A method of mitigating and rehabilitating soil and land areas contaminated with forever chemicals such as PFAS (perfluoroalkyl and polyfluoroalkyl) based toxins involves manipulating genetic nucleotides of carrier organisms for expressing an enzyme reactive with the forever chemicals for rendering them benign. The carrier organisms pass the modified DNA that enables the enzyme to subsequent generations for maintaining an active population of enzyme-expressing organisms, typically worms, once introduced.