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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

TCP exhibits acute effects on aquatic micro-organisms.

Key value for chemical safety assessment

EC50 for microorganisms:
290 mg/L

Additional information

Blum & Speece (1991) report results from four different assays employing micro-organism communities and specific strains. However methanogens were most susceptible with regard to the endpoint inhibition of gas production (48-h IC50 0.63 mg/L), the aerobic heterotrophic community with the endpoint inhibition of oxygen uptake represent the relevant community for assessment. The study protocol is comparable to OECD TGD 209 and the study is considered valid and conclusive and yielded a 24-h IC50 of 290 mg/L.

The assay employing nitrifying bacteria (Nitrosomonas sp.) with the endpoint inhibition of ammonia consumption revealed an 24-h IC50 of 30 mg/L. This is in agreement with ECHA (2008, information requirements and chemical safety assessment, chapter R.10., p 30) who recommends an assessment factor (AF) of 10 to be applied to result of a sludge respiration test, reflecting the lower sensitivity of this endpoint as compared to nitrification.

Finally a Microtox® model 2055 assay (ISO 11348) employing a specific bacterial population (Vibrio fischeri) with the endpoint inhibition of bioluminescence showed an 5-min IC50 value of 19 mg/L.