Registration Dossier

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

Hazard assessment conclusion:
no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Conclusion on classification

The poorly soluble substance zirconium praseodymium yellow zircon is evaluated by comparing the dissolved metal ion levels resulting from the transformation/dissolution test after 7 days (acute) and 28 days (chronic) at a loading rate of 1 mg/L with the lowest acute and chronic ecotoxicity reference values (ERVs) as determined for the (soluble) metal ions, respectively. The ERVs are based on the lowest EC50/LC50 (acute) or NOEC/EC10 (chronic) values for algae, invertebrates and fish. Acute and chronic ERVs were obtained from the Metals classification tool (MeClas) database as follows:


 


Regarding the short-term toxicity, hazard information for praseodymium is not included in the MeClas database. Nevertheless, soluble praseodymium salts (Praseodymium trichloride, EC 233-794-4, CAS 10361-79-2; Praseodymium trinitrate, EC 233-796-5, CAS 10361-80-5) are self-classified as Aquatic Acute 1 (M-factor 1) indicative of an L(E)C50 of > 0.1 ≤ 1 mg/L (https://echa.europa.eu/information-on-chemicals/cl-inventory-database, accessed on 12.03.2021), which is applied to evaluate the aquatic hazard potential of zirconium praseodymium yellow zircon. An acute ERV for silicon has not been derived since a concern for short-term (acute) toxicity of silicon ions was not identified. The acute ERV for zirconium in the MeClas database amounts to 74 mg Zr/L. According to ECHA’s Guidance on the Application of the CLP Criteria (Version 5.0, July 2017), “Where the acute ERV for the metal ions of concern is greater than 1 mg/L the metals need not be considered further in the classification scheme for acute hazard.” Metal release in the T/D test at the 1 mg/L loading and pH 6 resulted in dissolved concentrations of 2.10 µg/L Pr and 0.17 µg/L Zr after 7 days, whereas silicon concentrations remained below the LOD (< 0.07 µg/L Si). Due to the lack of an aquatic hazard potential for silicon and zirconium ions and the fact that dissolved praseodymium concentrations were well below the respective L(E)C50 estimate of > 0.1 ≤ 1 mg/L, it can be concluded that the substance zirconium praseodymium yellow zircon is not sufficiently soluble to cause short-term toxicity at the level of the acute ERVs (expressed as EC50/LC50).


 


Supporting studies (Munk, 1992; Neri, 2010) of the acute toxicity of zirconium praseodymium yellow zircon to zebra fish (Brachydanio rerio) and Pseudokirchneriella subcapitata support the conclusion since toxic effects were not observed at the limit test concentrations of 10,000 mg/L (nominal total concentration of dispersion) and 100 mg/L (nominal concentration of filtered fraction after 3-d stirring), respectively.


 


In accordance with Figure IV.4 “Classification strategy for determining acute aquatic hazard for metal compounds” of ECHA Guidance on the Application of the CLP Criteria (Version 5.0, July 2017) and section 4.1.2.10.2. of Regulation (EC) No 1272/2008, the substance zirconium praseodymium yellow zircon is poorly soluble and does not meet classification criteria for acute (short-term) aquatic hazard.


 


Regarding the long-term toxicity, hazard information for praseodymium is not included in the MeClas database. Nevertheless, soluble praseodymium salts (Praseodymium trichloride, EC 233-794-4, CAS 10361-79-2; Praseodymium trinitrate, EC 233-796-5, CAS 10361-80-5) are self-classified as Aquatic Chronic 1 (M-factor 1) indicative of a NOEC/EC10 of > 0.01 ≤ 0.1 mg/L (https://echa.europa.eu/information-on-chemicals/cl-inventory-database, accessed on 12.03.2021), which is applied to evaluate the aquatic hazard potential of zirconium praseodymium yellow zircon. A chronic ERV for silicon has not been derived since a concern for long-term (chronic) toxicity of silicon ions was not identified. A chronic ERV has also not been derived for zirconium. Metal release in the T/D test at the 1 mg/L loading and pH 6 resulted in dissolved concentrations of 0.79 µg/L Pr and < 0.08 µg/L Zr (< LOD) after 28 days, whereas silicon concentrations remained also below the LOD (< 0.07 µg/L Si). Due to the lack of an aquatic hazard potential for silicon and zirconium ions and the fact that dissolved praseodymium concentrations were well below the respective NOEC/EC10 estimate of > 0.01 ≤ 0.1 mg/L, it can be concluded that the substance zirconium praseodymium yellow zircon is not sufficiently soluble to cause long-term toxicity at the level of the chronic ERVs (expressed as NOEC/EC10).


 


A supporting study (Neri, 2010) of the toxicity of zirconium praseodymium yellow zircon to Pseudokirchneriella subcapitata supports the conclusion since toxic effects were not observed up to and including the limit test concentration of 100 mg/L (nominal concentration of filtered fraction after 3-d stirring).


In accordance with Figure IV.5 „Classification strategy for determining long-term aquatic hazard for metal compounds “of ECHA Guidance on the Application of the CLP Criteria (Version 5.0, July 2017) and section 4.1.2.10.2. of Regulation (EC) No 1272/2008, the substance zirconium praseodymium yellow zircon is poorly soluble and does not meet classification criteria for chronic (long-term) aquatic hazard.


 


In sum, the substance zirconium praseodymium yellow zircon is poorly soluble and does not meet classification criteria of Regulation (EC) No 1272/2008 for acute (short-term) and chronic (long-term) aquatic hazard.

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