Antimony trioxide (CAS 1309-64-4) is a commonly used plastics additive, and in PET manufacturing it is often used as a catalyst. Residuals of antimony (Sb) may still be present in the final product. Sb is of concern because it is probably carcinogenic to humans (WHO IARC Group 2A), and California warns consumers about the presence of this chemical in products sold on its market.
In an article published on November 24, 2023, in the Journal of Chromatography Open, Paulo Henrique Massaharu Kiyataka from Universidade Estadual de Campinas, Sao Paulo, Brazil, and co-authors analyzed 19 polyethylene terephthalate (PET) bottles for the presence and migration of antimony. The scientists purchased the water bottles in Sao Paulo, Brazil, and quantified Sb levels in the bottles by heating them to over 300 °C under high pressure. Furthermore, they performed migration experiments at 40 °C for 10 days and 60°C for 10 days, according to Brazil’s food contact regulation (Resolution RDC No. 51/2010) and the European regulation for plastic food contact materials (EC 10/2011), respectively. Sb levels were assessed by inductively coupled plasma optical emission spectrometry (ICP-OES).
The Sb content in the PET bottles was between 173 and 253 mg/kg packaging. This meets “the limit of total Sb in PET of 350 mg/kg established by Germany,” the only country that has established limits for Sb content in PET packaging. Concerning migration, the scientists reported that Sb concentrations were below the limit of detection at 40 °C (0.52 µg/L) but between 1.59 and 4.42 µg/L at 60 °C. This is below the specific migration limits of 40 µg/L and 40 µg/kg established by Brazilian and European legislation, respectively.
Another article published on December 16, 2023, in the Journal of Chromatography Open, also investigated Sb migration from PET bottles. Gursel Isci and Elif Dagdemir from Agri Ibrahim Cecen University, Agri and Ataturk University, Erzurum, Turkey, respectively, focused on how storage conditions influence Sb migration.
The scientists acquired 25 PET bottles of different types of beverages from local supermarkets in Turkey and subjected them to storage conditions of 4, 25, and 40°C for 90, 180, and 365 days before Sb analysis by ICP-mass spectrometry. Before storage, all but one sample contained Sb, but over time, the concentrations increased. Sb levels also increased with temperature. Comparing the levels in the different types of beverages, the authors reported that migration was higher in drinks with low pH and high gas pressure, but always stayed below 7.5 ng/mL. This confirms findings of previous scientific studies that have shown that antimony is present in plastics and can migrate into foods (FPF reported), with migration increasing with temperature (FPF reported) and drink acidity (FPF reported).
Isci and Dagdemir further performed a survey with 580 individuals to assess daily beverage consumption and compare the intake of Sb with the tolerable daily intake (TDI) value of the World Health Organization’s (WHO’s) drinking water guideline. They reported that estimated daily intakes, no matter the storage time and temperature, were below the WHO’s TDI of 6 µg/kg bw/day. The authors also calculated hazard quotients to be below one, and concluded: “that the studied compounds in PET-bottled beverages were safe,.., suggesting minimal non-carcinogenic health risks.” Besides Sb, the researchers also tested for migration of phthalate esters.
Opposed to these two recent studies, a report published in 2022 detected antimony in unsafe levels in 40 % of the tested beverages from major brands bottled in PET (FPF reported).
References
Massaharu Kiyataka, P. H. et al. (2023). “Migration of antimony from polyethylene terephthalate bottles to mineral water: Comparison between test conditions proposed by Brazil and the European Union.” Journal of Food Composition and Analysis. DOI: 0.1016/j.jfca.2023.105859
Isci G. and Dagdemir E. (2023). “Human Health Risk Assessment of Phthalate Esters and Antimony Levels in Beverages Packaged in Polyethylene Terephthalate under Different Storage Conditions.” Journal of Food Composition and Analysis. DOI: 0.1016/j.jfca.2023.105922
