Airborne trichloroacetic acid and its deposition in the catchment area of the Caspian Sea

The main sources of pollution discharge into the Caspian Sea are metal and oil processing plants in the catchment areas of the Ural and Volga rivers, as well as the coastal and offshore oil industry in the countries bordering the sea. The high evaporation from the surface of this largest inland sea introduces highly volatile C-2-chlorohydrocarbons into the atmosphere. Subs equent reactions with OH radicals and other oxidants results in the formati on of secondary pollutants, such as phytotoxic trichloroacetic acid (TCA), which are then delivered by the air or rain into the neighbouring ecosystem s of various vegetation zones. Biomonitoring investigations in the catchmen t area of the Caspian Sea have revealed that differences in pollution level s in the southern Russian area between the Black Sea and the Caspian Sea, r esulting from TCA originating in the atmosphere, are attributable to climat ic conditions and the geographical position of the measuring sites. (C) 199 9 Elsevier Science Ltd. All rights reserved.