Use of a vial equilibration technique to measure the change in fugacity capacity of avian food and feces samples for 1,2,3,4-tetrachlorobenzene.

A vial equilibration technique was used to estimate the fugacity capacities of food and feces samples for 1,2,3,4-tetrachlorobenzene (TCB). The method was calibrated using different volumes of n-octanol and by comparing the measured and predicted fugacity capacity (Zoct) of n-octanol for TCB. The vial equilibration technique showed linearity with increasing amounts of n-octanol added to the vial. However, the measured Zoct was on average 8.5 times lower than the literature estimate and interpreted to be influenced by co-solvent effects. The ratio of fugacity capacities of food/feces was 2.9 and was consistent with the ratio estimated using Zt calculation methods (4.3) which considers partitioning capacity of both lipids and non-lipid organic matter. These results provide experimental support to the use of lipid equivalent approaches as opposed to lipid normalization when estimating the partition capacity of biological samples containing low lipid contents.