Metal contaminants or other chemicals of concern can be chemically stabilised to ensure no further transmission or transgression. Typically a chemical fixation process is utilised that “locks up” the contaminant and stops further infiltration into the environment. The fixation treatment renders the contaminant as an inert compound in acid or alkaline environment and is safely protected for many future years. Depending on the contaminant, many different types of chemical fixation reagents may be recommended.