There was a massive problem with aliminium in the water in Camelford in the '80s.
I've found the link but there doesn't seem to have been a resulting mass of Alzheimer cases.

Hello saffie
I found this article after reading your post
,very interesting thank you
jimbo

Village of the damned: Mysterious suicides. Agonising illness. And now, 25 years after UK's worst case of mass poisoning, the first evidence that dirty water has KILLED people
Camelford in Cornwall was poisoned with aluminium sulphate in 1988
A van accidentally dumped 20 tons into the household water supply
Villagers were immediately poisoned, but water was soon deemed safe
Since then, several deaths and illnesses have been linked to aluminium
Dead villagers have been found to have had high levels in their brain
They all suffered early onset dementia and died relatively early
By Simon Trump

When the end came – suddenly, silently but not entirely unexpectedly – it was probably a blessing for Richard Gibbons.
He had spent more than 20 years racked with pain, mentally confused, agitated and obsessed by the very thing which he feared would kill him, and almost certainly did.

His decline and early death at 60 was a tragedy for the Gibbons family. The rapid onset of dementia had left him, in the words of his daughter, ‘a shell of a man’.
Just a few weeks ago, it was established beyond doubt that the former businessman died with abnormally high levels of aluminium in his brain, a fact that will cause fresh anxiety in a region already battered by more than 25 years of lingering health fears.
It is a quarter of a century since massive quantities of aluminium sulphate, a chemical used to keep drinking water clear, were accidentally dumped into the public supply at Camelford’s Lowermoor treatment works.
It was the worst case of mass poisoning in British history. The effects were noticed within 90 minutes and included diarrhoea and vomiting, severe joint aches, and blistering. Hands and lips stuck together. Hair turned green, fingernails blue.
It seems a long time ago. But if, to the outside world, the matter had been safely laid to rest, a small but determined group of locals has long insisted that the effects of the disaster could be both long-term and devastating. Now, their worst fears appear to be justified.

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