Calcination products of BaCO3, SrCO3, MgO, Al2O3, Eu2O3 and MnCO3

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics, other

Remarks:

Toxicokinetic assessment of the substance based on the available data

Type of information:

other: expert statement

Adequacy of study:

key study

Study period:

Not applicable

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: since this is a theoretical assessment, the Klimisch value cannot be 1.

Objective of study:

other: Toxicokinetic assessment of the substance based on the available data

Qualifier:

according to guideline

Guideline:

other: Guidance for the implementation of REACH. Guidance on information requirements and chemical safety assessment. Chapter R.7c: Endpoint specific guidance. European Chemical Agency

Version / remarks:

Version 2.0; November 2014

Deviations:

no

GLP compliance:

no

TOXICOKINETIC ASSESSMENT

A substance can enter the body via the gastrointestinal tract, the lungs, or the skin, depending on the route of exposure.

After oral administration, in general, a compound needs to be dissolved before it can be taken up from the gastro-intestinal tract. L 125 PLUS is considered to be insoluble in water, therefore passive diffusion (passage of small water-soluble molecules through aqueous pores or carriage of such molecules across membranes with the bulk passage of water) is expected to be low. Due to its insolubility in water and its limited ability to penetrate biomembranes related to its size, oral absorption is considered to be limited. For risk assessment purposes oral absorption of L 125 PLUS is set at 10%. The oral toxicity data do not provide reason to deviate from the proposed oral absorption factor.

Once absorbed, wide distribution of L 125 PLUS throughout the body is not expected based on its insolubility in water and absorbed L 125 PLUS is not expected to bio-accumulate significantly in the body upon exposure.

L 125 PLUS particles are relatively small with more than 85% of the particle smaller than 10 μm. In general, particles with aerodynamic diameters below 100 μm have the potential to be inhaled. Particles with aerodynamic diameters below 50 μm may reach the thoracic region and those below 15 μm can enter the alveolar region of the respiratory tract in humans. This indicates that during exposure by inhalation to L 125 PLUS, the substance can reach the nasopharyncheal region and subsequently the tracheo/bronchial/pulmonary region. Once L 125 PLUS reaches the lung tissue, it will not dissolve within the mucus lining of the respiratory tract due to its insolubility in water. L 125 PLUS deposited in the tracheobronchial region is expected to be cleared from the lungs by the mucocilliary mechanism and swallowed. However, a small amount may be engulfed by alveolar macrophages, although its particle size does not favour phagocytosis which is more likely to occur with smaller particles (around 1 μm). In case of uptake, macrophages will then either translocate particles to the ciliated airways or carry particles into the pulmonary interstitium and lymphoid tissues. Based on the above data, for risk assessment purposes the inhalation absorption of L 125 PLUS is set at 50%.

L 125 PLUS is a powdery solid. Given the fact that L 125 PLUS is insoluble in water, it is not expected to be dissolved in the moisture of the skin and uptake will therefore be limited, and consequently dermal absorption is likely to be low. Furthermore, its inorganic nature is not indicative for fast uptake. According to the criteria given in the REACH Guidance, 10% dermal absorption will be considered in case MW >500 and log Pow <-1 or >4, otherwise 100% dermal absorption should be used. As no partition coefficient is available, due to the water insoluble properties of the substance, L 125 PLUS cannot be tested against the criteria for limited dermal absorption. It is however generally accepted that dermal absorption is equal or lower compared to oral absorption for non-irritating/non-corrosive substances, and therefore a dermal absorption of 10% is considered to be more appropriate. Therefore, for risk assessment purposes dermal absorption is set at 10%.

Conclusions:

For risk assessment purposes, 10% is used for oral and dermal absorption and 50% is used for inhalation absorption.

Description of key information

For risk assessment purposes, 10% is used for oral and dermal absorption and 50% is used for inhalation absorption.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

10

Absorption rate - dermal (%):

10

Absorption rate - inhalation (%):

50

Additional information

A substance can enter the body via the gastrointestinal tract, the lungs, or the skin, depending on the route of exposure. After oral administration, in general, a compound needs to be dissolved before it can be taken up from the gastro-intestinal tract. L 125 PLUS is considered to be insoluble in water, therefore passive diffusion (passage of small water-soluble molecules through aqueous pores or carriage of such molecules across membranes with the bulk passage of water) is expected to be low. Due to its insolubility in water and its limited ability to penetrate biomembranes related to its size, oral absorption is considered to be limited. For risk assessment purposes oral absorption of L 125 PLUS is set at 10%. The oral toxicity data do not provide reason to deviate from the proposed oral absorption factor.

Once absorbed, wide distribution of L 125 PLUS throughout the body is not expected based on its insolubility in water and absorbed L 125 PLUS is not expected to bio-accumulate significantly in the body upon exposure.

L 125 PLUS particles are relatively small with more than 85% of the particle smaller than 10 μm. In general, particles with aerodynamic diameters below 100 μm have the potential to be inhaled. Particles with aerodynamic diameters below 50 μm may reach the thoracic region and those below 15 μm can enter the alveolar region of the respiratory tract in humans. This indicates that during exposure by inhalation to L 125 PLUS, the substance can reach the nasopharyncheal region and subsequently the tracheo/bronchial/pulmonary region. Once L 125 PLUS reaches the lung tissue, it will not dissolve within the mucus lining of the respiratory tract due to its insolubility in water. L 125 PLUS deposited in the tracheobronchial region is expected to be cleared from the lungs by the mucocilliary mechanism and swallowed. However, a small amount may be engulfed by alveolar macrophages, although its particle size does not favour phagocytosis which is more likely to occur with smaller particles (around 1 μm). In case of uptake, macrophages will then either translocate particles to the ciliated airways or carry particles into the pulmonary interstitium and lymphoid tissues. Based on the above data, for risk assessment purposes the inhalation absorption of L 125 PLUS is set at 50%.

L 125 PLUS is a powdery solid. Given the fact that L 125 PLUS is insoluble in water, it is not expected to be dissolved in the moisture of the skin and uptake will therefore be limited, and consequently dermal absorption is likely to be low. Furthermore, its inorganic nature is not indicative for fast uptake. According to the criteria given in the REACH Guidance, 10% dermal absorption will be considered in case MW >500 and log Pow <-1 or >4, otherwise 100% dermal absorption should be used. As no partition coefficient is available, due to the water insoluble properties of the substance, L 125 PLUS cannot be tested against the criteria for limited dermal absorption. It is however generally accepted that dermal absorption is equal or lower compared to oral absorption for non-irritating/non-corrosive substances, and therefore a dermal absorption of 10% is considered to be more appropriate. Therefore, for risk assessment purposes dermal absorption is set at 10%.