Examination of Witnesses (Questions 300-319)
3 DECEMBER 2003
PROFESSOR CHRISTOPHER
POLLOCK, DR
NICK BRICKLE,
DR BRIAN
JOHNSON AND
DR MARK
AVERY
Q300 Mr Thomas: Do you feel that you
can make some extrapolations of an accumulative effect?
Professor Pollock: There are cumulative
measurements made on repeat maize; there are also, of course,
follow-up measurements made on the following crop, some of which
will be made for two years and others for one, and again, when
they are grouped together, and the final data published in the
last part of the study. We still have not published the winter/summer
oilseed rape information yet but I am sure that this information
will, if you like, add to the stature of the trials rather than
diminish them.
Q301 Mr Thomas: The criticism is made,
though I accept that you will not get a follow-on necessarily
in all these crops, that in a whole farm system you have follow-on
within that acreage, or whatever.
Professor Pollock: With respect,
for the rotational crops, you do not. That is the whole point.
You then move into cultivation of another crop. The importance
of biodiversity, if you look across the rotation, and the key
concern which has been so well expressed by my colleagues from
English Nature and RSPB, is that the use of these break crops,
which ought to replenish the natural seed bank, is in some way
disturbed by the cultivation of GMHT. Across an entire rotation
you should get back to where you started from, or better still
enhance the seed bank. The data that we have for GMHT beet and
rape suggests that does not happen under some circumstances, although
the number of sample points for the follow-up fields is inevitably
smaller and so the error bars get larger, but there will be the
need for further re-evaluations of some of that information as
fresh data becomes available.
Q302 Mr Thomas: The only thing I am not
clear about from that otherwise comprehensive answer is whether
that was part of the planning of field scale evaluations from
the start or whether it is a benefit that has come out of the
results.
Professor Pollock: The fact is
that for three out of the four cropping systems it was not going
to happen anyway, and that is independent of the results. For
maize, the fact that we ended up with some follow-on fields we
would regard as a bit of a bonus. We have been able to realise
that bonus because, if you like, of the tightness of the datasets.
Q303 Chairman: What you have just said
in that answer to Mr Thomas is very interesting. It shows that
there is still information coming out about these trials. Of course,
the results of the winter rape trials have yet to be published.
How do you square all of that with the statement in your memorandum
that "at the first meeting of the SSC it was agreed that
no results would be published before the trials were complete
and, as a result, we need an independent peer review? This is
exactly what happened".[8]
Professor Pollock: That is right.
Q304 Chairman: It sounds to me, from
what you have said this afternoon, that they are not really complete?
Professor Pollock: I am saying
that we were able to advise Ministers on the "null hypothesis",
which is what the SSC was set up to do, but further work to improve
the general applicability of these data to a wider set of issues,
and also to look at the possibility of mathematical modelling,
was never going to be undertaken in the three years. The Scientific
Steering Committee took the view that what it would not do is
release data until it was deemed by peer review to be statistically
sound, and that is what we have done, and that it would only publish
data that allowed us to comment to advise Ministers on the "null
hypothesis", which again we have done. All information from
scientific studies goes into the scientific domain and other people
use it. It would be, I think, completely anomalous if this were
not so, particularly since these are incredibly valuable datasets.
I can put my hand on my heart and say that I have no idea what
interesting information will come out of re-analysis of this information
in four or five years' time or via its conjunction with other
datasets.
Q305 Mr Thomas: We turn to one proposition,
in particular maize. Can I ask you when you first became aware
that atrazine was likely to be banned?
Professor Pollock: I was aware
that it was going to be banned when it was banned, which was earlier
this year. I knew that there had been discussion about all pesticides
of that sort but I was not aware of the minutiae of the debate.
Q306 Mr Thomas: Was the fact that 75%
of the conventional maize crop should be treated with a herbicide
that was about to be banned ever discussed by the Committee which
you were chairing?
Professor Pollock: No, because
the position when the trials were set up was that it was very
clear that we should go with current agronomic practice for a
range of pesticides. It was also agreed that we accepted that
those would change during the course of the trials, as they did
in some of the other crops as well.
