Cycle of Halocarbons in the Air-Water Phase

Abstract

Halocarbons are widely distributed in environment: atmosphere, hydrosphere, lithosphere and biosphere. This report presents the data on the cycle of halocarbons in air-water phase. Low-boiling-point halocarbons were monitored and about 10 kind of substances which include chlorofluorocarbon (CFC) were detected in the environment The concentrations of halocarbons in air are influenced by weather conditions, especially by wind speed. Three CFCs, CFC-11, CFC-12 and CFC-113, were detected at the level of 0.18-1.70 ppb on the day (wind speed 0-lm/sec), and 0.05-0.40 ppb (5-10m/sec). Other halomethanes, chloroform and carbon tetrachloride, were detected at the level of 0.06-0.72 ppb and 0.03-0.06 ppb; a haloethane, 1,1,1-trichloroethane, was 0.50-5.3 ppb and 0.12-0.95 ppb; and haloethylenes, trichloroethylene and tetrachloroethylene, were 0.02-4.1 ppb and 0.01-1.8 ppb on days of wind speed below lm/sec and 5-10m/sec, respectively. Substances found in air were also detected in water phase. Concentration of above-mentioned halocarbons in water were at the level of 0.001-0.0095 ppb in river water, 0.002-0.06 ppb in ground water, 0.001-0.036 ppb in seawater, and 0.001-0.53 ppb in rain water. In comparison with concentration of halocarbons of environmental measurement and estimation value by using the predictive fate model of chemical substances, haloethanes and haloethylenes in air exceeded the value of estimation. On the other hand, halomethanes in air almost agreed with its value, and in water phase were quite similar to the estimation.