Ashes (residues), rice husk

Endpoint summary

Description of key information

Rice husk ashes are not irritating to the skin and eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation

Rice husk ashes were tested for acute dermal irritation/corrosion according to OECD guideline 404 and complying with GLP. Three albino rabbits were exposed to 0.5 g of test substance, applied onto the clipped skin for 4 h using a semi-occlusive dressing. Skin reactions were evaluated after patch removal and observations were made at 1, 24, 48 and 72 hours and up to 9 days after exposure. The test substance was applied first on the skin of one rabbit (No. 1), in which no signs of irritation/corrosion were observed upon removal of the patch after the 4-hour exposure. In a confirmatory test, two more rabbits were used (No. 2 and 3). The test item showed irritant but reversible effects on the intact skin of the two animals after a contact time of 4 hours. From days 2-8 in animal No. 2, and from days 3-5 in animal No. 3, both the test site as well as the control site showed redness, which was more in the beginning and thereafter reduced. The irritant effects were fully reversible within 9 days in animal No. 2 and within 6 days in animal No. 3. Neither mortalities nor significant clinical signs of toxicity were observed. For each individual animal (No. 1/2/3), the mean erythema and edema scores over 24, 48 and 72 h were 0/2/1.34 and 0/0.34/0, respectively (Ahuja, 2010).

 

Eye irritation

Rice husk ashes were tested for eye irritation/corrosion inalbino rabbits in a study performed according to the OECD guideline 405 and complying with GLP. The test material (0.1 g) was applied into the conjunctival sac of one eye and removed after 24 h by rinsing with water; the other eye served as control. The eyes were examined and scored 1, 24, 48 and 72 h after application. Initially, one animal was tested only (No. 1), in which no corrosive or severe irritant effects were observed. The negative response was confirmed using two additional animals (No. 2 and 3). One hour post-instillation redness, chemosis and discharge of the conjunctiva were noted in all test animals. Redness of the conjunctiva was observed in animal No. 2 at 24 h, and in animals No. 1 and 3 at 48 h post-instillation. Changes were fully reversible within 72 h post-instillation in animals No. 1 and 3 and within 48 h post-instillation in animal No. 2. Neither mortalities nor significant clinical signs of toxicity were observed. For each individual animal (No. 1/2/3), the mean conjunctiva and chemosis scores over 24, 48 and 72 h were 0.67/0.33/0.67 and 0.33/0.0/0.0, respectively. The mean cornea and iris scores were both 0.0 for all animals (Ahuja, 2010).

Effect level: empty Endpoint conclusion: Adverse effect observed

Justification for classification or non-classification

The available data on the skin and eye irritating potential of rice husk ashes is conclusive but not sufficient for classification according to DSD and CLP criteria for classification and labelling.