Determination of Henry's law constant of formaldehyde as a function of temperature: application to air-water exchange in Tahtali Lake in Izmir, Turkey.

The Henry's law constant (H) is an important parameter in predicting the transport, behavior and fate of organic compounds in environment. H is also required to model the air-water exchange of chemicals. Henry's law constant of formaldehyde (HCHO) was determined at six temperatures (50, 40, 30, 20, 10, and 5 degrees C) using a bubble-column technique. The apparent Henrys law constant (H*) values were strongly correlated to inverse of temperature (1/T, K) and the following relationship was obtained: In H* = (-1,641.3/T)-3.089. Seven concurrent ambient air and aqueous samples were also collected between October 11-17, 2005 at a sampling site located on the shoreline of Tahtali dam Lake in Izmir, Turkey to determine the magnitude and direction (deposition or gas-out) of HCHO flux. In all cases, the modeled gas-phase flux was positive (average +/- SD, 3,181 +/- 408 microg m(-2) day(-1)) indicating that atmospheric HCHO deposited to the Tahtali Lake.