reaction mass of neodymium carbonate and praseodymium carbonate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Three OECD 422 studies conducted on analogues of the reaction mass of neodymium carbonate and praseodymium carbonate were available and used in a weight-of-evidence approach. These studies were awarded a reliability score of 2 (Klimisch, 1997), due to read-across (ECHA Practical Guide n°6), and were thus considered sufficient for assessment of fertility impairment via oral route, therefore the overall quality of the dataset is considered to be good.

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

There was no reproduction toxicity study available on the reaction mass of neodymium carbonate and praseodymium carbonate. However, 3 studies were available on analogous substances of the reaction mass (i.e. dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide). The reaction mass of neodymium carbonate and praseodymium carbonate was a solid substance with a high melting point (> 450°C), a molecular weight of 926 - 940 g/mol, and a slight water solubility of 3.93 mg/L. As the substance was an inorganic, no partition coefficient (log Pow / Kow) could be determined. In addition, the reaction mass displayed a weak bioavailability and a low potential for toxicity. The physico-chemical and toxicological characteristics of the 3 analogues, dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide, were similar to the ones of the reaction mass: solid inorganic substances with a high melting point > 300°C, a relatively high molecular weight > 330 g/mol, a low water solubility ranging from 7.8 µg/L to 3.95 mg/L, weak bioavailability and a low potential for toxicity (see the justification document for read across attached in section 13 for a detailed argumentation). Therefore, the data from these analogues were used in a weight-of-evidence approach to conclude on the reproduction toxicity of the reaction mass of neodymium carbonate and praseodymium carbonate for the oral route of exposure.

 

First, the fertility effects of dicerium tricarbonate were tested in rats by the oral route in a combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (Davies R., 2008). Conducted in accordance with the OECD guideline 422 and in compliance with GLP, this study was scored as Klimisch 2 (due to read-across approach) and flagged as weight of evidence. Male and female Sprague-Dawley rats (10/sex and dose) were daily administered, by gavage, the test item at 0 (vehicle: 0.5% aqueous methylcellulose), 150, 450 or 1000 mg/kg bw/day for around 4 (male) to 8 weeks (female), i.e. 2 weeks before mating, throughout mating for both sexes, and during gestation and until day 5 post-partum for females. The following parameters and endpoints were evaluated in parental animals and pups: mortality, clinical signs, detailed functional tests and observations, bodyweights, food consumption, clinical pathology parameters (haematology, and blood biochemistry), gross necropsy findings, organ weights, and histopathological examinations, mating and pregnancy performance, fertility, maternal care and pup performance (litter size, pup number and weights, gross pathology).

 

There were no adverse effects of treatment at any dose-level on mortality, clinical signs, body weight or food consumption. Animals treated at 1000 mg/kg bw/day had lower white blood cell counts and females in this group had lower chloride concentration and higher glucose, potassium, inorganic phosphorus and urea levels. These effects were considered not toxicologically relevant.

There were no effects in any group on mating, fertility or delivery and no treatment-related effects on the mean numbers of corpora lutea, implantations or pups. There were no effects on mean pup body weight, survival or sex.

There were no treatment-related organ weights and macroscopic changes in rats treated at 1000 mg/kg/day.

At 450 or 150 mg/kg/day, there were no treatment-related organ weights and macroscopic changes.

However, there were microscopic treatment related findings in the stomach that consisted of increased incidence and/or severity of submucosal eosinophil infiltration and pyloric gland hyperplasia in rats from both sexes treated at 1000 mg/kg/day and males at 450 mg/kg/kg. However, the microscopic findings in the stomach were likely to be related to portal-of-entry irritating effects, due to the high concentrations of the substance given as a bolus by gavage.

No microscopic treatment related changes were observed in the testes and ovaries.

 

Based on the experimental conditions of this study, the No Observed Effect Level (NOEL) for reproductive effects in rats was considered to be 1000 mg/kg bw/day for both males and females and the NOEL for toxic effects on progeny was 1000 mg/kg bw/day. Therefore, dicerium tricarbonate induced no fertility impairment, based on the absence of adverse effects on mating, fertility, and progeny up to the limit-dose level of 1000 mg/kg bw/day.

