Reaction mass of 3-[(3aS,7aR)-octahydro-1H-4,7-methanoinden-1-yl]propanal and 3-[(2s,3aR,7aS)-octahydro-1H-4,7-methanoinden-2-yl]propanal and 3-[(2r,3aR,7aS)-octahydro-1H-4,7-methanoinden-2-yl]propanal

Toxicity to aquatic algae and cyanobacteria

Description of key information

A study was performed to assess the effect of the test material on the growth of the green alga Pseudokirchneriella subcapitata.The method followed that described in the OECD TG No 201. Following a preliminary range-finding test, the algae were exposed to WAF solutions of the test material at loading rates of 0.32, 1.0, 3.2, 10 and 32 mg/L. (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 21 - 22 °C
Samples were taken from all treatments at t = 0 and 72h and analysed with a validated GC-FID method. The concentrations measured at the start of the test were between 0.16 and 14 mg/L and increased with the applied loading rate. At the end of the test the concentrations in the two lowest WAFs were below the limit of quantification of the analytical method. At the remaining loading rates the concentrations were between 7.3 and 43% of initial. The concentration measured in the WAF prepared at 3.2 mg/L incubated without algae was at the level of 65% of initial at the end of the test, which is considerably higher than in the remaining concentrations and indicates that algal biomass could be (partially) responsible for the decrease of concentrations.
Based on these results, the following average exposure concentrations were calculated: 0.058, 0.12, 0.48, 1.5, 4.5 and 8.1 mg/L
Growth rates were in the range of the controls at the two lowest concentrations during the 72-hour test period, whereas the growth rate of algae exposed to 0.48 mg/L and higher were increasingly reduced.
Statistically significant inhibition of growth rate was found at measured concentrations of 0.12 mg/L and higher, however, the effect observed at 0.12 mg/L was considered biologically insignificant (<10%) and therefore the NOEC was set to 0.12 mg/L.
The measured ErC10 and ErC50 were 0.17 and 0.63 mg/L, respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.63 mg/L

EC10 or NOEC for freshwater algae:

0.17 mg/L

Additional information

A study was performed to assess the effect of the test material on the growth of the green alga Pseudokirchneriella subcapitata.The method followed that described in the OECD TG No 201. Following a preliminary range-finding test, the algae were exposed to WAF solutions of the test material at loading rates of 0.32, 1.0, 3.2, 10 and 32 mg/L. (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 21 - 22 °C.

Water Accommodated Fractions (WAFs) were prepared with individual loading rates ranging from 0.32 to 100 mg/L applying a 2-day period of magnetic stirring followed by an one hour settlement period. Thereafter, the aqueous phases were siphoned off through glass wool and used as test concentrations. The final test solutions were all clear and colourless and contained a slight floating layer of undissolved test material. After preparation, volumes of 120 mL were added to each replicate of the respective test concentration. Subsequently, 2.4 mL of an algal suspension was added to each replicate providing a cell density of 10^4 cells/ml.

Samples were taken from all treatments at t = 0 and 72h and analysed with a validated GC-FID method. The concentrations measured at the start of the test were between 0.16 and 14 mg/L and increased with the applied loading rate. At the end of the test the concentrations in the two lowest WAFs were below the limit of quantification of the analytical method. At the remaining loading rates the concentrations were between 7.3 and 43% of initial. The concentration measured in the WAF prepared at 3.2 mg/L incubated without algae was at the level of 65% of initial at the end of the test, which is considerably higher than in the remaining concentrations and indicates that algal biomass could be (partially) responsible for the decrease of concentrations.

Based on these results, the following average exposure concentrations were calculated: 0.058, 0.12, 0.48, 1.5, 4.5 and 8.1 mg/L

Growth rates were in the range of the controls at the two lowest concentrations during the 72-hour test period, whereas the growth rate of algae exposed to 0.48 mg/L and higher were increasingly reduced.

Statistically significant inhibition of growth rate was found at measured concentrations of 0.12 mg/L and higher, however, the effect observed at 0.12 mg/L was considered biologically insignificant (<10%) and therefore the NOEC was set to 0.12 mg/L.

The measured ErC10 and ErC50 were 0.17 and 0.63 mg/L, respectively