Q307 Mr Thomas: Does that no invalidate
the trials?
Professor Pollock: No, it does
not. It asks questions about the extent to which agronomic practice
will change as a result of banning atrazine. I cannot comment
on that in terms of my chairmanship of the Scientific Steering
Committee. My understanding as a scientist is that it will still
be necessary to look for forms of early season weed control in
forage maize, even though atrazine-like herbicides will be banned.
Dr Avery: May I add that I think
"invalidate" is quite a loaded word for scientists,
and we are all scientists.
Q308 Mr Thomas: It is not for politicians!
Dr Avery: That is why I am attempting
to help you here. To say that the late news of the future banning
of atrazine would invalidate the study of maize would be wrong
because scientifically it was just as good a study as the studies
for oilseed rape and beet. Clearly the relevance of that study,
looking forward in policy terms, is much reduced by the fact that
the comparison that was done is now outdated, and so there is
the possibility to look within the data that were collected to
look at the non-atrazine fields that were in the study. Whether
those would provide enough information to inform, properly, future
policy decisions is in question, but that would be the first place
to look.
Q309 Mr Thomas: That is a good point
to which I will return. I understand that that work is going to
be done by the research consortia. They are looking at the non-atrazine
fields?
Professor Pollock: There are some
evaluations ongoing, yes.
Q310 Mr Thomas: Are you as the Steering
Committee overseeing that or is that done separately now?
Professor Pollock: No, we are
not overseeing it, although obviously our scientists will have
a very strong interest in it.
Q311 Mr Thomas: What would your interest
be in that work, which is based on 25% of the conventional maize
crop? We as a committee had evidence earlier which suggests that
these field scale evaluations almost failed in scientific terms
because of the damage done to certain fields and just about enough
data was collected to make them valid. Does that not call into
question whether we can use the non-atrazine results in any meaningful
way?
Professor Pollock: I would contest
your second assertion absolutely. You only have to look at the
statistical parameters in the published studies to show that actually
the data are extremely robust. There is a level of redundancy
built into the experimental design, not in order to plan for vandalism
but to plan for the vagaries of nature. Fortunately the vagaries
of nature were significantly less than we expected. I would contest
vigorously the assertion that the data are not reliable. I would
agree, however, that it would be very difficult on its own to
extrapolate significantly from the relatively restricted number
of fields that did not receive atrazine. However, that will provide
a guideline for discussion, which I am sure will involve Defra,
about what would be necessary, as Dr Firbank said, if you like,
to re-benchmark that part of the study.
Q312 Mr Thomas: Moving on, therefore,
what would be the case for re-benchmarking a conventional maize
crop when we know what the preferred herbicide would be in the
future and we know what farmers and companies are going to be
using. Would there not be a case then for re-running the field
scale evaluations with that new herbicide being used on conventional
maize crops?
Professor Pollock: I think it
would be appropriate to seek evidence as to what the potential
impact of that would be. I would go with the statement from Dr
Firbank that a complete re-run would not be necessary.
Q313 Mr Thomas: Could I ask Dr Johnson
whether he agrees with that, as the originator of the idea of
having herbicides?
Dr Johnson: I think that the impact
of herbicides on biological systems in farmers' fields has proved
to be very interesting indeed as a result of these experiments.
We now understand much more than we did about the impact of different
herbicide regimes on biodiversity. I would like to see those kinds
of experiments carried out routinely, not necessarily experiments
of this scale, as part of the evaluation system by which this
country chooses the herbicides that it wishes to be used on farmland.
I think this has been a very interesting exercise from that perspective.
I would hope that the pesticide regulatory authorities will look
at this set of experiments and ask precisely those questions:
what sort of herbicide is going to be used on maize in the future?
Is it going to be better for wildlife generally or worse than
atrazine? Would the GM herbicide tolerant system be better or
worse than that? These are interesting questions; they need to
be answered.
