Biodegradation of trichloroacetic acid in Norway spruce/soil system

Trichloroacetic acid (TCA) belongs to secondary atmospheric pollutants affecting the forest health. Distribution of [1,2-C-14]TCA-residues and TCA biodegradation were investigated in 4-year-old nursery-grown trees of Norway spruce [Picea abies (L.) Karat.] in the whole plant/soil system. Radioactivity was monitored in needles, wood, roots and soil as well as in the air. During two weeks of exposure TCA was continuously degraded, especially in the soil. Estimates of radioactivity balance showed loss of radioactivity into the atmosphere in the form of (CO2)-C-14; unincorporated [1,2-C-14]TCA, chloroform, carbon monoxide and methane were not detected at all. TCA degradation to CO2 was indicated also in the spruce needles. Moreover, it was found that soil litter contained [1,2-C-14]TCA unavailable to microorganisms.