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Environmental fate & pathways

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Stability:

Phototransformation in air :

The atmospheric oxidation half life of N,N-dimethyl-p-toluidinewas estimated using level III multimedia model it indicates thatN,N-dimethyl -p-toluidineis not persistent in air medium as the half life period ofN,N-dimethyl-p-toluidinein air is only 0.079 days.

The supporting study also indicates the half life of N,N-dimethyl-p-toluidine to be 0.025 days

From this it is concluded thatN,N-dimethyl-p-toluidineis rapidly phototransformed in air.

Medium

Halflife

percent in medium

Air

0.079

0

 

Hydrolysis :

The Hydrolysis rate constant of N,N-dimethyl-p-toluidine was estimated to be 0.0000000002026656 (202.6656 E-12 ) cm3/molecule-sec. at a half life of 0.633 hrs. The estimated half life indicates that N,N-dimethyl-p-toluidine is rapidly hydrolysable.

Phototransformation in water :

No experimental data available. As this study is not a standard information requirement in REACH and there is no indication from the CSA on the need to investigate further the fate and behaviour of the substance (Annex X requirement), no further testing is considered necessary.

Phototransformation in soil :

No experimental data available. As this study is not a standard information requirement in REACH and there is no indication from the CSA on the need to investigate further the fate and behaviour of the substance (Annex X requirement), no further testing is considered necessary.

Biodegradation :

Biodegradation in water: screening tests :

based on the weight of evidence approach, the number of studies were reviewed for biodegradation in water from reliable sources having Klimish rating 2.

The summary of the results is presented below:

Sr.No

Endpoint

Half-life

Remark

Sources

1

Biodegradation in water

-

Not readily biodegradable

Predicted data of Target chemical

2

Biodegradation in water

-

Not Readily biodegradable

Data is from database from CAS NO 91-66-7

 

Based on the study and predicted data, it is concluded that the chemical is not readily biodegradeble and thus considered to be persistent in water medium

Biodegradation in water and sediment :

As per biowin model N,N-dimethyl-p-toluidine is not readily biodegradable in water as the Biowin3 (ultimate survey model) result is p = 2.5707 months ( if in days or weeks then readily biodegradable), AND the Biowin5 (MITI linear model) probability is p= 0.3002 ( less than 0.5 is not readily biodegradable), while on the basis of fugacity model half life of N,N-dimethyl-p-toluidine in sediment is 337.5 days (8100 hrs.).Based on these half life values of it is concluded that N,N-dimethyl-p-toluidine is non biodegradable in sediment. However, since there is negligible diffusion of the substance in the sediment medium as evident from the reported data (0.175%) and hence persistence in the sediment compartment is not likely to be critical.

 Biodegradation in soil :

Based on level III fugacity model halflife period ofN,N-dimethyl-p-toluidine was estimated.

Half life period of N,N-dimethyl-p-toluidine in Soil was observed to be 75 days which does not exceeds the threshold criteria of 120 days. Based on these half life values it is concluded that N,N-dimethyl-p-toluidine is readily biodegradable (not persistent) in Soil medium.

Media

Half life

(Days)

% in medium

Soil

75

78

 

 

Media

Half life

(hrs)

% in medium

Emissions

 (kg/hr)

Soil

1800

78

1000

Bioaccumulation :

Bioaccumulation: aquatic / sediment :

No. of studies reviewed for bioaccumulation in aquatic/ sediment and presented as weight of evidence; from reliable sources having Klimish rating 2 to 4

The summary of the results are presented below

Sr.no

Endpoint name

value

unit

source

1

BCF

33

-

Estimated data

2

BCF

33.19

L/Kg wet wt

Estimated data

3

BCF

29.09

-

Data is from study report

 

From this it is concluded that the substanceN,N-dimethyl-p-toluidineis having BCF values in the range of 29.09- 33.19 and thus not expected to bioaccumulate in the food chain as it does not exceed the threshold criteria of 2000.

 

Transport and distribution :

Adsorption and desorption :

Soil Adsorption Coefficient i.e Koc value of N,N-dimethyl-p-toluidine was estimated as 126.2 (Log Koc = 2.1010) at 25 deg Cby means of MCI method. This indicates thatN,N-dimethyl-p-toluidine have low adsorption to the organic carbon fraction of the soil and will have a moderate migration potential to groundwater.

Henry,s law constant :

Henry's Law Constant of N,N-dimethyl-p-toluidine was estimated as 9.58E+000 Pa-m3/mole at 25 deg C using Bond Contribution Method.