Bioremediation and Leaching Potential of Pentachlorophenol (PCP) in Biodiesel Versus Diesel Carriers

Biodiesel is believed to be more environmentally friendly than petroleum-based diesel when used as a carrier for impregnating wood products with pentachlorophenol (PCP) for decay protection. A 6-mo study was conducted to evaluate bioremediation of PCP in biodiesel vs diesel in soil. Different percentages of biodiesel, diesel, and PCP were mixed with clean soil from a forested site and tested. Samples were taken bimonthly and analyzed for oil and grease, PCP concentration, and microbial enumeration. Soil moisture content was adjusted twice weekly if needed. In addition, toxicity and toxicity characteristic leaching potential were measured at Days 0 and 180. Results showed that with an increase in percentage of biodiesel, there was an increase in degradation of diesel and diesel-amended PCP. The greatest decrease of PCP concentration and toxicity occurred in biodiesel alone by Day 180. Results also showed a significant decrease with time in oil and grease concentration, PCP concentration, and toxicity among different treatments. Based on this study, it appears that the cometabolic effect of biodiesel on micro-organisms could accelerate degradation of PCP in treated wood after disposal