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Endpoint:
adsorption / desorption: screening
Data waiving:
study technically not feasible
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
The substance is a solid inorganic compound (comprising MgSiO3, SiO2, Si). Based on the physico-chemical properties the substance can be expected to have a low potential for adsorption as the substances elements (Mg, Si) have very low water solubility (< 0.05 mg/L by elemental analysis), which will limit potential for adsorption.

Testing for adsorption/desorption screening (by test method OECD 121 or 106) has not been conducted as it is not technically feasible to produce a scientifically meaningful result. Available analytical methods with sufficient accuracy are not suitable for this inorganic substance, as it would not be possible to quantify Mg or Si.

The test substance is not soluble in water and elemental analysis showed water solubility of the Mg and Si elements as <0.05 mg/L. The low water solubility would make testing by OECD 121 (HPLC method) or OECD 106 (batch equilibrium method) impractical.
Test guideline OECD 121 states the method is not suitable for inorganic compounds. Test Guideline OECD 106 states difficulties may arise in conducting the test for substances with low water solubility.
The test substance also isnt soluble in typical organic solvents, also making testing not feasible.

Therefore, determination of the adsorption coefficient was not performed according to OECD 121 or 106 as neither method is applicable to this inorganic substance.

Calculation of the adsorption coefficient from the octanol-water partition coefficient is not possible because the octanol-water partition coefficient is also not applicable to inorganic substances.

In addition, Mg and Si are naturally occuring in the environment and soils.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion

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