Mutant 59 The Plastic Eater

"Pedler and Davis reused the plot of the first episode of the series, "The Plastic Eaters", for their 1971 novel Mutant 59: The Plastic Eater, This was not technically a Doomwatch novel, however, and did not contain the characters from the series." [info from: https://en.wikipedia.org/wiki/Doomwatch]

First published in Britain 1971 by Souvenir Press Ltd. and simultaneously in Canada by J.M. Dent & Sons Ltd.
Cover artist is not credited. No visible signature.
The Book Palace / Illustrated Gallery credits this to Stephen Richard Boldero