Ditolyl ether

Endpoint summary

Additional information

Toxicity to fish:

A study on the acute toxicity of the substance to Danio rerio was conducted in accordance with the UBA test protocol: Letale Wirkung beim Zebrabaerbling Brachydanio rerio, (LC 0, LC 50, LC100; 48 - 96h) Stand Mai 1984. The test was performed under static conditions and mortality and abnormal behaviour were assessed after 24, 48, 72 and 96h. Groups of ten fish were exposed to test concentration of 0.5 to 50 mg/L (nominal concentration) of the substance. The LC50 (96h) was calculated to be 2.62 mg/L.

Toxicity to invertebrates:

A study on the acute toxicity of the substance to Daphnia magna was conducted in accordance with the OECD 202. The test was performed under semi-static conditions and mortality was assessed after 24 and 48h. The EC50 (48h) was calculated to be 0.16 mg/L.

The long-term toxicity of the substance to Daphnia magna was assessed in a 21-day semi-static test according to the OECD Guideline 202 (Daphnia sp., Acute Immobilisation and Reproduction Test; adopted: April 1984). The nominal concentrations tested were 0.158, 0.05, 0.016 and 0.005 in the first test and 0.158, 0.5 and 0.8 in the second test. Immobility of the parental generation and the number of offspring was assessed. The lowest 21-day NOEC for reproduction was determined to be 0.05 mg/L. However, due to shortcomings this study was rated as invalid in a Compliance Check and, therefore, a new study on chronic exposure to daphnids with ditolyl ether was conducted. Interestingly, this study came up with a 21 days-NOEC (reproduction) of 0.057 mg/L which is nearly identical with the previous study result. In conclusion, the new study confirmed the originally available data on chronic toxicity to daphnids and the fills the potential data gap for testing of chronic toxicity to daphnids.

Toxicity to algae:

The toxicity of the substance to algae was assessed in a 72h-growth inhibition test according to the OECD 201 (2006). Desmodesmus subspicatus was used as test species and the criteria of adverse effects examined were item-induced inhibition of yield and growth rate of the algal population determined by measuring the cell density in a microcell counter. The 72h-EC10 for growth was determined to be 0.02 mg/L and the 72h-EC50 for growth was determined to be 0.035 mg/L. The NOEC was found to be 0.01 mg/L.

Toxicity to microorganisms (activated sludge):

The toxicity of the substance to microorganisms was assessed in a study according to ISO 8192. The respiration rate of each mixture was determined after aeration periods of 3 hours. The substance showed no significant respiration inhibition of activated sludge at the highest concentration tested, and hence the IC50 is > 100 mg/L (based on nominal concentrations).