Chromium acetate

Endpoint summary

Description of key information

Animal experiments show that trivalent chromium salts can cause sensitisation when injected intradermally. The potency of trivalent chromium as a sensitiser is lower than hexavalent chromium. The potential for sensitisation appears to relate to solublity in water and therefore, it is considered that the chromium acetate is very likely positive.

Not further testing is considered necessary.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

As with all inorganic salts, the significance for toxicity or environmental assessment is the presence of specific ions that will form when in solution or when in biological systems.In the case of Cr III salts, the counter ion will have an effect on solubility and this is itself dependant on the type of media being used and in particular the pH of that media. It is generally accepted that in the case of metal salts, testing with salts that are soluble in the respective test media will ensure maximum exposure of the metal ions. This will include chlorides and nitrates as being more soluble and will indeed have relevance when dissolved in acid media, such as if ingested.Read-across to other chromium III salts is therefore considered valid as long as the exposure in the test system is greater than wold be expected for the substance under review for registration.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

Maximised method

Principles of method if other than guideline:

The purpose of the study was to examine cross sensitisation between Cr(VI) and Cr(III). The test method was modiifeid to provide a consistently successful level of sensitisation.

GLP compliance:

no

Remarks:

Study predates GLP

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Existing data; further animal studies not justified

Species:

guinea pig

Strain:

other: albino

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS- Weight at study initiation: 300-500 g

Key result

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

66 mg/l

No. with + reactions:

0

Total no. in group:

30

Clinical observations:

No adverse effects

Remarks on result:

no indication of skin sensitisation

The eliciting dose produced at 48 hrs a well defined indurated erythematous papule at least 10 mm in diameter.

Ten out of 13 animals developed positive reactions (at least +1). four of these were read as +2. None developed +3 or +4 reactions. Eight out of 10 of these animals also reacted to KCr2O7 (Cr(VI). The differences in the level of reaction were not statistically significant.

Table II Skin test reactions to potassium dichromate and chromic chloride in guinea pigs sensitised to chromic chloride

Guinea pig number	Chromic chloride	Potassium dichromate
1	+1	+1
2	+2	+1
3	+1	+2
4	+1	+1
5	+1	+1
6	+2	+2
7	+1	-
8	+2	+1
9	+1	+1
10	+2	-

Note: (—)= noresponse; (±) =equivocal response, less than 10 mm diameter; (+1) = response of 10 mm diameter; (+2) = response of 15mm diameter; (+3) response of 20 mm diameter; (+4) response of 20 mm diameter with central necrosis.

Similar studies were also carried out with solutions of four other trivalent chromium salts. The highest concentrations  which were not irritating to control animals were determined by serial dilution and subsequently used for skin testing. These were: chromic acetate (2.5 x 10-3M), chromic nitrate (9.6 x 10-4M), chromic oxalate (2.5 x10-4M), chromic sulfate (2.4 X 10 M). Three animals sensitized to CrCl3 showed weaker cross-reactions to the same compounds.

TABLE IV Skin test reactions to chromium salts in guinea pigs which had been sensitized to chromic chloride

Guinea pig no	Chromic chloride	Potassium dichromate	Chromic acetate	Chromic nitrate	Chromic sulfate	Chromic oxalate
1	+1	+1	-	+1	+1	±
2	+2	+1	+1	+1	+1	±
3	+2	-	+1	+2	+1	-

 

Attempts to sensitize guinea pigs with the above trivalent salts, other than CrC13, were uniformly unsuccessful. Concentrations of 1.7 x 10-2 M to 5 x 10-2 M were used with Freund's complete adjuvant in a schedule identical to that which had been successfully used for potassium dichromate and chromic chloride.

Interpretation of results:

sensitising

Remarks:

Migrated information

Conclusions:

Guinea pigs were sensitised to chromic chloride in a procedure designed to mazimise the sensitisation response. attempts to sensitise guinea pigs to other chromium (III) salts (chromic acetate, chomic nitrate, chromic oxalate and chromic sulfate were uniformly unsuccessful.

Executive summary:

Thirteen guinea-pigs were given chromium chloride hexahydrate by three subcutaneous injections in the nape 1 week apart. The sensitizing injections contained 0.5 ml of FCA with 0.5 ml of 3.4 × 10−2 M chromium chloride. Three weeks later, the animals were tested with an intradermal injection into clipped or epilated skin. The eliciting dose was 0.1 ml of 4.2 × 10−4 M chromium chloride. After 48 h, this produced moderate positive responses in 10 of the 13 animals, whereas the control animals (injected only with FCA) showed no reactions.

Of the 10 guinea-pigs sensitized to chromium chloride, 3 elicited weaker cross-reactions after intradermal injection of chromium acetate, chromium nitrate and chromium sulfate. Chromium oxalate did not elicit significant reactions. Using the same study method, the authors also attempted to sensitize guinea-pigs with chromium acetate, chromium nitrate, chromium sulfate and chromium oxalate, but without success.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Thirteen guinea-pigs were given chromium chloride hexahydrate by three subcutaneous injections in the nape 1 week apart. The sensitizing injections contained 0.5 ml of FCA with 0.5 ml of 3.4 × 10−2 mol chromium chloride hexahydrate/l. Three weeks later, the animals were tested with an intradermal injection into clipped or epilated skin. The eliciting dose was 0.1 ml of 4.2 × 10−4 mol chromium chloride hexahydrate/l.

After 48 h, this produced moderate positive responses in 10 of the 13 animals, whereas the control animals (injected only with FCA) showed no reactions. In the same study, sensitization to hexavalent chromium was achieved by intradermal injections of potassium dichromate with 10-fold lower concentrations than required for sensitization to chromium chloride. Of 26 guinea-pigs sensitized to potassium dichromate, all reacted to intradermally applied chromium chloride.

Of the 10 guinea-pigs sensitized to chromium chloride, 3 elicited weaker cross-reactions after intradermal injection of chromium nitrate (9.6 × 10-4 mol/l) and sulfate (2.4 × 10−4 mol/l).

Using the same study method, the authors also attempted to sensitize guinea-pigs with chromium acetate and chromium oxalate, but without success