Hi. I need to replace screen in my old Galaxy i9000. It's completly cracked and I wonder if it's safe to replace it. I know that LCD screen may contain Mercury but what about AMOLED? It should be organic but is it safe? I really appreciate any help.
The only part of an LCD that contains mercury is the cold-cathode fluorescent lamp and practically all sub-20" LCDs have switched to LED backlighting several years ago.
AMOLED displays are emissive so they forgo backlighting altogether. Even if it contained mercury, it would be blended in one of the inner polymer layers and unlikely to go anywhere unless you plan to burn the OLED display and breathe the fumes.
Even if your device had a CCFL tube in it, you would need to eat a couple of tubes; not merely touch them; before it might become a significant health risk. If mercury was so dangerous that you had to worry about the minute amounts contained in miniature CCFL bulbs, governments would have banned their production and sale.
Same goes for most other heavy metals: you want to minimize exposure in general everyday life but they are still mostly safe to handle on an occasional basis - just remember to clean your work area, hands and anything else that may have been contaminated after you are done.