Reaction mass of 1-methyl-4-(4-methylpentyl)cyclohex-3-ene-1-carbaldehyde and 1-methyl-3-(4-methylpentyl)-3-cyclohexene-1-carboxaldehyde

Ecotoxicological Summary

Conclusion on classification

Environmental classification and labelling of a substance is generally based on data from short-term aquatic toxicity results, the ready biodegradability of the substance and an experimentally determined BCF (or if absent the measured octanol/water partition coefficient). Available adequate chronic toxicity data is also relevant for the assessment of long-term aquatic hazards (Regulation 286/2011/EC).

 

Short-term aquatic toxicity data is available for two trophic levels (daphnia and algae). A short-term daphnia study is available for the registered substance (Vernaldehyde; Reaction mass of 1-methyl-3-(4-methylpentyl)-3-cyclohexene-1-carboxaldehyde and 1-methyl-4-(4-methylpentyl)-3-cyclohexene-1-carboxaldehyde, EC50 = 0.17mg/L) and an algal inhibition study for a closely related structural analogue (Precyclemone B; Reaction mass of 1-methyl-3-(4-methyl-3-pentenyl)cyclohex-3-ene-1-carbaldehyde and 1-methyl-4-(4-methyl-3-pentenyl)cyclohex-3-ene-1-carbaldehyde, ErC50 = 1.8 mg/L).

 

The lowest short-term EC50 is for daphnia, which is a 48h EC50 of 0.17 mg/L. Since the EC50 is <= 1mg/L, the substance is classified Category Acute 1 (H400) for short-term hazards to the aquatic environment according to the CLP Regulation 1272/2008/EC. In accordance with Table 4.1.3 of the regulation & adaptation 286/2011/EC, in order to classify a mixture containing the substance an M-factor of 1 should be used when applying the summation method since the EC50 is > 0.1mg/L and <= 1mg/L.

 

Chronic aquatic toxicity data is only available for one trophic level (algae). Therefore, the long-term hazard has been assessed based on both:

a) The chronic aquatic toxicity data for algae (72 hr ErC10 = 0.19 mg/l, estimate from analogue substance), which for a non-rapidly degradable substance results in a Chronic 2 classification, and

b) The acute aquatic toxicity data for daphnia (48 hr EC50 = 0.17 mg/L) and environmental fate data (not readily biodegradable and log Kow of 5.3), which results in a Chronic 1 classification,

and classifying according to the most stringent outcome.

 

Thus it is concluded that the substance is classified Aquatic Chronic 1 (H410) according to the CLP Regulation 1272/2008/EC & adaptation 286/2011/EC. In accordance with Table 4.1.3 of the regulations, in order to classify a mixture containing the substance an M-factor of 1 should be used, since the daphnia EC50 is > 0.1g/L. The algae ErC10 of > 0.1 mg/L is not relevant in this case.

 

Under the old DSD regulation the substance would be classified as R50/53 (highly toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment) based on the EC50 value of < 1mg/L, log Kow of > 3 and not readily biodegradable status.