Tritium radiation is pretty harmless unless you inhale the gas. Even then, there is only a tiny amount in a typical sight. Still, there's no sense in ruining a relatively expensive part. If your sights are night sights, take the gun to a gunsmith for adjustment.
If it's not (and I'm betting it's not because...)
It sounds like you have a Beretta Elite II.
Beretta cuts their dovetails on the small side. You can take it to a gunsmith with a sight adjustment tool, or you can keep whacking it with a brass punch and hammer. From experience, I can tell you that it can be difficult to make delicate adjustments on a very tight dovetail sight with the hammer method.
If you decide to go the hammer method then clearly mark the position of the sight so that you can see how much you have moved it. It also helps to do a little math so as to determine the exact amount you need to move the sight.
Here is the formula.
M = the distance you wish to move your group left or right in INCHES.
S = the sight radius of your pistol. The distance from the back of the rear sight to the back of the front sight in INCHES
D = the distance from the back of the rear sight to the target in FEET.
A = the adjustment distance in INCHES.
A = (M x S) / (D x 12)
