OCCURRENCE, SOURCES, AND FATE OF TRICHLOROACETIC-ACID IN SWISS WATERS

The occurrence, sources, and fate of trichloroacetic acid (TCA) has be en investigated in surface waters, ground waters, drinking waters, was tewaters, and rainwater in Switzerland. The concentrations found in su rface waters varied between less than 27 ng/L (limit of quantification ) and 340 ng/L, whereas the concentrations in ground water were always below 27 ng/L. It was found that the main sources of TCA in surface w aters were the effluents of wastewater treatment plants (average conce ntration, 430 ng/L; range, 40-1060 ng/L). The average TCA concentratio n in rainwater was 300 ng/L range, (<27-900 ng/L). A dynamic mathemati cal model revealed that TCA is not significantly degraded in a lake (h alf-life >230 d). A detailed mass balance in the catchment area of a s mall lake (Greifensee) and a very rough mass balance over Switzerland indicate that rain is the major source of TCA in Switzerland (>90%), b ut they also show that about 60 to 80% of the TCA deposited by rain is eliminated, most probably in the soil.