ic mineral-water and soft-drinks bottles are
gradually replacing glass. Plastic bottles are made of
either PET (polyethylene terephtalate), or PVC (polyvinyl
chloride), both containing additives like UV-stabilisators
to increase their stability or to protect them and their
content from oxidation and UV radiation. Additives are
large molecules which hardly imigrate through the PET
material. Still, they are a potential health risk. In PET,
additives are much less used than in PVC (less than 1%
for PET), making PET the preferred material for SODIS
treatment. Various types of transparent plastic materials
are good transmitters in the UV and visible range of
solar spectrum.