Is PET bottle-to-bottle recycling safe? Evaluation of post-consumer recycling processes according to the EFSA guidelines

摘要

For almost 15 years now in Europe, used plastic bottles made of polyethylene terephthalate (PET) have been recycled in such a way that the recyclate can be used for new PET bottles. Several recycling plants have been established all over Europe. Since May 2008 the European Recycling Regulation 282/2008 has been in force. According to this regulation, every recycling process must be individually approved by the European Food Safety Authority (EFSA). For this evaluation process, EFSA has developed a conservative evaluation concept in order to protect consumers. The evaluation is partly based on mathematical calculation of the migration. The current migration model overestimates the migration. EFSA acknowledges that the migration model overestimates by at least a factor of 5. This applies for small molecules such as toluene. However, higher molecular weight contaminants such as benzophenone are even more overestimated. The reason for this overestimation is that the currently used migration model is based on a fixed activation energy of diffusion. Conversely, the curve of the maximum bottle wall concentration calculated using the current migration model increases much too gradually with the molecular weight. New developments in migration modelling consider more precisely the activation energies of diffusion. Consequently, using the new, more realistic diffusion coefficients influences significantly the EFSA evaluation criteria.