Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Biodegradation :

Biodegradation in water : Screening test :

Based on level III fugacity model the half life period of Phthalylsulfathiazole was estimated. Phthalylsulfathiazole was 50% biodegradable in water in 38 days (half-life) indicating that phthalylsulfathiazole is readily biodegradable in water since the half life is less than the threshold of 60 days (to qualify the chemical as persistent)

Media

Half life

(days)

Percent in Medium

Water

38

19%

Biodegradation in Water and Sediment :

Based on level III fugacity model the half life period of phthalylsulfathiazole was estimated.Half life period of phthalylsulfathiazole in water was estimated to be 38 days while in sediment it is 340 days.Based on these half life values it is concluded that phthalylsulfathiazole is readily biodegradable in water where as it is non biodegradable in sediment. However, since there is no diffusion of the substance in the sediment as evident from the reported data (0% in sediment) and hence persistence in the sediment compartment is not likely to be critical.

Media

Half life

(days)

Percent in Medium

Water

38

19%

sediment

340

0%

 

Biodegradation in Soil :

Based on QSAR prediction half life period of phthalylsulfathiazole in Soil was estimated to be 99.2 days which exceeds the EPA criteria of 60 days

Also from the other weight of evidnece study it is found that the substance is 50% degradable in 75 days which also exceeds the EPA criteria of 60 days

Based on these half life values it is concluded that phthalylsulfathiazole is not readily biodegradable (persistent) in Soil.

No. of studies reviewed for biodegradation in water endpoints from reliable sources having Klimish rating 2

The summary of the results are presented below

 

Sr. No

Endpoint name

Value

Units

Half life

1

% degradation 50 % in 99.2 days

 2

 % degradation  50  %   in 75 days

 3

  % degradation 50   %   in 75 days

 

Based on the above information it can be concluded that the substance is not readily biodegaradable and hence persistent in Soil according to CLPregulation.