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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The 72-hour EbC50, ErC50 and EyC50 values for growth rate and yield, were 2.1 mg/L, 3.0 mg/L and 2.1 mg/L, respectively. The 72-hour EC10 value for growth rate was determined to be 1.6 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
3 mg/L
EC10 or NOEC for freshwater algae:
1.6 mg/L

Additional information

In a conclusive, reliable and valid study, the effects of the test item Allyl Cyclohexyl Propionate on the growth of the freshwater green alga Pseudokirchneriella subcapitata were examined after 72 and 76 hours of exposure in a closed test system, according to OECD TG 201, EC No. L383 Method C.3 and OCSPP Number 850.4500.

Measured concentrations of Allyl Cyclohexyl Propionate declined over the 96 hour exposure period indicating that the test substance was not stable under the conditions of the test. The results of the study were based on day 0 measured concentrations of 0.28, 0.74, 1.9, 4.5, 9.2 and 15 mg/L, as per U.S. E.P.A. guidance for instable substances in algal growth inhibition studies (U.S. Environmental Protection Agency. 1994. Pesticide Re-registration Rejection Rate Analysis – Ecological Effects. Test Material Decline in Algae and Diatom Tests).

After 72 hours of exposure, inhibition of area under the growth curve in the 0.28, 0.74, 1.9, 4.5, 9.2 and 15 mg/L treatment groups was 36, 2, 44, 99, 100 and 100 %, respectively, relative to the negative control response. Inhibition of growth rate at the 0-72 hour interval in the 0.28, 0.74, 1.9, 4.5, 9.2 and 15 mg/L treatment groups was 10, 0, 13, 82, 98 and 100 %, respectively, relative to the negative control, and inhibition of yield after 72 hours of exposure was 36, 2, 44, 99, 100 and 100 %, respectively, relative to the negative control. Reductions in area under the growth curve, growth rate and yield were statistically significant (Jonckheere-Terpstra trend test; p < 0.05) in the 1.9, 4.5, 9.2 and 15 mg/L treatment groups when compared to the negative control response. The 72-hour NOEC was determined to be 0.74 mg/L, based on statistically significant reductions in area under the growth curve, growth rate and yield after 72 hours of exposure. The 72 -hour ErC10 value is 1.6 mg/L. The 72-hour EbC50, ErC50 and EyC50 values for growth rate and yield, were 2.1 mg/L, 3.0 mg/L and 2.1 mg/L, respectively.