Resistance of alkylphenol ethoxylate containing six ethoxylene units to biodegradation under the conditions of OECD (Organization for Economic Co-operation and Development) screening test

Abstract

Biodegradation of a commercially available mixture of octylphenol ethoxylates (Triton X-100) under the condition of OECD 301E screening test was studied by using electrospray ionisation mass spectrometry. It was found that ethoxylate containing six ethoxylene units (OPEO 6) is more resistant to the biodegradation process than other ethoxylates (e.g. than OPEO 5 and OPEO 7). After 40 days of biodegradation process the signal of OPEO 6 was clearly seen, but signals of OPEO 5 and OPEO 7 were not detected. After 40 days, all OPEO n with n > 4 were converted into carboxylated derivatives. Carboxylated derivatives were observed in negative ion mode as OPEO n-CH 2COO − ions. Biodegradation of OPEO 5-CH 2COOH (carboxylated derivative correspondent of OPEO 6) occurred slower than biodegradation of the others, as resulted from obtained ESI mass spectra.