Occurrence, release and risk assessment of metal elements in polylactic acid food containers from China

Global consumption of polylactic acid (PLA) food containers is growing rapidly, and the release of chemicals from these containers poses a potential health risk to consumers. However, the available information on metal elements of these food containers is extremely limited. This study investigated the occurrence, release and risk assessment of metal elements in PLA food containers from China. The results showed that detection rates of 13 common metal elements were from 14.89 % to 100 % with average contents ranged from 0.002 to 181.91 mg/kg, respectively. Furthermore, Al, Ni, Cu, Cr, Zn and Pb were released to 4 % acetic acid (HAC) at average levels of 0.38–352.14 μg/kg under the 60℃ for 6 h. The average estimated daily intake (EDI) values were 0.0064–5.8690 μg/kg b.w. Based on the observed release levels, we estimated that there is potential risk in exposure to Pb. The degrees of metal elements leaching into food simulants were different with an order of in 4 % HAC solutions > 20 % ethanol > water > hexane. As expected, higher temperature and prolonged exposure accelerated the release of metal elements, even after a long exposure time (60°C for 10 days). In addition, multiped use aggravated releasing of metal elements, as well. In conclusion, it is worthwhile to evaluate and manage the risk of Pb exposure and the cumulative risks of multiple metal elements in PLA food containers.