Registration Dossier
Registration Dossier
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EC number: 266-340-9 | CAS number: 66402-68-4 This category encompasses the various chemical substances manufactured in the production of ceramics. For purposes of this category, a ceramic is defined as a crystalline or partially crystalline, inorganic, non-metallic, usually opaque substance consisting principally of combinations of inorganic oxides of aluminum, calcium, chromium, iron, magnesium, silicon, titanium, or zirconium which conventionally is formed first by fusion or sintering at very high temperatures, then by cooling, generally resulting in a rigid, brittle monophase or multiphase structure. (Those ceramics which are produced by heating inorganic glass, thereby changing its physical structure from amorphous to crystalline but not its chemical identity are not included in this definition.) This category consists of chemical substances other than by-products or impurities which are formed during the production of various ceramics and concurrently incorporated into a ceramic mixture. Its composition may contain any one or a combination of these substances. Trace amounts of oxides and other substances may be present. The following representative elements are principally present as oxides but may also be present as borides, carbides, chlorides, fluorides, nitrides, silicides, or sulfides in multiple oxidation states, or in more complex compounds.@Aluminum@Lithium@Barium@Magnesium@Beryllium@Manganese@Boron@Phosphorus@Cadmium@Potassium@Calcium@Silicon@Carbon@Sodium@Cerium@Thorium@Cesium@Tin@Chromium@Titanium@Cobalt@Uranium@Copper@Yttrium@Hafnium@Zinc@Iron@Zirconium
Toxicity to soil microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
Based on the justification of both main components, it can be concluded:
Aluminium, aluminium powders and aluminium oxide are non hazardous (not classified for the environment). Aluminum (Al) is the most commonly occurring metallic element, comprising eight percent of the earth's crust (Press and Siever, 1974) and is therefore found in great abundance in both the terrestrial and sediment environments.
In the environment, lime substances rapidly dissociate or react with water. From these reactions it is clear that the effect of calcium oxide will be caused either by calcium or hydroxyl ions. Since calcium is abundantly present in the environment and since the effect concentrations are within the same order of magnitude of its natural concentration, it can be assumed that the adverse effects are mainly caused by the pH increase caused by the hydroxyl ions.
Key value for chemical safety assessment
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 this substance is an UVCB substance with aluminium oxide (AL2O3) and calcium oxide (CaO) as main constituents, data and justification based on both main components were taken into account.
Aluminium-compounds:
Aluminium, aluminium powders and aluminium oxide are non hazardous (not classified for the environment). Aluminum (Al) is the most commonly occurring metallic element, comprising eight percent of the earth's crust (Press and Siever, 1974) and is therefore found in great abundance in both the terrestrial and sediment environments. Concentrations of 3-8% (30,000-80,000 ppm) are not uncommon. The relative contributions of anthropogenic aluminium to the existing natural pools of aluminium in soils and sediments is very small and therefore not relevant either in terms of added amounts or in terms of toxicity. Based on these exposure considerations additional sediment and/or soil testing is not warranted. More information about exposure based waiving for aluminium in soil and sediments can be found in attached document (White paper on exposure based waiving for Fe and Al in soils and sediments final 15-03-2010. pdf, see attachment).
Calcium-compounds:
The chronic study on the effect of calcium dihydroxide on the nitrogen transformation in an agricultural loamy sand soil (Schulz, 2007a) was carried out according to OECD 216. The study is well documented, all validity criteria are fulfilled. As such a Klimisch 1 score was assigned to the study. Reported 96d-EC50 and 96d-NOEC values for nitrogen transformation equalled >12 g Ca(OH)2 /kg soil dw and ≥12 g Ca(OH)2 /kg soil dw, respectively.
The chronic study on the effect of calcium dihydroxide on the dehydrogenase activity in an agricultural loamy sand soil (Schulz, 2007b) was conducted according to German guidelines for testing of plant protection products (BBA VI, 1-1, 1990). The methods and results are well documented. As such a Klimisch 1 score was assigned to the study. Reported 96d-EC50 and 96d-NOEC values for dehydrogenase activity equalled 8.7 g Ca(OH)2 /kg soil dw and 4 g Ca(OH)2 /kg soil dw, respectively.
In the environment, lime substances rapidly dissociate or react with water. These reactions, together with the equivalent amount of hydroxyl ions set free when considering 100mg of the lime compound (hypothetic example), are illustrated below:
Ca(OH)2 <-> Ca2+ + 2OH-
100 mg Ca(OH)2 or 1.35 mmol sets free 2.70 mmol
CaO + H2O <-> Ca2+ + 2OH-
100 mg CaO or 1.78 mmol sets free 3.56 mmol
From these reactions it is clear that the effect of calcium oxide will be caused either by calcium or hydroxyl ions. Since calcium is abundantly present in the environment and since the effect concentrations are within the same order of magnitude of its natural concentration, it can be assumed that the adverse effects are mainly caused by the pH increase caused by the hydroxyl ions. Furthermore, the above mentioned calculations show that the base equivalents are within a factor 2 for calcium oxide and calcium hydroxide. As such, it can be reasonably expected that the effect on pH of calcium oxide is comparable to calcium hydroxide for a same application on a weight basis. Consequently, read-across from calcium hydroxide to calcium oxide is justified.
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