Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Note that much of the data was proved by ECHA under the 12 year data access rule. No robust summary was available at the time of preparation of this document and some key data was not included in the information from ECHA.

The substance will rapidly degrade in light (the function is UV curing agent) and from the water solubility data provided by ECHA, it is unclear if the water solubility of 5.9 mg/l was recorded from measurements in the dark, or if this low figure is only recording residues after photolytic breakdown. A hydrolysis study was performed (environmental fate and pathways), but only 10% loss was reported (assumed performed in the dark). Analysis from fish and Daphnia testing using semi-static conditions reported up to 95% loss of test substance under light conditions over 24 hours.

The partition coefficient Log Pow 2.9 would suggest a low risk of bioaccumulation. This was performed by HPLC and interaction of light should not have been significant. EPISuite modelling predicted a partition coefficient of Log Kow 4.5.

The results of testing suggest that the substance is poorly biodegradable, but insufficient data were provided in the summaries supplied by ECHA to comment on whether toxicity or solubility limits could have affected the results. Modelling with EPISuite would indicate a low level of biodegradation, so it is likely that this result give the correct range of results.

The adsorption coefficient study was not performed as part of the original registration (Notification under 6th Amendment), but estimates by established modelling methods are considered sufficient to provide adequate information for risk assessment purposes. It must also be noted that exposure to the environment of the substance is unlikely as the substance will quickly breakdown in light and will lose its identity in waste water treatment processes. The photolysis products are being assessed.

Limited information on the hydrolysis study was provided, but from the apparent stability in water in this study and from the poor stability as a result of the fish and Daphnia tests, it appears likely that this study was performed in the dark. This is consistent with accepted good practice. It can be concluded that the substance will degrade in the presence of light in water, but not in the absence of light.

Further investigations into the identity of the degradation products from reaction in light and water are planned and these degradation products will be assessed.

Summary and discussion of environmental distribution

The major alpha-cleavage reaction of Speedcure BDMB produces a 4-morpholinobenzoyl radical and a 1-phenyl-2-(dimethylamino)butane-2 radical.  The latter is the more reactive and will be involved with the polymerisation.  The former radical is more likely to abstract a hydrogen atom, or disproportionate with the other radical, to produce 4-morpholinobenzaldehyde, which is the major photoproduct.

There is some minor (estimated 20%) beta cleavage that gives a phenacyl radical and a dimethylamino radical and again the latter is the more reactive but it can give traces of dimethylamine and 1-phenyl-2-(4’-morpholinobenzoyl)butane.

Recombination of the morpholinobenzoyl radical and the dimethylamino radical will lead to traces of 4-morpholino-(N,N,-dimethyl)-benzamide.


Smiles for (1)  Speedcure BDMB  CCC(Cc1ccccc1)(C(=O)c3ccc(N2CCC(O)CC2)cc3)N(C)C

Smiles for (2) 4-morpholinobenzaldehyde    O=Cc2ccc(N1CCC(O)CC1)cc2

Smiles for (3) 1-phenyl-2-(dimethylamino)butane-2   CCC(C)(Cc1ccccc1)N(C)C

Smiles for (4) phenacyl derivative  CCC(O)(Cc1ccccc1)C(=O)c3ccc(N2CCC(O)CC2)cc3

Results of assessment

The results of testing and models have been summarised in the table below.  Dimethylamine has not been considered in detail as the properties are well understood and it is known to be volatile and readily biodegradable.

Speedcure BDMB (data)

Speedcure BDMB (modelled)

(2)

Aldehyde

(3)

Amine

(4)

Phenacyl

Water Solubility

5.9 mg/l

875 mg/l

> 150 g/l

218 mg/l

642 mg/l

Partition Coefficient

Log Kow 2.9

Log Kow 4.71

1.71

3.38

3.69

Ready biodegradation

Not biodegradable

Slow

Fast

Slow

Slow

Adsorption coefficient

Not tested

Log Koc 3.6

1.0

3.75

1.9

Toxicity to fish

0.46 mg/l

1.9 mg/l

28 mg/l

6.9 mg/l

6.8 mg/l

Daphnia inhibition

0.5 mg/l

0.2 mg/l

16 mg/l

1.6 mg/l

8.1 mg/l

Algal inhibition

Not technically possible

1.0 mg/l

184 mg/l

18 mg/l

5.6 mg/l

BCF

Not tested

2.1

0.62

1.9

1.3

Bioaccumulation

Bioaccumulation factors have been assessed using BCFWINNT model and are included in the summary table in 4.2.4.  Modelling suggests that the predicted degradation products have a lower BCF than the parent substance.

Secondary poisoning

Secondary poisoning has been assessed in the EUSES model and there is not considered to be a high risk of secondary poisoning on a regional scale, although if discharge takes place into rivers, local concentrations of the substance in the food chain may be a risk to higher predators. 

Risk management measures recommend against discharge to surface water.

This information is reproduced in the CSR, including structures for the degradation products