PAPER AS REFERENCE MATERIAL IN STURM TEST APPLIED TO INSOLUBLE SUBSTANCES

The ever-increasing use of plastics for the packaging, wrapping, and t ransportation of goods is causing serious concern in regard to their e nvironmental fate when they are carelessly discarded (visual pollution ), or disposed off by dumping or by incineration. For this reason in t he last few years in Italy legislation was introduced, specifing that the plastics used in the manufacturing of shopping bags must be ''biod egradable.'' The selected test for assaying biodegradability was the m odified Sturm method. In applying this assay the choice of reference s tandard materials, which associates two characteristics-biodegradabili ty and insolubility-is a major problem. The possibility was investigat ed of utilizing a paper sample. The modified Sturm method revealed tha t the biodegradability of six paper samples varied from 54.5 to 75.2%; papers of two shopping bags showed a biodegradadability of 48.0 and 9 5.0%, respectively. The variability in the results was due to the comp osition of the paper. Results from this study indicate that the kind o f paper to be used as reference material in the modified Sturm method has to be strictly selected in order to guarantee the reproducibility of the measures. (C) 1994 by John Wiley & Sons, Inc.