 

In a second reprotoxicity study, the fertility effects of neodymium oxide were tested in rats by the oral route in a combined repeated dose toxicity study with the reproduction/developmental toxicity screening test, as described above for dicerium tricarbonate (Laidlaw K., 2014). Conducted in accordance with the OECD guideline 422 and in compliance with GLP, this study was scored as Klimisch 2 (since used as read-across) and flagged as weight of evidence. Three groups of 10 male and 10 female Sprague-Dawley rats were dosed once daily, by gavage, with the test material at dose levels of 0 (vehicle: 1% w/v carboxymethylcellulose), 100, 300, or 1000 mg/kg bw/day.The males were treated for 2 weeks prior to mating, then through mating, until the day prior to necropsy (ca. 4 weeks of treatment). Females were treated for 2 weeks prior to mating, then through mating, gestation and until at least Day 4 of lactation (ca. 7 weeks of treatment). The following parameters and end points were evaluated: mortality, clinical signs, bodyweights, bodyweight changes, food consumption, ophthalmology, detailed functional tests and observations, clinical pathology parameters (haematology, coagulation and clinical chemistry), gross necropsy findings, organ weights, and histopathological examinations, mating and pregnancy performance, fertility, maternal care and pup performance (litter survival and pup weights).

 

Mating performance, fertility indices, corpora lutea and implantation counts, duration of gestation, and the mean number of live pups born per litter were similar between control and treated females. Litter survival, litter weights and mean pup weights were similar between litters derived from control and treated females.

 

Under the conditions of this study in Sprague-Dawley rats, the NOEL for reproductive effects was considered to be 1000 mg/kg bw/day for both males and females. The NOEL for toxic effects on progeny was 1000 mg/kg bw/day. Therefore, neodymium oxide induced no fertility impairment, based on the absence of adverse effects on mating, fertility, and on progeny up to the limit-dose level of 1000 mg/kg bw/day.

 

These results were further corroborated by a third reproduction/developmental toxicity screening test on another analogue of the reaction mass: praseodymium(III,IV) oxide (Wallace I., 2012). Conducted in accordance with the OECD guideline 422 and in compliance with GLP, this study was scored as Klimisch 2 (since used as read-across) and flagged as weight of evidence. Male and female Sprague-Dawley rats (10/sex and dose) were daily administered, by gavage, the test item at 0 (vehicle: 0.5% w/v methylcellulose), 100, 300, or 1000 mg/kg bw/day for around 4 (male) to 7 weeks (female), i.e. prior to mating, throughout mating for both sexes, and during gestation and the first 4 days of lactation for females. The following parameters and end points were evaluated in this study: clinical signs, bodyweights, food consumption, ophthalmology, detailed functional tests and observations, reproductive parameters (mating and pregnancy performance, fertility, maternal care and pup performance), clinical pathology parameters (haematology, coagulation and clinical chemistry), organ weights, and gross and microscopic pathological examinations.

 

Mating performance, fertility indices, corpora lutea and implantation counts, duration of gestation, and the mean number of live pups born per litter were similar between control and treated animals. Litter survival, litter weights and mean pup weights were similar between litters derived from control and treated females.

 

Thus, the No Observed Adverse Effect Level (NOAEL) for reproductive effects in Sprague-Dawley rats was considered to be 1000 mg/kg bw/day for both males and females. The NOAEL for toxic effects on progeny was 1000 mg/kg bw/day. Therefore, praseodymium(III,IV) oxide induced no fertility impairment, based on the absence of adverse effects on mating, fertility, and progeny up to the limit-dose level of 1000 mg/kg bw/day.

 

Regarding fertility effects via inhalation and dermal routes, no study was available. Indeed, based on the available data and in accordance withcolumn 2 adaptation of REACh Annex VIII (section 8.7) and section 1 of REACH Annex XI, reproduction toxicity studies via inhalation and dermal routes do not need to be conducted if these studies do not appear to be scientifically necessary. The screening for reproduction and developmental toxicity studies conducted via oral route and performed according to the OECD guideline 422 (weight of evidence from dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) already sufficiently address the reproduction toxicity data requirements for the reaction mass. Furthermore, as the substance is used as an intermediate, the exposure will be limited only to professionals using appropriate protection equipment.

