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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

Basic toxicokinetics

There are no studies available in which the toxicokinetic behaviour of bismuth chloride oxide (CAS 7787-59-9) has been investigated.

Therefore, in accordance with Annex VIII, Column 1, Section 8.8.1, of Regulation (EC) No 1907/2006 and with Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance (ECHA, 2017), assessment of the toxicokinetic behaviour of bismuth chloride oxide (CAS 7787-59-9) is conducted to the extent that can be derived from the relevant available information. This comprises a qualitative assessment of the available substance specific data on physico-chemical and toxicological properties according to Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance (ECHA, 2017) and taking into account further available information on structural analogue substances.

Bismuth chloride oxide (CAS 7787-59-9) is a solid at 20°C with a molecular weight of 260.43 g/mol and a water solubility of < 1 µg/L. As the substance is an inorganic compound, the octanol/water partition coefficient was not determined.

 

Absorption

Absorption is a function of the potential for a substance to diffuse across biological membranes. The most useful parameters providing information on this potential are the molecular weight, the octanol/water partition coefficient (log Pow) value and the water solubility (ECHA, 2017).

 

Oral

In general, molecular weights below 500 and log Pow values between -1 and 4 are favourable for absorption via the gastrointestinal (GI) tract, provided that the substance is sufficiently water soluble (> 1 mg/L). Lipophilic compounds may be taken up by micellar solubilisation by bile salts, but this mechanism may be of particular importance for highly lipophilic compounds (log Pow > 4), in particular for those that are poorly soluble in water (≤ 1 mg/L) as these would otherwise be poorly absorbed (Aungst and Shen, 1986).

The low water solubility (< 1 µg/L) of bismuth chloride oxide (CAS 7787-59-9) indicates that absorption may be limited by the inability to dissolve into GI fluids.

Moreover, studies on acute oral toxicity of bismuth chloride oxide (CAS 7787-59-9) showed no signs of systemic toxicity resulting in a LD50 value greater than 5000 mg/kg bw (please refer to Section 7.2.1). Furthermore, available data on subchronic oral toxicity of bismuth chloride oxide (CAS 7787-59-9) showed no adverse systemic effects resulting in a NOAEL > 1000 mg/kg bw/day (please refer to Section 7.5.1).

Overall, taking into account the physico-chemical properties of bismuth chloride oxide (CAS 7787-59-9) and available toxicological data, oral absorption is limited and/or the acute oral toxicity and subchronic oral toxicity of the substance is low, respectively.

 

Dermal

There are no data available on dermal absorption or on acute dermal toxicity of bismuth chloride oxide (CAS 7787-59-9). On the basis of the following considerations, the dermal absorption of the substance is considered to be limited.

The dermal absorption rate was not calculated by QSAR analysis using Dermwin v2. 02 as the entered structure is an inorganic compound, which were not included in the training data set for the methodology utilized in that program. Therefore, inorganic compounds are outside the estimation domain. Bismuth chloride oxide is a solid with a molecular weight of 260.43 g/mol and a water solubility < 1 µg/L. A molecular weight less than 100 favours dermal uptake and above 500 the molecule may be too large. However, liquids and substances in solution are taken up more readily than dry particulates. Dry particulates will have to dissolve into the surface moisture of the skin before uptake can begin. Considering the water solubility, the substance must be sufficiently soluble in water to partition from the stratum corneum into the epidermis. Therefore if the water solubility is below 1 mg/l, dermal uptake is likely to be low (ECHA, 2017). Considering the molecular weight of 260.43 g/mol, a dermal uptake cannot be excluded. However, bismuth chloride oxide forms a tetragonal crystal structure, which will probably lead to a lower absorption rate. Based on the low water solubility the dermal uptake and the partition from the stratum corneum into the epidermis are considered to be limited.

