reaction mass of neodymium carbonate and praseodymium carbonate

Endpoint summary

Description of key information

LD50 oral, rat > 2000 mg/kg bw
LC50 inhalation, rat (4h) > 5.03 mg/L

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28-MAR-2013 to 19-AUG-2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in compliance with GLP and according to the OECD guideline 423.

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: 8 weeks old on the day of treatment
- Weight at study initiation: 198 to 219 g (mean bodyweight of 208 g)
- Fasting period before study: Overnight before treatment for food only
- Housing: 3 from the same group/polycarbonate cage with stainless steel lids (Techniplast 2154.940 cm²) containing autoclaved sawdust (SICSA, Alfortville, France)
- Diet: Ad libitum, SSNIFF R/M-H pelleted maintenace diet (SSNIFF Spezialdiäten GmbH, Soest, Germany)
- Water: Ad libitum, tap water filtered using a 0.22-µm filter
- Acclimation period: At least 5 days before treatment
- Other: Nulliparous and non-pregnant

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 50 ± 20%
- Air changes (per hr): 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h (light: 7h-19h)

IN-LIFE DATES: From 13-MAY-2013 to 04-JUN-2013

Route of administration:

oral: gavage

Vehicle:

other: 0.5% methylcellulose aqueous solution

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 200 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg
- Justification for choice of vehicle: A homogeneous solution of test material was obtained at the concentration of 200 mg/mL in 0.5% methylcellulose aqueous solution.
- Lot/batch no. (if required): 079K0054
- Purity: The 0.5% methylcellulose was prepared in drinking water treated by reverse osmosis using ELIX 5 (Millipore SA).

DOSAGE PREPARATION (if unusual): The dose formulation was stirred for at least 10 min prior to its administration to the animals and then continuously throughout the dosing procedure.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Based on available test material toxicity data (from separated OECD 420 studies with neodymium carbonate and praseodymium carbonate components) no morbidity or mortality was expected to occur at the dose-level of 2000 mg/kg. This was therefore chosen as the starting dose-level.

Doses:

2000 mg of active ingredient/kg bodyweight (nominal conc.)

The test item concentration was corrected to take into account the water content of the test item by a correction factor of 1.577. Thus, the active ingr. concentration of 2000 mg/kg corresponds to 3124 mg of test item/kg.

No. of animals per sex per dose:

3 per group

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Mortality and morbidity of each animal were checked frequently during the hours following administration, then at least once a day until the end of the observation period, including weekends and public holidays. The body weight of each animal was recorded on the day of allocation of the animals into groups then on the day of treatment (i.e. day 1) and on days 8 and 15.
- Necropsy of survivors performed: Yes (on completion of the observation period)
- Other examinations performed: Clinical signs (at least once during the first 30 min, periodically during the first 4 h, then once a day for a total of 14 days, at approximately the same time), body weight, macroscopic post-mortem examination (digestive tract, heart, kidneys, liver, lungs, pancreas, spleen and any other organs with obvious abnormalities)

Statistics:

not included

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

act. ingr.

Remarks:

(correction factor due to water content: 1,577)

Remarks on result:

other: no deaths

Mortality:

No unscheduled deaths occurred during the study for both groups of females.

Clinical signs:

other: No clinical signs were observed in any animals for both groups of females.

Gross pathology:

There were no findings considered to be related to the test item administration.

