Post crystallisation of ammonium sulfate aqueous phase products resulting from ammoniac neutralisation of sulfuric acid waste waters formed during methylmethacrylate synthesis

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The potential of the test item to induce delayed contact hypersensitivity using the murine Local Lymph Node Assay (LLNA) was evaluated (Rokh, 2010b). Evaluation of local irritation was also carried out in parallel. This study was conducted in compliance with the principles of Good Laboratory Practice Regulations. A preliminary test was first performed in order to define the concentrations of test item to be used in the main test. In the main test, twenty-eight female CBA/J mice were allocated to seven groups: Five treated groups of four animals receiving the test item at the concentration of 0.5, 1, 2.5, 5 or 10% in a mixture Ethanol/purified water (50/50, w/w), one negative control group of four animals receiving the vehicle (mixture Ethanol/purified water (50/50, w/w)), and one positive control group of four animals receiving the reference item, a-hexylcinnamaldehyde (HCA), a moderate sensitizer, at the concentration of 25% in a mixture acetone/olive oil (4/1, v/v). During the induction phase, the test item, vehicle or reference item was applied over the ears (25 µL per ear) for 3 consecutive days (days 1, 2 and 3). After 2 days of resting, the proliferation of lymphocytes in the lymph node draining the application site was measured by incorporation of tritiated methyl thymidine (day 6). The obtained values were used to calculate stimulation indices (SI). The irritant potential of the test item was assessed in parallel by measurement of ear thickness on days 1, 2, 3 and 6. The test item was soluble in Ethanol/purified water (50/50, w/w) at the maximum concentration of 10%. Consequently, the concentrations selected for the preliminary test were 1, 2.5, 5 and 10%. Since the test item was not excessively irritant in the preliminary test, the highest concentration retained for the main test was the maximal practicable concentration (10%). No mortality or clinical signs were observed during the study. No cutaneous reactions or notable increase in ear thickness were observed in the animals of the treated groups. A significant lymphoproliferation was noted in the positive control group given HCA. The study was therefore considered valid. No notable lymphoproliferation was noted at any of the tested concentrations (SI from 0.75 to 1.03). Under the experimental conditions of this study, the test item did not induce delayed contact hypersensitivity in the murine Local Lymph Node Assay.

Migrated from Short description of key information:
did not induce delayed contact hypersensitivity in the murine Local Lymph Node Assay.

Respiratory sensitisation

Endpoint conclusion

Additional information:

Migrated from Short description of key information:
No data available.

Justification for classification or non-classification

No classification is warranted for skin sensitization under EU Dangerous Substances Directive 67/548/EEC or CLP EU Regulation 1272/2008.