I did an interesting comission for the BUND. It was about illustrating a banner which would be used for an info stall. The picture was to show that microplastic in water is so harmful because beyond other things toxins stick to it, making the toxin concentration much higher than in the water around.
This is an early version of the illustration. In the final one the plancton is transparent, only outlines. Also the toxins don’t have eyes.

Mikroplastik im Meer mit Giftstoffen. Drumherum Plankton. Vorabversion

These are the toxins. Pictured are PCB and DDT but of course there are many more drifting in the sea, sticking to microplastic. I tried to depict the molecular structure a bit.