Barium carbonate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-12 to 2010-01

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline conform study with limited reporting, GLP like procedure

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment Number 29, 2001

Deviations:

no

Remarks:

Two loadings at one pH was tested.

Qualifier:

according to guideline

Guideline:

other: The Standard Operating Procedure for the Transformation/Dissolution of Metals and Sparingly Soluble Metal Compounds. CANMET / LISEC. February 2004.

Deviations:

no

Principles of method if other than guideline:

Barium carbonate powder was introduced at two loadings of 10 and 100 mg/L in a pH 6 CO2-buffered aqueous medium. Transformation/dissolution was accomplished by standardised agitation (100 rpm), sampling and analysing of the solutions at specific time intervals. The short-term transformation/dissolution endpoint is based on the dissolved barium concentrations obtained after a 7 days transformation/dissolution period.

GLP compliance:

no

Remarks:

GLP like procedure

Type of method:

flask method

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

>= 4.62 - <= 5.16 mg/L

Element analysed:

Ba

Loading of aqueous phase:

10 mg/L

Incubation duration:

24 h

Test conditions:

Target pH 6 at 22°C; measured pH 6.41

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

>= 3.76 - <= 3.86 mg/L

Element analysed:

Ba

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Target pH 6, 22°C; measured pH 6.24-6.39

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

>= 33.2 - <= 42.3 mg/L

Element analysed:

Ba

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

Target pH 6, 22°C; measured pH 7.3

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

>= 53.9 - <= 54.9 mg/L

Element analysed:

Ba

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Target pH 6, 22°C; measured pH 7.01-7.17

For the 10mg/L loading, the within-vessel variations were ≤ 4 % (i.e. ≤10%) and the between-vessel variation was 2% (i.e.≤20%) at the 7- day endpoint.

For the 100mg/L loading, the within-vessel variations were ≤ 1% (i.e. ≤10%) and the between-vessel variation was 1% at the 7-day endpoint.

 

The test item, barium carbonate, contains 70% w/w barium. After 24 hours about 70% for the 10 mg/L loading and 52% for the 100 mg/L loading of barium carbonate went into solution. Afterwards, the sampled volume was replenished with fresh medium in acordance with the OECD guideline. As there went a large amount of barium carbonate into solution, each sampling and replenishment had a diluting effect on the final barium concentrations. This was especially the case for the 10 mg/L loading, where already 70% of the test item was into solution within first 24 hours.

 

Dissolved barium concentration in blanks were below the detection limit.

Conclusions:

In the full T/D test, the solubility resulted in 3.82 mg/L (SD 0.06) and in 54.1 mg/L (SD 0.8) dissolved barium at the 10 and 100 mg/L loading, respectively, after 7 days in modified ISO 6341 media at pH 6.

Description of key information

Water solubility of barium carbonate: ≥14 mg/L at 20°C. According to Gmelin (2009) the water solubility of the test substance is not dependant on temperature (<3%/°C).
In the Transformation/Dissolution test, the solubility resulted after 7 days in modified ISO 6341 media at pH 6 in 3.82 and in 54.1 mg/L dissolved barium at the 10 and 100 mg/L loading, respectively.

Key value for chemical safety assessment

Water solubility:

14 mg/L

at the temperature of:

20 °C

Additional information

According to reliable handbook data (e.g. CRC handbook) the water solubility of barium carbonate is ≥14 mg/L at 20 °C. Handbook data considered to be from a trusted source acc. to "ECHA, Guidance on information requirements and chemical safety assessment – Chapter R.7a: Endpoint specific guidance" and therefore, the water solubility of ≥14 mg/L could be regarded as valid.

In the Transformation/Dissolution test, 3.82 and 54.1 mg/L dissolved barium were measured at the 10 and 100 mg/L loading, respectively, in modified ISO 6341 media at the target pH of 6 after 7 days.