Dr Avery: On your first question
about whether there needs to be more field work done on atrazine,
the jury is out. The sensible place to start is to look at the
data that have been collected. I would not rule out the need to
do some more field work but that probably would not be on the
scale of farm scale evaluations. The point that Brian Johnson
has made about the value of this type of large scale, ecological
study I think is a good one and that as well as pesticides there
would be other large land use changes that are being considered
by Government and in policy that could benefit from this type
of approach.
Q314 Mr Thomas: Who should pay for that
work?
Dr Avery: If the point of the
work was to look at the public benefit of particular types of
land use change, then I think it is the Government because public
money is now increasingly being given to farmers for public good
rather than for production purposes. One potential candidate for
that study would be organic farming because that would benefit
from the type of large-ranging study to look at the biodiversity
benefits and other natural resource benefits that many of us believe
accompany organic farming and whether those would be delivered
or not. A second one would be actually growing biomass for energy
production, which would be another large-scale change in land
use that Government policy is envisaging that would have big impacts
on landscape and also on biodiversity. We do not have the information
really to benchmark that.
Q315 Mr Thomas: I appreciate your comments
but this goes a bit wider than just GM crops. I appreciate why
you are saying that. I want to return to atrazine for a moment
and to Professor Pollock. One of the features of atrazine use
in Canada and North America is that it is also used in combination
with libertine in applications on GMHT maize. We have been discussing
conventional maize so far and the use of atrazine on that. Do
you have any concerns about the fact that that particular use,
which happens in North America and Canada, was not replicated
in these studies in the United Kingdom?
Professor Pollock: No, because
the agronomy that was being put forward for the cultivation for
forage maize—and I stress that we are talking about forage
maize here—for HT is that you will get adequate weed control,
as we did demonstrate, by the use of the broad spectrum herbicide
on its own. It would be a completely different agronomy if there
was also the incorporation of the atrazine type herbicide in there,
and of course anyway it is out of court now because you have banned
it. You cannot argue one way one minute and the other way the
next minute.
Q316 Mr Thomas: We are looking at how
useful these trials are for public policy planning, are we not,
and how you are formulating decisions about licensing these?
Professor Pollock: Yes, but since
you cannot license the crop to use ATZ because you have banned
atrazine, it seems to me that it is not germane to incorporate
that into the study.
Q317 Mr Thomas: I come back to my earlier
question: as GMHT maize is the best performer in biodiversity
terms, does that not in itself beg the question as to whether
we as legislators are making decisions based on the best and most
up-to-date information. I accept it is out of the Steering Committee's
hands because atrazine is banned, but nevertheless do you have
a set of facts and figures that are not necessarily useful to
us as legislators?
Professor Pollock: The viable
agronomy for maize, were it to be licensed in the UK, would be
for a broad spectrum herbicide only, since atrazine is banned,
and the conditions under which consent would be given could make
that clear.
Dr Brickle: That is the answer.
Q318 Chairman: But atrazine was not,
of course, banned at the time you were conducting these trials.
What efforts did you make to investigate the concerns arising
in America during that period about herbicide-resistant crops?
Professor Pollock: Again, it comes
back to the fact that the main agronomy in the US was sufficiently
distinctive that we did not feel that there was a great deal of
cross-talk; the agronomy that was being put forward to be used
with forage maize in the United Kingdom involved the use of a
single, broad spectrum herbicide to which the maize was resistant.
That gained adequate weed control. That was the argument put forward
by SCIMAC and indeed the data from the farm scale trials support
that the weed control was fully adequate using that agronomy.
Dr Avery: It is worth pointing
out that the organisation best placed to raise this as an issue
would have been SCIMAC. If the industry itself did not come along
and say, "Hang on, the guidelines we gave you a couple of
years ago when you started the trial are now out of date",
then it is hardly anybody else's fault.
Q319 Chairman: And the industry did not
do that?
Professor Pollock: No.
Dr Brickle: We were doing a risk
assessment of a management system that was proposed by the industry.
They were hoping that it would be grown somewhat differently in
the future. They did it in the knowledge that consent would be
restricted to what we carried out the risk assessment on.
8 Please see memorandum, Ev 74. Back
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