Trichloroacetic acid in the forest ecosystem.

Trichloroacetic acid (TCA) is a ubiquitous phytotoxic substance that oeeurs at various levels in the environment. The last eentury, it was produeed and used in agriculture as herbicide against perennial grasses for same time, before it was found as seeondary atmospherie pollutant. It was considered a reason of coniferous forest decline. TCA was further found among produets of disinfeetion of drinking water and of delignifieation of cellulose pulp by chlorine. In addition to these anthropogenie sources of TCA, is has been found to be formed in the forest ecosystem as a result of microbial chlorination of humic substances that subsequently yield TCA in the soil. TCA may be eonsidered important intermediate of soil organic matter degradation and belongs thus to naturally-produeed organohalogens and at thc same time to relevant xenobiotics and stressors affecting plants in thc fafest ecosystem. Hs role in the fafest ecosystem is clearly shown