High arsenic levels

While undergoing tests for Alzheimer's disease a 72yo friend was found to have elevated levels of arsenic (50mcg/L). Everyone else in the family has normal levels. The only difference in lifestyle is his heavy drinking and marijuana use. Is there any connection found between substance abuse and elevated arsenic?

[Roger Gould, M.D.]

I am not expert enough on that subject to answer, but if there was, it would probably be that arsenic was a contaminant of the marijuana...