Polyethyleneterephthalate (PET) was tested as a source of mutagen contamination from bottles used for beverage packaging. PET bottles were filled with mineral water and stored in daylight and in the dark for different periods of time. The water samples were concentrated and the concentrates (non-volatile compounds) tested for mutagenicity with the Ames test (static tests). Total organic carbon (TOC) leaching was determined concurrently. Leaching of mutagens was also studied using dynamic tests; shaking distilled water in PET bottles. New methods were also used to test the leaching potential of both volatile and non-volatile compounds: directly testing the mutagenicity in unconcentrated water stored in PET bottles and growing Salmonella strains directly in the plastic bottles. The results were positive only for the static test, which identified leaching of mutagens after 1 month of storage in PET bottles. This activity was higher after storage in daylight.