Paper as reference material in “Sturm test” applied to insoluble substances

The ever-increasing use of plastics for the packaging, wrapping, and transportation of goods is causing serious concern in regard to their environmental fate when they are carelessly discarded (visual pollution), or disposed off by dumping or by incineration. For this reason in the last few years in Italy legislation was introduced, specif ing that the plastics used in the manufacturing of shopping bags must be “biodegradable.” The selected test for assaying biodegradability was the modified Sturm method. In applying this assay the choice of reference standard materials, which associates two characteristics—biodegradability and insolubility—is a major problem. The possibility was investigated of utilizing a paper sample. The modified Sturm method revealed that 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 95.0%, respectively. The variability in the results was due to the composition of the paper. Results from this study indicate that the kind of 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. © 1994 by John Wiley & Sons, Inc..