from guardian.co.uk

• Caroline Davies
• The Observer,
• Sunday June 29, 2008
• Article history

Gardeners
have been warned not to eat home-grown vegetables contaminated by a
powerful new herbicide that is destroying gardens and allotments across
the UK.

The Royal Horticultural Society (RHS) has been inundated
with calls from concerned gardeners who have seen potatoes, beans,
peas, carrots and salad vegetables wither or become grossly deformed.
The society admitted that it had no idea of the extent of the problem,
but said it appeared 'significant'. The affected gardens and allotments
have been contaminated by manure originating from farms where the
hormone-based herbicide aminopyralid has been sprayed on fields.

Dow
AgroSciences, which manufactures aminopyralid, has posted advice to
allotment holders and gardeners on its website. Colin Bowers, Dow's UK
grassland marketing manager, told The Observer that links to their
products had been proved in some of the cases, but it was not clear
whether aminopyralid was responsible for all of them and tests were
continuing. 'It is undoubtedly a problem,' he said, 'and I have got
full sympathy for everyone who is involved with this.'

He said
the company was unable to advise gardeners that it was 'safe' to
consume vegetables that had come into contact with the manure because
of pesticide regulations. 'All we can say is that the trace levels of
aminopyralid that are likely to be in these crops are of such low
levels that they are unlikely to cause a problem to human health.'

The
Dow website says: 'As a general rule, we suggest damaged produce
(however this is caused) should not be consumed.' Those who have
already used contaminated manure are advised not to replant on the
affected soil for at least a year.

Aminopyralid, which is found
in several Dow products, the most popular being Forefront, a herbicide,
is not licensed to be used on food crops and carries a label warning
farmers using it not to sell manure that might contain residue to
gardeners. The Pesticides Safety Directorate, which has issued a
regulatory update on the weedkiller, is taking samples from affected
plants for testing.

Problems with the herbicide emerged late last
year, when some commercial potato growers reported damaged crops. In
response, Dow launched a campaign within the agriculture industry to
ensure that farmers were aware of how the products should be used.
Nevertheless, the herbicide has now entered the food chain. Those
affected are demanding an investigation and a ban on the product. They
say they have been given no definitive answer as to whether other
produce on their gardens and allotments is safe to eat.

It
appears that the contamination came from grass treated 12 months ago.
Experts say the grass was probably made into silage, then fed to cattle
during the winter months. The herbicide remained present in the silage,
passed through the animal and into manure that was later sold. Horses
fed on hay that had been treated could also be a channel.

Bryn
Pugh, legal consultant at the National Society of Allotments and
Leisure Gardeners, said he was preparing claims for some members to
seek financial compensation from the manure suppliers. But it was
extremely difficult to trace the exact origins of each contaminated
batch. 'It seems to be everywhere. From what I know, it is endemic
throughout England and Wales. We will be pressing the government to ban
this product,' he said.

Aminopyralid is popular with farmers,
who spray it on grassland because it controls weeds such as docks,
thistles and nettles without affecting the grass around them. It binds
itself to the woody tissue in the grass and only breaks down when
exposed to bacteria in the soil.

Shirley Murray, 53, a retired
management consultant with an allotment near Bushy Park in Hampton,
south-west London, said several of her allotment neighbours had used
the same manure bought from a stables and all were affected. 'I am
absolutely incensed at what has happened and find it scandalous that a
weedkiller sprayed more than one year ago, that has passed through an
animal's gut, was kicked around on a stable floor, stored in a muck
heap in a field, then on an allotment site and was finally dug into or
mulched on to beds last winter is still killing "sensitive" crops and
will continue to do so for the next year,' she said.

'It's very
toxic, it shouldn't get into the food chain. You try to be as organic
as you can and we have poisoned ourfood. I've been everywhere, emailed
all the right people, but nobody will speak on the record to guarantee
what is safe to eat. We all think it is a scandal. Not to mention what
it has cost in time and money.'

