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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

No effects are expected on activated sludge due to lack of emission to sewers. The 30 minute and 3 hour EC50s of HFP kinetic dimer to activated sludge were >1000 mg/L in an OECD TG209 assay. No NOEC was assigned due to volatility of the substance.

Key value for chemical safety assessment

Additional information

HFP kinetic dimer has a high vapor pressure and Henry's Law constant, and a low water solubility limit. We have proposed waiving of activated sludge toxicity tests based on lack of release to sewers during registered uses. Any material accidentally released to sewers would be lost from sewage during transit to a wastewater plant, so that organisms would not be exposed even during a spill scenario. The 30 minute and 3 hour EC50s of HFP kinetic dimer to activated sludge were >1000 mg/L in an OECD TG209 assay, with no inhibition at either time point. Test substance concentration was not analytically determined, but given loading rate and contact time it is unlikely that the entire sample was lost during the experiment. Nevertheless, no exposure of activated sludge organisms would be expected during actual sewage processing. No NOEC was assigned due to volatility of the substance.

Other tests of microorganisms are available, but are not considered reliable. HFP kinetic dimer was reported to be harmless (unschädlich) in a 24-h fermentation tube test, but no details of the study were available and the result cannot be classified as to its reliability. In a Microtox ® test, water accomodated fractions (WAFs) of HFP kinetic dimer which had been prepared up to a loading rate of 1000 mg/L had no effect on light output. However, the WAF was removed from contact with undissolved substance and was further processed before start of testing. Concentrations were not confirmed analytically, and the HFP kinetic dimer was not guaranteed to have remained in solution for the test. This test is considered not reliable.