Calcium

Endpoint summary

Description of key information

Metallic calcium used in industrial processes exhibits only risk through inhalation and dermal exposure when emitted from the process as oxidated and subsequently hydroxylated form, which will release hydroxyl ions as first contact effects. This first contact effect will have alkali effects as the main irritant effect which prolonged may cause severe local alterations, including inflammation, metaplasia and hyperplasia which can ultimately lead to chronic inflammation and increased risk of development of cancer. Long-term exposure of low levels of CaO-Ca(OH)2 dust particles are expected to cause sensory irritation and decrease of the lung function parameters. Sensory irritation is the primary effect and may be prevented by STEL-level of 1 mg/m3 of respirable dust as demonstrated by an acute inhalation toxicity study (See section 7.10 of IUCLIC, Cain et al (2004)), 8h-TWA OEL was recommended to set at 4 mg/m3. Prevention of first contact to external surfaces by appropriate risk management measures will minimize the risk of these long-term effects effectively (see chapter 9 of CSR).

Additional information

Metallic calcium used in industrial processes exhibits only risk through local effects from inhalation and dermal exposure when emitted from the process as oxidated and subsequently hydroxylated form, which will release hydroxyl ions as first contact effects. This first contact effect will have alkali effects as the main irritant effect.Given that dissolution is widely considered to be required prior to percutaneous absorption, this may be interpreted as a likely indication of low bioavailability via the dermal exposure route.Prolonged exposure for hydroxyl ions may cause severe local alterations, including inflammation, metaplasia and hyperplasia which can ultimately lead to chronic inflammation and increased risk of development of cancer. Long-term exposure of low levels of CaO-Ca(OH)2 dust particles are expected to cause sensory irritation and decrease of the lung function parameters. Sensory irritation is the primary effect and may be prevented by STEL-level of 4 mg/m3 of respirable dust as demonstrated by an acute inhalation toxicity study (See section 5.3 of CSR). 8h-TWA OEL was recommended to set at 1 mg/m³. Prevention of first contact to external surfaces by appropriate risk management measures will minimize the risk of these long-term effects effectively (see chapter 9 of CSR).) Based on exposure scenarios (chapter 9 of CSR) and risk characterization (chapter 10 of CSR) risk of prolonged exposure for hydroxyl ions is considered irrelevant, since RMMs are already in place within industries covered based on occupational recommendations.

Justification for classification or non-classification

Besides the local first contact effects of calcium oxide and calcium hydroxide, calcium ion does not exhibit any long-term systemic effects. Since calcium levels are regulated tightly by homeostasis in the various compartments of human body systemic effects are not foreseen. Calcium serves numerous biological, cellular and transmitter properties in the human body as an essential mineral. Ubiquitous presence in the environment as various calcium compounds and presence in human diet usually as ionized soluble forms withholds the necessity for further toxicity testing and risk analysis. Absorption and excretion, as well as homeostasis (intra- and extracellular), are tightly regulated by the human body (see section 7.1 of IUCLID). Therefore, calcium and its metabolites do not accumulate in the human body and do not raise a concern for repeated-dose toxicity. There is no need for classification of calcium (metal form) for this hazard class.