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Environmental fate & pathways

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No valid stability studies are available, but as p-TSA is readily biodegradable this is not necessary.

Two studies show that p-TSA is readily bidoegradable; one is a publication, valid with restrictions, in wich the degradation pathway is described and from which can be concluded that p-TSA is readily biodegradable and the other is a full GLP Closed bottle Test according to standard guideline whih shows that p-TSA is readily biodegradable and not toxic to the microorganisms at 2 mg/L.

p-TSA is also completely mineralized in soil as can be seen from a study with Chloramine-T (CAS 127 -65 -1) Chloramine-T trihydrate is a strong oxidizing agent in aqueous solution and when brought into contact with organic matter (soil) it reacts and leaves p-tolunenesulfonamide as the only detectable transformation product. The rate and route of p-toluenesulfonamide biodegradation depends on the soil type. But in each tested soil type p-toluenesulfonamide is totally mineralised.

Worst case values were found in humic sand soil: Disappearanceof p-tofuenesulfonamide was calculated with DT50 and DT90 values of 68 days and 249 days, respectively. 

p-TSA does not have a potential to bioaccumulate. A study with Oncorhynchus mykiss, performed with Chloramine-T (CAS 127 -65 -1) shows the following: The kinetic whole body BCF as calculated from the accumulation and depuration from fingerling half-lives using the p-TSA equivalent concentration (worst-case). The k1/k2 ratio as calculated according to OECD guideline 305 is 2.2 based on LSC. It should be noted that this ratio must be considered as a worst-case value because it is calculated using the p-TSA equivalent concentration for fingerlings, using the average depuration rate during the whole curve expressed in relation to the whole body. Lower ratios would be obtained if the data for juvenile rainbow trout would have been used.

Adsorption to soil or sediment is not expected as p-TSA is readily biodegradable, has a low log Kow and is highly soluble in water, therefore adsorption is waived.