Calcium magnesium oxide

Toxicological Summary

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:

1 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

Overall assessment factor (AF):

1

Acute/short term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

4 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

Overall assessment factor (AF):

1

Workers - Hazard via dermal route

Systemic effects

Acute/short term exposure

DNEL related information

Additional information - workers

No acute and long-term DNEL for workers exposed via inhalation are derived from animal studies, because recommendations on occupational exposure limits for calcium oxide and calcium hydroxide are available from the Scientific Committee on Occupational Exposure Limits (SCOEL/SUM/137, February 2008): STEL (15 min) = 4 mg/m³ respirable dust for short-term exposure to prevent local sensory irritation due to the irritation potential of the substance, and OEL (8 h) = 1 mg/m³ respirable dust (operator exposure limit, TWA, 8 h) to prevent local sensory irritation and decrease of lung function parameters as critical effects. No further assessment factors are applied to the exposure limits proposed by the SCOEL. These values are read-across to calcium magnesium oxide in view of the anticipated equivalent local effect (pH is comparable to that of CaO and Ca(OH)2), and the non-relevance of magnesium for both local and systemic effects.

General Population - 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:

1 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

Overall assessment factor (AF):

1

Acute/short term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

4 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

Overall assessment factor (AF):

1

General Population - Hazard via dermal route

Systemic effects

Acute/short term exposure

DNEL related information

General Population - Hazard via oral route

Systemic effects

Acute/short term exposure

DNEL related information

Additional information - General Population

For the oral route, no DNELs are derived in view of the role of calcium and magnesium as essential mineral nutrients. Upper intake levels (UL) have been derived by the Scientific Committee on Food as 2500 mg/d for calcium and 250 mg/d for magnesium. These values are sufficiently protective both with respect to acute and long-term exposure.

No acute and long-term DNELs for exposure of the general population via inhalation are derived from animal studies, because recommendations on occupational exposure limits for calcium oxide and calcium hydroxide are available from the Scientific Committee on Occupational Exposure Limits (SCOEL/SUM/137, February 2008): STEL (15 min) = 4 mg/m³ respirable dust for short-term exposure to prevent local sensory irritation due to the irritation potential of the substance, and OEL (8 h) = 1 mg/m³ respirable dust (operator exposure limit, TWA, 8 h) to prevent local sensory irritation and decrease of lung function parameters as critical effects. These values are read-across to calcium magnesium oxide in view of the anticipated equivalent local effect (pH is comparable to that of CaO and Ca(OH)2), and the non-relevance of magnesium for both local and systemic effects.

These indicative exposure limits are considered as sufficiently protective also for the general population and are therefore proposed to be adopted. No further assessment factors are applied to the exposure limits proposed by the SCOEL.