Registration Dossier
Registration Dossier
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EC number: 200-839-4 | CAS number: 75-10-5
Short-term toxicity to aquatic invertebrates
Administrative data
Link to relevant study record(s)
Description of key information
The 48-h LC50 for daphnids estimated using ECOSAR v1.11 for neutral organics is 833 mg/l.
Given the physical nature of difluoromethane and due to the difficulty to test it meaningfully, no experimental aquatic results are available. Instead, QSAR methods were used to estimate the toxicity of the substance to aquatic organisms. The effect concentrations of difluoromethane were estimated using the method described in the EU Technical Guidance Document (2003) and/or the US EPA program ECOSAR (v1.11, 2012). The measured log Kow value of 0.21 was used for the predictions using both QSARs.
Only calculated effect concentrations are available, all calculations are reliable and the substance properties fall within the applicability domain of the QSARs as described in the QPRF report attached. The calculated acute effect parameter using ECOSAR v1.11 resulted in an LC50 (48h) = 833 mg/l and this result is used in the assessment.
In a supporting read-across study with the analogue substance HFC-245fa, no daphnid immobilization or other effects were observed at a nominal concentration of 100 mg/l (mean measured concentration 97.9 mg/l). The study design was developed to minimize volatilization and obtain the maximum attainable concentration. Therefore, although the EC50 could not be identified, it must be > 100 mg/l. This study supports the fact that substances in this category are not likely to be toxic to aquatic invertebrates, even when volatilization is minimized.
Key value for chemical safety assessment
Fresh water invertebrates
Fresh water invertebrates
- Effect concentration:
- 833 mg/L
Additional information
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