Dicerium tricarbonate

Endpoint summary

Additional information

There is no data on the dicerium tricarbonate, but data on the ecotoxicity of the cerium oxide in soil exist. If we compare these two substances, the physico-chemical, toxicological andecotoxicological properties are very closed and similar (please see the enclosed table, presenting these properties). According to these strong similarities, the read across for the assessment of the soil ecotoxicity –part 6.3 of the dossier) between the cerium oxide (existing datas) and dicerium tricarbonate is appropriate.

Physico-chemical properties	Cerium Oxide	Dicerium Carbonate
Physical state at 20°C and 1013 hPa	Inorganic solid appearing under the form of a white ivory to creamy white-pale beige powder at ambient temperature and pressure.	Inorganic white to beige solid or in some case powder at normal pressure and temperature.
Melting / freezing point	Cerium dioxide did not melt under the conditions of the test. Melting point > 400°C.	Dicerium tricarbonate did not melt under the conditions of the test. Melting point > 400°C.
Boiling point	Cerium dioxide did not boil under the conditions of the test. Boiling point > 400°C	Dicerium Tricarbonatedid not boil under the conditions of the test. Boiling point > 400°C
Relative density	7.20 g/cm3 at 20.3°C+/- 0.1°C.	2.29 g/cm3 at 20.3°C +/- 0.1°C.
Water solubility	< 0.123 µg/L at 20°C .	3.95 mg/L (+/- 0.2 mg/L) at 20°C
Flammability	Flammability: not highly flammable under the conditions of test.   Pyrophoricity and flammability in contact with water: Based on the absence of structutal alerts and on the knowledge from use and handling, it is unlikely that cerium dioxide shows such properties.	Flammability:not highly flammable under the conditions of test.   Pyrophoricity and flammability in contact with water: Based on the absence of structutal alerts and on the knowledge from use and handling, it is unlikely that dicerium tricarbonate shows such properties.
Explosive properties	Cerium dioxide does not present a danger of explosion under the conditions of the test.	Dicerium tricarbonate does not present a danger of explosion under the conditions of the test.
Self-ignition temperature	> 400°C (pressure not indicated).	> 400°C (pressure not indicated)
Oxidising properties	Cerium dioxide has no oxidizing properties under the conditions of the test.	Dicerium tricarbonate has no oxidizing properties under the conditions of the test.
Ecotoxicity tests	Cerium Oxide	Dicerium Carbonate
6.1.1 Short term toxicity to fish (96h)	LL50 > 100 mg/L NOELR > 100 mg/L   No acute toxic effects on fish	LL50 > 100 mg/L NOELR > 100 mg/L   No acute toxic effects on fish
6.1.3 Short term toxicity to aquatic invertebrate (48h)	NOEC>1000 mg/L LL50 > 1000 mg/L                 No acute toxic effects on Daphnia magna	NOEC>100 mg/L LL50 > 100 mg/L      No acute toxic effects on Daphnia magna
6.1.4 Long term toxicity to aquatic invertebrate (21 d)	NOERC > 100 mg/L LOELR > 100 mg/L   No toxic effect on survival and reproduction of Daphnia magna	NOERC > 130 mg/L LOELR > 130 mg/L   No toxic effect on survival and reproduction of Daphnia magna
6.1.5 Toxicity to aquatic algae and cyanobacteria	72h-LOELR = 100 mg/L. 72h-NOELR = 50 mg/L. 72h-EL50 > 100 mg/L.   The reduction of growth here observed was probably caused by an indirect effect of phosphate lack, rather than a toxic effect of cerium dioxide.	72h-LOELR = 50 mg/L. 72h-NOELR = 25 mg/L. 72h-EL50 > 100 mg/L.   The growth inhibition determined at these loading rates may have been caused by depletion of phosphate in the test medium, rather than a toxic effect of dicerium tricarbonate.
6.1.7 Toxicity to activated sludge in a respiration inhibition test	3h NOEC>1003.8 mg/L 3h EC 20 > 1003.8 mg/L 3h EC 50 > 1003.8 mg/L 3h EC 80 > 1003.8 mg/L   No acute toxic effects on microorganisms	3h NOEC>1000 mg/L 3h EC 20 > 1000 mg/L 3h EC 50 > 1000 mg/L 3h EC 80 > 1000 mg/L No acute toxic effects on microorganisms
Toxicity Tests:	Cerium Oxide	Dicerium Carbonate
7.2.1 Acute toxicity: oral (rat)	Oral LD50 Combined male/female > 5000 mg/kg bw   Substance not classified	Oral LD50 Combined male/female > 5000 mg/kg bw   Substance not classified
7.2.2 Acute toxicity: dermal (rat)	Dermal LD50 > 2000 mg/kg bw   Substance not classified	Dermal LD50 > 2000 mg/kg bw   Substance not classified
7.3.1 Skin Irritation / Corrosion	Irritation Score (Draize Method): 0   Cerium Oxide is not a dermal irritant.	Irritation Score (Draize Method): 0   Dicerium Tricarbonate is not a dermal irritant.
7.3.2 Eye Irritation / Corrosion	Mean ocular irritation scores (Draize) were 9.33, 1.33 and 0.67 at 1 h after instillation and on days 1 and 2, respectively. All the irritation signs had reversed by day 3   The test substance was not classified as irritant to the eye, according to the criteria of Annex VI Directive 67/548/EEC.	Draize scores: Unwashed eyes (3 rabbit mean): 6.7 (24h), 2.0 (48h), 0.7 (72h) Draize scores: Washed eyes (3 rabbit mean): 4.7 (24h), 2.0 (48h), 1.3 (72h)     Dicerium Tricarbonate is slightly irritant to the eye but not classified according to EU criteria.
7.4.1 Skin Sensitisation	Dicerium Tricarbonate is not classified as skin sensitising according to Annex VI of the Directive 67/548/EEC.	Dicerium Tricarbonate is not classified as skin sensitising according to Annex VI of the Directive 67/548/EEC.
7.5.1 Repeated Dose Toxicity: Oral	NOEL = 1000 mg/kg LD50 > 1000 mg/kg   Cerium Oxide is not classified as skin sensitising according to Annex VI of the Directive 67/548/EEC.	NOEL = 450 mg/kg LD50 > 1000 mg/kg   Dicerium Tricarbonate is not classified as skin sensitising according to Annex VI of the Directive 67/548/EEC.
7.6.1 Genotoxicity in vitro -	No mutagenic effect at 5000 µg/plate   Cerium Oxide is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.	No mutagenic effect at 5000 µg/plate   Dicerium tricarbonate is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.
7.6.1 Genotoxicity in vitro –Gen. Tox in vitro HPRT	Cerium Oxide did not induce gene mutations at the HPRT locus in V79 cells up to the concentration of 1800 µg/mL with or without S9.   No evidence of gene mutations at the HPRT locus in V79 cells up to the concentration of 1800 mg/mL with or without S9	Dicerium Tricarbonate did not induce gene mutations at the HPRT locus in V79 cells up to the concentration of 2300 µg/mL with or without S9.   As a conclusion it can be stated that under the experimental conditions reported the test item did not induce gene mutations at the HPRT locus in V79 cells.
7.8.1 Toxicity to reproduction	NOEL parent = 1000 mg/kg/day NOEL progeny = 1000 mg/kg/day. Substance not classified	NOEL parent = 1000 mg/kg/day NOEL progeny = 1000 mg/kg/day. Substance not classified