 

As a consequence, by analogy, the reaction mass of neodymium carbonate and praseodymium carbonate is considered to have no potential for fertility effects via the oral route and therefore does not need to be classified according to the criteria of Annex VI of Directive 67/548/EEC, Regulation (EC) No. 1272/2008 and UN GHS.

 

Reproduction toxicity	Reaction mass of neodymium carbonate and praseodymium carbonate	Dineodymium tricarbonate	Dipraseodymium tricarbonate	Dicerium tricarbonate	Neodymium oxide	Praseodymium(III,IV) oxide
Oral route - rat	no data	no data	no data	NOEL (mating and fertility, both sexes) = 1000 mg/kg bw/day NOEL (progeny) = 1000 mg/kg bw/day (OECD 422, GLP)	NOEL (mating and fertility, both sexes) = 1000 mg/kg bw/day NOEL (progeny) = 1000 mg/kg bw/day  (OECD 422, GLP)	NOAEL (mating and fertility, both sexes) = 1000 mg/kg bw/day NOAEL (progeny) = 1000 mg/kg bw/day  (OECD 422, GLP)
Inhalation route	no data	no data	no data	no data	no data	no data
Dermal route	no data	no data	no data	no data	no data	no data

Short description of key information:
- Mating and fertility (weight-of-evidence approach based on dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide):
NOAEL (oral, rat) = 1000 mg/kg bw/day for both males and females

- Toxicity to progeny (weight-of-evidence approach based on dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide):
NOAEL (oral, rat) = 1000 mg/kg bw/day

Justification for selection of Effect on fertility via oral route:
Three studies done on analogous substances of the reaction mass were selected in a read-across strategy and considered together using a weight-of-evidence approach to conclude on the reaction mass of neodymium carbonate and praseodymium carbonate (i.e. dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide).
All studies were conducted in compliance with GLP and according to the OECD guideline 422. Well described and meeting the generally acceptable scientific principles, these studies were awarded a reliability score of 2 (Klimisch, 1997), since used as read-across (ECHA Practical Guide n° 6), and were flagged as weight of evidence.

Justification for selection of Effect on fertility via inhalation route:
Based on the available data and in accordance with column 2 adaptation of REACh Annex VIII (section 8.7) and section 1 of REACH Annex XI, the reproduction toxicity study via the inhalation route does not need to be conducted if the study does not appear to be scientifically necessary. Three screening for reproduction and developmental toxicity studies performed via oral route and conducted according to the OECD guideline 422 (weight of evidence from dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) already sufficiently address the reproduction toxicity data requirements for the reaction mass. Furthermore, as the substance is used as an intermediate, the exposure will be limited only to professionals using appropriate protection equipment.

Justification for selection of Effect on fertility via dermal route:
Based on the available data and in accordance with column 2 adaptation of REACh Annex VIII (section 8.7) and section 1 of REACH Annex XI, the reproduction toxicity study via the dermal route does not need to be conducted if the study does not appear to be scientifically necessary. Three screening for reproduction and developmental toxicity studies performed via oral route and conducted according to the OECD guideline 422 (weight of evidence from dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) already sufficiently address the reproduction toxicity data requirements for the reaction mass. Furthermore, as the substance is used as an intermediate, the exposure will be limited only to professionals using appropriate protection equipment.

Effects on developmental toxicity

Description of key information

- Developmental toxicity (weight-of-evidence approach based on dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide): 
NOAEL (oral, rat) = 1000 mg/kg bw/day

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Three OECD 422 studies conducted on analogues of the reaction mass of neodymium carbonate and praseodymium carbonate were available and used in a weight-of-evidence approach. These studies were awarded a reliability score of 2 (Klimisch, 1997), due to read-across (ECHA Practical Guide n°6), and were thus considered sufficient for assessment of developmental toxicity via oral route, therefore the overall quality of the dataset is considered to be good.