Pesticide expert Professor Vyvyan
Howard, a toxico-pathologist at Ulster University, said it was 'a very
powerful herbicide' but in his opinion was 'unlikely to pose any human
health risks'. However, advice about its use should be strengthened, he
said. 'I think the thing that is going to drive this is the commercial
damage that could be done to market gardeners,' he said.

Guy
Barter, the RHS head of horticultural advisory services, said they were
receiving more than 20 calls a week. 'Our advice is not to eat the
vegetables because no one seems to have any idea whether it is safe to
eat them and we can't give any assurances,' he said. 'It is happening
all over the country. A lot of cases we are seeing is where people have
got manure from stables and the stable have bought their hay from a
merchant, and the merchant might have bought hay from many farmers,
possibly from different parts of the country. So they have no idea
where the hay came from. So finding someone to blame is quite
difficult.' Weedkiller in the soil should dissipate by next year, but
in stacks of contaminated manure it might take two or more years to
decay, he added.

Dow is planning a major publicity campaign to
reiterate warnings to farmers over usage, and to encourage allotment
holders to check the provenance of manure that they put down in an
effort to prevent the problem escalating. On compensation, it was less
forthcoming. 'There is no easy answer to that,' said Bowers. 'The first
port of call is always where the manure comes from. From that point on,
I can't really comment.

'The chain is horrendously complicated.
In the cases we have managed to trace back, we might find that the
farmer who supplied the manure didn't spray anything himself, but he
might have bought in a couple of bales of silage from one of his
neighbours, and that farm might have sprayed.'

Robin and
Christina Jones spread a large amount of manure over their flower
garden and vegetable patch at their home in Banstead, Surrey. When the
potatoes failed, Robin took a sample to the RHS, which identified
aminopyralid. His neighbour, who bought from the same source, suffered
the same problems. 'We have lost 80 per cent of our vegetable patch,'
said Jones, 65, a retired sound engineer. Raspberries, French beans,
onions, leeks, even a newly planted robina tree were all affected. 'We
are distraught. But what worries me is that the courgettes look very
healthy. Had we not had the problem with the potatoes, we might never
have realised. Now we are advised not to eat them.

'This is a very serious issue, and people must be made aware of the advice not to eat vegetables grown in contaminated manure.'

Sue
Ainsworth, 58, an education consultant, said around 20 allotments at
her site in Hale, Cheshire, had been affected. 'We first noticed with
the potatoes. As they came through, they were deformed, all curled over
and rotten underneath. But the worry is that the courgettes also
planted on the manure are fine - but are they safe to eat? This must
have affected thousands of people. I am really worried about this
product and really think it should be withdrawn.'

She said the
farmer who supplied the manure said he had used nothing unusual. 'But
he may have bought in the straw and genuinely knew nothing about the
herbicide used.'

Susan Garrett, 57, an IT consultant, said 20
plots were affected at her allotment in Wakefield, West Yorkshire. 'And
that is just the plants we can see are damaged. We are angry it has
been allowed to happen - not with the chemical company, but because
there doesn't seem to be any protection for us or anything to stop it
happening again.'

What's the solution? Join the debate and find out more on our food blog

How to deal with the problem

Do you have contaminated manure?
Tell-tale
symptoms of crop damage include distorted foliage, with cupping of
leaves and fern-like growth. There are no remedies once damage has
occurred. Susceptible crops include potatoes, tomatoes, beans, peas,
carrots and lettuce.

How should you deal with the affected area?
Experts
say rotavation is the best practice, or forking over several times as
soon as possible. This incorporates the plant tissue into the soil,
where it will decompose and the chemicals will eventually be degraded
by soil microbes. Repeat the rotavation in late summer/early autumn.

Should you replant this season?
No. The plant residues need to be given time to break down. The advice is not to replant for a year.

Why has the chemical lasted so long?
Aminopyralid, like other herbicides, works by binding strongly to plant
tissues. Once the plant's tissues decay, the chemical breaks down in
the soil. If manure is stacked it takes far longer.

· This
article was amended on Thursday July 17 2008. Its original title
referred to a "toxic fertiliser", when we meant "toxic herbicide". This
has been corrected.