Dipotassium 3,4,5,6-tetrabromophthalate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Assessment based on review of acid form under biological pH
The potassium salt is highly water soluble under neutral-alkaline conditions and does not dissolve in octanol
However, it is expected that at lower pH, with formation of the aicd form, water solublity will be greatly reduced.
The partition coefficient of the acid is considered more relevant for purposes of risk assessment as this reflects the potential effects following ingestion or exposure to environmental confditions when diluted.

Qualifier:

no guideline followed

Principles of method if other than guideline:

It has been established that the potassium salt as supplied at pH 9 - 10 is highly water soluble and does not dissolve appreciably in octanol.
However, if diluted at reduced pH, the acid can form and an assessment of the potemntial for accumulation of the acid is consdiered more pertienet for risk assessment.

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

The substance is the hysrolysed form of tetrbromophalate anhydride

Analytical method:

other: No applicable

Type:

log Pow

Partition coefficient:

ca. 4.6

Temp.:

25 °C

pH:

< 6

Details on results:

A pH of < 6 is used to ensure it exists in acid form. The temperature is used in the EPISuite model
Log Octanol-Water Partition Coef (SRC): Log Kow (KOWWIN v1.68 estimate) = 4.63
Water Solubility Estimate from Log Kow (WSKOW v1.42): Water Solubility at 25 deg C (mg/L): 0.104

Conclusions:

Under dilute acidic condition, the acid form is likely to exist and this is shown to have a partition coefficient of concern. However, it is also possible that in the presence of metal ions, including clays or organic particles, there could be significant adosption and interaction to form other salts.

Description of key information

The highly water soluble potassium salt quickly dissociates in water and under dilute conditions, will form less water soluble salts and behave in the same way as the acid form

The acid form has been used for CSR assessment

Key value for chemical safety assessment

Log Kow (Log Pow):

2.27

at the temperature of:

20 °C