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Physical & Chemical properties

Water solubility

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Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2013-01-07 to 2013-01-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The study was conducted according to an internationally recognised method, and under GLP. Validity criteria are fulfilled. Substance identification is specified with purity and isomers composition. Therefore full validation applies.
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
GLP compliance:
yes (incl. certificate)
Remarks:
UK GLP compliance programme (inspected on 18-20 June 2012 / signed on 19 September 2012)
Type of method:
flask method
Remarks:
modified with slow-stirring
Specific details on test material used for the study:
Storage condition of test material: Room temperature.
Key result
Water solubility:
4.7 mg/L
Incubation duration:
43 - 73 h
Temp.:
20 °C
pH:
6.4 - 6.5
Remarks on result:
other: in purified water
Water solubility:
4.6 mg/L
Temp.:
20 °C
pH:
7.5 - 7.8
Remarks on result:
other: in daphnia reconstituted medium

Purified water

Time (hours) at 20°C Concentration
(mg/L)
pH
Vessel A Vessel B Vessel A Vessel B
43.0 4.50 4.50 6.4 6.4
49.5 4.77 4.55 6.5 6.5
66.5 5.09 4.60 6.4 6.4
73.0 4.95 4.67 6.5 6.5

Mean solubility = 4.70 ± 0.22 mg/l (RSD = 4.6%)

 

Daphnia medium

Time (hours) at 20°C Concentration
(mg/L)
pH
Vessel A Vessel B Vessel A Vessel B
43.0 4.50 4.22 7.7 7.8
49.5 4.50 3.89 7.8 7.8
66.5 5.20 4.98 7.5 7.6
73.0 4.41 4.79 7.6 7.6

 Mean solubility = 4.56 ± 0.42 mg/l (RSD = 9.2%)

The detector calibration was found to be linear over the range 0 to 30 mg/l of standard solutions in hexane with a regression coefficient (r) of 1.0000.

Quantitative recoveries from fortified control samples in purified water and Daphnia medium were achieved (99 and 102% respectively), whilst no significant interfering peaks were evident in blank control solutions.

Conclusions:
Interpretation of results (migrated information): slightly soluble (0.1-100 mg/L)
Executive summary:

The water solubility of the test substance was measured according to the OECD 105 guideline, flask method modified with slow stirring, in both pure water and daphnia medium.

Four samples were taken from 43 to 73 hours stirring at 20°C, and analysed by GC. Quantification was derived from bracketing standards, and linearity was checked. The average value of all samples was retained, as equilibrium was considered to be reached.

The solubility of the test substance is similar in both pure water and reconsituted natural (daphnia) medium, respectively 4.7 and 4.6 mg/L at 20°C, and neutral pH.

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1994-04-20 to 1994-06-02
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
documentation insufficient for assessment
Remarks:
The study was conducted according to an internationally recognised method, and under GLP. Purity is specified, however batch number is not identified, so the isomers composition could not be retrieved from the notifier. Moreover, the study shows several weaknesses, and the test substance is likely to volatilize. Therefore validation cannot be granted.
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
yes
Remarks:
samples prepared at 20 times the saturation level instead of 5 times
GLP compliance:
yes (incl. certificate)
Remarks:
UK GLP compliance programme (inspected on 31 January 1994 / signed on 16 March 1994)
Type of method:
flask method
Specific details on test material used for the study:
Storage condition of test material: metal canister at 4°C in the dark.
Water solubility:
>= 2.74 mg/L
Temp.:
20 °C
pH:
6.9 - 7.4

The preliminary tetst determined the water solubility to be less than 40 mg/L.

The peak heights relating to the standard and sample solutions are detailed below:

 Solution  Mean total peak height
Standard 102 mg/L  1.284 x 105
Standard 109 mg/L  1.307 x 105
Sample 1  1.032 x 105
Sample 2  8.590 x 104
Sample 3  8.223 x 104

The concentration of test material in the sample solutions is shown in the table below:

 Sample number  Time shaken at ca 30°C (hours)  Time equilibrated at 20°C (hours)  Concentration (mg/L)  Solution pH
 1 25 1/2 25 1/4 3.36 7.2 
 2 49 24 1/2 2.80 6.9 
 3 72 1/4 24 2.68 7.4 

As the reproducibility is more than 15% between samples 1 and 2, the retained value will be the mean of samples 2 and 3.

Conclusions:
slightly soluble (0.1-100 mg/L)
Executive summary:

The water solubility of the test substance was measured under GLP, according to EU A6 guideline, flask method.

Measurements were performed by GC analysis. The mean of results at 48 and 72h was retained, and considered as a limit value, due to observed decrease in concentration; volatilisation is suspected.

The water solubility of the test substance is at least 2.74 mg/L at 20°C and pH 6.9 -7..4.

Description of key information

Slighlty soluble in pure water: 4.7 mg/L at 20°C (pH of saturated solution 6.5);

and in natural medium: 4.6 mg/L at 20°C.

Calculated as sum of isomers.

Key value for chemical safety assessment

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

Additional information

An old study (SPL 1994), despite conducted according to EC guideline and GLP, could not be assigned as reliable, mainly because of decrease in concentration observed during the experiment. It was not disregarded because testing fulfilled method requirements, but the result can only be considered as a lower limit value, therefore unsufficient for purpose. As no degradation was anticipated in the conditions considered, volatilisation was suspected.

A new, fully reliable experimental study (HLS 2013), was conducted according to a recognized ISO/EC method and under GLP, in closed conditions. It is considered as the key study, and the result is retained as key data for purpose of CSA.