Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Relevant phys.-chem. substance properties

The submission item is a multiconstituent substance consisting of four main components. One compound is soluble in water to ca. 2 g/L whereas the three other main components have low water solubilities. All four major components have a low vapour pressure. The substance (in its non-ionised form) exhibits surface-active properties and has a high octanol-water partition coefficient of log Kow >6.2.

Transport and distribution

The constituents of the submission item may occur in an ionised form under environmental pH conditions. This is because the amine groups present will be ionised at pH values found in the environment and the cationic species tend to bind strongly to soil/particles due to partitioning onto organic matter or interactions with clay minerals. In conclusion, it can be expected that the submission item has the potential to adsorb to soil and sediment particles under environmental conditions. The low vapour pressure of the substance results in a low Henry's Law constant, which makes it unlikely that the substance will be released from water surfaces or the soil compartment to the atmosphere in significant amounts.

Stability - abiotic and biotic degradation

The submission item is unlikely to undergo hydrolysis in significant amounts under environmental conditions and the hydrolysis half-lives of the four components are greater than 1 year at 25 °C. In addition, there is no hint that the substance may be transformed by sunlight irradiation. Considering the lack of biodegradation observed in the ready biodegradation test, it is to be expected that the submission item is unlikely to be degraded to a significant extent under the conditions of an inherent biodegradability study, unless a toxic effect to the microorganism community was the reason for the absence of degradation. In the study of Clarke (2002) on the toxicity to microorganisms according to OECD TG 209 the NOEC was found to be 10 times lower than the initial concentration in the ready biodegradation test of 100 mg/L. The EC 50 in this study was at 70 % of the concentration used in the MITI test for ready biodegradability. It seems therefore possible, that significant intoxication of the microorganism community prevented biodegradation the MITI test. Nonetheless, as long as no data are becoming available indication ultimate biodegradability of the substance under real environmental conditions, the test item should be regarded as non-biodegradable. Based on these grounds the screening assignment "P/vP" shall be given.

Bioaccumulation

The submission item shall not be considered to fulfil the B criterion of PBT substances, based on the following:

1) BCFWIN computations lead to log BCF results of 1.37, 2.99, and 2.82, respectively, for the three major substance components. These results all below the cut-off value for the B criterion of log BFC 3.3 (BCF 2000).

These BCFWIN-computed data even are to be seen as worst case results (i.e. tendency of overestimation of the BCF results as computed via BCFWIN), as they include a number of worst case assumptions:

2) In the environmentally relevant pH range 5 - 9, the ionised species of the three major components of the submission item are prevailing, whereas the BCFWIN computation was based on log Kow estimates of the non-ionised species (Kow estimates for non-ionised species are higher than for the ionised species).

3) Computed pH-dependent log D values show clearly that these log D data within the environmentally relevant pH range 5 - 9 are much lower than the BCFWIN estimates for log Kow (and lower as the HPLC-based log Kow results, which also were being obtained with non-ionised substance species).

4) BCF computations based on log D values reveal log BCF results of 0.36, 1.9, and 1.94, respectively, which all are well below the regulatory cut-off value for the B criterion of 3.3.

With the evidence provided it safely can be assumed that the substance is not fulfilling the B criterion, and that the submission item therefore shall not be considered as a PBT or vPvB substance. Based on these grounds, a study on bioaccumulation can be waived, what further can be supported by the fact that (referring to the restricted industrial uses of the substance, and based on the high adsorption potential) a direct or indirect exposure to the aquatic environment is unlikely.