This is what a perfluorooctanoic acid molecule looks like. The carboxylate head on the end would normally disassociate in water because carboxylic acids are weak, but because of the fluorocarbon tail, the molecule is very stable. How do you remove the head from the rest of the molecule? Could you use UV radiation to perform homolytic fission for the decarboxyliation?
To provide some context, this molecule is used in flame retardants, and those flame retardants are polluting drinking water reservoirs. The head of this molecule, once the pollutant is inside the body, binds to proteins and behaves like hormones, disrupting normal hormonal function.