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Physical & Chemical properties

Water solubility

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Description of key information

The water solubility was determined by the slow-stirring method.
The water solubility of (-)-beta-pineneis 6.95 mg/L at 20 °C.

Key value for chemical safety assessment

Water solubility:
6.95 mg/L
at the temperature of:
20 °C

Additional information

A recent study was performed in order to determine the water solubility of (-)-beta-pinene (Madru, 2013). In this study, the water solubility of (-)-beta-pinene was determined to be 6.95 mg/L using the slow-stirring method (at 20°C and pH 4-7), which is the preferred method for this kind of substances. This value is retained to be used as Key value for the chemical safety assessment. This result is supported by literature data on beta-pinene, which could have been slightly overestimated due to the methods used: 8.06 mg/L (Copolovici, 2005: geometric mean of three literature values), 11.03 mg/L (Fichan, 1999 : two liquid phase contact methods giving an emulsion treated in 2 ways, settling and centrifugation); 12.7 mg/L (Tamura, 2005: close to the flask method not suitable for low solubility substances).  

It must be noted that the study performed in 2010 to determine the water solubility of (-)-beta-pinene using the elution method, led to a water solubility value ≤ 0,02 mg/L at 20ºC and pH 8. After re-examination, this study is considered as not reliable and is disregarded for the following reasons:

-The water solubility measured at 20°C (≤ 0.02mg/L) in this study, is not consistent with previously reported values for beta-pinene: 11.03 mg/L (Fichan, 1999); 12.7 mg/L (Tamura, 2005) and 8.06 mg/L (Copolovici, 2005) and with the result of the Madru’s recent study on (-)-beta-pinene (slow-stirring, 6.95 mg/L at 20°C).

-The mean values obtained from the three consecutive tests conducted with different flow rates differed by more than 30%. Therefore, according to the OECD 105 guideline criteria, the study is not valid. The water solubility decreased, when the water flow rate decreased. This can be explained by an insufficient quantity of the test item loaded on the support material, leading to erroneous results.

Therefore, the water solubility value of (-)-BETA PINENE found in the more recent study (6.95 mg/L) is considered as the most accurate and is selected to be used as key value for the chemical safety assessment of this substance.