Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability (hydrolysis):

The stability of the substance towards hydrolysis was determined (Bayer, 1999a). Based on kinetic parameters, the following dissipation half-lives were derived:

pH 4 (25 °C): t1/2: 529.88 h (extrapolation)

pH 4 (50 °C): t1/2: 34.92 h

pH 7 (50 °C): t1/2: 1.48 h

pH 9 (50 °C): t1/2: 0.98 h

The assumption that the ester functions were hydrolysed was proven by LC-MS. It could be shown that up to two ester functions within one molecule were cleaved by hydrolysis forming carboxylic acid functions. No further analysis was performed to determine the exact identity of the hydrolysis products.

Using the van´t Hoff´s rule the dissipation half-lives at 25°C for pH 7 and pH 9 were calculated:

pH 7 (25°C): t1/2: 7.89 h

pH 9 (25°C): t1/2: 5.21 h

Biodegradation (in water, screening test):

The ready biodegradability of the substance was determined (Bayer AG, 1999b): 30 % degradation after 28 days. The substance is not readily biodegradable.

The inherent biodegradability of the substance was determined (Currenta, 2011a): 18 % degradation after 28 days. The substance is not inherently biodegradable.

Bioaccumulation:

The substance is characterised by an estimated bioconcentration factor of 128.3 L/kg wwt (Currenta, 2011b, 2011c, 2011d). As the value is calculated, the program does not consider any decomposition of the substance in water.

Both possible hydrolysis products (bis-aspartic-mono-acid triethylester, bis-aspartic-di-acid diethylester) have a calculated BCF value of 3.162 L/kg wwt.

Adsorption / desorption:

The potential of the substance is described by a log Koc between 2.09 and 3.00. The area % weighted log Koc accounts for 2.7. Measurements were carried out at pH 6 (Currenta, 2010a). According to the classification of Swann et al. (1983), the substance has a medium potential to sorb on soil.

Henry´s Law constant:

The substance is characterised by a calculated Henry Law Constant between 7.68 E-5 and 1.15 E-4 Pa m³/mol (Currenta, 2010b). According to Thomas, cited in the "Handbook of Chemical property Estimation Methods" (Lyman, 1980), the substance is less volatile than water. Therefore, the substance is scored as being non-volatile from water.