Farnesol

Endpoint summary

Description of key information

Short-term toxicity to fish: The 96-hour LC50 value for Pimephales promelas exposed to nerolidol was determined to be 1.43 mg/L. Nerolidol is a suitable as a read-across substance to farnesol based on similarity of chemical structure.

Short-term toxicity to aquatic invertebrates: The 48-hour EC50 for immobilisation of Daphnia magna was determined to be 0.568 mg/L.

Toxicity to aquatic algae and cyanobacteria: The EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were 1.49 and 0.334 mg/L, respectively. The EC10-values for inhibition of growth rate (ErC10) and yield (EyC10) after 72 hours were 1.17 and 0.0785 mg/L, respectively. The NOEC-values of growth rate and yield after 72 hours were 0.0832 and 0.0472 mg/L, respectively.

Toxicity to microorganisms: The 30-min EC20 was determined to be 75 mg/L and 180-min EC50 was > 1000 mg/L.

Additional information

Ecotoxicological endpoints are completed for this substance based on test data following standard guidelines. Some endpoints are completed using read-across from nerolidol. Read-across is appropriate as the test substance and nerolidol are very similar in chemical structure, differing only by the interchange of a hydroxyl group and double bond on carbon positions 1 and 2, and very similar in physico-chemical properties. Acute toxicities to Daphnia were in the same order of magnitude for both substances, and this was observed to be the most sensitive aquatic species in acute tests. Given the similarities in chemical and biological effects, nerolidol is considered to be a suitable read-across substance. All data are considered to be reliable and relevant for the endpoint concerned.

 

Short-term toxicity to fish: This endpoint is completed using read-across data for nerolidol and supporting data for the test item. In the key study, Pimephales promelas were exposed to nerolidol for 96 hours. The LC50 was determined to be 1.43 mg/L and the EC50 for behavioural abnormalities was determined to be 1.34 mg/L. The guideline and GLP status of the study are unknown, however the study is well-reported and is reliable with restrictions (Klimisch 2). Supporting data is also available for the test item itself, in which the 96-hour LC50 for Oncorhynchus mykiss was determined to be 1.8 mg/L. The original study is referenced from the US EPA (1992) and could not be retrieved, therefore the reliability of the study could not be assigned (Klimisch 4).

 

Short-term toxicity to aquatic invertebrates: The short-term toxicity to Daphnia magna was determined in a 48 hour test according to OECD guideline 202 and conducted in compliance with GLP (2015). Organisms were exposed to measured concentrations (geometric mean) of 0.247, 0.532, 1.11, 2.36 and 5.52 mg/L. The EC10, EC50 and EC100 based on mobility were determined to be 0.532, 0.568 and 1.11 mg/L, respectively. This study is considered reliable and relevant (Klimisch 1) and is suitable for use as a key study.

 

Toxicity to aquatic algae and cyanobacteria: The algal toxicity of the test item was assessed in a 72 -hour static test with green alga Pseudokirchneriella subcapitata (2017). Algae were exposed to 1.00, 3.16, 10.0, 31.6 and 100% of a saturated solution, corresponding to the geometric mean measured test item concentrations of 0.0299, 0.0472, 0.0832, 1.42 and 6.37 mg/L, alongside an untreated control and positive control. The EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were 1.49 and 0.334 mg/L, respectively. The EC10-values for inhibition of growth rate (ErC10) and yield (EyC10) after 72 hours were 1.17 and 0.0785 mg/L, respectively. The NOEC-values of growth rate and yield after 72 hours were 0.0832 and 0.0472 mg/L, respectively. This study is considered to be reliable without restriction (Klimisch 1) as it was GLP-compliant and was conducted according to OECD 201 and EU C.3.

 

Toxicity to microorganisms: In a respiration inhibition test with activated sludge, the 30-min EC20 was determined to be 75 mg/L and the EC50 was not reached after 180 minutes at the highest nominal test concentration of 1000 mg/L (1998). This study was conducted according to GLP and followed OECD guideline 209, however there are minor limitations in experimental design and reporting (no blank control, four concentrations tested only, replication not reported, no statistical analysis of data). This study is considered to be reliable with restriction (Klimisch 2).