GM crops and other crops, or other
features in the environment.
Separation distances are used to deliver product integrity. The industry
body, SCIMAC, working with MAFF, has developed a code of practice and
guidance for farmers on the growing and management of GMHT crops. This
is designed to safeguard the GM crop and nearby conventional crops by
the use of good agricultural management, separation distances and volunteer
control. The level of interaction and resulting presence of GM traits
in conventional crops is a matter for ongoing discussion between all interested
parties. It will need to be resolved if GM crops are to enter commercial
agriculture in the UK.
With respect to the GM crops in the farm-scale evaluations, the separation
distances being used will ensure that a very small amount of GM material
arising from cross-pollination with conventional crops, if any, will enter
the UK food and feed chain.
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