BIODEGRADABILITY OF PHENOXYPROPANOLS

Phenoxypropanols have been used for some time as ingredients in surfac e and instrument disinfectants. Since the residual solutions of these preparations are discharged into the waste-water, the biodegradability of the ingredients used is of great importance. Tests by means of the Zahn-Wellens test in accordance with OECD guidelines have shown that phenoxypropanols are biodegradable. In further studies it was investig ated whether unwanted intermediate products are formed in considerable amounts. Of particular interest was the question of the possible deve lopment of phenol outside the bacterial cells. To test the biodegradab ility of the aromatic alcohols and to ascertain whether there is extra cellular formation of phenol, microorganisms were isolated from the mu nicipal sewage plant at Stellinger Moor, Hamburg, and from water from the River Elbe. Phenoxypropanol-containing solutions were then inocula ted with the bacteria and incubated at 30 degrees C. At regular interv als both the concentration of the alcohols was determined and the test for phenol was performed by means of liquid chromatography on reverse phase material (RP 18) and detection with a photodiode array detector . The breakdown of the phenoxypropanols was monitored for a period of up to 4 weeks. During this period a clear breakdown of the aromatic al cohols was observed. No phenol was detected.