2-(2-(2-methoxyethoxy)ethoxy)ethanol

Endpoint summary

Additional information

Guideline studies are available for 2 -(2 -(2 -methoxyethoxy)ethoxy)ethanol in two different fish species. Studies show that the substance is effectively non toxic to fish with LC0 values between 5000 -10000mg/l and LC50 values in excess of 10000mg/l.

2-(2 -(2 -methoxyethoxy)ethoxy) ethanol (TEGME) and its main metabolite (2 -(2 -methoxyethoxy)ethoxy) acetic acid (TEGMEA) were 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 substance at various concentrations up to a maximum tolerated dose ascertained by a dose range finder study, which in the case of TEGME was 10mM and TEGMEAA 5mM. The lower figure was used for the main study for both substances. Both substances were found to cause some isolated effects across all doses in both the range finder and main study. There was no dose response or consistency in the findings with the highest doses showing the least effects. The findings were interpreted as random and not treatment related. The positive controls (ethanol and methoxyacetic acid) used exhibited a wider range of developmental effects (growth retardation and malformations). Both substances were considered as negative by the study authors in this assay. The NOAEL was 5.0mM (820mg/L) for TEGME and 5mM (890mg/L) for TEGMEA, the maximum tested doses.

There is no data available on marine fish.

 

Two measured values are available for the acute toxicity in daphnia magna. One study established that the EC0 was in excess of the maximum tested dose of 500mg/l whilst a second study established that the LC50 was in excess of the maximum tested dose of 10000mg/l. A QSAR predicts that the EC50 is much higher at around 47000mg/l. On this basis, it seems reasonable to conclude that the acute toxicity EC50 is likely to be in excess of 10000mg/l and that selecting this value is a conservative choice for the key parameter. There is no data availalble on marine invertebrates.

In a growth inhibition acute toxicity test, the green algae Scenedesmus subspicatus were exposed to concentrations of 2 -(2 -(2 -methoxyethoxy)ethoxy)ethanol at concentrations up to 500mg/l for a period of 72 hours. No growth inhibition was seen, indicating that the substance is practically non-toxic to algae. Whilst only an EC20 is quoted (>500mg/l), it is assumed based on information available in this and other studies that this would be the same as the EC10. This result is supported by information from the ECOSAR QSAR model, which predicts that the 96hr EC50 value for algae would be 4975mg/l and the 96hr NOEC 1068mg/l and from a surrogate substance predicted by the QSAR to be inherently more toxic which shows a NOEC of 1000mg/l . The QSAR result is used as a basis for the EC50 whilst the surrogate result is used as a basis for the EC10 supported by the results available from the experimental 'key' study.

In an activated sludge respiration inhibition test, no inhibition was found up to the maximum tested concentration of 2000mg/l. In a Microtox assay using a photobacterium, the IC50 was not reached up to the maximum tested concentration of 5000mg/l. The data indicates that the substance is effectively non toxic to micro-organisms.

QSAR data indicates that fish are the least sensitive and algae the most sensitive of the three key trophic levels.

2-(2 -(2 -methoxyethoxy)ethoxy) ethanol (TEGME) and its main metabolite (2 -(2 -methoxyethoxy)ethoxy) acetic acid (TEGMEA) were 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 substance at various concentrations up to a maximum tolerated dose ascertained by a dose range finder study, which in the case of TEGME was 10mM and TEGMEAA 5mM. The lower figure was used for the main study for both substances.

Both substances were found to cause some isolated effects across all doses in both the range finder and main study. There was no dose response or consistency in the findings with the highest doses showing the least effects. The findings were interpreted as random and not treatment related. The positive controls (ethanol and methoxyacetic acid) used exhibited a wider range of developmental effects (growth retardation and malformations). Both substances were considered as negative by the study authors in this assay. The NOAEL was 5.0mM (820mg/L) for TEGME and 5mM (890mg/L) for TEGMEA, the maximum tested doses.