Migration of organic compounds from PET bottles

The Swiss Federal Laboratories for Materials Testing and Research (EMPA) studied the migration of organic components from polyethylene terephthalate (PET) bottles to the water under the conditions of solar water disinfection (SODIS): 6 bottles were exposed to sunlight at 60°C. For comparison, 6 bottles were exposed to sunlight at ambient temperature (maximum water temperature 34°C) and 3 bottles were kept in the shade at room temperature (25°C), respectively. Total time of exposure to sunlight was 17 hours. In order to elaborate the possible influence of further parameters, new and used bottles from different countries (Honduras, Nepal, and Switzerland) were selected.

Qualitative analyses of the water samples revealed traces of several organic compounds possibly due to flavour components of the originally bottled beverages. Above a detection limit of 1 µg/L, no further organic components could be detected.

Levels of the plasticizers di(2-ethylhexyl)adipate (DEHA) and di(2-ethylhexyl)phthalate (DEHP) detected in the water were 0.010 ? 0.046 µg/L for DEHA and 0.10 ? 0.71 µg/L for DEHP. These detected levels have to be considered as maximum levels, as they are in the range of background levels detected in pure water stored in glass bottles without any previous contact with PET (average 0.018 µg/L for DEHA and 0.11 µg/L for DEHP). These background levels are due to the ubiquitous presence of traces of these plasticizers. The contribution of migration of plasticizers to the background contamination is not significant.

If the highest detected levels are used for a toxicological assessment of DEHA and DEHP (0.046 µg/L for DEHA and 0.71 µg/L for DEHP), the carcinogenic risk posed by permanent exposure to these levels is 1.6 * 10-9 for DEHA and 2.8 * 10-7 for DEHP, being below a carcinogenic risk of 1 in 106. Furthermore, these levels are distinctly below the WHO guidelines for drinking water quality (80 µg/L for DEHA and 8 µg/L for DEHP).

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Reference: Lilya, D. (2001). Analysis and risk assessment of organic chemical migration from reused PET plastic bottles. (MScThesis Environmental Engineering). USA, University of Idaho, Environmental Science Program.

Contact: Martin Wegelin (SANDEC), fax: +41-1-823 53 99, martin.wegelin@eawag.ch, http://www.sodis.ch
Peter Schmid (EMPA), mailto: peter.schmid@empa.ch

Source: Kohler, M. (2003). Migration of organic components from polyethylene terephthalate (PET) bottles into water. (Report 429670). St. Gallen, Switzerland, Swiss Federal Laboratories for Materials Testing and Research (EMPA)

Keywords

• Water quality