Palladium dihydroxide

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP status not known, guideline experimental study minor restrictions in design and/or reporting but otherwise adequate for assessment

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

Water solubility:

0.1 µg/L

Temp.:

21.8 °C

pH:

>= 5.68 - <= 5.79

Remarks on result:

other: pH 6 24-hr scoping study. Test Duration; 24 Hours, Pd(OH)2 Loading; 100 mg/L, σ = 0.1 µg/L, σ % = 54, Temperature Range; 21.7 - 21.9 ºC, DO; 5.1 - 10.6 mg/L

Water solubility:

0 µg/L

Temp.:

22.6 °C

pH:

>= 8.28 - <= 8.46

Remarks on result:

other: pH 8.5 24-hr scoping study. Test Duration; 24 Hours, Pd(OH)2 Loading; 100 mg/L, σ = 0.0 µg/L, Temperature Range; 22.3 - 22.8ºC, DO; 3.2 - 10.4 mg/L

Water solubility:

0.01 µg/L

Temp.:

20.8 °C

pH:

>= 5.32 - <= 6.06

Remarks on result:

other: Test Duration; 28 Days, Pd(OH)2 Loading; 1 mg/L. Concentration at 168 hours reported. σ = 0.01 µg/L, σ % = 173, Temperature Range; 21.9 - 22.4 ºC, DO; 4.4 - 11.6 mg/L

Water solubility:

0.13 µg/L

Temp.:

22.1 °C

pH:

>= 5.32 - <= 6.35

Remarks on result:

other: Test Duration; 28 Days, Pd(OH)2 Loading; 1 mg/L. Concentration at 672 hours reported. σ = 0.04 µg/L, σ % = 30,Temperature Range; 21.1 - 22.4 ºC, DO; 4.4 - 11.6 mg/L

Water solubility:

0.21 µg/L

Temp.:

22.4 °C

pH:

>= 5.49 - <= 6.12

Remarks on result:

other: Test Duration; 7 Days, Pd(OH)2 Loading; 10 mg/L, σ = 0.06 µg/L, σ % = 26, Temperature Range; 22.1 - 22.5 ºC, DO; 6.7 - 16.2 mg/L

Water solubility:

0.4 µg/L

Temp.:

22.3 °C

pH:

>= 5.49 - <= 6.14

Remarks on result:

other: Test Duration; 7 Days, Pd(OH)2 Loading; 100 mg/L, σ = 0.24 µg/L, σ % = 60, Temperature Range; 22.0 - 22.5 ºC, DO; 6.7 - 16.5 mg/L

Details on results:

In the 24 hour scoping tests, palladium hydroxide was slightly soluble, with net changes being 0.1 and 00.0 µg/L for pH 6 and pH 8 respectively. Since both values were less than the ERV, the definitve test were perfromed at pH 6. The T/D data from the definitive test show that net concentration changes for PdO were 0.21 µg/L (σ % = 26) and 0.4 µg/L (σ % = 60) after 7 days for 10 and 100 mg Pd(OH)2/L loadings at pH 6 respectively. The maximum Pd(OH)2 concentration observed from the 7- and 28-day definitive tests was 1.02 µg/L (σ % = 13), after 6 hours for the 100 mg Pd(OH)2/L loadings.

Conclusions:

In the 24 hour scoping tests, palladium hydroxide was slightly soluble, with net changes being 0.1 and 00.0 µg/L for pH 6 and pH 8 respectively. Since both values were less than the ERV, the definitve test were perfromed at pH 6. The T/D data from the definitive test show that net concentration changes for PdO were 0.21 µg/L (σ % = 26) and 0.4 µg/L (σ % = 60) after 7 days for 10 and 100 mg Pd(OH)2/L loadings at pH 6 respectively. The maximum Pd(OH)2 concentration observed from the 7- and 28-day definitive tests was 1.02 µg/L (σ % = 13), after 6 hours for the 100 mg Pd(OH)2/L loadings.

