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Toxicological information

Carcinogenicity

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Description of key information

The current weight of evidence does not support an association between inhalation exposure to aluminium metal/aluminium oxide and cancer in the respiratory organs. The weight of evidence does not support a systemic carcinogenic effect from exposure to aluminium metal, aluminium oxide and calcium compounds as well.

Key value for chemical safety assessment

Justification for classification or non-classification

Based on the weight of evidence approach for carcinogenicity no classification is required according to DSD or CLP classification criteria.

Additional information

There are no studies available for "Reaction product of thermal process between 1000°C and 2000°C of mainly aluminium oxide and calcium oxide based raw materials with at least CaO+Al2O3 >80% , in which aluminium oxide and calcium oxide in varying amounts are combined in various proportions into a multiphase crystalline matrix". As the substance is an UVCB substance with aluminium oxide (Al2O3) and calcium oxide (CaO) as main constituents, data from aluminium and calcium compounds were taken into account by read across following a structural analogue approach.

Read-across from aluminium compounds:

Systemic Effect

Human studies

Systemic carcinogenic effects from exposure specifically to aluminium have not been investigated in epidemiological studies. One study (Friesen et al., 2009, see section 7.10.2 of the technical dossier) that investigated associations between alumina dust exposure and cancer incidence did not found evidence of an increase in risk of any cancer. The study was based on relatively few cases observed during a short follow-up period, and only crude adjustment for smoking was done. Although aluminium production has been classified by IARC as Group 1 (Carcinogenic to humans), the ATSDR (2008) states that “It is important to emphasize that the potential risk of cancer in the aluminium production industry is probably due to the presence of known carcinogens (e.g., PAHs) in the workplace and is not due to aluminium or its compounds.” The evidence from epidemiological studies does not support a carcinogenic effect.  

 

Animal studies

Available animal studies do not provide evidence supporting a systemic carcinogenic effect of the target compounds. 

 

Local (Respiratory organs)

Human studies

Local carcinogenic effects from exposure specifically to aluminium have not been investigated in epidemiological studies. One study that examined associations between exposure to alumina dust and cancer incidence (Friesen et al., 2009, see section 7.10.2 of the technical dossier) provides no evidence of an increase in the risk of cancers in the respiratory organs. The study was based on relatively few cases observed during a short follow-up period, and only crude adjustment for smoking was done. The available evidence from epidemiological studies does not support a carcinogenic effect.

 

Animal studies

The studies by Gross et al. (1973) (Klimisch Score = 2) and Pigott et al. (1981) do not support a carcinogenic effect for aluminium metal and aluminium oxide.

One study of ultrafine Al2O3 particles administered by intratracheal instillation to rats was identified. Induction of lung tumours was observed. The results from this study lack relevance to actual human exposures due to the mode of administration and the high doses administered.

Due to the high doses applied and the high dose rate, rat-specific effects due to lung overload are likely. 

The available evidence from animal studies does not support a carcinogenic effect specific to aluminium oxide and aluminium metal in humans.

 

In-vitro studies and Mechanism of Action

The results from in-vitro studies indicate that aluminium oxide has low cytotoxicity. 

Overall, the current weight of evidence does not support an association between inhalation exposure to aluminium metal/aluminium oxide and cancers in the respiratory organs. The weight of evidence also does not support a systemic carcinogenic effect from exposure to aluminium metal and aluminium oxide.

 

Read-across from calcium compounds:

A long term toxicity/carcinogenicity study of calcium lactate was performed with 50 male and 50 female F344 rats per group, receiving 2.5 or 5 % calcium lactate via drinking water for 104 weeks (2 years). None of the experimental groups showed a significant increase in the incidence of any specific tumours compared with the corresponding control value, and also no positive trend was noted in the occurrence of any tumour. Therefore, the NOAEL for tumour formation in this study is represented by the high dose of 5 %, corresponding to calcium lactate doses of 2150 and 2280 mg/kg bw/day to male and female rats, respectively. This is equivalent to calcium doses of approximately 279.5 and 296.4 mg Ca/kg bw/day for male and female rats. Accordingly, the lower NOAEL value of 279.5 mg Ca/kg bw/day (male rats) is established as a NOAEL for carcinogenicity hazard assessment (Maekawa et al., 1991).

In addition, a human clinical study suggests that calcium supplementation is associated with a moderate significant reduction of the risk of recurrent colorectal adenomas (Baron et al., 1999).

Furthermore, epidemiological data on cement workers (cement used as a surrogate for lime) indicate no increased overall cancer risk due to inhalation of cement dust in this population (Vestbo et al., 1991).