R5 AM Perflourochemical Biodegradation, Fate, and Transport
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in 321-323

(LIU-1117-819955) Sorption and Biotransformation of 8:2 Fluorotelomer Alcohol by Surface Soils.

Liu, J¹, Nies, L², Nakatsu, C, Lee, L¹, ¹ Agronomy Department, Purdue University, West Lafayette, IN, USA² Civil Engineering Department, Purdue University, West Lafayette, IN, USA

ABSTRACT- Telomer-based polymers and surfactants serve as excellent surface modification and protective chemicals. However, they are suspected to degrade into perfluorinated acids during disposal and contribute to the global contamination in humans, wide life and environmental compartments. Elucidating the mobility and persistence of fluorotelomer alcohols in soils is an important step towards understanding the fate of these polymers and surfactants in the environment particularly in landfills where products with these coatings such as carpets and paper utensils are disposed. Sorption and biotransformation in soils were investigated for 8:2 fluorotelomer alcohol (CF₃-(CF₂)₇-(CH₂)₂-OH), which is the most abundant species among fluorotelomer alcohols of different carbon chain lengths. Sorption from aqueous solutions by five soils representing a wide range of properties was determined directly and extrapolated from data measured in acetone/water solutions using a log-linear cosolvency model, which minimizes experimental artifacts from volatilization, degradation, and dissolved organic carbon (DOC). Extrapolated aqueous sorption coefficients from the cosolvency method were in good agreement but consistently higher than those measured directly, which was attributed to fluorotelomer alcohol association with the DOC in aqueous solutions. 8:2 fluorotelomer alcohol sorption was exothermic and appeared to be primarily driven by hydrophobic partitioning with a log K_oc value (OC-normalized soil-water distribution coefficient, L/kg) of 4.13±0.16, which is comparable to a 3-ring polyaromatic hydrocarbon. Aerobic biotransformation was investigated in the presence of different organic co-substrates (methanol, ethanol, octanol, acetone, ethyl acetate, and 1,4-dioxane). The high volatility of the 8:2 fluorotelomer alcohol requires that it be added to soil microcosms via a cosolvent. In a preliminary 7-day, the 8:2 fluorotelomer alcohol was aerobically transformed into 8:2 saturated and unsaturated acids with all co-substrates. Longer incubation studies are being conducted to assess if pathways for further transformation, reaction rates, and microbial consortium are affected by co-substrates.

Key words: Fluorotelomer alcohols, Sorption, Cosolvency, Biotransformation