Chromium (III) hydroxide

Endpoint summary

Description of key information

A modern LLNA showed that the responses in mice of a low-solubility chromium salt was below the thresholds for classification.

Older Guinea Pig experiments show that water soluble trivalent chromium salts can have a potential to cause sensitisation when injected intradermally. The potency of trivalent chromium as a sensitiser is lower than hexavalent chromium.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

Performed to high standards, but using read across.
When assessing inorganic substances, it is acceptable to only study the key ions. The substance assessed in this study contains chromium III ions in a similar state of low water solubility as the chromium hydroxide and has been considered suitable for read-across / grouping.

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Principles of method if other than guideline:

Threshold values of the stimulation indices of lymph node cell count and ear weight were calculated by dividing the average values per group of the test item treated animals by the vehicle treated ones. Values above 1.4 (cell count) or 1.1 (ear weight) are considered positive

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Specific details on test material used for the study:

No details available

Species:

mouse

Strain:

NMRI

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg
7, 97633 Sulzfeld, Germany
- Age at study initiation: 8 weeks
- Weight at study initiation: 22- 27 g
- Housing: The animals were kept singly in MAKROLON cages (III) with a basal surface of approx. 39 cm
X 23 cm and a height of approx. 15 cm. Granulated textured wood (Granulat A2, J. Brandenburg, 49424
Goldenstedt, Germany was used as bedding material for the cages.
- Diet (ad libitum): Commercial diet ssniff® R/M-H V1534 (ssniff Spezialdiäten GmbH, 59494 Soest,
Germany)
- Water (ad libitum): Tap water
- Acclimation period: At least 5 days
ENVIRONMENTAL CONDITIONS
- Temperature: 22 +/- 3 °C (maximum range)
- Relative humidity: 55% +/- 15 % (maximum range)
- Air changes: 12 -18 times per hour
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Vehicle:

other: acetone/olive oil (3 + 1, v/v)

Concentration:

10 % w/w, 25 % w/w, and 50 % w/w

No. of animals per dose:

6

Details on study design:

A preliminary experiment was carried out in 3 animals to examine the irritating potential and handling/application of the test item in order to select the appropriate concentrations.
Three concentrations of 10, 25 and 50 % in acetone/olive oil (3 + 1 v/v), w/w, were examined.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Yes

Positive control results:

The positive control group caused the expected increases in lymph node cell count (statistically significant at p≤ 0.01). The value for the stimulation index of lymph node cell count was 1.78

Key result

Parameter:

SI

Value:

> 1 - < 1.4

Variability:

10% SI 1.01, 25% 1.02, 50% 1.29

Treatment at concentrations of 10 %, 25 % or 50 % did not reveal statistical significantly increased values for lymph node cell count. The stimulation indices of the lymph node cell

count did not exceed the threshold level of 1.4. Hence, the test item is classified as not sensitising in the

course of this study.

The threshold level for the ear weight of 1.1 was not exceeded; however, the lymph node weights were

increased in a dose-related way. This finding could point to irritating properties of the test item specifically

in mice although no acute skin reactions could be observed.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the present test conditions, Colorante negro at concentrations of 10 %, 25 % or 50 % (w/w) in acetone/olive oil (3 +1, v/v) did not reveal any sensitising properties in the local lymph node assay and therefore should not be classified and labelled according to regulation (EC) No.: 1272/2008.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)