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Environmental fate & pathways

Adsorption / desorption

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Description of key information

The adsorption coefficient (logKoc) on soil and on sewage sludge of -1.3 (KOC = 0.05) was measured at 25 °C and pH 6.4.

Key value for chemical safety assessment

Koc at 20 °C:
0.05

Additional information

For agricultural soils or tanks of sewage treatment plants pH norrnally varies between pH 5.5 and 7.5. Forthis reason the test is performed at pH 6 (adding citrate buffer to the mobile phase). In case more than 10 % of the test substance is dissociated at pH 6, a second lest has to be performed at a pH where the lest substance is undissociated.

Because the test substance is a sodium salt of an aliphatic sulfuric acid, these salts are dissociated in water. An undissociated form of the test substance of the salt of a sulfuric acid would be the undissociated form of the sulfuric acid, which is not investigated in this study. Therefore no investigation at the second pH value was performed.

Assuming the nonionic form a log Koc value of 1.00 was calculated with the software PCKOCWIN vl.66, which is owned by the U.S.Environmental Protection Agency.