Executive summary:

This is a guideline experimental study, of unknown GLP status, there are minor restrictions in design and/or reporting but otherwise adequate for assessment as a key study for this endpoint. In the 24 hour scoping tests, palladium hydroxide was at or below analytical limits, with net concentation changes being 0.1 and 0.0 µg/L for pH 6 and pH 8 respectively. Since both values were less than the ERV, the definitve test were perfromed at pH 6. The T/D data from the definitive test show that net concentration changes for Pd(OH)₂ were 0.21 µg/L (σ % = 26) and 0.4 µg/L (σ % = 60) after 7 days for 10 and 100 mg Pd(OH)₂/L loadings at pH 6 respectively. The maximum Pd(OH)₂ concentration observed from the 7- and 28-day definitive tests was 1.02 µg/L (σ % = 13), after 6 hours for the 100 mg Pd(OH)₂/L loadings.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP status not known, guideline experimental study minor restrictions in design and/or reporting but otherwise adequate for assessment

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

Water solubility:

7.6 µg/L

Temp.:

21.9 °C

pH:

>= 5.7 - <= 5.77

Remarks on result:

other: pH 6 24-hr scoping study. Test Duration; 24 Hours, PdO.H2O Loading; 100 mg/L, σ = 0.8 µg/L, σ % = 10, Temperature Range; 21.8 - 22.0 ºC, DO; 4.4 - 11.4 mg/L

Water solubility:

6.5 µg/L

Temp.:

22.3 °C

pH:

>= 8.3 - <= 8.49

Remarks on result:

other: pH 8.5 24-hr scoping study. Test Duration; 24 Hours, PdO.H2O Loading; 100 mg/L, σ = 0.1 µg/L, σ % = 2. Temperature Range; 21.7 - 22.6 ºC, DO; 3.3 - 10.8 mg/L

Water solubility:

0 µg/L

Temp.:

22.1 °C

pH:

>= 5.35 - <= 6.34

Remarks on result:

other: Test Duration; 28 Days, PdO.H2O Loading; 1 mg/L. Concentration at 168 hours reported. σ = 0.0 µg/L, Temperature Range; 21.2 - 22.6 ºC, DO; 4.1 - 12.6 mg/L

Water solubility:

0 µg/L

Temp.:

22.1 °C

pH:

>= 5.35 - <= 6.34

Remarks on result:

other: Test Duration; 28 Days, PdO.H2O Loading; 1 mg/L. Concentration at 672 hours reported. σ = 0.0 µg/L, Temperature Range; 21.2 - 22.6 ºC, DO; 4.1 - 12.6 mg/L

Water solubility:

8 µg/L

Temp.:

22.4 °C

pH:

>= 5.71 - <= 6.24

Remarks on result:

other: Test Duration; 7 Days, PdO.H2O Loading; 10 mg/L, σ = 1.0 µg/L, σ % = 13, Temperature Range; 22.1 - 22.6 ºC, DO; 7.4 - 9.1 mg/L

Water solubility:

98.9 µg/L

Temp.:

22.3 °C

pH:

>= 5.76 - <= 6.12

Remarks on result:

other: Test Duration; 7 Days, PdO.H2O Loading; 100 mg/L, σ = 5.3 µg/L, σ % = 5, Temperature Range; 22.0 - 22.5 ºC, DO; 6.7 - 9.4 mg/L

Details on results:

In the 24 hour scoping tests, hydrous palladium oxide was soluble, with net changes being 7.6 and 6.5 µg/L for pH 6 and pH 8 respectively. Since both values were less than the ERV, the definitve test were perfromed at pH 6. The T/D data from the definitive test show that net concentration changes for PdO were 8 µg/L (σ % = 13) and 98.9 µg/L (σ % = 5) after 7 days for 10 and 100 mg PdO.H2O/L loadings at pH 6 respectively.

