PURITY OF RECYCLED FIBER-BASED MATERIALS

In order to study the purity of recycled fibre-based materials, produc ts containing recycled fibre as well as recycled pulp were examined wi th regard to their chemical impurities, toxicity and microbiological q uality. The study was carried out to clarify both qualitatively and qu antitatively the variations in microbiological quality. The levels of several classes of chemical substances were analysed and semi-volatile and volatile substances identified. The toxicity and mutagenicity of virgin fibre and recycled fibre materials were screened using the Phot obacter toxicity test and the Ames Salmonella mutagenicity test. Preli minary chemical characterization of the mutagens was carried out. Iden tification of the compounds found in the mutagenic fractions was perfo rmed by gas chromatography/mass spectrometry (GC/MS). The concentratio n of various substances analysed was found to be low, although the var iety of substances present appeared to be very broad. Preliminary chem ical characterization revealed that some samples contained compounds k nown to have mutagenic or other toxic activity. Also, the recycled fib re pulps contained large amounts of various microbes, the microbial lo ad consisting mainly of aerobic spore-forming bacteria. The paper-maki ng process was found to clearly have reduced the total microbial count s.