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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Link to relevant study record(s)

Description of key information

The toxicity of alpha-Terpinyl Acetate to aquatic algae was determined in a GLP-compliant OECD 201 guideline study (Harlan, 2011). Algae (Desmodesmus subspicatus; circa 1000 cells/mL) were exposed to nominal concentrations of 3.6 to 42 mg/L and a control for 72 hours in completely filled and stoppered test vessels. Due to the low solubility of the test substance, test concentrations were prepared by saturated solution method. Based on test concentration analysis at t=0 and t=72 hours, geometric mean concentrations were calculated at 2.7, 4.0, 8.7, 19 and 41 mg/L. There were no statistically significant differences between the growth rates and yield of the control and the 3.6 mg/L test concentration. At all other test concentrations significant differences were observed. For growth rate, at the test concentrations of 2.7, 4.0, 8.7, 19 and 41 mg/L percentages of inhibition were 2, 10, 73, 95 and 110, respectively. Based on these findings, the 72 -h ErC50 and 72 -h ErC10 were determined at 6.9 and 4.1 mg/L, respectively. The NOEC was determined at 2.7 mg/L (based on mean analytical concentrations).

Key value for chemical safety assessment

EC50 for freshwater algae:
6.9 mg/L
EC10 or NOEC for freshwater algae:
4.1 mg/L

Additional information

Two algae studies are available for alpha-Terpineol Acetate.The key study is presented in the section 'short description of key information' and 'information used for the PNEC derivation' and shows the lower ErC50 value. The NOEC in both tests is similar: around 3 mg/l. This supporting study is a GLP-compliant OECD 201 guideline study (Wildlife International Ltd, 2013). Algae (Pseudokirchneriella subcapitata; circa 5000 cells/mL) were exposed for 72 hours to nominal concentrations of 1.1 to 18 mg/L. The test concentrations were analytically verified and determined at 0.91 to 11 mg/L (day 0 measurement). After 72 hours of exposure, inhibition of growth rate was 1, 2, 0, 6 and 10%, respectively, relative to the control. After 72 hours of exposure, there were no signs or noticeable aggregation, flocculation or adherence to the test chambers in the negative control or in any treatment groups. P. subcapitata cells at all test levels appeared normal when compared to cells present in the negative control. The 72-h ErC50 value based on measured concentrations is >11 mg/L, the 72-h NOErC value based is 3.2 mg/L.