Study of photochemical oxidation of standard chlorinated paraffins and identification of degradation products

The kinetics of the photolytical oxidation of standard chlorinated paraffins by a combination of ultraviolet light and hydrogen peroxide was studied in various diluted aqueous solution. The most efficient degradation of the chlorinated paraffins was found in a 0.1% acetone-water medium in the series of experiments (aqueous solution with H2O2 or without H2O2 addition). The half-lives of Hordalub 500 and Hordaflex LC 50 in 0.1% acetone aqueous phase were less than 1 h (t(1/2) < 1 h), other chlorinated paraffins (CP 30, CP 40, CP 52 and CP 56) ranged between 2.5 and 5.2 h. Free chloride was determined as a function of progressing degradation. Long-chain alkanes were identified as degradation products of short-chain chlorinated paraffins. The ecotoxicity tests investigated showed that in the green algae test for chlorinated paraffins, no inhibition of cell growth was observed. By means of biological tests of chlorinated paraffins, a significant acute toxicity for Daphnia as well as a chronic toxicity for luminescent bacteria were determined. (C) 2001 Elsevier Science B.V. All rights reserved.