Use and production

Polystyrene (PS) is a colorless, transparent polymer composed of styrene monomers and has a specific gravity of 1.04–1.07 g/cm3. PS is soluble in organic solvents, such as ketones, esters, and aromatic hydrocarbons. It is resistant to acids, alkalis, salts, mineral oils, organic acids, and alcohols. As a hard and solid plastic, PS is often used to manufacture transparent products, such as food packaging and laboratory ware. Lightweight polystyrene foam provides excellent thermal insulation for many applications, such as roofing, building walls, refrigerators, and freezers.

Toxicity

Humans may experience oxidative stress, cytotoxicity, neurotoxicity, immune system disruption, and transfer of microplastics (MPs) to other tissues after being exposed to them. The toxic effects of MPs in both fish and human are still unknown. 

Due to high surface to volume ratio and hydrophobicity, nanoplastics and microplastics of PS can adsorb toxic chemicals from the surrounding seawater and transfer them to marine organisms, a phenomenon called “Trojan horse effect. Several persistent organic pollutants (POPs) have been detected in plastic particles collected from different beaches around the world.

Studies also indicate that nanoplastics are more dangerous than microplastics.

The European Commission requested the European Chemicals Agency (ECHA) to prepare a restriction dossier concerning the use of intentionally added microplastics to consumer or professional use products. The Commission will soon assess ECHA’s submission and reflect on the most appropriate measures.