Reaction mass of aluminium and aluminium oxide and calcium oxide and magnesium oxide

Endpoint summary

Description of key information

It is recommended that aluminium oxide is not to be classified for acute oral, dermal and inhalation toxicity.
Oral LD50 (rat) > 2000 mg/kg bw
Inhalation LC50 (rat) >  2.3 mg/L

Additional information

Oral route:

The available data are adequate to meet the REACH information requirements for aluminium oxide with respect to acute toxicity. According to the reported results (acute oral toxicity study, Hazleton Laboratories, USA 1969; Central Institute for Nutrition and Food Research, Germany 1979a; Central Institute for Nutrition and Food Research, Germany 1979b, Central Institute for Nutrition and Food Research, Germany 1979c; IUCLID, Aluminium Oxide Dataset, 2000; and Balasubramanyam et al., 2009b and Balasubramanyam et al., 2009a), the oral LD₅₀for aluminium oxide is above 2000 mg/kg bw in both female and male rats.

 

Based on the available data, it is proposed that aluminium oxide need not be classified for acute oral toxicity.

Dermal route:

In a human dermal absorption study, Flarend et al. (2001) showed, that aluminium is absorbed into the systemic circulation on single application with occlusion of aluminium chlorohydrate to underarms. Based on urine measurements, 0.01% of the applied aluminium was absorbed showing that aluminium does not cross the dermal barrier effectively. Thus, a dermal study is not necessary.

Inhalation route:

Animal Studies

The study by Cabot (1996) was conducted according to EPA Guidelines for Test Procedures Subdivision F, Series 81-3 and TSCA 40 CFR 798.1150. Five healthy male and five healthy female Wistar Albino rats were exposed to fumed alumina in an inhalation chamber for 4 hours. The number of animals used and the exposure duration were adequate according to the guidelines. The air concentration in the chamber, determined gravimetrically, was 2.3 mg/L.  Only one concentration was tested. The average mass median diameter was 2.58 µm with a geometric standard deviation of 3.10 µm (2.31 µm, GSD 2.97 in the first 30 second sampling period and 2.85 µm, GSD 3.22 in a second sampling period). Chamber airflow, temperature (20.7 – 23.3 ºC) and humidity (60 to 61%) were monitored throughout the exposure period. Animals were observed for signs of toxicity at approximately one hour intervals during exposure, at one hour post exposure and then daily during a 14 day exposure period. Body weights were recorded pre-test, weekly and at termination.  No deaths were observed during exposure or during the 14 day post-exposure period. All animals had closed eyes, wet nose/mouth areas and fur coated with the test materials during the exposure. Observations were normal during the 14-day post-exposure period. Weight gain was normal in all the male animals. Weight loss was observed in two females on day 7 of the post-exposure period and in another two females on day 14. Lungs that were darker than normal with red areas were observed in only one female on necropsy. Based on the results of this study, the LC₅₀ is greater than 2.3 mg/L. The main limitations of this study were the lack of description of the test materials and the use of only one concentration with no rationale provided for the level chosen. 

Justification for classification or non-classification

According to DSD (67/548/EEC) or CLP (1272/2008/EC) classification criteria for acute toxicity, no classification is warranted.