- BODY WEIGHTS:

 

Sex	Females
Group Dose-level (mg/kg bw)	Historical control data 0	1 2000	2 2000
Body weight (mean ± SD) [g] day -1 day 1 day 8 day 15	226 (± 10.9) 208 (± 11.7) 246 (± 12.7) 266 (± 14.0)	236 (± 3.6) 215 (± 3.5) 258 (± 5.1) 274 (± 5.6)	220 (± 6.9) 200 (± 3.2) 243 (± 2.1) 254 (± 9.3)
Body weight change (mean ± SD) [g] day 1-8 day 8-15 day 1-15	+39 (± 11.7) +20 (± 6.3) +58 (± 5.8)	+43 (± 1.5) +16 (± 0.6) +59 (± 2.0)	+42 (± 0.6) +11 (± 8.7) +53 (± 7.9)

SD: standard deviations

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the experimental conditions of this study, the oral LD50 of the test item, Reaction mass of neodymium carbonate and praseodymium carbonate, was higher than 2000 mg/kg bw in rats. Therefore, the test item is not classified as toxic by the oral route according to the criteria of CLP Regulation.

Executive summary:

The objective of this study was to evaluate the potential acute toxicity of the reaction mass of neodymium carbonate and praseodymium carbonate, following a single oral administration (gavage) to rats according to OECD guideline 423 and in compliance with GLP.

 

Prepared in 0.5% methylcellulose, the test item was administered once at the starting dose-level of 2000 mg (as active ingredient) /kg body weight (bw) by the oral route (gavage) to two groups of three fasted female Sprague-Dawley rats under a dosage-volume of 10 mL/kg. Each animal was observed at least once a day for mortality and clinical signs for 15 days. Body weight was recorded on day 1 and then on days 8 and 15. On completion of the observation period, the animals were sacrificed and then submitted to a macroscopic post-mortem examination.

 

No unscheduled deaths and no clinical signs were observed in any animals during the study for both groups of females. Body weight gain was unaffected by the test item treatment compared to historical control data. Moreover, no test item-related macroscopic findings were observed.

 

In conclusion, under the experimental conditions of this study, the oral LD50 of the test item, reaction mass of neodymium carbonate and praseodymium carbonate, was higher than 2000 mg/kg bw in female rats. Therefore, the test item is not classified as toxic by the oral route according to the criteria of Directive 67/548/EEC (DSD), Regulation (EC) No. 1272/2008 (CLP) and UN GHS.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

In addition to the key study, five additional studies on constituents and analogous substances were available. These studies were performed according to OECD/EU guidelines or similar, were well reported, and met the generally acceptable scientific principles. However, since the data were used in a read-across approach, the maximal reliability score was decreased from 1 to 2, according to Practical Guide n°6.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29-MAY-2013 to 10-FEB-2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in compliance with GLP and according to the OECD guideline 436.

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Deviations:

yes

Remarks:

(see below)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Deviations:

yes

Remarks:

(see below)

Principles of method if other than guideline:

Deviations:
The temperatures in the inhalation chamber were slightly increased (not more than +1.0°C) during the second part of the exposure (from 1h45 of the 4-h exposure period) and thus exceeded the required range of 22 ± 3°C.

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sulzfeld
- Age at study initiation: Approximately 8 weeks old
- Weight at study initiation: 336-353 g (males); 203-213 g (females)
- Fasting period before study: No
- Housing: 3 animals per polycarbonate solid floor cage (type III) with stainless steel mesh lids (L x W x H in cm = 38 x 38 x 18)
- Diet: Ad libitum, ssniff SM R/M "Autoclavable complete feed for rats and mice - breeding and maintenance" (sniff Spezialdiäten GmbH, Soest, Germany)
- Water: Ad libitum, tap water from the muncipal supply
- Acclimation period: At least 5 days prior to involvement in the study (additional acclimation to the test apparatus [restrain procedures] for a short period prior to testing to lessen the stress during exposure)
- Other: Lignocel Hygienic Animal Bedding (J. Rettenmaier & Söhne GmbH + Co.KG, Rosenberg, Germany)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 30-70%
- Air changes (per hr): At least 15 air exchanges per hour
- Photoperiod (hrs dark / hrs light): 12 h of continuous artificial light in each 24-h period (from 6.00 a.m. to 6 p.m.)

