Rhodium

Additional toxicological data

Administrative data

Endpoint:

additional toxicological information

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April - June 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Type of study / information:

Metals or metallic compounds are subjected to a media that mimic gastric juice, in terms of pH and
body temperature (pH 1.5 and 37 °C), for an exposure time of 1 hour with agitation. Then the
compounds are incubated for another hour without agitation, before aliquots are taken, filtered and
bio-accessible metal quantified by ICP-MS.

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: EN1881, Reference test method for release of nickel from products intended to come into direct and prolonged contact with skin, CEN, Ref No EN 1811: 1998 E, November 1998.

Version / remarks:

November 1998

Deviations:

yes

Remarks:

with the refinements included in the SOP of Eurometaux (Standard Operating Procedure (SOP) for the Bioaccessibility Testing Programme, November 10, 2010, directed by Eurometaux)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: ASTM D5517-17: Standard Test Method for Determining Extractability of Metals from Art Materials, D5517-94, Philadelphia, PA: American Society for Testing and Materials,

Version / remarks:

2007

Deviations:

yes

Remarks:

refinements included in the SOP of Eurometaux (Standard Operating Procedure (SOP) for the Bioaccessibility Testing Programme, November 10, 2010, directed by Eurometaux.)

GLP compliance:

no

Remarks:

Testing lab is no GLP facility, however, they follow as close as possible the OECD Good Laboratory Guidelines (ENV/MC/CHEM(98)17) and meet the standard technical requirements for the protocols.

Test material

Test material information

Constituent 1

Reference substance name:

Rhodium

EC Number:

231-125-0

EC Name:

Rhodium

Cas Number:

7440-16-6

Molecular formula:

Rh

IUPAC Name:

rhodium(2+)

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Rhodium black
- Substance type: powder
- Physical state: soild
- Analytical purity: 99.5 % w/w
- Purity test date: 28/03/2012
- Lot/batch No.: 8225/00-L1
- 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 = 21.080 µm (50th percentile of the particle size cumulative distribution as measured by volume)
- d90 = 47.211 µm (90th percentile of the particle size cumulative distribution as measured by volume)
- BET = 3.61 m2/g

Specific details on test material used for the study:

rhodium powder 99.978% purity
d50=178.65 µm, d90=533.968 µm; BET:0.181 m²/g

Results and discussion

Any other information on results incl. tables

Results of the perspiration bio-elution test are presented in this table. The results correspond to the 7 day tests performed at pH 6.5 under a constant temperature of 30 °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.

	Time (h)	Temp (°C)	O2 (mg/L)	pH	Vessel1	Vessel2	Vessel3	Rhodium (µg/L)	Rhodium (µg/g)
blanc	before	30.0	6.9	6.44	BDL	BDL	BDL	/	/
	24	30.5	6.7	5.94	BDL	BDL	BDL	/	/
	169	30.5	5.4	5.91	BDL	BDL	BDL	/	/
rhodium powder	before	30.0	6.9	6.44	BDL	BDL	BDL	/	/
	24	30.5	6.7	5.91	0.5	0.6	0.6	0.6 (SD 0.002)	0.3
	169	30.5	5.4	5.47	1.5	1.4	1.4	1.4 (SD 0.06)	0.7

BDL: Below detection limit.

 

Results of the gastric bio-elution test are presented. The results correspond to the 2 hours tests performed at pH 1.5 under a constant temperature of 37 °C and a mass loading of 200
mg/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

	time (h)	temp (°C)	02 (mg/L)	pH	Vessel1	Vessel2	Vessel3	Rh(µg/L)	Rh (µg/g
blanks	before	37	6.9	1.52	BDL	BDL	BDL	/	/
	2	37	6.7	1.53	0.15	BDL	0.14	0.15 (SD 0.01)	0.74
Rh powder	before	37	6.9	1.52	0.63*	0.57*	BDL	/	/
	2	37	6.7	1.50	1.7	1.0	1.5	1.4 (SD0.37)	6.9

*Values regarded as outliers and are not considered in the calculations
BDL: Below detection limit.

Applicant's summary and conclusion

Conclusions:

The perspiration and gastric bioaccessibility of Rh powder was determined as 7x10(-5)% (SD 3x10-6) and 7x10(-4)% (SD 2x10-4) respectively.

Executive summary:

A study to estimate metal bio-accessibility in synthetic media simulating gastric juice and perspiration fluid, were performed.

Rhodium powder was assayed following Eurometaux Standard Operating Procedure (SOP) defined for a bio-accessibility testing programme on the 10th of November 2010. The results obtained showed low solubilities in perspiration fluid. As expected, the solubility in synthetic gastric medium (pH 1.5) was higher than the values measured in perspiration fluid. Metal solubility results, calculated as the percentage between the dissolved metal, after each bio-elution test, and total metal content of the compound is 7x10(-4)% in gastric fluid and 7x10(-5)% in perspiration fluid after 168h.