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Ecotoxicological information

Toxicity to terrestrial plants

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Description of key information

Effect values (EC50) in a seedling emergence test (Alfalfa, Barley, Northern Wheatgrass) were > 1000 mg/kg soil dw.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:
1 632 mg/kg soil dw

Additional information

In accordance with column 2 of REACH Annex IX and X, the toxicity testing to terrestrial organisms shall be proposed depending on the results of the chemical safety assessment. For substances being considered as „readily biodegradable“, it can be assumed that they will be completely biologically degraded within the STP process. Indirect exposure to soil is not likely e.g. via agricultural use of sewage sludge since 2,2'-iminodiethanol is readily biodegradable. Furthermore, for substances not passing the STP-process but being readily biodegradable, it can be assumed that they will be also biological degraded in the surface water within a short time. Direct exposure to soil is not likely, since the substance is not intentionally applied to soil. The substance has no potential to bioaccumulate nor is it considered as a PBT/vPvB substance. Adsorption to solid soil phase is not expected (log Koc < 3).

 

A seedling emergence study with three plant species (dicots: Alfalfa; monocots: Barley, Northern Wheatgrass) was performed according to a guideline by Environment Canada (Stantec, 2006). A series of 10 test item concentrations was tested (252 to 15000 mg/kg soil dw) in addition to a control. Analytical monitoring was not performed. Observed endpoints were emergence, shoot length and mass as well as root length and mass. Only those endpoints are evaluated which are in accordance with OECD 208: emergence, shoot length and biomass. Effects on Alfalfa and Northern Wheatgrass were determined after 21 d of exposure, while the exposure period of Barley was 14 d. The report only contains EC25 and EC50 values; therefore the results are considered as acute effect values.

 

It can be concluded that Alfalfa was the most sensitive species to DEA (EC50 = 1632 mg/kg soil dw, shoot dry mass). All observed effect values were above the normally used highest tested concentration of 1000 mg/kg soil dw.

The test substance is not supposed to be directly applied to soil and an indirect exposure to soil is unlikely since the substance is readily biodegradable. For substances being considered as readily biodegradable, it can be assumed that they will be biologically degraded within the STP process. In special cases, if the substance is not entering the STP process but is readily biodegradable, it can be assumed that it will be rapidly biological degraded in the surface water. In both cases, a transfer to the soil compartment is unlikely.

 

The PNEC soil was derived based on experimental data only according to REACH Guidance R.10.6.2 as short-term data are available for producer, consumer, and decomposer.

 

Therefore, no additional tests on terrestrial plants are provided.