IN-LIFE DATES: From 17-OCT-2013 to 07-NOV-2013

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Nose-only exposure unit (TSE Systems GmbH, Bad Homburg, Germany)
- Exposure chamber volume: 3.85 L
- Method of holding animals in test chamber: Animals held in polycarbonate restraint tubes located around the chamber
- Source and rate of air: At least 0.5 L/min (with O2 > 19% and CO2 < 1%)
- Method of conditioning air: No data available
- System of generating particulates/aerosols: In a dust generator according to Wright (TSE GmbH, Bad Homburg, Germany) located at the top of the exposure chamber
- Method of particle size determination: 7-stage cascade impactor of Mercer style (TSE Systems GmbH, Bad Homburg, Germany), performed three times during the exposure period
- Treatment of exhaust air: No data available
- Temperature, humidity, pressure in air chamber: 24.1-26.0°C; 4.1-4.2% relative humidity
TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric measurements at regular intervals during exposure by pulling a suitable, known volume of test atmosphere, from the exposure chamber, through GF10 glass fibre filters (Whatman, Whatman GmbH, Dassel, Germany Ref No: 10370302 or similar)
- Samples taken from breathing zone: Yes

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: analysis using a 7-stage casacde impactor of Mercer style (TSE Systems GmbH, Bad Homburg, Germany); collection of samples three times during each exposure period with one during the first hour and one during the last hour (at animal's beathing zone)
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 2.72 µm / 2.36

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: Based on available test material toxicity data (from an OECD 436 study with praseodymium carbonate constituent) no morbidity or mortality was expected to occur at the dose-level of 5 mg/L. This was therefore chosen as the starting dose-level.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 4 h

Concentrations:

5.03 mg/L (analytical concentration)

No. of animals per sex per dose:

3, by sex, per cage

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Morbidity/mortality checked twice daily, early and late during the normal working day; weighing on the day of exposure (day 0) prior to exposure, on days 1, 3, 7, 14, and at death
- Necropsy of survivors performed: Yes
- Other examinations performed: Clinical signs (after 1-, 2-, 3-h exposure, at least twice on the day of exposure, and then at least once daily for 14 days), body weight, macroscopic examination (of the respiratory tract notably), other: changes in skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous system, somato-motor activity, behaviour pattern, tremors, convulsions, salivation, diarrhoea, lethargy, sleep, and coma

Statistics:

not included

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.03 mg/L air (analytical)

Based on:

test mat.

Mortality:

Among male and female rats exposed, no animals died during the entire study period.

Clinical signs:

other: Slight laboured respiration was observed in all exposed animals on the day of exposure. Additionally, wet fur and/or ruffled fur and/or red-brown staining were commonly observed in all animals on Day 0. All these observations were considered to be relate

Body weight:

Slight bodyweight loss (1.0-6.3%) was observed between Day 0 and Day 1 in all animals with exception of a single female rat (3843) on Day 1. All rats returned to the initial values by Day 7 at the latest.

Gross pathology:

Dark/red diffuse discoloration of the lungs was recorded in all animals at necropsy, which effect was considered to be related to the test item. No other macroscopic findings were observed in exposed animals.

Table 1: Test Atmosphere Concentrations

Exposure Duration (minutes)	Sample Volume (L)	Test Material Collected (mg)	Atmospheric Concentration of reaction mass of neodymium carbonate and praseodymium carbonate (mg/L)
0	1.0	4.86	4.86
11	1.0	4.91	4.91
23	1.0	4.97	4.97
38	1.0	5.08	5.08
51	1.0	4.82	4.82
67	1.0	5.11	5.11
82	1.0	5.06	5.06
99	1.0	4.92	4.92
114	1.0	4.97	4.97
129	1.0	5.29	5.29
144	1.0	5.08	5.08
164	1.0	5.31	5.31
177	1.0	4.99	4.99
188	1.0	4.86	4.86
200	1.0	4.94	4.94
215	1.0	5.29	5.29
230	1.0	5.09	5.09

 

