Sodium 3-mercaptopropanesulphonate

Endpoint summary

Additional information

Stability

No experimental data are available for 1-Propanesulfonic acid, 3 -mercapto-, monosodium salt (CAS 17636-10-1). The phototransformation in air can be determined with the help of the computer program AOPWIN v1.92 (EPIWIN software) of US-EPA (Chemservice S.A., 2011). An atmospheric half-life of 0.243 days (around 2.913 hours) was calculated. Neither an ozone reaction nor any nitrate radical reaction is important for the target chemical. This modelling is a scientifically accepted calculation method and is therefore reliable with restrictions and can be used for the chemical safety assessment.

The hydrolytical half-life at pH 9 at a temperature of 25 °C was experimentally determined as 52.3 days (Tarran, 2012). At pH 4 and 7, the substance is considered as stable, since the half-lives are greater than 1 year.

Biodegradation

For 1-Propanesulfonic acid, 3-mercapto-, monosodium salt (CAS 17636-10-1) the biodegradability can be predicted by the computer program BIOWIN v4.10 (EPIWIN software) of US-EPA (Chemservice S.A., 2011). The program calculates with seven different models. According to Biowin 1 and 2 the substance is biodegrading fast. The Ultimate Biodegradation Timeframe is "weeks", whereas the Primary Biodegradation Timeframe reveals "days" as result. Both MITI Models predict that the substance is not readily biodegradable. Overall Ready Biodegradability Prediction: No.

Further prediction can be made using the modelling tool Toxtree (v.2.5.0), which uses the START (Structural Alerts for Reactivity in Toxtree) plug-in. This is a developed rulebase, which estimates the biodegradability potential of a chemical compound based on structural alerts compiled from the Canadian EPA (START2008). The chemical was assigned to the class III - unknown biodegradability.

Bioaccumulation

1-Propanesulfonic acid, 3 -mercapto-, monosodium salt (CAS 17636-10-1) was not investigated for its aquatic bioaccumulation potential so far. The computer program BCFBAFWIN v3.00 was used to predict the bioconcentration factor (BCF) of the substance (Chemservice S.A., 2011). Using the regression-based estimate (traditional method) a BCF of 3.16 L/kg wet-wt was calculated. Using the Arnot-Gobas method, based on the mechanistic first principles, the BCF results in a value of 0.90 L/kg wet-wt. The metal compounds (Na, K, Li) were removed for its calculation procedure. Hence, bioaccumulation in aquatic organisms is not to be expected.

Transport and distribution

The adsorption potential to soil of 1 -Propanesulfonic acid, 3 -mercapto-, monosodium salt (CAS 17636-10-1) was determined by the scientifically accepted calculation method with KOCWIN v2.00 (Chemservice S.A., 2011) Two different models are used, whereby the MCI method is taken more seriously into account, due to the fact that is includes improved correction factors. For this chemical compound, the metal compound (Na) has been removed by the program to allow the estimation via the MCI method, resulting in a Koc value of 2.857 L/kg. The traditional method gives a value of 0.086 L/kg. It is noted that these results represent a best-fit to the majority of experimental values, due to the fact that the Koc of this structure may be sensitive to the surrounding pH.

Additionally, the Henry´s Law constant was predicted by the EPIWIN software HENRYWIN v3.20 (Chemservice S.A., 2011). The Bond Method resulted in a value of 0.0000801 Pa*m³/mol (8.01 E-5 Pa*m³/mol) at an ambient temperature of 25 °C.