Soil and/or groundwater remediation process

A method of treating contaminants in an in situ environment, comprising the steps of:

• preparing an aqueous catalyst solution comprising an effective amount of a metal catalyst selected from at least one member of the group consisting of Fe (II) salts, Fe (III) salts, Fe (II) chelates, Fe (III) chelates and combinations thereof;
• maintaining said aqueous catalyst solution at a pH of from about 5 to 8;
• adding a source of an oxidizing agent to said in situ environment in an amount sufficient to treat said contaminants;
• and
• adding said aqueous catalyst solution to said in situ environment in the presence of said source of the oxidizing agent in an amount sufficient to promote the formation of the oxidizing agent in an amount sufficient to treat said contaminants.