The important principle of toxicology here is
> The dose makes the poison
by Paracelsus.
You have to find out the quantity of the adjuvant to compare it to known safety data. You can check Material safetey data sheets (MSDS) for those substances, or directly search for safety studies about those substances, e.g. on Pubmed.
The quantity of most additives in vaccines is very small, far below dangerous amounts.