Palladium monoxide

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

no hazard identified

Marine water

Hazard assessment conclusion:

no hazard identified

STP

Hazard assessment conclusion:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

no hazard identified

Sediment (marine water)

Hazard assessment conclusion:

no hazard identified

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Conclusion on classification

Environmental classification for the poorly water soluble Pd substances under consideration is based on the lowest acute and chronic threshold values from the Pd ecotoxicity test data combined with TDp test data generated as outlined in OECD Guidance Document on Transformation/Dissolution of Metals and Metal Compounds in Aqueous Media (OECD, 2001).

 

The acute and chronic ERV values have been derived as specified in the read-across justification document attached in IUCLID Section 13:

-acute ERV: lowest acute threshold value is 3.57 µg Pd/L (geometric mean EC50 value (growth rate) with P. subcapitata, based on the experimental results for diamminedichloropalladium (EC50=2.96 µ Pd/L; Wenzel 2012) and tetraamminepalladium dichloride (EC50 = 4.31 µg Pd/L; Wenzel 2018))

-chronic ERV: lowest chronic threshold value is 2.26 µg Pd/L (geometric mean EC10 value (growth rate) with P. subcapitata, based on the experimental results for diamminedichloropalladium (EC10 = 1.88 µg Pd/L; Wenzel 2012) and tetraamminepalladium dichloride (EC10=2.72 µg Pd/L; Wenzel 2018)).

The derivation of both ERV values is detailed in the Read-across justification report and PNEC derivation report (cfr. IUCLID Section 13).

 

For classification purposes, these ERVs have been recalculated to the values expressed as the concentration of the substance (conversion based on molecular weight conversion from soluble ion to the substance considered – cfr. details in below table), and compared to the TDp test results (cfr table below) as outlined in ECHA Guidance on the application of the CLP criteria (version 5.0; ECHA, 2017). Details of the TDp test results are included in IUCLID Section 4 ‘Water solubility’. Based on the results of the 24h TDp screening test (loading = 100 mg/L) at pH 6 and 8.5, full 7-d TDp (1-10-100 mg/L loading) and 28-d TDp (1 mg/L loading) assays at the worst case pH value have been performed. The metal release data are compared to the substance specific ERV values as outlined in ECHA Guidance on the application of the CLP criteria (version 5.0; ECHA, 2017) - cfr. below table. Based on the ERVs and the TDp test data, it is concluded that the metal release at all doses and durations are well below the ERV values, and that none of the substances considered need classification.

 

Acute ERV (µg TI/L)

Chronic ERV (µg TI/L)

24h Screening*

7d TDp

28d TDp

Acute aquatic hazard

Long-term aquatic hazard

MWt

Pd Wt%

100 mg/L@pH6

100 mg/L@pH8.5

1 mg/L

10 mg/L

100 mg/L

1 mg/L

Palladium

Pd

106.42

100.0

3.57

2.26

<0.01

<0.01

<0.01

<0.01

<0.01

<0.01

not classified

not classified

palladium monoxide

PdO

122.42

86.9

4.11

2.60

0.06

1.06

<0.05

<0.05

<0.05

<0.05

not classified

not classified

palladium dihydroxide

Pd(OH)2

140.44

75.8

4.71

2.98

0.1

<0.01

0.01

0.21

0.4

0.13

not classified

not classified

* values in bold give the highest metal release. The consequent 7 and 28 day tests are performed at this pH value. For Pd metal, the general observation for metals that metal release is higher at lower pH values is followed, and the 7 and 28-day tests are perfomed at pH 6.