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Short-term toxicity to aquatic invertebrates

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Description of key information

The 48-h LC50 is > 100 mg/L in Daphnia magna for the structural analogues HFC 245fa and HFC 365mfc

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
100 mg/L

Additional information

The assessment of the possible aquatic toxicity of HFC 227ea has been carried out by considering available data on structurally analogue substances.

Experimental data for acute toxicity on Daphnia magna are available for HFC 245fa (1,1,1,3,3-pentafluoropropane) and HFC 365mfc (1,1,1,2,2 -pentafluorobutane).

In both cases, studies were conducted in closed system to avoid substance volatilisation.

Both HFC 365mfc and HFC 245fa showed a low toxicity to D. magna and no 48 -h EC50 could be identified as low immobility was observed up to the highest tested concentrations for the other substances. Overall, a 48 -hour LC50= 100 mg/l (i.e. the lowest experimental value determined for sturctural analogs) can be considered as a conservative estimation of the HFC 227ea acute toxicity to aquatic invertebrates.

HFC 245fa:Pentafluoropropane was tested for acute toxicity in D. magna following OECD Guidelines. Water fleas were exposed for 48 consecutive hours to a nominal limit concentration of 100 mg/l. A concurrent negative control group was included in the test. The test substance concentration was monitored at the test initiation and termination. The average measure concentration was 97.9 mg/l HFC 245fa. No immobility was observed in the control and treatment groups. A 48 -h EC50 > 100 mg/l was determined.

HFC365mfc:The acute toxicity of pentafluorobutane to Daphnia magna was tested following OECD Guidelines. Water fleas (3 replicates of 10 organisms/concentration) were exposed to 0, 100, 150, 200 mg/l pentafluorobutane for 48 hours in a closed system to avoid the test substance evaporation. The substance concentration in the samples was monitored at the test initiation and termination. A difference of less than 20% was observed among the nominal and measured concentrations.

No immobility was observed in controls. Some immobile water fleas were observed at 150 and 200 mg/l (6.7 and 13% of immobility, respectively), but the NOEC calculated by means of the Fisher's exact test was 200 mg/l. A NOEC of 100 mg/l was set for sublethal effects (water fleas were lying at the bottom of the flasks after 48 h exposure to 150 and 200 mg/l). An EC50> 200 mg/l was determined. All validity criteria were fulfilled.