Trifluoroacetate retention in a northern hardwood forest soil

Chlorofluorocarbons (CFCs) catalyze the breakdown of stratospheric ozone. As a result, international agreements now require the use of CFCs to be discontinued. Trifluoroacetate (TFA) is formed as an important breakdown product in the atmospheric degradation of CFC replacement compounds. Manufacturers have proposed that TFA should be inert and conservatively transported in water. In this experimental study, TFA and bromide (Br), widely used as a hydrologic tracer, were added to upland northern hardwood forest plots within the Hubbard Brook Experimental Forest, New Hampshire. Analysis of soil solutions, collected by lysimetry, showed TFA and Br concentrations to be highly correlated with similar temporal patterns. Application of a simple hydrologic model was done to estimate solute fluxes. Due to the extremely dry summer in 1995, significant amounts of TFA and Br probably were taken up by plants or retained within the soil. Drainage losses did not support the hypothesis for conservative transport through surface organic layers; retention in the lower mineral soil horizons was minimal. Transport of TFA and Br in this upland soil is controlled primarily by hydrologic processes.