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

There was no developmental toxicity study available on the reaction mass of neodymium carbonate and praseodymium carbonate. However, 3 studies were available on analogous substances of the reaction mass (i.e. dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide). The reaction mass of neodymium carbonate and praseodymium carbonate was a solid substance with a high melting point (> 450°C), a molecular weight of 926 - 940 g/mol, and a slight water solubility of 3.93 mg/L. As the substance was an inorganic, no partition coefficient (log Pow / Kow) could be determined. In addition, the reaction mass displayed a weak bioavailability and a low potential for toxicity. The physico-chemical and toxicological characteristics of the 3 analogues, dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide, were similar to the ones of the reaction mass: solid inorganic substances with a high melting point > 300°C, a relatively high molecular weight > 330 g/mol, a low water solubility ranging from 7.8 µg/L to 3.95 mg/L, weak bioavailability and a low potential for toxicity (see the justification document for read across attached in section 13 for a detailed argumentation). Therefore, the data from these analogues were used in a weight-of-evidence approach to conclude on the developmental toxicity of the reaction mass of neodymium carbonate and praseodymium carbonate for the oral route of exposure.

 

First, the developmental effects of dicerium tricarbonate were tested in rats by the oral route in a combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (Davies R., 2008). Conducted in accordance with the OECD guideline 422 and in compliance with GLP, this study was scored as Klimisch 2 (since used as read-across) and flagged as weight of evidence. Male and female Sprague-Dawley rats (10/sex and dose) were daily administered, by gavage, the test item at 0 (vehicle: 0.5% aqueous methylcellulose), 150, 450 or 1000 mg/kg bw/day for around 4 (male) to 8 weeks (female), i.e. 2 weeks before mating, throughout mating for both sexes, and during gestation and until day 5 post-partum for females. The following parameters and endpoints were evaluated in parental animals and pups: mortality, clinical signs, detailed functional tests and observations, bodyweights, food consumption, clinical pathology parameters (haematology, and blood biochemistry), gross necropsy findings, organ weights, and histopathological examinations, mating and pregnancy performance, fertility, maternal care and pup performance (litter size, pup number and weights, gross pathology).

 

There were no adverse effects of treatment at any dose-level on the following parameters: mortality, clinical signs, body weight, food consumption, organ weights, gross necropsy, mating, fertility, delivery, mean numbers of corpora lutea, implantations, mean pup body weight, survival or sex. No microscopic treatment related changes were observed in the ovaries.

However, females treated at 1000 mg/kg bw/day had lower white blood cell counts, lower chloride concentration and higher glucose, potassium, inorganic phosphorus and urea levels. Moreover, microscopic treatment related findings were observed in the stomach that consisted of increased incidence and/or severity of submucosal eosinophil infiltration and pyloric gland hyperplasia in females treated at 1000 mg/kg/day. However, the microscopic findings in the stomach were likely to be related to portal-of-entry irritating effects, due to the high concentrations of the substance given as a bolus by gavage.

 

Based on the experimental conditions of this study, the No Observed Effect Level (NOEL) for developmental effects on progeny was 1000 mg/kg bw/day. Therefore, although local stomachal effects could be observed in parent females at the highest dose level of 1000 mg/kg bw/day, dicerium tricarbonate induced no developmental toxicity, based on the absence of adverse effects on progeny up to the limit-dose level of 1000 mg/kg bw/day.

 

In a second study, the developmental effects of neodymium oxide were tested in rats by the oral route in a combined repeated dose toxicity study with the reproduction/developmental toxicity screening test, as described above for dicerium tricarbonate (Laidlaw K., 2014). Conducted in accordance with the OECD guideline 422 and in compliance with GLP, this study was scored as Klimisch 2 (since used as read-across) and flagged as weight of evidence. Three groups of 10 male and 10 female Sprague-Dawley rats were dosed once daily, by gavage, with the test material at dose levels of 0 (vehicle: 1% w/v carboxymethylcellulose), 100, 300, or 1000 mg/kg bw/day. The males were treated for 2 weeks prior to mating, then through mating, until the day prior to necropsy (ca. 4 weeks of treatment). Females were treated for 2 weeks prior to mating, then through mating, gestation and until at least Day 4 of lactation (ca. 7 weeks of treatment). The following parameters and end points were evaluated: mortality, clinical signs, bodyweights, bodyweight changes, food consumption, ophthalmology, detailed functional tests and observations, clinical pathology parameters (haematology, coagulation and clinical chemistry), gross necropsy findings, organ weights, and histopathological examinations, mating and pregnancy performance, fertility, maternal care and pup performance (litter survival and pup weights).