In addition, available subacute and subchronic dermal data with bismuth chloride oxide (CAS 7787-59-9) showed no adverse effects resulting in NOAEL values greater than 500 mg/kg bw/day (please refer to Section 7.5.3). Moreover, the irritation and sensitisation studies with bismuth chloride oxide (CAS 7787-59-9) showed no irritating or sensitising effects (please refer to Section 7.3.1 and 7.4).

Overall, taking into account the physico-chemical properties of bismuth chloride oxide (CAS 7787-59-9) and available toxicological data, dermal absorption is limited and/or the subacute and subchronic dermal toxicity of the substance is low, respectively.

 

Inhalation

In humans, 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 the alveolar region of the respiratory tract (ECHA, 2017). Based on the granulometry data (L50 = 12.85 µm), inhalation of bismuth chloride oxide (CAS 7787-59-9) cannot be excluded. However, for poorly water-soluble dusts, the rate at which the particles dissolve into the mucus will limit the amount that can be absorbed directly. Poorly water-soluble dusts depositing in the nasopharyngeal region could be coughed or sneezed out of the body or swallowed (ECHA, 2017). Such dusts depositing in the tracheo-bronchial region would mainly be cleared from the lungs by the mucocilliary mechanism and swallowed. However a small amount may be taken up by phagocytosis and transported to the blood via the lymphatic system. Poorly water-soluble dusts depositing in the alveolar region would mainly be engulfed by alveolar macrophages. The macrophages will then either translocate particles to the ciliated airways or carry particles into the pulmonary interstitium and lymphoid tissues (ECHA, 2017).

Available data on acute inhalation toxicity revealed LC50 values > 5 mg/L after 4 h exposure to an aerosol (dust) of the appropriate structural analogue dibismuth trioxide that shows also low water solubility (CAS 1304-76-3) (please refer to Section 7.2.2).

Based on the physical state and the physico-chemical properties of bismuth chloride oxide (CAS 7787-59-9) and dibismuth trioxide (CAS 1304-76-3) absorption via the lung cannot be excluded, however without leading to adverse effects based on the results of an acute inhalation toxicity study.

 

Distribution and accumulation

Distribution of a compound within the body depends on the rates of absorption and on the physico-chemical properties of the substance; especially the molecular weight, the lipophilic character and the water solubility. In general, the smaller the molecule, the wider is the distribution (ECHA, 2017).

The absorption potential of the substance is anticipated to be low. Due to the tetragonal crystal structure of the test substance a higher molecular weight than that of the monomer can be considered. In addition, bismuth chloride oxide (CAS 7787-59-9) has low water solubility, thus, based on the physico-chemical properties, distribution of the test substance is negligible.

In general, lipophilic substances have the potential to accumulate within the body. However, other substances that can accumulate within the body include poorly soluble particulates that deposited in the alveolar region of the lungs, substances that bind irreversibly to endogenous proteins and certain metals and ions that interact with the matrix of the bone (ECHA, 2017). Poorly water and lipid soluble particles (i.e. log P values around 0 and water solubility around 1 mg/l or less) with aerodynamic diameters of 1 μm or below have the potential to deposit in the alveolar region of the lung (ECHA, 2017). Based on the granulometry data (L50 = 12.85 µm), accumulation in the lung of bismuth chloride oxide (CAS 7787-59-9) is considered to be low. In addition, based on the acute toxicity data following inhalation no adverse effects after exposure with the test substance were observed.

 

Metabolism

Bismuth chloride oxide (CAS 7787-59-9) is an inorganic substance and hence, will not undergo metabolic transformation.

 

Excretion

Very low to no absorption is expected for bismuth chloride oxide (CAS 7787-59-9) via the gastrointestinal tract and the skin, thus the main portion of the ingested substances is considered to be excreted unchanged in the feces.

 

 

Reference list

ECHA (2017) Guidance on information requirements and chemical safety assessment, Chapter R.7c: Endpoint specific guidance.

Aungst B. and Shen D.D. (1986). Gastrointestinal absorption of toxic agents. In Rozman K.K. and Hanninen O. Gastrointestinal Toxicology. Elsevier, New York, US.