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Additional information

Solubility of (-)-beta-pinene in water

The water solubility of (-)-beta-pinene was determined to be 6.95 mg/L by the slow-stirring method. This is the most appropriate method for the determination of the water solubility of this substance.

Poorly water-soluble substances are substances with a limit of water solubility below 100 mg/L according to OECD Guidance No 23 (2000) on aquatic toxicity testing of difficult substances and mixtures. Therefore, (-)-beta pinene meets the definition of poorly water soluble substances and has to be considered as a "difficult substance to test".

Volatility of (-)-beta-pinene from water

The Henry’s law constant (H) for a substance is a measure of its equilibrium between an ideal solution phase and the vapour phase. As such it is a measure of the potential for a substance to be lost from solution by evaporation (OECD GD No 23). As an approximation, if H is greater than 100 Pa.m3/mol, more than 50% of the substance could be lost from the water phase in 3-4 hours (Mackay, 1992 cited by OECD GD No 23).

The H constant is estimated by: H = VP*MOLW / SOL (ECHA Guidance on information requirement R.16). Considering the water solubility of 6.95 mg/L and vapour pressure of 519 Pa, this gives a Henry’s Law constant of 10173 Pa.m3/mol. This result provides evidence that the substance is difficult to test for aquatic toxicity. The highest concerns are media preparation and maintaining required exposure concentrations, due to low water solubility and volatilisation from the test solutions.

The following precautions were therefore taken to reduce the loss of test substance:

• study design: flow-through or semi-static for fish and Daphnia tests,

• closed system with minimising headspace,

• analytical determination of exposure concentrations.

Available ecotoxicological information

Measured acute data

Reliable short-term toxicity data are provided for the registered substance for three trophic levels (fish, invertebrates, algae).

The relevant values are:

Fish: 96h-LC50= 0.502 mg/L (Pimephales promelas, measured concentrations), 96h-LC50= 0.557 mg/L (Cyprinus carpiomeas.)

Daphnia magna: 48h-EC50= 1.250 mg/L (measured concentrations), 48h-EC50= 1.248 mg/L (measured concentrations)

Algae: 48h-EC50= 0.826 mg/L (Pseudokirchneriella subcapitata, measured concentrations)

Predicted acute data

Fish: 96h-LC50= 0.68 mg/L

Daphnia: 48h-EC50= 1.09 mg/L

Algae: 72h-EC50= 0.70 mg/L

The predictions are obtained with QSAR for the Mode of Action 1, based on validated data derived from standard toxicity test, for which the concentrations of the test item had been determined by chemical analyses over the test period. The predictions are sufficiently robust, and are appropriate for the purposes of chemical safety assessment required for REACH.

Based on this results, (-)-beta-pinene is classified:

- dangerous for the environment according to Directive 67/548/EEC "R50/53: very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment"

- and hazardous to the aquatic environment under Regulation (EC) No 1272/2008 (CLP) - Category Acute 1 and Category Chronic 1.