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Physical & Chemical properties

Surface tension

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Endpoint:
surface tension
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
The test substance is aluminium sulphate basic, of formula Al2 (OH)0.16 (SO4)2.92, and not pure alum inium sulphate Al2 (SO4)3; however, according to the notifier, limited basicity may occur in the technical substance. Therefore, the chemical similarity (only 0.8% OH) is considered sufficient for supporting data on the hydrated form, the reference substance for the REACh registration dossier being the anhydrous form.
Reason / purpose:
read-across source
Surface tension:
73 mN/m
Temp.:
20 °C
Conc.:
1 g/L
Conclusions:
Not expected to be surface-active.
Executive summary:

From analogue, the surface tension of a 1 g/L solution of the 15 - 16 H2O hydrated form is anticipated to be above the cut-off value of 60 mN/m.

Endpoint:
surface tension
Type of information:
experimental study
Adequacy of study:
key study
Study period:
09 March 2010- 04 June 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
This study has been performed according to OECD and EC guidelines and according to GLP principles. Test substance is adequately characterised. Therefore full validation applies.
Qualifier:
according to
Guideline:
OECD Guideline 115 (Surface Tension of Aqueous Solutions)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.5 (Surface Tension)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
ring method
Surface tension:
73 mN/m
Temp.:
20 °C
Conc.:
1 g/L

mean of five consistent measurements: 70.2 mN/m (before correction)

calibration factor: 1.04

Conclusions:
Not surface active.
Executive summary:

The surface tension of aluminium sulphate basic hydrated was investigated according to OECD/EC guidelines, ring method. The mean of five consecutive consistent measurements, at the maximum testing concentration of 1 g/L in double-distilled water and 20°C, was corrected for calibration factor and according to Harkins-Jordan table. The final retained result is 73.0 mN/m.

Description of key information

Aluminium sulphate (anhydrous) is NOT anticipated to be surface-active (from experiment on analogue).

Key value for chemical safety assessment

Additional information

No data is available on the reference substance (anhydrous form), but a reliable experimental study was conducted on analogue, showing a result much above the threshold of 60 mN/m.

Despite the reference anhydrous substance should be tested at a concentration ca twice as done for the hydrated analogue, the margin of safety is considered sufficient for a qualitative assessment. Furthermore, inorganic substances are generally known to have no impact or slightly increase the surface tension of water.