Registration Dossier

Administrative data

Endpoint:
surface tension
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because based on structure, surface activity is not expected or cannot be predicted
the study does not need to be conducted because surface activity is not a desired property of the material
Justification for type of information:
JUSTIFICATION FOR DATA WAIVINGIn accordance with column 2 of REACh Annex VII, the study needs only to be conducted if based on structure, surface activity is expected or can be predicted. The present substance is not intended to be used as a surfactant (i.e. not a desired property), and it does not contain groups (such as distinct polar and non-polar parts) indicating that it will have surface active properties in solution.However, despite the substance is not considered as a true surfactant, based on the observed behaviour in the water solubility and partition coefficient experimental studies, it may have surface-active properties in these test conditions.
Cross-referenceopen allclose all
Reason / purpose:
reference to other study
Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
other information
Study period:
03-25 April 2006
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
unsuitable test system
Remarks:
The study was conducted according to an internationally recognised method, and under GLP. However, surface-active behaviour is suspected. Therefore validation cannot be granted.
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient - Shake Flask Method)
GLP compliance:
yes (incl. certificate)
Remarks:
signed 24 February 2006
Type of method:
flask method
Partition coefficient type:
octanol-water
Analytical method:
gas chromatography
Type:
log Pow
Partition coefficient:
1.37
Temp.:
20 °C

In a first experiment, 40 mL of pre-saturated water were mixed with 4 mL of the 10 g/L stock solution. The tubes were centrifuged for 10 min at 5000 rpm and 20°C.

Concentrations as high as 120 mg/L were measured in the water phase, which exceed the measured hydrosolubility, and the results were not retained. The hypothesis was that the system was saturated with test item, and hat micro-drops still remain in the water phase.

In a second experiment, 40 mL of pre-saturated water were mixed with 4 mL of pre-saturated n-octanol and 0.4 mL of the 10 g/L solution. The tubes were centrifuged 10 min at 5000 rpm and 20°C.

Here also the water concentrations exceeded the water hydrosolubility, and the results were not retained.

The third experiment was performed using 40 mL of pre-saturated water, 4 mL of pre-saturated n-octanol and 40 µL of the 10 g/L stock solution.

In this case, the water concentrations complied with the value of hydrosolubility ans the test was reproduced using half and twice, respectively, the above volume ratio.

  n-octanol:water ratio 1:10 ratio 2:10 ratio 1:20
  replicate vessel 1 2 1 2 1 2
volumes (mL) n-octanol 4,0 4,0 8,0 8,0 2,0 2,0
  water 40,0 40,0 40,0 40,0 40,0 40,0
  stock solution 0,04 0,04 0,08 0,08 0,02 0,02
nominal amount (mg)   0,40 0,40 0,80 0,80 0,20 0,20
conc. in octanol (mg/L)   68,1 67,6 80,8 81,1 53,9 54,9
conc. in water (mg/L)   2,6 2,6 4,2 4,2 2,2 2,2
log Kow   1,42 1,41 1,28 1,29 1,39 1,40
measured amounts (mg)              
  in n-octanol 0,275 0,273 0,653 0,655 0,109 0,111
  in water 0,103 0,105 0,169 0,167 0,088 0,087
  total 0,378 0,378 0,822 0,822 0,197 0,198
recovery (%)   93,8 93,8 101,9 101,9 97,4 98,2
Executive summary:

The partition coefficient of the test substance was determined under GLP according to EU A.8 guideline, flask method. In the first two series, concentrations in the water phase were found above the solubility, suggesting surface-active potential. The third run, conducted at lower concentrations, fulfilled the validity criteria, and the average value was retained.

The log Kow has been determined to be 1.37 at 20°C.

Reason / purpose:
reference to other study
Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
other information
Study period:
03-25 April 2006
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
unsuitable test system
Remarks:
The study was conducted according to an internationally recognised guideline, and under GLP. However, the method used is not suitable, and surface-active behaviour is suspected. Therefore validation cannot be granted.
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
GLP compliance:
yes (incl. certificate)
Remarks:
signed 24 February 2006
Type of method:
column elution method
Water solubility:
19 mg/L
Incubation duration:
>= 16 - <= 19 h
Temp.:
20 °C
pH:
6.6

Preliminary assessments were aimed at the estimation of the hydrosolubility with no success: it was this suspected that the test item was able to form micro-drops of oily matter in suspension in water, and analysis of the hydrosolubility was not feasible. The micro-elution method was thus justified, even though final hydrosolubility was higher than 10 mg/L recommended for this testing method as a maximum.

Experiment n°1 - 25 mL/h flow rate

A 4.0103g sand portion was coated with 256.9 mg of test item. A sample of 1.0219g was introduced in the micro-column thus corresponding to 65 mg of test item.

About 31 mg of the test item were controlled to be voided in the rinsed volume (15 mL).

A total of five successive samples were submitted to the analysis which corresponded to the elution throughout a 16-h period.

Mean concentration in water = 17.9 (+/- 1.7) mg/L.

pH of the resulting solution = 6.62

Experiment n°2 - 13 mL/h flow rate

The micro-column was charged with a new 1 g sample of coated sand. About 30 mg test item were controlled to be voided in the rinsed volume (15 mL).

A total of five successive samples were submitted to the analysis which corresponded to the elution throughout a 19-h period.

Mean concentration in water = 20.8 (+/- 1.9) mg/L.

pH of the resulting solution = 6.59

Executive summary:

The water solubility of the test substance was determined under GLP according to EU A.6 guideline, elution method. In the preliminary testing, no saturation concentration could be determined, suggesting surface-active potential. The main test fulfilled the validity criteria, and the average value was retained. However, reliability is highly questionable.

The solubility has been determined to be 19 mg/L at 20°C.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion