Slags, ferrochromium-manufg.

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vitro / ex vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Read-across to chromium metal. FeCr-slag contains chromium in the form of metal drops and in Fe-Mg-Cr-Al spinels. Comparable to guideline study.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

In vitro percutaneous absorption of metal compounds

Author:

Larese F, Gianpietro A, Venier M, Maina M and Renzi N

Year:

2007

Bibliographic source:

Toxicol Letters 170, 49-56

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 428 (Skin Absorption: In Vitro Method)

Deviations:

not specified

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Chromium

EC Number:

231-157-5

EC Name:

Chromium

Cas Number:

7440-47-3

IUPAC Name:

chromium(2+)

Details on test material:

- Name of test material (as cited in study report): Chromium

- Substance type: metal
- Physical state: powder
- Analytical purity: 99.8% purity (metals basis)
Average particle size (APS) <10 µm
Manufacturer: Alfa Aesar (Karlsruhe, Germany)

Radiolabelling:

no

Administration / exposure

Details on in vitro test system (if applicable):

SKIN PREPARATION
- Source of skin: human (surgical waste: at least two donors for each experiment, male and female 40-65 years)
- Ethical approval if human skin: no data
- Type of skin: full thickness skin
- Preparative technique: Skin obtainead as surgical waste. Prior to freezing, subcutaneous fat was removed and hair shaved.
- Thickness of skin (in mm): average thickness 1mm ; mean exposed skin area 3.92 cm2
- Membrane integrity check: Skin integry was checked before and after each experiment using electrical conductibility by means of a conductometer (Metrohm, 660 Conductometer, Herisau, Switzerland). The electrical conductance data (as µS) were converted to K[omega]cm-2. Cells with a resistance <3.95 ± 0.27 K[omega]cm-2were considered to be damaged.
- Storage conditions: Freezer -25 C for a period up to (but not exceeding) 4 months
- Justification of species, anatomical site and preparative technique: no data


PRINCIPLES OF ASSAY
- Diffusion cell: Franz diffusion cells
- Cr metal powder was suspended in a synthetic sweat solution with pH 6.5 (donor fluid)
- Receptor fluid: phosphate buffered saline (PBS) (pH 7.35)
- Solubility od test substance in receptor fluid: no data
- The chromium powder in synthetic sweat was added to the exposure chamber.
- Test temperature: 32 C
- Humidity: no data
- Occlusion: no data
- Reference substance(s): no data
- Other: At 24 h the dermal bathing solution was removed and Cr concentration in the receptor fluid was determined by electro-thermal atomic absorption spectrometry.
After the experiments the skin was stored in a freezer at -25 C. Before analysis, the skin membranes were dried for 24 h at room temperature. Then the exposed area was cut into sections, weighted and digested in 70% v/v HNO3.

Results and discussion

Absorption in different matrices:

Cr permeated the skin in very low amounts and it was not possible to calculate a flux and lag time for the permeation.
Polarographic analysis of the filtered donor phase showed that Cr was not detectable as ion (limit of detection 10 ppb); indicating that synthetic sweat pH 6.5 was not able to oxidise metallic Cr.

Applicant's summary and conclusion

Conclusions:

An in vitro percutaneous absorption study with Cr metal suspended in artificial sweat (pH 6.5) showed a very low absorption. The concentration of Cr ions were below 0.1 mg/L, indicating that Cr metal is not oxidised at pH 6.5, and therefore the risk of absorption is very low under these conditions.

Executive summary:

An in vitro percutaneous absorption study with Cr metal suspended in artificial sweat (pH 6.5) showed a very low absorption. The concentration of Cr ions were below 0.1 mg/L, indicating that Cr metal is not oxidised at pH 6.5, and therefore the risk of absorption is very low under these conditions.