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1B+C Abiotic Transformations + Biodegradation (MOP/29) A new biodegradable antimicrobial: 4,4'-dichloro-2-phenoxy-phenol (DCPP). Part I: Environmental Risk Assessment and final fate. Richner, P.1, Wolf, Th..2, Peter, R.1, 1 Ciba Specialty Chemicals Inc., Basel, Switzerland2 Solvias AG, Basel, Switzerland ABSTRACT- Ciba developed a new antimicrobial for household applications with a high biological efficacy, namely 4,4'-dichloro-2-phenoxy-phenol (DCPP). Consumer products are usually released into the communal sewage. Residual amounts may be traced in natural waters. To confirm no adverse effect to the environmental compartments we conducted studies to characterise the degradation and final fate of this substance as well as a risk assessment. DCPP can be considered as biodegradable and non bioaccumulative. The bio concentration factor (BCF) according to OECD 305 was determined to be 77 at 2 Key words: degradation, antimicrobial, risk assessment, eco-toxicology |
g/L. Degradation tests conducted according to OECD 301F/302B/303A showed an almost complete degradation of more than 99%, measured with substance specific analytical methods and considering the balance of water and sludge. DCP has a high and fast sludge adsorption followed by desorption and biodegradation. The expected primary metabolites (4-chlorophenol, 3-chlorophenol and 3-chlorocatechol) are below detection limit. And Environmental Risk Assessment (ERA) with EUSES 1.0 confirms no adverse effect to the environmental compartments water, sludge, sediment and soil. Microorganisms can methylate a small portion of DCPP to 4,4'-dichloro-2-phenoxy-methoxybenzene (Methyl-DCPP) and vice versa. This methylated metabolite is being tested for aquatic toxicity and bioaccumulation. The results are expected to be similar to DCPP and will be reported in the poster. 4,4'-dichloro-2-phenoxy-phenol is a new antimicrobial with an attractive technical, toxicological and environmental profile.