 

Toxicity to soil macroorganisms:

Only one study of reliability 2 according to Klimisch was available (Hooftman R N & Henzen L, 1996) and was selected as a key study.

Cerium Dioxide has been tested for acute toxicity toEisenia foetida. The study was carried out according to the OECD Guideline 207 and in compliance with the principles of Good Laboratory Practices.

Worms were exposed to cerium dioxide mixed with artificial soil at a concentration of 1000 mg/kg of dry soil for a 14-day period.

No significant effect with respect to survival, weight, behaviour or appearance was observed.

This data is used in a read-across approach to conclude on the acute toxicity of dicerium tricarbonate to terrestrial organisms. As cerium dioxide is considered as not harmful to the tested terrestrial organism, dicerium tricarbonate should not be considered as harmful to the terrestrial organisms either.

Toxicity to terrestrial plants:

Only one study of reliability 2 according to Klimisch was available (Hooftman R N & Henzen L, 1996) and was selected as a key study.

Cerium dioxide has been tested for its toxicity to plant speciesAvena sativa, Lactuca sativaandBrassica rapa,according to the OECD Guideline 208 and in compliance with the principles of GLP.

Four replicate of 5 plants were grown in a mixture of agricultural soil and coarse sand, supplemented with potassium and phosphorus.

Cerium dioxide was tested at the limit concentration of 1000 mg/kg dry soil for the three plant species, in parallel to a control.

Cerium dioxide did not cause reduction of emergence for any of the plant species tested.

This data is used in a read-across approach to conclude on the acute toxicity of dicerium tricarbonate to terrestrial plants. As cerium dioxide is not considered as harmful to the tested plant species, we conclude that dicerium tricarbonate will not be considered as harmful to the tested plant species.

Toxicity to soil microorganisms:

Only one study of reliability 2 according to Klimisch was available (Muttzall P.I. & Hanstveit A.O., 1996) and was selected as a key study.

Cerium dioxide has been tested for its toxicity on the carbon mineralisation activity of soil microorganisms. The study was carried out according to a draft proposal for a new OECD Guideline (June 1996) and in compliance with the principles of Good Laboratory Practices.

A non limiting glucose concentration of 1000 mg/kg was added to a sandy loam soil as carbon source. The following nominal concentration of cerium dioxide were tested : 0, 10, 32, 100, 320 and 1000 mg/kg dry soil. After 14 and 28 days of incubation the carbon mineralisation activity was determined by measuring the CO2 evolution.

The statistical evaluation of the carbon mineralisation activity shows two significant deviation compared tothe control; a stimulation of the activityat 10 mg/kg and an inhibition of the activity at 32 mg/kg. But as this inhibitory effect was not observed at higher concentrations of cerium dioxide, it is considered as an artefact.

Cerium dioxide at a concentration of at least 1000 mg/kg dry soil shows no adverse effect on the carbon mineralisation activity of the microbial biomass in soil. The NOEC is equal or higher than 1000 mg/kg. Cerium dioxide, and by read-across dicerium tricarbonate, are therefore not expected to have a long-term influence on carbon mineralisation in soil.

This data is used in a read-accross approach to conclude on the toxicityof dicerium tricarbonateto the soil micro-organisms. As cerium dioxide shows no adverse effect on the carbon mineralisation activity of the microbial biomass in soil, dicerium carbonate is not expected to present this kind of toxic properties neither.