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Environmental fate & pathways

Adsorption / desorption

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Description of key information

The adsorption coefficient of the substance was determined on activated sludge by the batch equilibrium method in accordance with OECD Guideline 106. 

Key value for chemical safety assessment

Koc at 20 °C:
825

Additional information

The adsorption coefficient of the substance was determined as a function of the organic carbon content of the activated sludge. Activated sludge was selected for testing and was characterized for percent organic carbon. The percent adsorption, the adsorption coefficient (Kd) and the adsorption coefficient as a function of organic carbon (KOC) were determined from adsorption experiments. The percent desorption and the desorption coefficient (Kdes) were determined from the desorption kinetic experiments. Analysis of the test samples was performed by total organic carbon (TOC) analysis due to the rapid hydrolysis of the parent compound. The study was performed following the laboratory protocol entitled “TPSA – Determining the Adsorption Coefficient (KOC) Following OECD Guideline 106” and was conducted to meet the requirements specified in OECD Guideline No. 106.

The adsorption of the substance was evaluated using activated sludge at 20 ± 2°C. The Kd, and KOCand values for the test substance were determined at a sludge-to-solution ratio of 1:400 using data through 6 hours. The initial concentration of the test substance in the aqueous phase was 6.4 mg/L. The Kdand KOCvalues indicate that the test substance is moderately mobile (Koc<1000) and what adsorption there is, most likely is reversible considering the desorption values. The Kocfor the substance was reported as Koc= 825 L/kg, or log Koc= 2.916.

[LogKoc: 2.916]