Findings supporting the natural formation of trichloroacetic acid in soil

The concentrations of trichloroacetic acid (TCAA) in soil and of chlorinated solvents in soil air from simultaneously taken samples from four sites are presented. The data show that there is a significant positive correlation between the concentrations of TCAA and chloroform - but not between TCAA and other chlorinated solvents — in soil. The calculated half-life of TCAA shows that the contribution of decarboxylation to the chloroform concentration in soil is negligible. Since TCAA and chloroform were found to be formed from humic acids in the chloroperoxidase (CPO)-mediated reaction and CPO activity has been detected in soil, the observed correlation between the concentrations of TCAA and chloroform provides novel support for the hypothesis that TCAA is formed naturally in soil.