Biodegradation of Pyrene by Using Earthworm in Soil

Abstract

Pyrene, a toxic four benzene ring Polycyclic Aromatic Hydrocarbons (PAHs) that persists in the environment, is highly resistant to degradation. Therefore, this study aims are to investigate the mechanism and optimum pyrene degradation rate with minimum toxic by-products by using earthworms. The earthworms were collected randomly from soil at Universiti Teknologi Malaysia (Malaysia) as pyrene degrader to eliminate pyrene in soil. Several factor such as soil to earthworm ratio, soil moisture content, effect of soil sterilization and comparison of pyrene degradation using different experimental approaches on pyrene degradation efficiency were examined.  In this study was found by using earthworms, 25% of pyrene was removed by earthworms from 200 g of soil containing 100 mg L^-1 of pyrene after 14 days treatment, suggesting that wild earthworms were able to degrade the pyrene with higher efficiency in the natural soil without sterilization. However, no metabolite was detected during the pyrene removal process. The pyrene might be fully degraded or accumulated in fatty tissue in earthworms. Nevertheless, in the treatment using wild earthworms are suitable to be used as pyrene degrader.