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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge 4-nitro-o-toluidine(CAS No.99-52-5) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to functional group similarity with the test substance and calibration graph prepared. The reference substances were 4 -methylaniline, aniline, nitrobenzene, xylene, ethylbenzene and toluene, having Koc value ranging from 1.9 to 2.649. The Log Koc value was found to be 2.0875 ± 0.0002 at 25°C.

Additional information

Adsorption / desorption

Four studies including experimental study and predicted data from validated models for adsorption (KOC) endpoint of target chemical 2-methyl-4-nitroaniline (Cas no. 99-52-5) were summarized as follows:

 

First study from experimental report by UERL laboratory; 2017 which suggest the adsorption coefficient Koc in soil and in sewage sludge 4-nitro-o-toluidine(CAS No.99-52-5) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to functional group similarity with the test substance and calibration graph prepared. The reference substances were 4 -methylaniline, aniline, nitrobenzene, xylene, ethylbenzene and toluene, having Koc value ranging from 1.9 to 2.649. The Log Koc value was found to be 2.0875 ± 0.0002 at 25°C.

 

Above results also supported by prediction using KOCWIN model (v2.00) of EPI suite which indicated the adsorption value of 2-methyl-4-nitroaniline was estimated as Koc 178.6 L/kg (log Koc = 2.25) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 2-methyl-4-nitroaniline has a low sorption to soil and sediment and therefore have moderate migration potential to groundwater.

 

Another prediction model i.e Chemspider - ACD/PhysChem Suite for target indicate the soil adsorption coefficient i.e Koc value of test substance 2-methyl-4-nitroaniline was estimated to be 161.70 (log koc: 2.20) at pH 5.5 and 7.4 and temp.25 deg.C Koc values at mentioned pH indicates that the substance 2-methyl-4-nitroaniline has slow sorption to soil and sediment and therefore have moderate migration potential to groundwater.

Last study from Scifinder database suggest the soil adsorption coefficient i.e Koc value of test substance 2-methyl-4-nitroaniline was estimated to be 71.0 (Log koc: 1.85) at pH 1, 120 (Log koc: 2.07)at pH 2 and  130 (Log koc:2.11) at pH 3-10 at temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 2-methyl-4-nitroaniline has low sorption to soil and sediment and therefore have moderate migration potential to groundwater.

Thus all available studies for adsorption endpoint gives the common conclusion that the test substance 2-methyl-4-nitroaniline (Cas no. 99-52-5) is expected to have moderate mobility in soil and sediment compartment.