Why does plastic take so long to disappear in nature?

The main reason is that nature still doesn’t know how to get rid of it. “Bacteria and fungi that decompose the materials did not have time to develop enzymes to degrade the substance”, says chemical engineer Marilda Keico Taciro, from the Technological Research Institute (IPT). Plastic is a new material in nature – the first model appeared only in 1862, created by the British Alexander Parkes. Each of its molecules has hundreds of thousands of atoms, mostly carbon and hydrogen. Because the bonds between atoms are so stable, decomposers cannot break material down into smaller pieces to destroy it. Result: some types of plastic, such as PET, used in soft drink bottles, take more than 200 years to disappear.

“With evolution, microorganisms must adapt, but this could take millions of years”, says biologist José Gregório Cabrera Gomes, also from the IPT. That’s why plastic disposal is a major headache for 21st century ecologists. The material produces toxic gases when burned and is difficult to recycle, because different types of plastic cannot be mixed. The way is to develop biodegradable models such as PHB, which, in sanitary landfills, turns to dust in just six months. But these are still expensive – up to five times more than conventional ones – and, therefore, account for only 1% of the total plastic sold in the world.