Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability

In accordance with REACH Annex VIII column 2, the hydrolysis study does not need to be conducted as the substance is readily biodegradable (HLS 1998, VCL246/972257).

Biodegradation

In a modified Sturm test DEGDB was found to have degraded by 17% after 2 days, 71% after 10 days, and by 93% at the end of the 28 -day biotic phase of the test (HLS 1998, VCL246/972257). The positive control substance, sodium benzoate, which was analysed contemporaneously degraded rapidly (65% degradation after 6 days), and confirmed that the inoculum was viable and that the test was valid.

Substances are considered to be readily degradable in this test if CO2 production is equal to or greater than 60% of the theoretical value within ten days of the level achieving 10%. In the Modified Sturm test, DEGDB met these criteria, so may be considered to be readily biodegradable.

In accordance with the adaptations found in column 2 of Annex IX, simulation studies of biodegradation in water, sediments and soils are waived due to the demonstrated ready biodegradation of the substance. 

 

Bioaccumulation

According to the adaptations found in column 2 of annex IX, the bioconcentration in aquatic species study can be waived if direct and indirect exposure to the aquatic environment is unlikely. This substance has no defined uses where direct application to the aquatic environment would occur, and because the substance is readily biodegradable, wastewater treatment would also make indirect exposure to the aquatic environment unlikely. In addition, evidence of a low bioaccumulation potential is provided by QSAR estimates showing BCF values < 100 L/kg using a regression method based upon the experimental log Kow value of 3.2, and using the Arnot-Gobas QSAR method the BCF/BAF values for all trophic levels are < 10 L/kg when biotransformation rates are utilized and ~ 200 L/kg when biotransformation is not included in the estimation. For these reasons, and for animal welfare reasons, it is believed that a bioconcentration study is not justified and is not proposed.

 

Transport and distribution

A value of log10Kocfor DEGDB of 3.2 was obtained (equivalent Koc= 1.5 x 103) at 20°C (HLS 1999, VCL 261/972408).