Conclusions:

In the 24 hour scoping tests, hydrous palladium oxide was soluble, with net changes being 7.6 and 6.5 µg/L for pH 6 and pH 8 respectively. Since both values were less than the ERV, the definitve test were perfromed at pH 6. The T/D data from the definitive test show that net concentration changes for PdO were 8 µg/L (σ % = 13) and 98.9 µg/L (σ % = 5) after 7 days for 10 and 100 mg PdO.H2O/L loadings at pH 6 respectively.

Executive summary:

This is a guideline experimental study, of unknown GLP status, there are minor restrictions in design and/or reporting but otherwise adequate for assessment as a key study for this endpoint. In the 24 hour scoping tests, hydrous palladium oxide was soluble, with net changes being 7.6 and 6.5 µg/L for pH 6 and pH 8 respectively. Since both values were less than the ERV, the definitve test were perfromed at pH 6. The T/D data from the definitive test show that net concentration changes for PdO were 8 µg/L (σ % = 13) and 98.9 µg/L (σ % = 5) after 7 days for 10 and 100 mg PdO.H2O/L loadings at pH 6 respectively.

Description of key information

In the definitive T/D tests, performed at pH 6, the net concentration changes for palladium dihydroxide were 0.01, 0.21 µg/L and 0.4 µg/L after 7 days for 1, 10 and 100 mg palladium dihydroxide loadings, respectively. After 28 days, at a loading rate of 1 mg/L, the concentration was 0.13 µg/L. In a second test with a sample considered to be equivalent to palladium dihydroxide results were < LOQ (0.1 µg/L), 8 µg/L and 98.9 µg/L, after 7 days at loading rates of 1, 10 and 100 mg/L, respectively. After 28 days, at a loading rate of 1 mg/L, measured palladium concentrations were <LOQ (0.1 µg/L). 

Key value for chemical safety assessment

Water solubility:

0.13 µg/L

at the temperature of:

22.1 °C

Additional information

Skeaff and Beaudoin (2012) is a non-GLP, guideline transformation / dissolution study and is suitable for use as a key study for this endpoint. In the 24-hour scoping tests, palladium hydroxide was at or below analytical limits, with net concentration changes being 0.1 and 0.0 µg/L for pH 6 and pH 8 respectively. The definitive test was performed at pH 6. The T/D data from the definitive test show that net concentration changes for palladium dihydroxide were 0.01, 0.21 µg/L and 0.4 µg/L after 7 days for 1, 10 and 100 mg palladium dihydroxide loadings, respectively. After 28 days, at a loading rate of 1 mg/L, the concentration was 0.13 µg/L.

Testing has also been conducted on a sample of ‘palladium monoxide (hydrate)’. Further assessment of the substance identity of the test item indicated that based on the analytical data this sample was the same substance as palladium dihydroxide. Studies conducted on the sample of ‘palladium monoxide (hydrate)’ are therefore included in the dossier for palladium dihydroxide. Skeaff and Beaudoin (2012) is a non-GLP, guideline transformation / dissolution study conducted with palladium monoxide (hydrate). The study is considered to be suitable for use as the key study for this endpoint. In the definitive T/D test performed with ‘palladium monoxide (hydrate)’, performed at pH 6, the net concentration changes for ‘palladium monoxide (hydrate)’ were <LOQ (0.1 µg/L), 8 µg/L and 98.9 µg/L, after 7 days at loading rates of 1, 10 and 100 mg/L, respectively. After 28 days, at a loading rate of 1 mg/L, measured palladium concentrations were <LOQ (0.1 µg/L).

Water solubility testing was also conducted with palladium monoxide (hydrate) in a GLP compliant, guideline study (O’Connor and Woolley 2011). The study determined that the concentration of palladium monoxide (hydrate) in solution was less than 5.0 x 10^-5g/L of palladium at 20.0 ± 0.5°C. This was equivalent to a palladium monoxide solubility of less than 6.6 x 10^-5g/l of solution at 20.0 ±0.5°C.