Vertical and horizontal variation in natural chloroform in two adjacent soil profiles in a coniferous forest

Abstract

Naturally produced chloroform is occasionally detected in soil and groundwater of non-urban areas in concentrations that can exceed the regulatory levels. In this study, we present the distribution of naturally produced chloroform in a temperate coniferous forest from top soil to upper groundwater. Chloroform is most likely produced by the activity of fungi, and the production varies therefore with the domains of certain unidentified fungi. We show that the differences in concentration within 10 metres can approach two orders of magnitude in the top soil. The difference in chloroform concentrations in upper groundwater within the same distance is almost one order of magnitude. The concentration of chloroform in the top soil varies significantly with season, while season affect deeper levels much less.