Migration of antimony from virgin polyethylene terephthalate (PET) bottles into drinking water under various storage conditions: Implications for public safety and health in Benin

Abstract

The increasing use of polyethylene terephthalate (PET) bottles for drinking water packaging raises concerns about the migration of potentially toxic elements such as antimony (Sb). The study aimed to evaluate the influence of temperature and storage duration on the migration of Sb from virgin PET bottles into tap water in Benin. The experiment involved twenty-one new 500 mL bottles filled with tap water and subjected to three thermal regimes (0-6 °C, 25 °C, and 50 °C) over a 90-day period. Analyses were conducted at day 0 (J₀), day 60 (J₆₀), and day 90 (J₉₀) using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES, Thermo Fisher iCAP 6500). Each sample was microwave-digested following a standardized protocol, then analyzed for Sb quantification at a wavelength of 206.833 nm. The limit of quantification (LOQ) was established at 0.01 µg/L, and the regulatory reference value used for data interpretation was the European Union standard of 5 µg/L for drinking water. The results indicated that at 0-6 °C and 25 °C, no detectable migration occurred up to 90 days (≤ LOQ). In contrast, at 50 °C, the mean concentration increased from undetectable levels to 2.319 ± 0.023 µg/L at J60 and 5.812 ± 0.028 µg/L at J₉₀, exceeding the European threshold. These findings confirm a strong temperature- and time-dependent behavior of Sb migration, consistent with previous studies reporting enhanced diffusion behavior from 50 °C onward. In conclusion, Sb migration remains negligible at refrigeration and ambient temperatures but becomes significant under prolonged thermal stress. These results support recommendations to avoid long-term storage of PET bottles in hot environments and highlight the need for further investigation into Sb diffusion kinetics under tropical conditions.