Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

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Additional information

Kaolin, calcined is an inorganic solid and poorly soluble in water. Due to its chemical nature and stability, hydrolysis is not expected. However, ion exchange processes are possible depending on the surrounding environment to transfer the substance in another, as very limited, not quantifiable hydrolysis is involved in the dissolution of silicates in water.

Based on the chemical nature, inorganic structure and chemical stability of kaolin, calcined, phototransformation in air, water and soil is not expected. For the same reasons, biodegradation in water, sediment or soil is not applicable as environmental fate process.

Kaolin, calcined is an inorganic solid insoluble in n-octanol. Due to its inherent chemico-physical properties, bioaccumulation is not expected. Besides, as the substance is poorly soluble, low concentrations are expected in the aquatic compartment. Low quantities which might be taken up are considered to be not bioavailable as it is known that no toxicologically relevant absorption of Al occurs, whereas absorbed Si levels are known to be rapidly excreted in urine and faeces. Thus, kaolin, calcined contains no bioaccumulation potential.

If released into the environment, the substance is expected to combine indistinguishably with the soil or sediment due to its similarity with inorganic soil/sediment matter and will be subjected to natural processes under environmental conditions (cation exchange, dissolution, sedimentation).

Due to low water solubility and extremely low vapour pressure, it is expected to distribute mainly into soils and sediments, weakly into water and probably not at all into the air.