Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

p-TSH is not readily biodegradable according to OECD Guideline no. 301C.

The hydrolytic half life of p-TSH at 20 °C was:

138.63 h at pH 4

38.51 h at pH 7

40.77 h at pH 9

These data suggest that p-TSH will degrade hydrolytically at environmentally relevant pH and temperature conditions. The primary degradation products are hydrazine and p-Toluenesulfonic acid.

Once released into the water environment, p-TSH will readily - due to hydrolysis - be degraded into primarily hydrazine and p-Toluenesulfonic acid

Some retention of the waste water within in the industrial settings can be expected. The travelling time from p-TSH is released into waste water until arrival in the STP can vary quite much - in dependence of the distance to plant and the flow velocity. Typically, the flow velocity in the sewer is about 1 m/s, and with an average distance between the point of discharge and STP of 10 km, a retention time in the sewer of approximately 3 hours is calculated. In the sewer, a pH above 7 is usual (in order to limit the concentration of free H2S and to limit the corrosion due to the presence of sulfuric acid).

The overall retention time in a standard SimpleTreat sewage treatment plant (STP) is approximately 15 hours. Overall, a total retention time of 1 day = 24 hours is assessed to be a reasonable value to apply for the risk assessment. A pH between 7 - 8 is expected in the sewer and the sewage treatment plant.

In conclusion, a total hydrolytic transformation of approximately 65% before final discharge into the environment is assessed to be a reasonable value to use for the environmental risk assessment.

Additional information

p-TSH is not readily biodegradable according to OECD Guideline no. 301C.

The hydrolytic half life of p-TSH at 20 degrees celcius was:

138.63 h at pH 4

38.51 h at pH 7

40.77 h at pH 9

These data suggest that p-TSH will degrade hydrolytically at environmentally relevant pH and temperature conditions. The primary degradation products are hydrazine and p-Toluenesulfonic acid.

Once released into the water environment, p-TSH will readily - due to hydrolysis - be degraded into primarily hydrazine and p-Toluenesulfonic acid

Some retention of the waste water within in the industrial settings can be expected. The travelling time from p-TSH is released into waste water until arrival in the STP can vary quite much - in dependence of the distance to plant and the flow velocity. Typically, the flow velocity in the sewer is about 1 m/s, and with an average distance between the point of discharge and STP of 10 km, a retention time in the sewer of approximately 3 hours is calculated. In the sewer, a pH above 7 is usual (in order to limit the concentration of free H2S and to limit the corrosion due to the presence of sulfuric acid).

The overall retention time in a standard SimpleTreat sewage treatment plant (STP) is approximately 15 hours. Overall, a total retention time of 1 day = 24 hours is assessed to be a reasonable value to apply for the risk assessment. A pH between 7 - 8 is expected in the sewer and the sewage treatment plant.

In conclusion, a total hydrolytic transformation of approximately 65% before final discharge into the environment is assessed to be a reasonable value to use for the environmental risk assessment.