STUDIES ON BIO-DEGRADATION OF LDPE-OBSERVATION OF LDPE FILMS SCATTERED IN AGRICULTURAL FIELDS OR IN GARDEN SOIL

Agricultural mulch films and package films scattered in fields or in garden soil were observed by an optical microscope after staining with lactophenol cotton blue as well as by SEM and FT-IR microscope. The part of these samples which was concealed in soil was whitened in appearance. We observed a lot of small holes passing through the film. The microscope FT-IR analysis showed the existence of-C=C-double bond (1640cm-1) around the surface of the whitened part. Significant levels of hydroperoxide and hydroxide absorption bands were also observed. Optical microscope observations of films stained with lactophenol cotten blue revealed that the bio-activity of the film surface was especially high in the vicinity of small holes. We found several colonies of microbes by optical microscope with cotton blue staining as well as by SEM. We concluded that the bio-degradation of thin LDPE films in soil was unexpectedly fast because of the synergistic action of oxidative and/or photo-oxidative degradation on biological activity which is probably due to the increasing hydrophilicity of the film surface.