2-(2-(2-butoxyethoxy)ethoxy)ethanol

Short-term toxicity to fish

Description of key information

Freshwater:

P Promelas (96hr LC50): 2400mg/l

L idus, 96hr LD0=2150mg/l;, LD100=4640mg/l

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2 400 mg/L

Additional information

In a reliable guideline acute fish toxicity study, Leuciscus idus were exposed to the test substance 2-(2-(2-butoxyethoxy)ethoxy)ethanol for a period of up to 96 hours. Because of the mortality profile, it was not possible to determine an exact LD50, only a range. The LD0 was 2150mg/l whilst the LD100 was 4640mg/l. In a 96hr acute toxicity study in fathead minnows (Pimephales Promelas) for which only very basic information is available, an LC50 value of 2400mg/l was established.  Based on the information available, this substance would be not be classified toxic to the environment according to the classification system of the EU.

2-(2 -(2-butoxyethoxy)ethoxy) ethanol (TEGBE) was evaluated using the zebrafish embryotoxicity test (ZET). The morphological characteristics of each embryo were assessed at 72 and 96 hours post fertilization (hpf) following exposure to the test substance at various concentrations up to a maximum tolerated dose ascertained by a dose range finder study. At 72 hpf, the embryos were evaluated for dead or alive. At 96 hpf, the embryos and larvae were evaluated for a wide series of normal or anomalous developmental characteristics. TEGBE was found to cause some delay in hatching in 25% of embryos. Although this was significantly lower than the delays seen in the concurrent controls, it was within the range of controls used throughout this study which examined 10 substances in total. The positive controls (ethanol and methoxyacetic acid) used exhibited a wider range of developmental effects (growth retardation and malformations). This result is considered unclear.

2-(2 -(2-butoxyethoxy)ethoxy)acetic acid (TEGBEAA) was evaluated using the zebrafish embryotoxicity test (ZET). TEGBEAA was evaluated as this assay does not have metabolic capacity and TEGBEAA is the main metabolite of 2 -(2 -(2 -butoxyethoxy)ethoxy)ethanol, the subject of this dossier. The morphological characteristics of each embryo were assessed at 72 and 96 hours post fertilization (hpf) following exposure to the test substance at various concentrations up to a maximum tolerated dose ascertained by a dose range finder study. At 72 hpf, the embryos were evaluated for dead or alive. At 96 hpf, the embryos and larvae were evaluated for a wide series of normal or anomalous developmental characteristics. TEGBEAA was considered as positive by the study authors in the embryonic zebrafish screening test.  Only two end points were affected, one associated with embryotoxicity (pericardial edema) and the other with teratogenicity (malformations of the chorda/spine).  Neither of these effects was seen in the negative control.  The former is seen extensively with methoxyacetic acid but the latter only with 2% ethanol. The NOAEL was 2.5mM (550mg/L).

The key parameter selected is the lowest available and 96hr LD50 (conventional acute toxicity parameter) that is consistent with the available reliable study