Mean achieved atmosphere concentration: 5.03 mg/L (standard deviation 0.15)

 

Nominal Concentration

- Amount of test material used: 117.11 g

- Total volume of air used: 5360 L

- Nominal concentration: 21.85 mg/L

 

Table 2: Test atmosphere particle size distribution data

Stage Number	Cut Point (µm)	Amount Collected (mg)					Total Collected per Stage (mg)
		Sample 1		Sample 2	Sample 3
1	10.550	0.14		0.40	0.39		0.93
2	6.655	0.13		0.43	0.45		1.01
3	3.555	0.69		1.65	1.45		3.79
4	2.105	1.01		2.26	2.11		5.38
5	1.550	0.50		0.94	0.81		2.25
6	0.960	0.34		0.54	0.51		1.39
7	0.550	0.22		0.25	0.29		0.76
Filter	< 0.550	0.27		0.31	0.30		0.88
Total Amount Collected (mg)							16.39
Size Range (µm)			Total Mass/stage (mg)			Cumulative Mass (%)
< 0.550			0.88			5.37
0.550 – 0.960			0.76			10.01
0.960 – 1.550			1.39			18.49
1.5550 – 2.105			2.25			32.21
2.105 – 3.555			5.38			65.04
3.555 – 6.655			3.79			88.16
6.655 – 10.550			1.01			94.33
> 10.550			0.93			100.00

 

MMAD: 2.72 µm

Geometric standard deviation: 2.36

Predicted amount <4 µm: 67.3%

 

Table 3: Individual Bodyweights

Animal Sex and Number	Bodyweight (g) on days					Bodyweight gain (g) between days
	0	1	3	7	14	0-1	1-3	3-7	0-7	7-14	0-14
Male 3826	336	315	330	368	402	-21	15	38	32	34	66
Male 3827	340	330	340	378	413	-10	10	38	38	35	73
Male 3828	353	331	355	390	434	-22	24	35	37	44	81
Female 3841	213	203	215	229	242	-10	12	14	16	13	29
Female 3842	203	201	212	226	240	-2	11	14	23	14	37
Female 3843	207	308	213	224	249	1	5	11	17	25	42

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The 4 hour LC50 was determined to be > 5.03 mg/L, therefore the reaction mass of neodymium carbonate and praseodymium carbonate requires no classification under the conditions of this study in accordance with EU criteria.

Executive summary:

An acute inhalation study was conducted to assess the toxicity potential of the reaction mass of neodymium carbonate and praseodymium carbonate, in accordance with the standardised OECD guideline 436.

 

Male and female Wistar rats (3 per sex) were exposed (nose only) for 4 hours to a dust atmosphere containing the test material at a mean concentration of 5.03 mg/L, with a MMAD of 2.72 µm. Following exposure, the animals were observed for 14 days for signs of mortality and toxicity. At the end of the observation period, all animals were subjected to necropsy.

 

No deaths occurred throughout the study and the 4-h LC50 was therefore determined to be > 5.03 mg/L. The reaction mass of neodymium carbonate and praseodymium carbonate requires no classification under the conditions of this study in accordance with criteria of Annex VI of Directive 67/548/EEC, Regulation (EC) No. 1272/2008 and UN GHS.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5 030 mg/m³ air

Quality of whole database:

In addition to the key study, 3 other studies on the reaction mass analogues were available. These studies were performed according to OECD guidelines, were well reported, and met the generally acceptable scientific principles. However, since the data were used in a read-across approach, the maximal reliability score was decreased from 1 to 2, according to Practical Guide n°6.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The acute toxicity of the reaction mass of neodymium carbonate and praseodymium carbonate was tested in rats using two usual routes of administration: oral and inhalation. One study of reliability 1 according to Klimisch quotation criteria was available for each route of administration and was selected as a key study.

