reaction mass of neodymium carbonate and praseodymium carbonate

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:

no hazard identified

Additional information - workers

The argumentation on the read-across strategy and the overall low potential of rare earth (RE) compounds for causing toxicity is given in the read-across justification attached to section 13 of the IUCLID.

 

Acute / short-term exposure - systemic and local effects

 

Inhalation:

As no local or systemic effects have been observed in the acute inhalation toxicity study done on the reaction mass of neodymium carbonate and praseodymium carbonate, up to 5.03 mg/L; and no local effect is further expected based on the irritation/corrosion studies available on the reaction mass, its constituents (dineodymium tricarbonate and dipraseodymium tricarbonate) and analogues (dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide), no short-term DNEL (systemic or local) needs to be derived.

 

Dermal:

No acute toxicity study for the dermal route is available for the reaction mass of neodymium carbonate and praseodymium carbonate. Indeed, based on column 2 adaptation of REACh Annex VIII (section 8.5.3), the study is not considered scientifically justified as acute toxicity studies using the oral and inhalation exposure routes are available, both studies showing no effect of the substance; and based on the physico-chemical properties of the reaction mass (e.g. low solubility, inorganic substance), the skin absorption is expected to be really limited. In addition, as the substance is used as intermediate, exposure will be limited only to professionals using appropriate protection equipment. At last, an acute dermal toxicity study is available on the analogue dicerium tricarbonate showing no effect using this exposure route.

Since there are no acute toxicity data available via dermal route for the test substance, no short-term DNEL (systemic or local) can be derived.

 

Long-term exposure - systemic and local effects

 

Inhalation:

No subacute or chronic toxicity study for the inhalation route is available for the reaction mass of neodymium carbonate and praseodymium carbonate. Nevertheless, repeated exposure studies are available on several analogues (dicerium tricarbonate, neodymium oxide and praseodymium(III,IV) oxide) showing similar physico-chemical properties.

 

Combined repeated dose toxicity studies with reproduction/developmental toxicity screening tests (OECD 422) are available for dicerium tricarbonate, neodymium oxide and praseodymium(III, IV) oxide, by oral route (see the justification for the read-across in the document attached in section 13 of the IUCLID). Globally, the three studies showed no relevant adverse systemic effects of treatment up to 1000 mg/kg bw/day (highest dose tested) for the following parameters: mortality, clinical signs, body weight, food consumption, organ weights, gross necropsy, mating, fertility, delivery, mean numbers of corpora lutea, implantations, gestation, mean pup body weight, pup survival, pup sex. Some hematological and clinical chemistry parameters showed variations but these modifications were generally considered as not biologically relevant. The local stomachal effects observed with dicerium tricarbonate seemed to be due to the carbonate form of the substance, as similar effects were described in male and/or female rats orally exposed to dilanthanum tricarbonate. This substance is not included in the read-across approach but is mentioned here for the discussion of local effects which were found to be similar to the ones observed with dicerium tricarbonate. Since such local stomachal effects were not observed in dogs repeatedly exposed to dilanthanum tricarbonate, it could be deduced that these stomachal lesions could be specific to rodents and their particular stomach morphology and thus corresponded to an adaptive response to direct administration of rare earth carbonate into the stomach (gavage) without food. These local effects are thus considered as not relevant in case of human exposure. As a consequence, the reaction mass of neodymium carbonate and praseodymium carbonate is therefore considered as not harmful following repeated oral exposure.

In addition, a study from Davison and Ramsey (1965) demonstrated that repeated inhalation of the analogue neodymium oxide at 30 mg/m³ for up to 120 days (6 hours/day) did not adversely affect either mice or guinea pigs.

 

None of the available studies on the reaction mass, its constituents and analogues displayed relevant adverse health effects (acute or subacute, oral or inhalation). This is mainly driven by the fact that the reaction mass of neodymium carbonate and praseodymium carbonate is an inorganic substance with a low water solubility (3.93 mg/L) and thus a very low bioavailability as demonstrated in the toxicokinetic assessment (see details in the toxicokinetic section (7.1)). Therefore, the reaction mass of neodymium carbonate and praseodymium carbonate is expected to have a toxicological pattern similar to the abovementioned RE carbonates and oxides if repeatedly administered by oral or inhalation route: i.e. substances with low potential for toxicity.

