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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

Performance of simulation tests for biodegradation in water and sediment was waived, as disodium persulfate is an inorganic substance. However, the rapid degradation observed in hydrolysis tests indicates that the substance will degrade rapidly in the natural environment.  Upon contact with water or water vapour substances of the Persulfate Category hydrolyse into cation and persulfate anion. Hydrolysis is temperature and pH dependent and decomposition rates increases with decreasing pH value and increasing temperature. The persulfate anion, independent of the cation, undergoes further decomposition in normal water or acid conditions, readily oxidizing water to oxygen, producing sulphate and hydrogen ions. All persulfate hydrolysis products are ubiquitous to the environment. Hydrolysis is metal catalysed, and rapid reaction with organic matter is possible.

Key value for chemical safety assessment

Additional information

In accordance with Column 2 of REACH Annex IX, simulation testing on ultimate degradation in surface water, information requirement 9.2.1.2, can be waived, if the substance is readily biodegradable. Although the biodegradation of the substance was waived, as persulfate salts are inorganic. The abiotic degradation observed in a hydrolysis test indicates that the substance will degrade in the natural water environment.

 

In accordance with Column 2 of REACH Annex IX, sediment simulation testing, information requirement 9.2.1.4, can be waiver, if direct or indirect exposure to sediment is unlikely. Additionally, the test item is considered to degrade rapidly in natural water environment.