 

The potential acute toxicity of the reaction mass of neodymium carbonate and praseodymium carbonate was first investigated following a single oral administration (gavage) to rats according to OECD guideline 423 and in compliance with GLP (Haag V., 2013). Prepared in 0.5% methylcellulose, the test item was administered once at the starting dose-level of 2000 mg (as active ingredient) /kg body weight (bw) by the oral route to 2 groups of 3 fasted female Sprague-Dawley rats. Each animal was observed at least once a day for mortality and clinical signs for 15 days. Body weight was recorded on day 1 and then on days 8 and 15. On completion of the observation period, the animals were sacrificed and then submitted to a macroscopic post-mortem examination. No unscheduled deaths and no clinical signs were observed in any animals during the study for both groups of females. Body weight gain was unaffected by the test item treatment compared to historical control data. Moreover, no test item-related macroscopic findings were observed. As a consequence, the oral LD50 of the reaction mass of neodymium carbonate and praseodymium carbonate in rats was higher than 2000 mg/kg bw, therefore warranting no classification.

This result was corroborated by other acute oral studies on both constituents of the reaction mass (i.e. dineodymium tricarbonate and dipraseodymium tricarbonate) and 3 analogous substances (i.e. dicerium tricarbonate, neodymium oxide, praseodymium(III,IV) oxide) in rats where no mortality occurred at test doses between 2000 and 5000 mg/kg bw (Rondot G., 1984; Lambert et al., 1993; Clouzeau J., 1994; Sanders A., 2010a; Bradshaw J., 2012).

 

An acute inhalation toxicity study was conducted to assess the toxicity potential of the reaction mass of neodymium carbonate and praseodymium carbonate, in accordance with the standardised OECD guideline 436 and in compliance with GLP (Matyas A., 2013). Male and female Wistar rats (3 per sex) were exposed (nose only) for 4 hours to a dust atmosphere containing the test material at a mean concentration of 5.03 mg/L, with a MMAD of 2.72 µm. Following exposure, the animals were observed for 14 days for signs of mortality and toxicity. At the end of the observation period, all animals were subjected to necropsy. No deaths occurred throughout the study and no clinical signs of toxicological relevance were observed during this study. As a consequence, the inhalation LC50 of the reaction mass of neodymium carbonate and praseodymium carbonate in rats exposed for 4 hours was higher than 5.03 mg/L, therefore warranting no classification.

This result was corroborated by other acute inhalation studies on one reaction mass constituent (i.e. dipraseodymium tricarbonate) and 2 analogues (i.e. neodymium oxide, praseodymium(III,IV) oxide) in rats where no mortality occurred at limit test concentrations ranging from 4.98 (maximal technically administrable concentration) to 5.25 mg/L (Griffiths D.R., 2012a, 2012b and 2012c).

 

By dermal route, no study was available on the reaction mass of neodymium carbonate and praseodymium carbonate. According to column 2 adaptation of REACh Annex VIII (section 8.5), an acute dermal toxicity study was not considered scientifically justified as (1) acute toxicity studies using the oral and inhalation exposure routes were available, both showing no effect of the substance; (2) based on its physico-chemical properties (e.g. low solubility, inorganic substance), the skin absorption is expected to be really limited.

However, a study done by dermal route was available on dicerium tricarbonate (Rokh N., 2007). Considered as an analogue of the reaction mass constituents due to its physico-chemical characteristics, dicerium tricarbonate's data were only mentioned as supplementary/supporting information in this dossier. The acute dermal toxicity of dicerium tricarbonate was evaluated in rats according to OECD guideline 402 and in compliance with GLP. The test item was applied to the skin of one group of ten Sprague-Dawley rats (five males and five females). The application was performed with the test item in its original form at the dose-level of 2000 mg (as active ingredient) /kg. The test site was then covered by a semi-occlusive dressing for 24 hours. Clinical signs, mortality and body weight gain were checked for a period of 14 days following the single application of the test item. All animals were subjected to necropsy. No deaths, no clinical signs and no cutaneous reactions at the treatment site were observed during the study. A slightly lower body weight gain was observed in some animals during the study. No apparent abnormalities were observed at necropsy in any animal. As a consequence, the dermal LD50 of dicerium tricarbonate in rats exposed for 24 hours was higher than 2000 mg/kg bw, therefore warranting no classification for this analogous substance.

