Investigating antimony leaching from polyethylene terephthalate (PET) bottles: characterization with SEM–EDX and ICP–OES

Abstract

Polyethylene terephthalate (PET) is currently the most widely used type of plastic. PET plastic benefits include that it is lightweight, safe, cheap, and recyclable. Drinking water is an important route for human exposure to contaminants. One method of exposure is through leaching of antimony (Sb) from polyethylene terephthalate PET plastic. Antimony is a toxic element which causes harmful symptoms such as respiratory irritation, dysphagia, vomiting and eye and mucous membrane irritation. Leaching of antimony from three commercially available PET plastics was investigated in this study. The potential leaching of Sb was observed under different pH values, temperatures, and storage times. In this study, elemental mapping using scanning electron microscopy–energy dispersive x-ray spectroscopy (SEM–EDX) and inductively coupled plasma–optical emission spectrometry (ICP–OES) were employed to determine the weight percentages of antimony (Sb) on the inner surfaces of the PET plastic. The results revealed the presence of Sb in PET material, with significantly higher concentrations in PET 3, measured at 0.844 μg/L. Temperature and pH were investigated as factors influencing Sb leaching over time. The concentrations of Sb in bottled water ranged from 0.02 to 2.14 μg/L at different temperatures (25, 40, 50, or 60°C) and from 0.02 to 1.9 μg/L at pH values (6.5, 7, or 7.5) over 200 days. The maximum Sb concentrations reaching 2.14 μg/L at 60°C after 200 days, exceeded the Japanese limit of 2.00 μg/L. These findings highlight the potential health risks associated with Sb leaching from PET bottles, particularly under elevated temperature and low pH conditions.