Palladium

Additional toxicological data

Administrative data

Endpoint:

additional toxicological information

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Non-GLP, follows a standard operating procedure, available as an unpublished report, reliable without restrictions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Standard Operating Procedure (SOP) prepared by Eurometaux on November 2010

Deviations:

no

Principles of method if other than guideline:

A bio-accessibility testing study has been designed to assay the metal release of Palladium black compounds in interstitial and lysosomal synthetic media. Metals or metallic compounds were subjected to a media that mimics interstitial fluid in the lungs for 7 days at 37 °C and 171 rpm agitation rate. Samples were taken at 24 hours and 168 hours of incubation, filtered and bio-accessible metal quantified by ICP-MS.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Palladium black

IUPAC Name:

Palladium black

Constituent 2

Reference substance name:

Palladium

EC Number:

231-115-6

EC Name:

Palladium

Cas Number:

7440-05-3

Molecular formula:

Pd

IUPAC Name:

palladium(2+)

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Palladium black
- Substance type: powder
- Physical state: soild
- Analytical purity: 97.26 % w/w
- Purity test date: 28/03/2012
- Lot/batch No.: 7494/02-10
- Other: Particle size distribution and specific surface area (BET analysis) values were taken from: Fraunhofer IKTS report N° 4198_4208_4214_4216 of 12.11.2012.
- d50 (50th percentile of the particle size distribution) = 0.387 µm
- d90 (90th percentile of the particle size distribution) = 1.044 µm
- BET = 25.5 m2/g

Results and discussion

Any other information on results incl. tables

1) The results of the interstilial bio-elution test of Palladium black are presented in the table below. The Palladium released from blanks and samples at pH 7.4 (2 g/L mass loading) were recorded before the sample was added and after 24 and 168 hours incubation at 37°C. The measurements of the metal released are reported in µg/L and µg/g for the blanks (top half of the table) and sample values (bottom half of the table).

Table 1–Palladium black 7 days bio-elution test in interstitial mimetic fluid: Palladium released from blanks and samples at pH 7.4 ( 2 g/L mass loading), were recorded before the sample was added and after 24 and 168 hours of incubation. The results are reported in µg/L and µg/g.

	Interstitial test parameters				Vessel 1	Vessel 2	Vessel 3	Palladium, µg/L			Palladium, µg/g
Blanks	Time, hr	Temp., °C	O2,mg/L	pH	R1	R2	R3	Mean, µg/L	St. Dev.	CV, %	Mean, µg/g	CV, %
	Before	37.0	5.7	7.45	BDL	BDL	BDL	-	-	-	-	-
	24	37.0	5.7	7.44	BDL	BDL	BDL	-	-	-	-	-
	168	37.0	5.6	7.45	BDL	BDL	BDL	-	-	-	-	-
Pd black	Time, hr	Temp., °C	O2,mg/L	pH	R1	R2	R3	Mean, µg/L	St. Dev.	CV, %	Mean, µg/g	CV, %
	Before	37.0	5.7	7.45	BDL	BDL	BDL	-	-	-	-	-
	24	37.0	5.7	7.53	7.6	9.0	7.9	8.2	0.71	9	4.1	9
	168	37.0	5.6	7.44	10.3	11.8	10.9	11.0	0.76	7	5.5	7

CV: corresponds to the coefficient of variation between vessels (the ratio between the standard deviation and the mean of metal released).

BDL: Below detection limit.

2) Results of lysosomal bio-elution tests of Palladium black are presented below. The results correspond to the 7 day tests performed at pH 4.5 under a constant temperature of 37 °C and a mass loading of 2 g/L. The measurements of metal released from the blanks are reported on the top half of the table and the sample values in the bottom half of the table.

 

Table 2–Palladium black 7 days bio-elution test in lysosomal mimetic fluid: Palladium released from blanks and samples at pH 4.5 ( 2 g/L mass loading), were recorded before the sample was added and after 24 and 168 hours of incubation. The results are reported in µg/L and µg/g.

 

	Lysosomal test parameters				Vessel 1	Vessel 2	Vessel 3	Palladium, µg/L			Palladium, µg/g
Blanks	Time, hr	Temp., °C	O2,mg/L	pH	R1	R2	R3	Mean, µg/L	St. Dev.	CV, %	Mean, µg/g	CV, %
	Before	37.0	6.7	4.55	BDL	BDL	BDL	-	-	-	-	-
	24	37.0	6.4	4.55	BDL	BDL	BDL	-	-	-	-	-
	168	37.0	6.2	4.54	BDL	BDL	BDL	-	-	-	-	-
Pd black	Time, hr	Temp., °C	O2,mg/L	pH	R1	R2	R3	Mean, µg/L	St. Dev.	CV, %	Mean, µg/g	CV, %
	Before	37.0	6.7	4.55	BDL	BDL	BDL	-	-	-	-	-
	24	37.0	6.4	4.54	9284	9890	9941	9705	365.8	4	4848	4
	168	37.0	6.2	4.57	983920	1130160	975040	1029707	87108.4	8	514339	8

CV: corresponds to the coefficient of variation between vessels (the ratio between the standard deviation and the mean of metal released).

BDL: Below detection limit.

Table 3. Summary of metals solubility from Palladium black sample; submitted to bio-elution tests in synthetic interstitial and lysosomal media. Metal releases from the bio-elution tests are reported, as percentage of solubility, after 24 and 168 hours of incubation.

 

Sample	% Solubility in Interstitial fluid		% Solubility in Lysosomal fluid
	24 h	168 h	24 h	168 h
Palladium black	4x10^-4	6x10^-4	0.5	52.9

Table 4 . Results of the metal release per surface area exposed to the media. The ratio between metal released in the bio-elution test, expressed in µg/g, and the specific surface area in m²/g are presented for Palladium black.

Sample	Interstitial fluid	Lysosomal fluid
	Metal release 168 h,µg/m^2	Metal release 168 h,µg/m^2
Palladium black	0.2	20170

 

 

 

The control standards used to assure the quality of the measurements obtained by ICP-MS, demonstrated an adequate stability and accuracy of the instrument during the metal quantification of the bio-elution samples. All the QC samples showed metal concentration measurements in the range of 20% around the certified value of the standards; criterion used to assure the quality of the measurements.   

 

Applicant's summary and conclusion

Conclusions:

In interstitial fluid palladium black showed solubility of 4 x 10-4 and 6 x 10-4 % after 24 and 168 hours, respectively. The solubility of palladium black in lysosomal fluid was 0.5 and 52.9 % after 24 and 168 hours, respectively.

Executive summary:

A study to estimate metal bio-accessibility for Palladium black in synthetic pulmonary fluids, was performed following Standard Operating Procedure (SOP, Eurometaux, November 2010). The test item was subjected to a media that mimics interstitial fluid in the lungs or to a media pH 4.5 - 5.0 that mimic intracellualr conditions of phagocythosis in alveolar and and interstitial macrophages (lysosomal fluid) for 7 days at 37 °C and 171 rpm agitation rate. Samples were taken at 24 hours and 168 hours of incubation, filtered and bio-accessible metal quantified by ICP-MS.

In interstitial fluid (pH 7.4) palladium black showed solubility of 4 x 10-4 and 6 x 10-4 % after incubation for 24 and 168 hours, respectively. The solubility of palladium black in lysosomal fluid (pH 4.5) was 0.5 and 52.9 % after 24 and 168 hours, respectively.