 

Mating performance, fertility indices, corpora lutea and implantation counts, duration of gestation, and the mean number of live pups born per litter were similar between control and treated females. Litter survival, litter weights and mean pup weights were similar between litters derived from control and treated females. However, in females at 1000 mg/kg/day there were a few instances of walking on tiptoes, irregular respiration and hunched posture during the treatment period, a decrease in bodyweight gain during lactation (also seen at 300 mg/kg/day), increases in the incidence of body held low, hunched posture and partial palpebral closure and a decrease in sectors crossed and number of rears noted in the arena during neurotoxicity assessments (also seen to a lesser extent at 300 mg/kg/day). There was a reduction in bodyweight gain during lactation for females at 300 mg/kg/day and above. There was a slight decrease in red blood cell count, haematocrit and haemoglobin at 300 mg/kg/day and above and an increase in alkaline phosphatase at 1000 mg/kg/day but there were no histological correlates for these findings. There seemed to be a treatment associated finding in the kidney in females dosed at 1000 mg/kg/day, where marked bilateral cortical tubular necrosis and mild diffuse cortical basophilic tubules (bilateral), were recorded in one animal and mild diffuse cortical basophilic tubules (bilateral) were noted in another.

 

Under the conditions of this study in Sprague-Dawley rats, the NOEL for developmental effects was considered to be 1000 mg/kg/day. Neodymium oxide induced no developmental toxicity, based on the absence of adverse effects on progeny up to the limit-dose level of 1000 mg/kg bw/day.

 

These results on developmental toxicity were further corroborated by a third reproduction/developmental toxicity screening test on another analogue of the reaction mass: praseodymium(III,IV) oxide (Wallace I., 2012). Conducted in accordance with the OECD guideline 422 and in compliance with GLP, this study was scored as Klimisch 2 (since used as read-across) and flagged as weight of evidence. Male and female Sprague-Dawley rats (10/sex and dose) were daily administered, by gavage, the test item at 0 (vehicle: 0.5% w/v methylcellulose), 100, 300, or 1000 mg/kg bw/day for around 4 (male) to 7 weeks (female), i.e. prior to mating, throughout mating for both sexes, and during gestation and the first 4 days of lactation for females. The following parameters and end points were evaluated in this study: clinical signs, bodyweights, food consumption, ophthalmology, detailed functional tests and observations, reproductive parameters (mating and pregnancy performance, fertility, maternal care and pup performance), clinical pathology parameters (haematology, coagulation and clinical chemistry), organ weights, and gross and microscopic pathological examinations.

 

No maternal toxicity was observed up to the maximum test concentrations. Moreover, mating performance, fertility indices, corpora lutea and implantation counts, and duration of gestation were similar between control and treated females.

The mean number of live pups born per litter was similar between control females and those receiving the test material. Litter survival, litter weights and mean pup weights were similar between litters derived from control females and litters derived from females receiving the test material. Total litter losses were suffered by 1/10 females at 100 mg/kg bw/day, and 1/10 females at 300 mg/kg bw/day versus none in the control females and the high dose group. Given the low absolute incidence and the absence of any litter losses at 1000 mg/kg bw/day, these litter losses were considered incidental.  The nature and incidence of the observations recorded for dams and their pups were similar between control females and females receiving the test material.

 

Thus, the No Observed Adverse Effect Level (NOAEL) for developmental toxicity was 1000 mg/kg bw/day. Therefore, praseodymium(III,IV) oxide induced no developmental impairment, based on the absence of adverse effects on maternal rats and progeny up to the limit-dose level of 1000 mg/kg bw /day.

