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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Adsorption / desorption

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Description of key information

From EPI suite KOCWIN Program (v2.00) predicted model the soil adsorption coefficient (Koc) value of 4-aminoazobenzene-3, 4’-disulphonic acid is estimated to be 871.3 L/kg i.e log Koc=2.9401 at 25 deg C,this log Koc value indicating that it is has a Moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

Key value for chemical safety assessment

Koc at 20 °C:

Additional information

By applying Weight of evidence approach for the target substance 4-aminoazobenzene-3, 4’-disulphonic acid (Cas no.101-50-8) studies are summarized as fallowed:

Both predicted sources i.e EPI Suite and PBT profiler indicate that the test substance4-aminoazobenzene-3, 4’-disulphonic acidhas a moderate sorption to soil and sediment and slow migration potential to groundwater. 

With following Koc values:

EPI SUITE - 871.3 (Log Koc=2.9401)

PBT profiler -870 (Log KoC=2.939)

Other weight of evidence studies for read across chemical from Scientific Bulletin journal (UPB Scientific Bulletin, Series B; Vol. 78, Iss. 1, 2016 P.137-148) indicate that the Soil adsorption test was conducted for test chemical tartrazine by using sorption floatation method.

Initial concentration of test chemical was 5-500 mg/L with pH range of 7-9 at temperature 20 deg C were selected to study tartrazine removal efficiency.

The removal efficiency of chemical tartrazine was found to be 9% using soil as adsorbent in sorption floatation technique.


 Overall all studies concluded that the test substance4-aminoazobenzene-3, 4’-disulphonic acid (Cas no.101-50-8)has a moderate sorption to soil.

[LogKoc: 2.9401]