Rhodium

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

equivalent or similar 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

Qualifier:

according to guideline

Guideline:

other: UN Transformation/Dissolution Protocol (T/DP) for Metals and Sparingly Soluble Metal Compounds.

GLP compliance:

not specified

Type of method:

other: Transformation/dissolution

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

0.03 µg/L

Element analysed:

Rhodium

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 6 (6.01 - 6.05), 22.7°C

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

0.02 µg/L

Element analysed:

Rhodium

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 8 (8.53 - 8.68), 21.9°C

Type of test:

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

Mean dissolved conc.:

0 µg/L

Element analysed:

Rhodium

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

pH 6 (5.87 - 6.35), 21.4°C

Type of test:

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

Mean dissolved conc.:

0.1 µg/L

Element analysed:

Rhodium

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

pH 6 (5.79 - 6.43), 21.9°C

Type of test:

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

Mean dissolved conc.:

0 µg/L

Element analysed:

Rhodium

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

pH 6 (5.71 - 6.17), 21.9°C

Details on results:

The results for the 24 hour scoping tests at pH 6 and 8.5 reveal that Rh was within the sub-µg/L analytical detection limits, and singularly unreactive at either pH. The 28-day T/D data for the 1, 10 and 100 mg Rh/L net concentration changes of values of 0.00 µg/L are evidence of the lack of activity of Rh metal.

Definitive 7 and 28 day T/D tests were only performed at pH 6 on the grounds that metals are generally more reactive at this pH than pH 8.5.

Conclusions:

The results from the 24-hour scoping tests at pH 6 and 8.5 revealed that Rh was within the sub-µg L-1 analytical detection limits, and singularly unreactive at either pH.

The 28-day TD data for the 1 mg Rh L-1 loading and the 7-day TD data for the 10 and 100 mg Rh L-1 loadings determined net concentration changes of

Executive summary:

This is a non-GLP study but follows a standard guideline for transformation/dissolution tests and is considered suitable for assessing this endpoint.

The results from the 24-hour scoping tests at pH 6 and 8.5 revealed that Rh was within the sub-µg L-1 analytical detection limits, and singularly unreactive at either pH.

The 28-day TD data for the 1 mg Rh L-1 loading and the 7-day TD data for the 10 and 100 mg Rh L-1 loadings determined net concentration changes of <LOQ (LOQ: 0.06 µg L-1), 0.1 µg L-1 and <LOQ (LOQ: 0.2 µg L-1), respectively.

Description of key information

The results from the 24-hour TD scoping tests at pH 6 and 8.5 revealed that Rh was within the sub-µg L-1 analytical detection limits, and singularly unreactive at either pH.

The 28-day TD data for the 1 mg Rh L-1 loading and the 7-day TD data for the 10 and 100 mg Rh L-1 loadings determined net concentration changes of <LOQ (LOQ: 0.06 µg L-1), 0.1 µg L-1 and <LOQ (LOQ: 0.2 µg L-1), respectively.

Key value for chemical safety assessment

Water solubility:

0.2 µg/L

at the temperature of:

21 °C

Additional information

Skeaff and Beaudoin (2011) is a non-GLP study but follows a standard guideline for transformation/dissolution (TD) tests and is considered suitable for assessing this endpoint.

The results from the 24-hour scoping tests at pH 6 and 8.5 revealed that Rh was within the sub-µg L-1 analytical detection limits, and singularly unreactive at either pH.

The definitive TD test was conducted at pH 6. The 28-day TD data for the 1 mg Rh L-1 loading and the 7-day TD data for the 10 and 100 mg Rh L-1 loadings determined net concentration changes of <LOQ (LOQ: 0.06 µg L-1), 0.1 µg L-1 and <LOQ (LOQ: 0.2 µg L-1), respectively.