 

Regarding developmental effects via inhalation and dermal routes, no study was available. Indeed, based on the available data and in accordance with column 2 adaptation of REACh Annex VIII (section 8.7) and section 1 of REACH Annex XI, developmental toxicity studies via inhalation and dermal routes do not need to be conducted if these studies do not appear to be scientifically necessary. Three screening for reproduction and developmental toxicity studies performed via oral route and according to the OECD guideline 422 (weight of evidence from dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) already sufficiently address the developmental toxicity data requirements for the reaction mass. Furthermore, as the substance is used as an intermediate, the exposure will be limited only to professionals using appropriate protection equipment.

 

As a consequence, by analogy, the reaction mass of neodymium carbonate and praseodymium carbonate is considered to have no potential for developmental effects via the oral route and, thus, does not need to be classified according to the criteria of Annex VI of Directive 67/548/EEC, Regulation (EC) No. 1272/2008 and UN GHS.

 

Developmental toxicity	Reaction mass of neodymium carbonate and praseodymium carbonate	Dineodymium tricarbonate	Dipraseodymium tricarbonate	Dicerium tricarbonate	Neodymium oxide	Praseodymium(III,IV) oxide
Oral route - rat	no data	no data	no data	NOEL (developmental toxicity) = 1000 mg/kg bw/day (OECD 422, GLP)	NOEL (developmental toxicity) = 1000 mg/kg bw/day  (OECD 422, GLP)	NOAEL (developmental toxicity) = 1000 mg/kg bw/day  (OECD 422, GLP)
Inhalation route	no data	no data	no data	no data	no data	no data
Dermal route	no data	no data	no data	no data	no data	no data

Justification for selection of Effect on developmental toxicity: via oral route:
Three studies done on analogous substances of the reaction mass were selected in a read-across strategy and considered together using a weight-of-evidence approach to conclude on the reaction mass (i.e. dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide).
All studies were conducted in compliance with GLP and according to the OECD guideline 422. Well described and meeting the generally acceptable scientific principles, these studies were awarded a reliability score of 2 (Klimisch, 1997), since used as read-across (ECHA Practical Guide n° 6), and were flagged as weight of evidence.

Justification for selection of Effect on developmental toxicity: via inhalation route:
Based on the available data and in accordance with column 2 adaptation of REACh Annex VIII (section 8.7) and section 1 of REACH Annex XI, the developmental toxicity study via the inhalation route does not need to be conducted if the study does not appear to be scientifically necessary. Three screening for reproduction and developmental toxicity studies performed via oral route and conducted according to the OECD guideline 422 (weight of evidence from dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) already sufficiently address the developmental toxicity data requirements for the reaction mass. Furthermore, as the substance is used as an intermediate, the exposure will be limited only to professionals using appropriate protection equipment.

Justification for selection of Effect on developmental toxicity: via dermal route:
Based on the available data and in accordance with column 2 adaptation of REACh Annex VIII (section 8.7) and section 1 of REACH Annex XI, the developmental toxicity study via the dermal route does not need to be conducted if the study does not appear to be scientifically necessary. Three screening for reproduction and developmental toxicity studies performed via oral route and conducted according to the OECD guideline 422 (weight of evidence from dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) already sufficiently address the developmental toxicity data requirements for the reaction mass. Furthermore, as the substance is used as an intermediate, the exposure will be limited only to professionals using appropriate protection equipment.

Justification for classification or non-classification

The available data on the analogues (dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) of the reaction mass were used in a weight-of-evidence approach to conclude on the reprotoxicity potential of the reaction mass of neodymium carbonate and praseodymium carbonate. The three studies showed no adverse effects on sexual function and fertility of parental animals, as well as on development of progeny after oral repeated exposure of parental rats up to the tested limit dose of 1000 mg/kg bw/day. Thus, given the similar physico-chemical characteristics between the three analogues and the reaction mass of neodymium carbonate and praseodymium carbonate (see the justification document for read-across attached in section 13), the latter is not classified, by analogy, according to the classification criteria of Annex VI of Directive 67/548/EEC, Regulation (EC) No 1272/2008 and UN GHS.