Calcium hydrosilicate, reaction product of natural quartz sand and technical lime by a hydrothermal and tribochemical process

Endpoint summary

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

No experimental data concerning inhalation, dermal or oral kinetics are available for Celitement. Therefore, an assessment of the toxicokinetic behaviour is based on the physico-chemical properties and the results of toxicological investigations with Celitement.

 

Physical-chemical properties

Celitement consists of inorganic solid particles at room temperature. The melting points of the constituents are far above 300 °C and the constituents have no vapour pressure. It is a highly insoluble substance. Intentional the substance reacts with water and forms insoluble hydration products.

 

Data from acute toxicity studies

Acute toxicity data showed low toxicity. In an acute dermal toxicity study in rats with Celitement, the LD50 was > 2000 mg/kg bw (TNO Triskelion, 2014). From an acute inhalation toxicity study in rats with Celitement, it was concluded that the 4-hour LC50 for Celitement was above 5.3 g/m³ (TNO Triskelion, 2014). Only local effects (effects on the respiratory tract and skin) were observed in the acute inhalation and dermal toxicity study. No systemic effects were reported.

 

Data from repeated dose toxicity studies

A combined repeated dose inhalation toxicity study and reproduction / developmental screening test (OECD 422 and OECD 412) in rats was performed with concentrations of 10.3, 50.3 and 205.8 mg/m³ (TNO Triskelion, 2015). In this study the following findings were noted:

The concentrations were selected on the basis of a 14-day range finding study in which groups of 5 male and 5 female rats were exposed to target concentrations of 0, 40, 200 or 1000 mg/m3. Effects in this range finding study at 1000 mg/m3 comprised the death of one rat, clinical signs, reduced body weights and food consumption, increased weights of the lungs, heart and adrenals, and macroscopic changes in the lungs, while at 200 mg/m3 increased lung and heart weights were still observed in females.

One female rat of the high-concentration group was found dead during the mating period. The death of this rat was not ascribed to treatment. Pre-exposure and postexposure observations did not reveal treatment-related clinical signs. Neurobehavioural observations and motor activity assessment did not indicate any neurotoxic potential of CELITEMENT.

There were no treatment-related differences in body weights or food consumption during the premating period, during the post-mating period in males, or in dams during the gestation period and the lactation period.

Haematology and clinical chemistry was conducted in 5 rats/sex/group at the end of the premating period. Total protein and albumin concentrations were decreased in males of the high-concentration group.

The rats were sacrificed after a total of 25 exposure days (males) or on day 4 of lactation (females).

Lung weights were increased in the high-concentration group in both sexes. Adrenals weights were increased in the high-concentration group in females.

Microscopic examination revealed bronchiolitis in the lungs in the mid- and highconcentration group, and accumulation of alveolar macrophages in the highconcentration group.

There were no effects of the test substance on fertility and reproductive performance, litter data or pup observations in any group.

Dermal absorption

Celitement consists of water insoluble and highly insoluble components. Therefore, dermal absorption is considered negligible. During hydration process small amounts of calcium hydroxide are formed. It is partly soluble and can be present as ions at the skin surface. Dermal absorption of these ionic species is considered negligible.