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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Adsorption / desorption

From HSDB authorative database the adsorption coefficient (Koc) of substance Oil pink i.e1-[(2-methoxyphenyl)azo]-2-naphtholwas found to be 290000 using a measured log Kow of 7.5 and regression derived equation.This Koc value indicates that oil pink will be immobile in soil.

Additional information

Adsorption / desorption

Five results including experimental data from authorative database and different predicted values from validated models for adsorption (KOC) endpoint of target chemical 1-[(2-methoxyphenyl)azo]-2-naphthol (Cas no. 1229-55-6) with relevant read across which is structurally similar to target were summarized as follows:

 

First study from HSDB authorative database which suggest the adsorption coefficient (Koc) of substance Oil pink i.e 1-[(2-methoxyphenyl)azo]-2-naphthol was found to be 290000 using a measured log Kow of 7.5 and regression derived equation. This Koc value indicates that oil pink will be immobile in soil.

 

 Followed prediction by KOCWIN model (v2.00) of EPI suite which indicate the adsorption value of 1-[(2-methoxyphenyl)azo]-2-naphthol was estimated as 34820 L/kg(log Koc=4.54) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 1-[(2-methoxyphenyl)azo]-2-naphthol has a very strong sorption to soil and sediment and therefore have negligible migration potential to groundwater. 

Above result is assist by result from CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application) V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical) indicate the adsorption coefficient i.e KOC for test substance 1-[(2-methoxyphenyl)azo]-2-naphthol was estimated to be 4610 L/Kg.The predicted KOC result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance 1-[(2-methoxyphenyl)azo]-2-naphthol is immobile in soil compartment.

And Scifinder database suggest the soil adsorption coefficient i.e Koc value of test substance 1-[(2-methoxyphenyl)azo]-2-naphthol was estimated to be 5690 (Log koc =3.75) at pH range 1-10 at temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 1-[(2-methoxyphenyl)azo]-2-naphthol has Strong sorption to soil and sediment and thus negligible to slow migration potential to groundwater.

 

Last study from authorative database HSDB; 2017 for read across chemical Solvent Red 23 (Cas no. 85-86-9) suggest Log Koc values for test substance Solvent Red 23 are based on calculations by Baughman and Perenich (1988) using a range of measured solubility for commercial dyes and an assumed melting point of 200 deg.C.During experiment the Log Koc (Organic carbonwater partition coefficient) (dimensionless) was reported to be 3.4 to 4.2. Based on the result it is concluded that the Solvent Red 23 has low water solubility and a relatively high Koc it is not likely to leach from sediments and soils means solvent Red 23 is immobile in soil and sediment.

Thus all above available studies for adsorption endpoint come to conclusion that the test substance chemical 1-[(2-methoxyphenyl)azo]-2-naphthol (Cas no. 1229-55-6) is expected be immobility in soil and sediment compartment.