 

Regarding the specific target organ toxicity - single exposure (STOT SE), no sign of impairment was observed in any organ investigated in the studies cited above, and this regardless of the route of administration (i.e. oral and inhalation).

 

Acute toxicity – LD/LC50	Reaction mass of neodymium carbonate and praseodymium carbonate	Dineodymium tricarbonate	Dipraseodymium tricarbonate	Dicerium tricarbonate	Neodymium oxide	Praseodymium(III,IV) oxide
Oral	> 2000 mg/kg bw (OECD 423, GLP)	> 2000 mg/kg bw (OECD 420, GLP)	> 2000 mg/kg bw (OECD 420, GLP)	> 5000 mg/kg bw (standardised guideline)	> 5000 mg/kg bw (EU B.1, GLP)	> 2000 mg/kg bw (OECD 401, GLP)
Inhalation	> 5.03 mg/L (OECD 436, GLP)	no data	> 5.25 mg/L (OECD 436, GLP)	no data	> 4.98 mg/L (maximal technically achievable concentration) (OECD 436, GLP)	> 5.21 mg/L (OECD 436, GLP)
Dermal	no data	no data	no data	> 2000 mg/kg bw (OECD 402, GLP)	no data	no data

 

Justification for selection of acute toxicity – oral endpoint
The key study was conducted on the test item, reaction mass of neodymium carbonate and praseodymium carbonate, in compliance with GLP and according to the OECD guideline 423. Well described and meeting the generally acceptable scientific principles, this study was awarded a reliability score of 1 in accordance with the Klimisch quotation criteria (1997).

Justification for selection of acute toxicity – inhalation endpoint
The key study was conducted on the test item, reaction mass of neodymium carbonate and praseodymium carbonate, in compliance with GLP and according to the OECD guideline 436. Well described and meeting the generally acceptable scientific principles, this study was awarded a reliability score of 1 in accordance with the Klimisch quotation criteria (1997).

Justification for selection of acute toxicity – dermal endpoint
In accordance with column 2 adaptation of REACH Annex VIII (section 8.5), an acute dermal toxicity study is not considered scientifically justified as (1) two acute toxicity studies are available on the reaction mass (one by oral route and the other one by inhalation route), both showing no effect of the substance; and (2) really limited skin absorption is anticipated due to the physico-chemical properties of the reaction mass (e.g. inorganic substance, really low solubility). Furthermore, oral and inhalation exposure routes are the most appropriate to assess the acute toxicity hazard presented by the substance based on its physico-chemical characteristics and use pattern. At last, as the substance is used as intermediate, exposure will be limited only to professionals using appropriate protection equipment.

Justification for classification or non-classification

The available data on the reaction mass of neodymium carbonate and praseodymium carbonate showed that no mortality occurred after exposure up to the tested limit doses/concentrations, regardless of the route of exposure (oral and inhalation). Thus, the reaction mass of neodymium carbonate and praseodymium carbonate is not classified according to the classification criteria of Annex VI of Directive 67/548/EEC, Regulation (EC) No. 1272/2008 and UN GHS.

These results (i.e. DL50 > 2000 mg/kg and CL50 > 5 mg/L) were similar to those observed with the constituents of the reaction mass (dineodymium tricarbonate and dipraseodymium tricarbonate) and with the analogues (dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide).

 

Moreover, no sign of impairment was observed in any organ investigated regardless of the substance studied and the route of administration (i.e. oral and inhalation), thus requiring no STOT SE classification for the reaction mass of neodymium carbonate and praseodymium carbonate according to Regulation (EC) No. 1272/2008 and UN GHS criteria.