Interestingly, the Abstract of the source article says
"Diseases of aging such as Alzheimer’s disease, other neurodegenerative diseases, arteriosclerosis, diabetes mellitus, and others may all be contributed to by excess copper and iron. A very disturbing study has found that in the general population those in the highest fifth of copper intake, if they are also eating a relatively high fat diet, lose cognition at over three times the normal rate. Inorganic copper in drinking water and in supplements is handled differently than food copper and is therefore more toxic. Trace amounts of copper in drinking water, less than one-tenth of that allowed in human drinking water by the Environmental Protection Agency, greatly enhanced an Alzheimer’s-like disease in an animal model."
Sadly (I don't have Subscriber status to read the full text) neither the abstract nor the Torygraph says what level of copper this is, nor how it compare to the levels of copper in UK drinking water.
Bit like saying "excessive amounts of biscuits are bad for you" without saying how much is "excessive"
Scare stories sell papers!