On 09/05/2011 14:48, wrote:
In ,
Martin wrote:

Photosensitising by (giant) hogweed seems the most likely explanation.
It can be pretty nasty. And also once sensitised I think you are always
in for a rough ride with it in future.

No, No, NO!!!

I beg to disagree. I reckon one of hogweed or giant hogweed is about the
most likely at this time of year strimming in rough ground. I did a
quick lookup and it doesn't require any presensitisation the damage is
done by the combination of sunlight and furocoumarins in the sap.

That's all true, but it's NOT particularly likely to be giant hogweed,
or even ordinary hogweed. LOTS of plants will do it to the same
extent, and not everybody reacts to giant hogweed, anyway. Common

Enough people do and badly enough that it is classified as a noxious
weed requiring careful handling.

Oh, God :-( I remember when that happened, and how. It started
with media hysteria over giant hogweed, causing the politicians
to react irrationally, and then that spread to cow parsley.

ISTR that the giant hogweed persecution in the UK began in the 60's
after children playing with the stems suffered appalling injuries to
face and arms as a result. I never really considered cow parsley that
much of a threat but the risk is possible - same with that tasty variety
of celery that they bred with potent photosensitivity.

It probably IS now recorded as responsible for the majority of
such reactions in the UK, because those that do such recording
have been brainwashed into thinking that it is the most likely
cause.

I think giant hogweed is fairly nasty if you get the wrong combination
of strong sun and sap on your skin. I don't know offhand what proportion
of people are affected but the chemistry is sufficiently nasty that I'd
expect it to be a lot and the reaction to it severe.

Those of us who lived in the relevant rural areas used to cut
masses down with a sickle and bare arms - and I did that even
with giant hogweed. The effect was rare, and usually associated
with some other plant. Yes, strimmers make the problem more
likely, but for ALL such plants.

A sickle gives a clean cut and limited spray. Using a strimmer generates
a mist of sap and plant fibres everywhere.

It's just like the asbestos hysteria, which has had the primary
effect of creating a totally unnecessary industry of asbestos
removal, and has almost certainly not had a measurable effect
on health.

I don't think your namesake Malcolm would be quite so cavalier about the
risks of asbestos. UK has too much blue and brown asbestos around in the
mix. The white form and concrete composite materials using it are
relatively benign by comparison and at least 100x less dangerous.

http://www.telegraph.co.uk/culture/m...aren-dies.html

But you cannot expect politicians or building workers with crowbars and
sledgehammers to recognise the different types of asbestos minerals. I
once saw an opo at a disposal site put asbestos cement board into a
crusher for general waste as he didn't recognise it for what it was.
There was a huge plume of white dust everywhere completely enveloping
him. They had proper double bagged and locked skip asbestos waste
disposal on site.

Regards,
Martin Brown