Solubility and sorption by soils of 8:2 fluorotelomer alcohol in water and cosolvent systems.

The solubility and sorption by five soils of 8:2 fluorotelomer alcohol (FTOH) were measured from water and cosolvent/ water solutions. Aqueous solubility and soil-water distribution coefficients (Kd,w, L kg(-1)) were extrapolated from cosolvent data using a log-linear cosolvency model and compared to direct aqueous measurements. Liquid chromatography tandem mass spectrometry with electrospray ionization was employed to analyze the 8:2 FTOH in solutions and soil extracts. The cosolvent-extrapolated water solubility is 0.224 mg L(-1), in good agreement with the measured value of 0.194 mg L(-1). All sorption isotherms were generally linear regardless of cosolvent composition or soil organic carbon (OC) content. Kd,w values extrapolated from cosolvent data were similar but consistently higher than those measured in aqueous solutions. The latter was hypothesized to be due to dissolved OC (DOC) in the aqueous slurries. An average log KDOC of 5.30 was estimated and supported by DOC and Kd,w measurements at two soil-water ratios. Sorption appeared to be driven by hydrophobic partitioning with a log KOC value of 4.13 +/- 0.16. Irreversible sorption was also observed and appeared to be related to OC content, with the extraction efficiency reduced from 85% to 45% with increasing contact time from 3 to 72 h for the highest OC soil.