The ECHA guidance on information requirements and chemical safety assessment (Part R.8) indicates that in the case there is no effect at any of the exposure ranges, the study should not be used for the derivation of the NOAEL, because there is no need to set a DNEL. As no adverse effects were considered relevant in the read-acrossed studies on dicerium tricarbonate, neodymium oxide and praseodymium(III, IV) oxide, no hazard was identified and a long-term DNEL (systemic or local) is therefore not required (ECHA guidance on information requirements and chemical safety assessment Part R.8).      

 

Exposure limits were defined in several European countries and set at 3 and 10 mg/m³ for non-specific alveolar and inhalable dusts, respectively, in most EU countries. As the reaction mass of neodymium carbonate and praseodymium carbonate did not show any relevant toxic effects in the available studies, no long-term DNELs were required to be derived according to ECHA guidance on information requirements and chemical safety assessment (Part R.8). However, the national exposure limits as mentioned above should be respected where relevant.

 

Dermal:

No study is available for the repeated dose toxicity of the reaction mass via the dermal route. Testing was waived based on the following justifications: subacute studies are available on analogues for the oral route of exposure and, according to the REACh Regulation, only one route of exposure should be tested for repeated dose toxicity (column 2 adaptation, Annex VIII, section 8.6.1). In addition, based on the physico-chemical properties of the reaction mass (e.g. inorganic substance, low solubility, low bioaccumulation), skin absorption is expected to be really limited. Moreover, as the substance is used as intermediate, exposure will be limited only to professionals using appropriate protection equipment. At last, an acute dermal toxicity study is available on the analogue dicerium tricarbonate showing no effect using this exposure route. Therefore, it was considered unnecessary to perform a repeated dose toxicity study via the dermal route (column 2 adaptation, Annex VIII, section 8.6.1).

 

Thus, there are no data available on long-term dermal toxicity for the reaction mass of neodymium carbonate and praseodymium carbonate, hence no long-term DNEL (systemic or local) can be derived for either systemic or local effects.

 

For the oral route, no long-term DNEL (systemic or local) was derived based on the above argumentation (i.e. no relevant adverse effects observed in the read-acrossed studies on dicerium tricarbonate, neodymium oxide and praseodymium(III, IV) oxide). Therefore, no dermal long-term DNEL (systemic or local) should be derived by extrapolation from oral repeated dose toxicity studies.

 

Hazards for the eyes

 

Based on read-across from studies on dineodymium tricarbonate, dipraseodymium tricarbonate, dicerium tricarbonate, neodymium oxide and praseodymium(III, IV) oxide, it was concluded that the reaction mass of neodymium carbonate and praseodymium carbonate presented no hazard for the eyes and thus was not classified as hazardous to the eyes.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown (no further information necessary)

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

General Population - Hazard via oral route

Systemic effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:

no hazard identified

Additional information - General Population

Acute / short-term exposure - systemic and local effects

 

Inhalation:

Since the reaction mass of neodymium carbonate and praseodymium carbonate is used as intermediate on site, exposure will be limited only to professionals and, thus, the general population will not be exposed to the test item. Therefore, it is considered unnecessary to derive a short-term DNEL (systemic or local).

 

Dermal:

Since the reaction mass of neodymium carbonate and praseodymium carbonate is used as intermediate on site, exposure will be limited only to professionals and, thus, the general population will not be exposed to the test item. Therefore, it is considered unnecessary to derive a short-term DNEL (systemic or local). 

 

Oral:

Since the reaction mass of neodymium carbonate and praseodymium carbonate is used as intermediate on site, exposure will be limited only to professionals and, thus, the general population will not be exposed to the test item. Therefore, it is considered unnecessary to derive a short-term DNEL (systemic or local)

 

Long-term exposure - systemic and local effects

 

Inhalation:

Since the reaction mass of neodymium carbonate and praseodymium carbonate is used as intermediate on site, exposure will be limited only to professionals and, thus, the general population will not be exposed to the test item. Therefore, it is considered unnecessary to derive a long-term DNEL (systemic or local)

 

Dermal:

Since the reaction mass of neodymium carbonate and praseodymium carbonate is used as intermediate on site, exposure will be limited only to professionals and, thus, the general population will not be exposed to the test item. Therefore, it is considered unnecessary to derive a long-term DNEL (systemic or local).

 

Oral:

Since the reaction mass of neodymium carbonate and praseodymium carbonate is used as intermediate on site, exposure will be limited only to professionals and, thus, the general population will not be exposed to the test item. Therefore, it is considered unnecessary to derive a long-term DNEL (systemic or local).

 

Hazards for the eyes

 

Since the reaction mass of neodymium carbonate and praseodymium carbonate is used as intermediate on site, exposure will be limited only to professionals and, thus, the general population will not be exposed to the test item.