>While more and more chemical are used to combat deseases and mite, could some of them impregnated into bee wax and caused death of larvea?
Yes. More so they interfere with having viable drones and viable queens. Fertility is a big issue.
Builds up in the wax.
>2. Oxalic acid
Oxalic already exists in the honey. It doesn't build up in the wax and the amounts in the honey are within the limits of what is usually there anyway. How good it is for the bees or larvae during the treatment, is another issue.
Leaves residue in the honey.
>4. Chosmophoros (spelling?)
Cumaphos, residue accumulates in the wax. Is an organophosphate. In sufficient amounts, will kill bees and humans. The amount that affects humans is not much over the amount that kills mites.
>5. Sodium hydrochoride
>6. Formic acid
See Oxalic acid above.