Toxic antimony species found in beverages stored in PET containers

Background

A recent study by Shotyk et al. reported elevated antimony levels in drinking water bottled in polyethylene terephthalate (PET) containers. Antimony (Sb₂O₃) is used as a catalyst in 90% of PET manufacturing world- wide. As a result most commercial PET material typically contains 190-300 mg/kg Sb. Antimony trioxide is a suspected carcinogen, and is listed as a priority pollutant by the USEPA and the EU. According to the results obtained by Shotyk's group Sb is leaching from the PET containers into drinking water, leading to concentrations 100 times elevated compared with uncontaminated water. While the measured concen- trations are below the guidelines commonly recommended for drinking water (WHO, 20 µg Sb L^-1; USEPA, 6 µg Sb L^-1; and Japan 2 µg Sb L^-1), the study raised some concern about the contamination of drinking water with possibly toxic antimony species.  

The present study:
Not only drinking water but also other beverages, for example fruit juices and carbonated soft drinks and food products such as vinegar are often stored in PET containers. Since it has been reported, that citric acid, a major constituent of citrus juices, efficiently extracts and preserves the valency state of antimony species present in solid materials, the question arises, whether such beverages enhance the leaching risk of antimony from the container material.

The results:
Helle R. Hansen and Spiros A. Pergantis from the University of Crete measured the total antimony concentrations in several beverages packed into different container materials (carton, glass, aluminium cans, PET bottlesd) by ICP-MS. The results are reported in the recent August issue of JAAS (see below). The lowest concentrations were found in cartons ((0.07 ± 0.06 µg Sb L^-1), whereas juices contained in glass (0.28–0.3 µg Sb L^-1) or cans (0.24–0.56 µg Sb L^-1) showed elevated levels indicating some contamination through the container material. Highest antimony levels were found in juices stored in PET bottles (ranging from 0.28 to 1.05 µg/L) with some relation to the storing time.

In order to determine and quantify the antimony species present in the beverages, a commonly used anion exchange HPLC method was used in conjunction with on-line ICP-MS detection. Three different species appeared in the chromtagrams, the first two were identified by comparing their retention times with standards as inorganic Sb(V) and Sb(III). The third and often major peak was identified by ESI-MS as Sb(V)-citrate. Either inorganic Sb(III) (44 ± 17%) or Sb(V)–citrate (41 ± 20%) were the main species present in the juices. However, only non-complexed inorganic Sb(V) was observed in analysed drinking water contained in PET bottles.

All the total Sb concentrations measured were below the guidelines recommended for drinking water and were not notably different from concentrations previously reported present in drinking waters contained in PET bottles (up to 1.14 µg Sb L^-1 ). Such levels have previously been evaluated as being of no (or little) concern to human health.

A notable difference between Sb in drinking water and citrus beverages, however, is the chemical form in which the Sb is present. Citric acid present in the juice indeed seems to stabilize the more toxic Sb(III) species which is otherwise prone to oxidation.


The original study:

 Helle Rusz Hansen, Spiros A. Pergantis, Detection of antimony species in citrus juices and drinking water stored in PET containers, J. Anal. At. Spectrom., 21/8 (2006) 731. DOI: 10.1039/b606367e


Related Studies:

 P.J. Fordham, J.W. Gramshaw, H.M. Crews, L. Castle, Element residues in food contact plastics and their migration into food simulants, measured by inductively coupled plasma mass spectrometry, Food Addit. Contam., 12/5 (1995) 651-669. DOI: 10.1080/02652039509374354

 L.-l. Wang, Y.-l. Bai, Determination of antimony in the resin and products of poly(ethylene terephthalate) [PET] by graphite-furnace atomic-absorption spectrometry, Guangpuxue Yu Guangpu Fenxi, 18/5 (1998) 606-608.

 J. Lintschinger, O. Schramel, A. Kettrup, The analysis of antimony species by using ESI-MS and HPLC-ICP-MS, Fresenius J. Anal. Chem., 361/2 (1998) 96-102. DOI: 10.1007/s002160050841

 Jian Zheng, Akihiro Iijima, Naoki Furuta, Complexation effect of antimony compounds with citric acid and its application to the speciation of antimony(III) and antimony(V) using HPLC-ICP-MS, J. Anal. At. Spectrom., 16/8 (2001) 812. DOI: 10.1039/b101943k

K. Nishioka, A. Hirahara, E. Iwamoto, Determination of antimony in polyethylene terephthalate bottles by graphite furnace atomic absorption spectrometry using microwave sample preparation, Bull. Inst. Life Sci. Hiroshima Prefectural Women's Univ., 8 (2002) 35-42.

William Shotyk, Michael Krachler, Bin Chen, Contamination of Canadian and European bottled waters with antimony from PET containers, J. Environ. Monit., 8/2 (2006) 288. DOI: 10.1039/b517844b

William Shotyk, Michael Krachler, Contamination of Bottled Waters with Antimony Leaching from Polyethylene Terephthalate (PET) Increases upon Storage, Environ. Sci. Technol., 41/5 (2007) 1560-1563. DOI: 10.1021/es061511+



Related information:

WHO: Antimony in drinking water
US EPA: Integrated Risk Information system: Antimony trioxide
ATSDR: Toxicological Profile for Antimony



Related EVISA News: