Here's my take on this.
We humans smell smells different than fish in that we breathe air. Fish get oxygen from water and smell entirely different from us by sensory cells that are sensitive to specific scents carried in the water. Not air. In fact, since fish "smell" in a water environment it is very unlikely that they would be able to something that is not water soluable....as in the plastic unless a water-based scent is on the surface of the plastic. If a plastic burns, we think it stinks....fish more than likely only see the color change or intensity of the light reflected. The remnants of burned plastic would have to be soluble in water and then only if the fishes smell receptors were geared to smelling those smells.
One of the arguments to this is fish scents. Many are oil based. However, the oils used in the scents that fish can smell or sense, are probably high in vegetable based oils that allow some mixing of water based ingredients in minute, but intense, amounts. Salad dressings offer an excellent example of vinegar and oil being able to mix with simple shaking. I use steam extracted Anise oil to make a scented worm oil to add to plastics. Since the Anise here is a water based derivative that has been blended with an oil, fish can likely pick up the scent of the anise. Burnt or singed plastic is entirely different. There is nothing involved to smell that is even slightly water-based.
The best way to determine of an oil is soluble is to determine if we can ingest it. If we can eat it, it is most likely an oil that can be mixed, at least in part, with water. If a scent can be mixed with water, it can be assumed the fish can smell it. The plastic I used to make these baits is in no way compromised to the point that it would be soluble so there is no way fro a fish to pick up this smell. And in fact this plastic did not have an order to it anyway other than the smell of plain old plastic.
