Platinum

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:

other: Non-GLP study following standard guidelines for a transformation/dissolution study, available as an unpublished report, reliable without restrictions

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.:

0.1 µg/L

Element analysed:

Platinum

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 6 (5.98 - 6.05), 22.5°C

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

0.1 µg/L

Element analysed:

Platinum

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 8.5 (8.48 - 8.71), 21.7°C

Type of test:

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

Mean dissolved conc.:

0 µg/L

Element analysed:

Platinum

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

pH 6 (5.92 - 6.46), 21.3°C

Type of test:

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

Mean dissolved conc.:

0.01 µg/L

Element analysed:

Platinum

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

pH 6 (5.83 - 6.1), 22.3°C

Type of test:

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

Mean dissolved conc.:

0.08 µg/L

Element analysed:

Platinum

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

pH (5.86 - 6.09), 22.2°C

Details on results:

The results for the 24 hour scoping tests at pH 6 and 8.5 reveal that Pt was within the sub-µg/L analytical detection limits, and singularly unreactive at either pH. The 28-day T/D data for the 1 mg Pt/L loadings reveal no change in concentration. For the 10 and 100 mg/L loadings net concentration changes of 0.01 µg/L (σ % = 34) and 0.08 µg/L (σ % = 18) were observed.

Definitive 7 and 28 days 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

Summary of Transformation / Dissolution (T/D) data for Platinum 

Substance name	Formula	Weighed loadings mg/L	Target pH	Test duration	Net averages µg/L
					Measured metal conc.	σ µg/L	σ %
Platinum	Pt	100	6	24-hour	0.1	0.0	15.1
		100	8.5	24-hour	0.1	0.1	49
		1	6	28-day	0.0	0.0
		10	6	7-day	0.0	0.0	42
		100	6	7-day	0.08	0.02	23

σ standard deviation

Conclusions:

The 28-day T/D data for the 1 mg Pt/L loadings reveal no change in concentration. For the 10 and 100 mg/L loadings net concentration changes of 0.01 µg/L (σ % = 34) and 0.08 µg/L (σ % = 18) were observed after 7 days.

Executive summary:

This is a non-GLP study but follows standard guidelines for performing a transformation / dissolution study. 24-hour scoping studies were carried out at pH 6 and pH 8, followed by a definitive study with loading rates of 1 mg Pt/L (28 days), and 10 and 100 mg Pt/L (7 days).

The 28-day T/D data for the 1 mg Pt/L loadings reveal no change in concentration. For the 10 and 100 mg/L loadings net concentration changes of 0.01 µg/L (σ % = 34) and 0.08 µg/L (σ % = 18) were observed after 7 days.

Description of key information

The 28-day T/D data for the 1 mg Pt/L loading revealed no change in concentration. For the 10 and 100 mg/L loadings net concentration changes of 0.01 µg/L (σ % = 34) and 0.08 µg/L (σ % = 18) were observed after 7 days.

Additional information

A transformation / dissolution (TD) test is available for this substance. TD tests are a standard method for assessing the solubility of poorly soluble metal substances and provide additional data that cannot be obtained from a standard OECD 105 water solubility study.

Skeaff & Beaudoin (2011) is a non-GLP study but follows standard guidelines for performing a transformation / dissolution study. 24-hour scoping studies were carried out at pH 6 and pH 8, followed by a definitive study with loading rates of 1 mg Pt/L (28 days), and 10 and 100 mg Pt/L (7 days).

The 28-day T/D data for the 1 mg Pt/L loading revealed no change in concentration. For the 10 and 100 mg/L loadings net concentration changes of 0.01 µg/L (σ % = 34) and 0.08 µg/L (σ % = 18) were observed after 7 days.