A convenient test method for photochemical transformation of pollutants in the aquatic environment

A test method, based on a modified Xenotest 1200, is described, and has been proved to be convenient for determination of the rate of photolytical degradation and by that it can make a valuable contribution to the evaluation of environmental stability of organic compounds. The test method was applied to testing of photochemical degradation of organic chemicals in aquatic media. Solutions of six chlorinated phenolic substances, 8-quinolinol and 9,10-anthraquinone were illuminated with filtered light, simulating daylight at controlled conditions. Quantum yields of photochemical degradation and half lifetimes (of conversion) were calculated using a sun spectrum at 60°N. Chlorophenols absorbing light at 295 – 350 nm were converted and theoretical half lifetimes of 0.75 –2.6 hours were obtained. The photochemical conversion of 8-quinolinol was slow. Anthraquinone was studied in ethanol/water and the degradation corresponded to a half lifetime of 2.8 hours.