Reaction mass of citronellyl propionate and geranyl propionate and neryl propionate

Toxicity to aquatic algae and cyanobacteria

Description of key information

In a 48-h toxicity study according to OECD 201 and in compliance with GLP, exponentially growing green algae (Raphidocelis subcapitata) were exposed to individually prepared WSF at loading rates of 0.1, 0.32, 1.0, 3.2 and 10 mg/L. In the range finder it was seen that the 0.1 mg/l dose level decreased to LOD values at 48 hours. The 10 mg/l WAF (measured 6.2 mg/l) dose level decreased to 2% (0.132 mg/l) after 72 hours. Such measured values would (partly) lead to effect values based on (half of ) LOD which is not considered related to the toxicity of the substance. Therefore a 48h exposure was used as this is given as a possibility in OECD TG 201. The exponential growth rated was maintained and the replication factor was 72 (>16). Exposure concentrations were verified by a validated method: at the start of the test, measured concentrations were 0.071, 0.16, 0.63, 2.1 and 4.6 mg/L and these concentrations decreased to concentrations below the LOD and 8.3% of initial. Effect parameters were therefore based on arithmetic mean concentrations, calculated to be respectively 0.041, 0.096, 0.35, 1.2 and 2.8 mg/L. The 48h-ErC50 was 2.0 mg/L (95% CI 1.7 - 2.2 mg/L); the ErC10 was 0.38 mg/L (95% CI 0.24 - 0.52 mg/L) and the NOECr was 0.096 mg/L. The study is considered to be reliable without restrictions.

Key value for chemical safety assessment

EC50 for freshwater algae:

2 mg/L

EC10 or NOEC for freshwater algae:

0.38 mg/L

Additional information

To limit the dissipation of the test material especially in the 48-72h period, the test period was shortened to 48 hours (as described in OECD TG 201). Unlimited, exponential growth during the test was maintained and the minimum multiplication factor of 16 was still reached.