Registration Dossier

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Acute/short term exposure
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
4 mg/m³
Acute/short term exposure
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Acute/short term exposure
DNEL related information

Workers - Hazard for the eyes

Additional information - workers

The surface composition of silicocalcium differs from the bulk composition. The surface was found to be covered by silicon-, calcium-, iron- and aluminium rich oxide phases. No manganese or titanium present in the bulk material was detected in the outermost surface layer.

Main elements released from silicocalcium in different fluids are silicon and calcium. The release is significantly higher in acidic fluids than observed at neutral conditions. The release of other elements like aluminium and iron present in silicocalcium is usually low, and for instance aluminium is released only in very acidic environment.

The significant exposure scenario for silicocalcium is the occupational inhalation exposure. To derive a proper DNEL, read-across from amorphous silica is used. The released amount of calcium is seen insignificant because of its ubiquitous presence in tissues.

DNEL values for both the inhalable and the respirable CaSi particles are derived because of the fact that the dustiness properties are likely to vary.

A NOAEL of 1.3 mg/m3(representing respirable particles) has been identified in animal tests with synthetic amorphous silicas (Reuzel et al. 1991). This can be taken as a starting point for the derivation of an inhalation DNEL forCaSi (respirable fraction). For the DNEL calculation, no allometric scaling between humans and rats shall be done in the case of local effects but the value should be corrected for differences in respiratory rates between rats and humans. This results in a starting point of 0.9 mg/m3 (1.3 mg/m3×6.7/10). ECETOC has suggested an assessment factor of 1 to be used for interspecies differences and a factor of 3 for interindividual differences in the case of local respiratory tract effects (ECETOC 2003). Application of these factors (1×3) to 0.9 mg/m3results in a DNEL of 0.3 mg/m3 for respirablefraction. This DNEL of 0.3 mg/m3 for respirable dust derived above is likely to be well on the safe side because of the small particle size and high particle surface area of synthetic amorphous silica used in these studies, which are likely to contribute the effects seen in the study by Reuzel et al. (1991). The derived value is similar to the current (2010) German MAK-value for silica fume.

However, since silicocalcium dust is likely to consist mainly on inhalable particles with only minority of respirable particles, also a DNEL for inhalabledust is suggested. Because of the apparent nontoxicity of silicocalcium, it is recommended that inhalable dust levels are controlled below 4 mg/m3, which is the recommendation by German MAK commission (DFG 2010) for inhalable general dust and represents currently the lowest OEL for general dust in Europe.

 

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
exposure based waiving
Acute/short term exposure
Hazard assessment conclusion:
exposure based waiving
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
exposure based waiving
Acute/short term exposure
Hazard assessment conclusion:
exposure based waiving
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
exposure based waiving
Acute/short term exposure
Hazard assessment conclusion:
exposure based waiving
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
exposure based waiving
Acute/short term exposure
Hazard assessment conclusion:
exposure based waiving

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
exposure based waiving
Acute/short term exposure
Hazard assessment conclusion:
exposure based waiving
DNEL related information

General Population - Hazard for the eyes

Additional information - General Population