Ceramic materials and wares, chemicals

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

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+MgO >80% , in which aluminium oxide, magnesium oxide and calcium oxide in varying amounts are combined in various proportions into a multiphase crystalline matrix”. As this substance is an UVCB substance with aluminium oxide (Al2O3), calcium oxide (CaO) and magnesium oxide (MgO) as main constituents, and since there is no evidence of any skin sensitisation potential for calcium compound, and Mg is neglected because of its essential physiological role, data from aluminium compounds were taken into account by read across following a structural analogue approach.

Read-across from aluminium compounds:

Animal Studies

Results from the non-guideline compliant study (based on the Landsteiner/Draize test) on the sensitisation potential of aluminium oxide (Central Institute for Nutrition and Food Research, 1979) indicate that aluminium oxide is not a skin sensitizer. Data on the physico-chemical characteristics of aluminium oxide and toxicokinetics, and evidence from sufficiently valid results for a closely related compound (aluminium hydroxide, LAB Research Ltd., 2010) and more bioavailable aluminium compounds (aluminium chloride hexahydrate, Basketter et al., 1999; aluminium chloride, Magnusson and Kligman, 1969) support this evaluation. The evidence from animal studies supports a low sensitisation potential for aluminium oxide and aluminium hydroxide on dermal exposure.

Overall, the weight of evidence supports a low sensitisation potential for aluminium oxide.

Based on the available data (Central Institute for Nutrition and Food Research, 1979; LAB Research Ltd, 2010), aluminium oxide and aluminium hydroxide does not require classification as a skin sensitizer.

 

Human Studies

One small study of relatively weak design (Hosovski et al. 1998) observed higher rates of skin hypersensitivity, increased aluminium dermal responsiveness and increased serum IgA and IgG levels among aluminium smelter workers compared with an “unexposed” control group. Thomas et al. (2003) found no positive patch-test reactions to ceramic alumina disks in a sample of 251 consecutive cases visiting a dermatology clinic. Although limited in amount, the evidence from human studies supports a low sensitisation potential for aluminium oxide on dermal exposure.

 

 

Calcium compounds:

There is no evidence of any sensitisation potential for calcium compounds. In presence of moisture the lime substances under consideration dissociate into calcium cations and hydroxyl anions, leading to a pH shift.

Generally a pH shift does not possess any sensitising potential. Calcium is abundantly available in the environment, in food and extensively distributed throughout the human body, which is contradictory to allegation of sensitisation potential. A skin sensitisation test would more or less mimic physiological conditions and thus, the result is clearly predictable as “negative”. Absence of any information indicating skin sensitising potential of calcium hydroxide is documented in the toxicity profile of Ca(OH)2, published by BIBRA (Anonymous, 1988).

Magnesium oxide (MgO):

Magnesium oxide (MgO) is exempted from registration according to EC 1907/2006 Annex V Section 10.

 

Migrated from Short description of key information:
Overall, the read-across from studies from aluminium compounds does not support a sensitisation potential 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+MgO >80% , in which aluminium oxide, magnesium oxide and calcium oxide in varying amounts are combined in various proportions into a multiphase crystalline matrix”

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

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+MgO >80% , in which aluminium oxide, magnesium oxide and calcium oxide in varying amounts are combined in various proportions into a multiphase crystalline matrix”. As this substance is an UVCB substance with aluminium oxide (Al2O3), calcium oxide (CaO) and magnesium oxide (MgO) as main constituents, and since there is no evidence of any respiratory sensitisation potential for calcium compound, and Mg is neglected because of its essential physiological role, data from aluminium compounds were taken into account by read across following a structural analogue approach.

 

 

Read-across from aluminium compounds:

Based on an assessment of the available data, the weight of evidence does not support an important role for alumina in the development of potroom asthma. The weight of evidence supports an irritative effect of the fluoride component of pot emissions (Taiwo et al., 2006; Søyseth et al., 1992, 1994, 1997; Sorgdrager et al., 1998; Kongerud and Samuelsen, 1991). Work-related asthmatic symptoms in potroom workers may result, in part, from non-specific “irritant” and also from “allergic inflammation” reactions (Sariҫet al., 1986; Mackay et al., 1990; Eklund et al., 1989). The relative contributions of these mechanisms are unclear and individuals with pre-existing bronchial hyper-responsiveness or a history of respiratory allergy may be at increased risk (Barnard et al., 2004; Kongerud and Samuelsen, 1991).

Some studies among aluminium welders have shown decrements in lung function (Fishwick et al., 2004; Abbate et al., 2003; Nielsen et al., 1993) and others have not (Sjogren and Ulfvarson, 1985; Kilburn et al., 1989). Sjogren and Ulfvarson (1985) observed an association between respiratory symptoms and exposures to ozone among welders. The small sample sizes, questionable comparability of referent groups (e.g. Kilburn et al., 1989) and possible (residual) confounding by smoking and irritative co-exposures such as ozone and other fume constituents are limitations of the available studies.

Results from a few case reports, notably Vandenplas et al. (1998) (also Park et al.,1996 and Burge et al., 2000) indicate that respiratory sensitization on exposure to poorly soluble aluminium substances can occur, but results from larger studies (Fritschi et al., 2001; Beach et al., 2001; Taiwo et al., 2006) suggest that it is rare. 

The only animal study identified that employed a guideline assay with results relevant to the respiratory sensitization endpoint and the target substances (the LLNA; Basketter et al., 1999) found that aluminium chloride, a more soluble aluminium substance, did not possess “significant ability to sensitize the skin”. As discussed by ECHA (2008): “In combination with other data it might be possible to conclude in a WoE assessment that chemicals that (at an appropriate test concentration and test conditions, i.e. skin penetration should have occurred) are negative in the LLNA, as well as being considered as not being skin sensitizers, can also be regarded as lacking the potential to cause allergic sensitisation of the respiratory tract.” (ECHA, 2008). The mouse study of Ichinose et al. (2008) supports a weak allergic inflammatory potential for Al2O3. In addition, the guideline compliant study by Lab Research Ltd. (2010) that tested the skin sensitisation potential of Al(OH)₃ reported negative results, thereby contributing to the weight of evidence supporting a low sensitizing potential for the poorly soluble target substances

 

Magnesium oxide (MgO):

Magnesium oxide (MgO) is exempted from registration according to EC 1907/2006 Annex V Section 10.

Migrated from Short description of key information:
Based on the read-across within a weight of evidence approach,“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+MgO >80% , in which aluminium oxide, magnesium oxide and calcium oxide in varying amounts are combined in various proportions into a multiphase crystalline matrix” does not require classification as a respiratory sensitizer.

Justification for classification or non-classification

Overall, according to DSD or CLP classification criteria for sensitisation, no classification is required.