TEMPERATURE EFFECT ON THE PARTITIONING OF POLYCYCLIC AROMATIC-HYDROCARBONS BETWEEN NATURAL ORGANIC-CARBON AND WATER

The influence of temperature on K-DOC was quantified for fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi ]perylene and indeno[1,2,3-cd]pyrene using the gas-purge technique and natural dissolved organic carbon from lake Ketelmeer, the Netherlands . Sorption of PAHs to DOC decreased with increasing temperature over a temperature range of 16 to 45 degrees C. Delta H degrees values range d from -18.3 kJ.mol(-1) for fluoranthene to -40.6 kJ.mol(-1) for benzo [ghi]perylene. A temperature decrease of 10 degrees C lead to an avera ge increase of K-DOC with 60%. The partition coefficients (K-POC and K -DOC) for sorption to particulate and dissolved organic carbon from th e same lake were also determined. Log K-POC-values ranged from 5.4 +/- 0.3 for fluoranthene to 6.8 +/- 0.3 for indeno[1,2,3-cd]pyrene and ar e in agreement with previously published values. Log K-DOC-values rang ed from 5.18 +/- 0.07 for fluoranthene to 6.86 +/- 0.03 for indeno[1,2 ,3-cd]pyrene, which is higher than previously reported for natural DOG . The data support the linear relationship between log K-POC and log K -DOC with a slope of nearly one. The effect of the temperature and PAH sorption to DOC influenced fate calculations for these components. Fo r compounds with low volatilization rates and high sorption partition coefficients such as the PAHs used in this study, sorption to DOC has a large influence on mobility in porous systems. The influence of temp erature is relatively small. Copyright (C) 1996 Elsevier Science Ltd