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EC number: 227-579-4
CAS number: 5895-46-5
Solubility: The substance has a low water solubility of 3.65 mg/L.
Acute toxicity to aquatic organisms: Acute data on the three trophic
levels (fish, Dapnia and algae); all show an absence of toxicity. In the
case of fish and algae results read-across from cerium carbonate the
EC50values are greater than the initial loading rate of 100 mg/L. For
these studies Water Accomodated Fraction (WAF) methodology was used to
prepare a super-saturated solution of test item: an initial loading rate
of 100 mg/L was added and then stirred during a period pre-determined to
allow a maximum solubility of the test item. At the end of the stirring
phase, a sedimentation period was conducted. Then, the supernatant was
collected and considered as a supersaturated solution containing the
maximum concentration of dissolved test item. Test organisms were
therefore exposed to the substance up to its solubility limit into
water. In the case of the acute toxicity to Daphnia study the test
results are quoted in terms of mean measured concentration based on
ICP-MS analysis of neodymium. In each study case it appears that the
maximum solubility limits were lower than those obtained during the
water solubility test using column elution method. rved this. This is
considered to be the the water media being different between water
solubility test (Milli-Q-water) and ecotoxicological studies (media
containing analytical grade salts). As a result of this during the
ecotoxicity tests, the test item, dineodymium carbonate, can complex
with salts from the test medium; resulting in a reduced concentration of
dissolved test item. In summary, it is considered that the maximum
solubility limit was attained during the ecotoxicity studies and that
since no adverse effects were observed up to this value dineodymium
carbonate has been shown not to be acutely harmful to aquatic organisms.
Biodegradation: Biodegradation tests are not applicable to inorganic
substances. Abiotic and biotic degradation will not occur.
Bioaccumulation: No bioaccumulation data are available on insoluble
salts of neodymium. However, literature data (Bioconcentration and
elimination of five light rare earth elements in carp, Hao et al, 1996,
as summarised in Section 5.3.1) provide data on the soluble salt
neodymium nitrate. These data show that the highest potential for
bioaccumulation is within the internal organs of carp (highest BCF = 634
after 29 days) but that BCF values begin to decline after this time,
reducing to 451 at 43 days (the end of the study period). Elimination is
considered to be via a first-order process and the half-life of
neodymium in internal organs is given as 6.30 days. By analogy to
neodymium carbonate it can be predicted that dineodymium tricarbonate is
unlikely to be bioaccumulative. Furthermore, being poorly water soluble
this substance can be expected to be less bioavailable than soluble
salts for bioaccumulation.
Chronic toxicity results: A chronic test on daphnids has been
read-across from cerium carbonate. This was performed using WAF
methodology. Based on the same reasoning reported above for the acute
fish and algal inhibition tests tests, it can be concluded that the
maximum concentration of dissolved test item was tested. As no chronic
effect was observed at the highest loading rate, cerium carbonate does
not show any chronic effect up to its solubility limit into water.
Conclusion: In the absence of toxicity to aquatic organisms in acute and
chronic studies in which the substance was tested up to its maximum
dissolved concentration and in the absence of a potential to
bioaccumulate it is concluded that classification of the substance for
environmental effects is not required.
PBT assessment: According to the Guidance on information requirements
and chemical safety assessment, Chapter R.11: PBT assessment, “the PBT
and vPVB criteria of Annex XIII to the regulation do not apply to
inorganic substances”. Therefore it is not considered necessary to
undertake further assessment of PBT properties.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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