Recycling of Post-Consumer Polystyrene Packaging Waste into New Food Packaging Applications—Part 3: Initial Contamination Levels in Washed Flakes from Europe

Polystyrene pots and trays are a promising input material for a closed packaging-to-packaging cycle. For the evaluation of the food law compliance it is necessary to know the possible contamination with substances from the first use but also from cross-contamination during recollection or even from possible misuse of the packing for storage of hazardous chemicals. As part of the study, 49 conventionally recycled PS samples from six European countries were analyzed for contamination. A rapid screening method was used, which has already been applied to PET recyclates. The 30 most highly concentrated substances were semi-quantified and identified. Overall, 10,310 individual post-consumer PS packages were investigated. Evidence of misuse of the PS pots and trays was found in one samples with the substance pinene at a concentration of 475 to 711 mg/kg. The incidence of misuse is therefore 0.0097%. The maximum initial concentration was determined 0.069 mg/kg or to 0.65 mg/kg under worst-case assumptions. Based on the data, an initial concentration of 1 mg/kg in post-consumer washed post-consumer rPS flakes is suggested as pragmatic worst-case approach in the evaluation of consumer safety of rPS containing food packaging.