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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Endpoint:
biodegradation in water: sediment simulation testing
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Transformation products:
not specified
Endpoint:
biodegradation in water: simulation testing on ultimate degradation in surface water
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Transformation products:
not specified

Description of key information

The performance of a biodegradation simulation test in water and sediment was waived because synthetic amorphous Silicic acid, aluminum sodium salt (CAS 1344-00-9, NAS) is an inorganic substance. Furthermore, silicon dioxide/silicate and aluminum are two of the most abundant materials on Earth´s surface, in fact, silicon is the second most abundant element in the Earth’s crust mass (approx. 28 %) after oxygen, and aluminum is the third most abundant element (approx. 8%).

Key value for chemical safety assessment

Additional information

Biodegradation testing in water and sediment is not applicable because synthetic amorphous aluminum sodium silicate is an inorganic, stable/inert compound, which is not biologically transformed. Furthermore, silicon dioxide/silicate is one of the most abundant materials on the Earth's surface, in fact, silicon is the second most abundant element in the earth’s crust mass (approx. 28 %) after oxygen. Synthetic amorphous silica and silicates released into the environment are expected to combine indistinguishably with the soil or sediment due to their similarity with inorganic soil/sediment matter and will be subjected to natural processes under environmental conditions (cation exchange, dissolution, sedimentation). Based on the chemical nature of synthetic amorphous silica and silicates (inorganic structure and chemical stability of the compound: Si-O bond is highly stable), no photo- or chemical degradation is expected. Biodegradation is not applicable to these inorganic substances. The bioavailable form of synthetic amorphous silica and silicate is the dissolved form that exists exclusively as monosilicic [Si(OH)4] acid under environmental pH.