Phthalylsulfathiazole

PBT assessment

PBT assessment: overall result

PBT status:

the substance is PBT / vPvB

Justification:

Classification of phthalylsulfathiazole for effects in the environment

Several major guideline – estimation values (Klimisch 2) are available for phthalylsulfathiazole, indicates slight toxic effect for all the 3 key trophic levels (fish, invertebrate and algae). Among the values lower values which lead to the classification of the substance the value which have been considered for further calculation (invertebrate) is LC50 = 19.051 mg/L.

 

In determining the classification appropriate to phthalylsulfathiazole, it is necessary to consider all available evidence concerning its persistence, potential to accumulate and predicted or observed environmental fate and behaviour that may present a long-term and/or delayed danger to the structure and/or functioning of aquatic ecosystems. These points are considered below.

 

Persistence

Reliable studies are available to demonstrate that phthalylsulfathiazole is non persistent in nature and so is considered to have rapid biodegradation in the environment. In other words phthalylsulfathiazole degradation may therefore be expected to be fast. Thus it can be inferred that phthalylsulfathiazole is non persistent in character. 

 

Phthalylsulfathiazole is non persistent and so do not satisfy the criteria for classification as persistent (P). 

 

Potential to accumulate

Predicted and measured log Kow values for phthalylsulfathiazole is less than 4 (Log Kow = -2). The potential for phthalylsulfathiazole to bioaccumulate in the tissues of organisms that inhabit aquatic or terrestrial matrices is negligible as the BCF factor for the substance is less than 1000.  

 

 The calculated BCF of phthalylsulfathiazole is 5.25 dimensionless and below the threshold of 2000. 

 

Phthalylsulfathiazole does not satisfy the criterion for classification as bioaccumulative (B).

 

The toxicity values of fish, invertebrates and algae are LC50 = 26.87273 mg/L, EC50 = 19.051 mg/L are EC50 = 19.3344 mg/L, respectively. The toxicity values of all the trophic levels fall in the criteria for classification (CLP regulation) and so will qualify for classification as per the aquatic CLP criteria for classification in category 3. 

So, phthalylsulfathiazole will satisfy for the environmental effects criterion for classification as toxic (T).

 

Thus it can be inferred that phthalylsulfathiazole is not P & B (including vPvB) substance, but will qualify as T.