Registration Dossier

Diss Factsheets

Physical & Chemical properties

Water solubility

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2017-07-17 to 2017-10-02
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Combination of guideline studies
Qualifier:
according to guideline
Guideline:
OECD Guideline 105 (Water Solubility)
Version / remarks:
dated July 27, 1995
Deviations:
yes
Remarks:
due to the properties of the test item (e.g. rapid hydrolysis in contact with water), this standard test guideline was not generally applicable and substantial modifications were necessary.
Qualifier:
according to guideline
Guideline:
EU Method A.6 (Water Solubility)
Version / remarks:
Council Regulation (EC) No 440/2008
Deviations:
yes
Remarks:
due to the properties of the test item (e.g. rapid hydrolysis in contact with water), this standard test guideline was not generally applicable and substantial modifications were necessary.
Qualifier:
according to guideline
Guideline:
OECD Series on Testing and Assessment No. 29 (23-Jul-2001): Guidance document on transformation/dissolution of metals and metal compounds in aqueous media
Deviations:
yes
Remarks:
due to the properties of the test item (e.g. rapid hydrolysis in contact with water), this standard test guideline was not generally applicable and substantial modifications were necessary.
Qualifier:
according to guideline
Guideline:
other: OECD Guideline for the testing of chemicals, 111 "Hydrolysis as a Function of pH"
Version / remarks:
dated April 13, 2004
Deviations:
yes
Remarks:
due to the properties of the test item (e.g. rapid hydrolysis in contact with water), this standard test guideline was not generally applicable and substantial modifications were necessary.
GLP compliance:
yes (incl. QA statement)
Type of method:
flask method
Water solubility:
>= 20 - <= 42.1 µg/L
Conc. based on:
element (dissolved fraction)
Remarks:
tungsten
Incubation duration:
30 min
Temp.:
25 °C
pH:
>= 2 - <= 3
Remarks on result:
other: Loading of aqueous phase: refer to "any other information on results incl. tables"; Temperature range: 20-25 °C.
Water solubility:
>= 38.6 - <= 39.1 µg/L
Conc. based on:
element (dissolved fraction)
Remarks:
tungsten
Incubation duration:
30 min
Temp.:
25 °C
pH:
4
Remarks on result:
other: Loading of aqueous phase: refer to "any other information on results incl. tables"; Temperature range: 20-25 °C.
Water solubility:
>= 44.7 - <= 44.9 µg/L
Conc. based on:
element (dissolved fraction)
Remarks:
tungsten
Incubation duration:
30 min
Temp.:
25 °C
pH:
7
Remarks on result:
other: Loading of aqueous phase: refer to "any other information on results incl. tables"; Temperature range: 20-25 °C.
Water solubility:
>= 44.6 - <= 46.1 µg/L
Conc. based on:
element (dissolved fraction)
Remarks:
tungsten
Incubation duration:
30 min
Temp.:
25 °C
pH:
9
Remarks on result:
other: Loading of aqueous phase: refer to "any other information on results incl. tables"; Temperature range: 20-25 °C.

Test Item in Water

The following table represents the results obtained from each analysis of the fivefold preparation of the test item in water:

preparation

sample mass [mg]

nominal concentration of tungsten in sample solution [µg/L]

actual

concentration of tungsten in sample solution [µg/L]

recovery of tungsten in sample solution [%]

1

654

607

40.6

6.7

2

558

517

20.0

3.9

3

660

611

42.1

6.9

4

608

564

30.4

5.4

5

603

559

24.1

4.3

 

mean

5.4

SD

1.4

RSD [%]

25.0

Test Item in Water after pH Adjustment

The following table represents the results obtained from each analysis of the threefold preparation of the test item in water adjusted to pH 4, pH 7, and pH 9:

preparation

pH value

sample mass [mg]

nominal concentration of tungsten in sample solution [µg/L]

actual

concentration of tungsten in sample solution [µg/L]

recovery of tungsten in sample solution [%]

1

4

654

607

38.6

6.4

2

4

654

607

39.1

6.4

3

4

654

607

39.1

6.4

 

 

 

 

mean

6.4

 

 

 

 

SD

0.05

 

 

 

 

RSD [%]

0.8

 

1

7

654

607

44.9

7.4

2

7

654

607

44.7

7.4

3

7

654

607

44.8

7.4

 

 

 

 

mean

7.4

 

 

 

 

SD

0.02

 

 

 

 

RSD [%]

0.3

 

1

9

654

607

46.1

7.6

2

9

654

607

44.6

7.3

3

9

654

607

45.4

7.5

 

 

 

 

mean

7.5

 

 

 

 

SD

0.12

 

 

 

 

RSD [%]

1.6

Conclusions:
The determined concentrations of tungsten in the sample solution after preparation of the test item in water varied between 20.0–42.1 µg/L, corresponding to a mean recovery of 5.4 % ± 1.4 %.
The determined concentrations of tungsten in the sample solution after preparation of the test item in water and pH adjustment to pH 4, pH 7 resp. pH 9 were between 38.6–39.1 µg/L, 44.7–44.9 µg/L resp. 44.6–46.1 µg/L, corresponding to mean recoveries of 6.4 % ± 0.05 %, 7.4 % ± 0.02 % resp. 7.5 % ± 0.12 %.
Executive summary:

The determined concentrations of tungsten in the sample solution after preparation of the test item in water varied between 20.0–42.1 µg/L, corresponding to a mean recovery of 5.4 % ± 1.4 %.

The determined concentrations of tungsten in the sample solution after preparation of the test item in water and pH adjustment to pH 4, pH 7 resp. pH 9 were between 38.6–39.1 µg/L, 44.7–44.9 µg/L resp. 44.6–46.1 µg/L, corresponding to mean recoveries of 6.4 % ± 0.05 %, 7.4 % ± 0.02 % resp. 7.5 % ± 0.12 %.

It can be summarised, that referring to the results of the pre-tests, tungsten hexachloride showed a rapid hydrolysis in contact with aqueous solutions. A temperature rise during the addition of aqueous solutions was observed due to the exothermic reaction. The dispersion of the WCl6 test item with water was acidic (pH-value 2–3) and within the study, after approx. 30 minutes agitation whilst cooling, an insoluble residue occured in water.

Description of key information

The determined concentrations of tungsten in the sample solution after preparation of the test item in water varied between 20.0 - 42.1 µg/L, corresponding to a mean recovery of 5.4 % ± 1.4 %.

The determined concentrations of tungsten in the sample solution after preparation of the test item in water and pH adjustment to pH 4, pH 7 resp. pH 9 were between 38.6 - 39.1 µg/L, 44.7 - 44.9 µg/L resp. 44.6 - 46.1 µg/L, corresponding to mean recoveries of 6.4 % ± 0.05 %, 7.4 % ± 0.02 % resp. 7.5 % ± 0.12 %.

It can be summarised, that referring to the results of the pre-tests, tungsten hexachloride showed a rapid hydrolysis in contact with aqueous solutions. A temperature rise during the addition of aqueous solutions was observed due to the exothermic reaction. The dispersion of the WCl6 test item with water was acidic (pH-value 2 - 3) and within the study, after approx. 30 minutes agitation whilst cooling, an insoluble residue occured in water.

Key value for chemical safety assessment

Water solubility:
46.1 µg/L
at the temperature of:
25 °C

Additional information