How to predict turbo failure

Just got an oil analysis report back from Blackstone, the second one in 6,000 miles saying that the copper, iron and lead levels indicate a mechanical problem developing.

At 66,000 miles:
Iron 23
Copper 9
Lead 4

At 75,000 miles
Iron 54
Copper 31
Lead 6

At 78,000 miles
Iron 75
Copper 28
Lead 8

Blackstone suggests it could be a turbo problem.

So, my questions are:

1.
How can I determine whether the turbo is failing/about to fail? What tests can I do to check the turbo condition?

and

2.
What is likely to be the result if it fails when I am towing, out in the booneys somewhere? Just lack of power?

3.
Could there be some other mechanical condition I should be testing for other than the turbo?

Thanks
Ted