DECOMPOSITION OF COTTON AND POLYESTER FABRICS IN SOIL AND RELATED FUNGI

Abstract

Previous studies have shown forensic mycology to be a potential tool from which post-burial interval can be determined. This work aimed to investigate decomposition of cotton and polyester materials in a tropical forest soil and to compare the obtained data with those obtained from a similar study in a temperate (North Wales, UK) soil. These experiments were carried out both during the dry season and rainy season in Thailand. The study utilized the soil burial method to determine the biodegradation rates of cotton briefs, 100% cotton bags and 100% polyester bags. Each textile sample was pre-soaked with a solution comprised of 5% urea and 2% glucose to simulate leakage of body fluid from a buried corpse. The weight loss, electron microscopy and visual examination revealed that cotton fabric samples (briefs and bags) are colonized by fungi and completely degraded within 6 weeks in the rainy season and 10 weeks in the dry season. When compared to the investigation in the UK, decomposition of cotton fabric in the Thai tropical soil took place at 2-3 times the rate of similar decomposition in a temperate soil in the UK according to season. In the enzyme assays for a selection of the fungi isolated from the cotton samples it was found that Trichoderma koningiopsis produced the most endogluconase, following by 2 Penicillium species. Moreover, the Denaturing Gradient Gel Electrophoresis (DGGE) confirmed that Trichoderma koningiopsis is the dominant fungus in both cotton samples. It is suggested that decomposition of clothing has potential in forensic investigations but reliability will require careful examination of the soil properties and the environmental conditions at the place and time of burial.